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Design
LP55231
SNOSCR5D – MARCH 2013 – REVISED DECEMBER 2016
LP55231 Nine-Channel RGB, White-LED Driver With Internal Program Memory
and Integrated Charge Pump - WQFN
1 Features
3 Description
•
The LP55231 is a 9-channel LED driver designed to
produce lighting effects for mobile devices. A highefficiency charge pump enables LED driving over full
Li-Ion battery voltage range. The device is equipped
with an internal program memory, which allows
operation without processor control.
1
•
•
•
•
•
•
•
•
•
•
•
•
•
Three Independent Program Execution Engines, 9
Programmable Outputs With 25.5-mA Full-Scale
Current, 8-Bit Current Setting Resolution and
12-Bit PWM Control Resolution
Adaptive High-Efficiency 1×/1.5× Fractional
Charge Pump - Efficiency up to 94%
LED Drive Efficiency Up to 93%
Charge Pump With Soft Start
Overcurrent and Short-Circuit Protection
Built-in LED Test
200-nA Typical Standby Current
Automatic Power Save Mode; IVDD = 10 µA
(Typical)
Two-Wire I2C-Compatible Control Interface
Flexible Instruction Set
Large SRAM Program Memory
Small Application Circuit
Source (High-Side) Drivers
Architecture Supports Color Control
2 Applications
•
•
•
•
•
•
•
•
•
•
•
•
Fun Lights and Indicator Lights
LED Backlighting
Haptic Feedback
Programmable Current Source
Fire Notification
Electronic Thermostats
Electronic Locks
Robotics
Intruder Notification
Light Switches and Dimmers
Gaming and Smart Headphones
Speakers
The LP55231 has an I2C-compatible control interface
with four pin-selectable addresses. The INT pin can
be used to notify processor when a lighting sequence
has ended (interrupt function). Also, the device has a
trigger input interface, which allows synchronization,
for example, between multiple LP55231 devices.
Excellent efficiency is maintained over a wide
operating range by autonomously selecting the best
charge pump gain based on LED forward voltage
requirements. The device is able to automatically
enter power-save mode when LED outputs are not
active, thus lowering idle current consumption down
to 10 µA (typical). Only four small and low-cost
ceramic capacitors are required.
Device Information(1)
PART NUMBER
LP55231
PACKAGE
BODY SIZE (NOM)
WQFN (24)
4.00 mm × 4.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
space
space
Typical Application
C1
0.47 µF
VIN = 2.7 V to 5.5 V
C1
0.47 µF
C2
0.47 µF
VDD
CIN
1 µF
D7
VIN = 2.7 V to 5.5 V
CIN
1 µF
G
D2
SDA
B
EN
D8
LP55231
R
ASEL1
GND
D4
D9
D4
LP55231
B
R
D6
TRIG
ASEL0
D7
GND
G
D5
INT
ASEL1
D5
D6
D3
EN
CLK
D3
TRIG
ASEL0
D2
SDA
G
INT
COUT1 µF
D1
SCL
MCU
CLK
C1+ C1- C2+ C2- VOUT
VDD
R
D1
SCL
MCU
COUT1 µF
C1+ C1- C2+ C2- VOUT
C2
0.47 µF
D8
D9
B
RGB LED
APPLICATION
WLED APPLICATION
NOTE: D7, D8 and D9 powered
directly from VIN
Copyright © 2016, Texas Instruments Incorporated
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LP55231
SNOSCR5D – MARCH 2013 – REVISED DECEMBER 2016
www.ti.com
Table of Contents
1
2
3
4
5
6
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11
6.12
7
1
1
1
2
3
4
Absolute Maximum Ratings ...................................... 4
ESD Ratings.............................................................. 4
Recommended Operating Conditions....................... 4
Thermal Information .................................................. 4
Electrical Characteristics........................................... 5
Charge Pump Electrical Characteristics ................... 5
LED Driver Electrical Characteristics ........................ 6
LED Test Electrical Characteristics........................... 6
Logic Interface Characteristics.................................. 6
Recommended External Clock Source Conditions . 7
Serial Bus Timing Parameters (SDA, SCL) ............ 7
Typical Characteristics ............................................ 8
Detailed Description ............................................ 10
7.1 Overview ................................................................. 10
7.2
7.3
7.4
7.5
7.6
8
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
Programming...........................................................
Register Maps .........................................................
10
11
17
18
20
Application and Implementation ........................ 46
8.1 Application Information............................................ 46
8.2 Typical Applications ................................................ 46
9 Power Supply Recommendations...................... 50
10 Layout................................................................... 50
10.1 Layout Guidelines ................................................. 50
10.2 Layout Example .................................................... 50
11 Device and Documentation Support ................. 51
11.1
11.2
11.3
11.4
11.5
11.6
Device Support......................................................
Trademarks ...........................................................
Receiving Notification of Documentation Updates
Community Resources..........................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
51
51
51
51
51
51
12 Mechanical, Packaging, and Orderable
Information ........................................................... 51
4 Revision History
Changes from Revision C (November 2016) to Revision D
Page
•
Added top nav icon for TI Designs ........................................................................................................................................ 1
•
Changed variable 1 spanning to go from Bit [3] to Bit [2] and variable 2 span from Bit [1] to Bit [0] in table 7 .................. 39
Changes from Revision B (May 2016) to Revision C
•
Page
Changed wording of data sheet title....................................................................................................................................... 1
Changes from Revision A (October 2014) to Revision B
Page
•
Added several new Applications ............................................................................................................................................ 1
•
Changed Handling Ratings to ESD Ratings; moved storage temperature to Abs Max table ............................................... 4
•
Changed RθJA value from 36.6C/W to 33.3C/W; add additional thermal information ............................................................. 4
•
Added Community Resources section ................................................................................................................................ 51
Changes from Original (March 2013) to Revision A
•
2
Page
Added Device Information and Handling Rating tables, Feature Description, Device Functional Modes, Application
and Implementation, Power Supply Recommendations, Layout, Device and Documentation Support, and
Mechanical, Packaging, and Orderable Information sections; moved some curves to Application Curves section ............. 1
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SNOSCR5D – MARCH 2013 – REVISED DECEMBER 2016
5 Pin Configuration and Functions
RTW Package
24-Pin WQFN
PIN 1 ID
1
2
3
4
5
18
6
17
16
15
14
13
24
7
19
12
23
8
20
11
22
9
21
10
21
10
22
9
20
11
23
8
12
24
7
19
18
17
16
15
14
1
13
2
3
4
5
6
PIN 1 ID
BOTTOM VIEW
TOP VIEW
Pin Functions
PIN
NUMBER
NAME
TYPE (1)
DESCRIPTION
1
C2+
A
Flying capacitor 2 positive terminal
2
C1+
A
Flying capacitor 1 positive terminal
3
VDD
P
Input power supply
4
GND
G
Ground
5
EN
I
Enable
6
CLK
I
32-kHz clock input; connect to ground if not used.
7
INT
OD/O
Interrupt for microcontroller unit; leave unconnected if not used.
8
SDA
I/OD
Serial interface data
Serial interface clock
9
SCL
I
10
TRIG
I/OD
11
D9
A
Current source output 9
Note: powered from VDD
12
D8
A
Current source output 8 (powered from VDD)
13
D7
A
Current source output 7 (powered from VDD)
14
D6
A
Current source output 6
15
D5
A
Current source output 5
16
D4
A
Current source output 4
17
D3
A
Current source output 3
18
D2
A
Current source output 2
19
D1
A
Current source output 1
20
ASEL0
I
Serial interface address select input
21
ASEL1
I
Serial interface address select input
22
VOUT
A
Charge pump output
23
C2−
A
Flying capacitor 2 negative terminal
24
C1−
A
Flying capacitor 1 negative terminal
DAP
(1)
Trigger. Connect to ground if not used
Connect the die attach pad to GND
A: Analog Pin; G: Ground Pin; P: Power Pin; I: Input Pin; I/O Input/Output Pin; O: Output Pin; OD: Open Drain Pin
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SNOSCR5D – MARCH 2013 – REVISED DECEMBER 2016
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1) (2)
Voltage on power pin VDD
MIN
MAX
UNIT
−0.3
6
V
Voltage
Voltage on D1 to D9, C1−, C1+,
C2−, C2+, VOUT
−0.3 V to VDD + 0.3 V with 6 V maximum
Power
Continuous power dissipation (3)
Internally limited
Temperature
Junction temperature, TJ-MAX
Maximum lead temperature (soldering)
Storage temperature, Tstg
(1)
(2)
(3)
(4)
See
V
125
°C
150
°C
(4)
–65
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
All voltage are with respect to the potential at the GND pin.
Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ = 150°C (typical) and
disengages at TJ = 130°C (typical).
For detailed soldering specifications and information, refer to AN-1187 Leadless Leadframe Package (LLP).
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2500
Charged-device model (CDM), per JEDEC specification JESD22-C101 (2)
±1000
Machine model: all pins
±250
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
Over operating free-air temperature range (unless otherwise noted) (1)
MIN
VDD
Input voltage
Voltage on logic pins (input or output pins)
NOM
MAX
UNIT
2.7
5.5
V
0
VDD
V
IOUT
Recommended charge pump load current
0
100
mA
TJ
Junction temperature
−30
125
°C
TA
Ambient temperature (2)
−30
85
°C
(1)
(2)
All voltage are with respect to the potential at the GND pin.
In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may
have to be derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP =
125°C), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the
part/package in the application (RθJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (RθJA × PD-MAX).
6.4 Thermal Information
LP55231
THERMAL METRIC (1)
RTW (WQFN)
UNIT
24 PINS
RθJA
Junction-to-ambient thermal resistance
33.3
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
27.3
°C/W
RθJB
Junction-to-board thermal resistance
11.4
°C/W
ψJT
Junction-to-top characterization parameter
0.2
°C/W
ψJB
Junction-to-board characterization parameter
11.4
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
2.2
°C/W
(1)
4
For more information about traditional and new thermal metrics, see Semiconductor and IC Package Thermal Metrics.
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SNOSCR5D – MARCH 2013 – REVISED DECEMBER 2016
6.5 Electrical Characteristics
Typical (TYP) values apply for TA = 25°C and minimum (MIN) and maximum (MAX) apply over the operating ambient
temperature range (−30°C < TA < 85°C). Specifications apply to the LP55231 Functional Block Diagram with: VDD = 3.6 V,
VEN = 1.65 V, COUT = 1 µF, CIN = 1 µF, C1–2 = 0.47 µF, unless otherwise specified. (1) (2) (3) (4)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
0.2
1
µA
1
1.7
µA
CHIP_EN=0 (bit), external 32-kHz clock
running
1.4
2.3
µA
External 32-kHz clock running, charge pump
and current source outputs disabled
0.6
0.75
mA
Charge pump in 1× mode, no load, current
source outputs disabled
0.8
0.95
mA
Charge pump in 1.5× mode, no load, current
source outputs disabled
1.8
VEN = 0V, CHIP_EN=0 (bit), external 32-kHz
clock running or not running
Standby supply current
IVDD
Normal mode supply current
ƒOSC
(1)
(2)
(3)
(4)
CHIP_EN=0 (bit), external 32-kHz clock not
running
UNIT
mA
Power save mode supply
current
External 32-kHz clock running
10
15
µA
Internal oscillator running
0.6
0.75
mA
Internal oscillator frequency
accuracy
TA = 25°C
−4%
4%
–7%
7%
The Electrical Characteristics tables list specifications under the listed Recommended Operating Conditions except as otherwise
modified or specified by the Electrical Characteristics Test Conditions and/or Notes. Typical specifications are estimations only and are
not verified.
All voltages are with respect to the potential at the GND pin.
Min and Max limits are verified by design, test, or statistical analysis.
Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.
6.6 Charge Pump Electrical Characteristics
Typical (TYP) values apply for TA = 25°C and minimum (MIN) and maximum (MAX) apply over the operating ambient
temperature range (−30°C < TA < 85°C). Specifications apply to the LP55231 Functional Block Diagram with: VDD = 3.6 V,
VEN = 1.65 V, COUT = 1 µF, CIN = 1 µF, C1–2 = 0.47 µF, unless otherwise specified. (1)
PARAMETER
ROUT
Charge pump output resistance
ƒSW
Switching frequency
IGND
tON
(1)
(2)
Ground current
VOUT turnon time
(2)
TEST CONDITIONS
Gain = 1.5×
Gain = 1×
MIN
TYP
MAX
UNIT
3.5
1
Ω
1.25
MHz
Gain = 1.5×
Gain = 1×
1.2
0.3
mA
VDD = 3.6 V, IOUT = 60 mA
100
µs
Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.
Turnon time is measured from the moment the charge pump is activated until the VOUT crosses 90% of its target value.
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6.7 LED Driver Electrical Characteristics
Typical (TYP) values apply for TA = 25°C and minimum (MIN) and maximum (MAX) apply over the operating ambient
temperature range (−30°C < TA < 85°C). Specifications apply to the LP55231 Functional Block Diagram with: VDD = 3.6 V, VEN
= 1.65 V, COUT = 1 µF, CIN = 1 µF, C1–2 = 0.47 µF, unless otherwise specified. (1)
PARAMETER
TEST CONDITIONS
ILEAKAGE
Leakage current (outputs D1 to D9)
PWM = 0%
IMAX
Maximum source current
Outputs D1 to D9
IOUT
Output current accuracy (2)
IMATCH
Matching (2)
ƒLED
LED switching frequency
VSAT
(1)
(2)
(3)
Saturation voltage
MIN
MAX
0.1
1
25.5
Output current set to 17.5 mA
−4%
Output current set to 17.5 mA, TA = 25°C
–5%
Output current set to 17.5 mA, TA = 25°C
UNIT
µA
mA
4%
5%
1%
2.5%
312
Output current set to 17.5 mA
TA = 25°C
(3)
TYP
Hz
45
100
mV
Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.
Output Current Accuracy is the difference between the actual value of the output current and programmed value of this current.
Matching is the maximum difference from the average. For the constant current outputs on the part (D1 to D9), the following are
determined: the maximum output current (MAX), the minimum output current (MIN), and the average output current of all outputs (AVG).
Two matching numbers are calculated: (MAX-AVG)/AVG and (AVG-MIN)/AVG. The largest number of the two (worst case) is
considered the matching figure. Note that some manufacturers have different definitions in use.
Saturation voltage is defined as the voltage when the LED current has dropped 10% from the value measured at VOUT – 1 V.
6.8 LED Test Electrical Characteristics
Typical (TYP) values apply for TA = 25°C and minimum (MIN) and maximum (MAX) apply over the operating ambient
temperature range (−30°C < TA < 85°C). Specifications apply to the LP55231 Functional Block Diagram with: VDD = 3.6 V,
VEN = 1.65 V, COUT = 1 µF, CIN = 1 µF, C1–2 = 0.47 µF, unless otherwise specified. (1)
PARAMETER
LSB
EABS
Total unadjusted error
tCONV
Conversion time
VIN_TEST
DC voltage range
(1)
(2)
TEST CONDITIONS
MIN
Least significant bit
TYP
MAX
30
(2)
VIN_TEST = 0 V to VDD, TA = 25°C
mV
< ±3
±4
2.7
TA = 25°C
UNIT
LSB
ms
0
5
V
Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.
Total unadjusted error includes offset, full-scale, and linearity errors.
6.9 Logic Interface Characteristics
Typical (TYP) values apply for TA = 25°C and minimum (MIN) and maximum (MAX) apply over the operating ambient
temperature range (−30°C < TA < 85°C). Specifications apply to the LP55231 Functional Block Diagram with: VDD = 3.6 V, VEN
= 1.65 V, COUT = 1 µF, CIN = 1 µF, C1–2 = 0.47 µF, unless otherwise specified. (1)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
LOGIC INPUT EN
VIL
Input low level
VIH
Input high level
1.2
II
Input current
–1
tDELAY
Input delay (2)
0.5
V
1
µA
V
2
µs
LOGIC INPUT SCL, SDA, TRIG, CLK, ASEL0, ASEL1
VIL
Input low level
VIH
Input high level
II
Input current
0.2 × VEN
0.8 × VEN
V
V
–1
1
µA
0.5
V
1
µA
LOGIC OUTPUT SDA, TRIG, INT
VOL
Output low level
IOUT = 3 mA (pullup current)
IL
Output leakage current
VOUT = 2.8 V
(1)
(2)
6
0.3
Low-ESR surface-mount ceramic capacitors (MLCCs) used in setting electrical characteristics.
The I2C host should allow at least 500 μs before sending data to the LP55231 after the rising edge of the enable line.
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6.10 Recommended External Clock Source Conditions
See (1) (2)
MIN
NOM
MAX
UNIT
LOGIC INPUT CLK
ƒCLK
Clock frequency
tCLKH
High time
6
µs
tCLKL
Low time
6
µs
tr
Clock rise time
10% to 90%
2
µs
tf
Clock fall time
90% to 10%
2
µs
(1)
(2)
32.7
kHz
Specification is verified by design and is not tested in production. VEN = 1.65 V to VDD.
The ideal external clock signal for the LP55231 is a 0-V to VEN 25% to 75% duty-cycle square wave. At frequencies above 32.7 kHz,
program execution is faster, and at frequencies below 32.7 kHz program execution is slower.
6.11 Serial Bus Timing Parameters (SDA, SCL)
See (1) and Figure 2
MIN
MAX
UNIT
400
kHz
ƒSCL
Clock frequency
1
Hold time (repeated) START condition
0.6
µs
2
Clock low time
1.3
µs
3
Clock high time
600
ns
4
Setup time for a repeated START condition
600
ns
5
Data hold time
50
ns
6
Data setup time
100
ns
7
Rise time of SDA and SCL
20 + 0.1 Cb
300
ns
8
Fall time of SDA and SCL
15 + 0.1 Cb
300
ns
9
Setup time for STOP condition
600
ns
10
Bus free time between a STOP and a START condition
1.3
µs
Cb
Capacitive load parameter for each bus line
Load of 1 pF corresponds to one nanosecond.
10
(1)
200
ns
Specification is verified by design and is not tested in production. VEN = 1.65 V to VDD.
Figure 1. External Clock Signal
Figure 2. Timing Parameters
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6.12 Typical Characteristics
Unless otherwise specified: VDD = 3.6 V, CIN = COUT = 1 µF, C1 = C2 = 0.47 µF, TA = 25°C. CIN, COUT, C1, C2: Low-ESR
surface-mount ceramic capacitors (MLCCs) used in setting electrical characteristics.
Figure 3. Charge Pump 1.5× Efficiency vs Load Current
6 × 1-mA Load (6 Nichia NSCW100 WLEDs On D1 To D6)
Figure 5. Gain Change Hysteresis Loop at Factory Settings
Load: 6 × Nichia NSCW100 WLEDs On D1 To D6 at 100% PWM
Figure 6. Effect of Adaptive Hysteresis on the Width of the
Hysteresis Loop
17.5-mA Current
17.5-mA Current
Figure 7. LED Current Matching Distribution
8
Figure 4. Output Voltage of the Charge Pump (1.5×) as a
Function of Load Current at Four Input Voltage Levels
Figure 8. LED Current Accuracy Distribution
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Typical Characteristics (continued)
Unless otherwise specified: VDD = 3.6 V, CIN = COUT = 1 µF, C1 = C2 = 0.47 µF, TA = 25°C. CIN, COUT, C1, C2: Low-ESR
surface-mount ceramic capacitors (MLCCs) used in setting electrical characteristics.
20
1k
INTERNAL CLK (LEFT SCALE)
15
500
10
IVDD (PA)
IVDD (PA)
750
EXTERNAL CLK (RIGHT SCALE)
5
250
VOLTAGE (2V/DIV)
SDA
STOP CONDITION
SCL
VOUT 2V/DIV
0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
0
5.5
TIME (40 Ps/DIV)
VDD (V)
Charge Pump In 1× Mode
If the charge pump is OFF the supply current is even lower.
Figure 9. Power Save Mode Supply Current vs VDD
51h To Addr 36h
ILOAD = 60 mA
VDD = 3.6 V
Figure 10. Serial Bus Write and Charge Pump Start-up
Waveform
6 x NICHIA NSCW100 WLED
3 x SHARP GM5WA06270A RGB-LED
85
EFFICIENCY (%)
EFFICIENCY (%)
80
75
70
9 x 10 mA
65
60
95
90
85
80
75
70
65
60
55
6 x 15 mA
6 x 10 mA
55
9 x 6.7 mA
2.7
3.3
3.9
4.5
2.7
5.1
3.3
3.9
4.5
5.1
VDD (V)
VDD (V)
Figure 11. 100% PWM RGB LED Efficiency vs VDD
Figure 12. 100% PWM WLED Efficiency vs VDD
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7 Detailed Description
7.1 Overview
The LP55231 is a fully integrated lighting management unit for producing lighting effects for mobile devices. The
LP55231 includes all necessary power management, high-side current sources, temperature compensation, twowire control interface and programmable pattern generators. The overall maximum current for each driver is set
by an 8-bit register.
The LP55231 controls LED luminance with a pulse-width modulation (PWM) scheme with a resolution of 12 bits.
Also, the temperature compensation is done by PWM.
7.2 Functional Block Diagram
C1
0.47 PF
C1+
C1-
C2
0.47 PF
C2+
C2-
VDD
CIN
1 PF
1.25-MHz
OSCILLATOR
VOUT
CHARGE PUMP
1x/1.5x
COUT
1 PF
PWM PATTERN
GENERATOR
VREF
PROGRAM
MEMORY
50H TO 6FH;
96 INSTRUCTIONS
PWM PATTERN
GENERATOR
PWM PATTERN
GENERATOR
BIAS
12-BIT PWM
PATTERN
CONTROL
ASEL0
TEMP
COMP
ASEL1
SCL
SERIAL
DATA
CTRL
REG
D1
SDA
INT
D2
CONTROL
CLK
DET
CURRENT
CONTROL
D/A
VDD
EN
CLK
POR
LED ERROR DETECTION
TRIG
8 BIT
MAXIMUM
D6
D7
D8
D9
IDAC AND HIGH
SIDE LED
DRIVERS
THERMAL
SHUTDOWN
GND
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7.3 Feature Description
7.3.1 Programming
The LP55231 provides flexibility and programmability for dimming and sequencing control. Each LED can be
controlled directly and independently through the serial bus, or LED drivers can be grouped together for preprogrammed flashing patterns.
The LP55231 has three independent program execution engines, so it is possible to form three independently
programmable LED banks. LED drivers can be grouped based on their function so that, for example, the first
bank of drivers can be assigned to the keypad illumination, the second bank to the funlights, and the third group
to the indicator LED(s).
Each bank can contain 1 to 9 LED driver outputs. Instructions for program execution engines are stored in the
program memory. The total amount of the program memory is 96 instructions, and the user can allocate the
memory as required by the engines.
7.3.2 LED Error Detection
The LP55231 has built-in LED error detection. Error detection does not only detect open and short circuit, but
provides an opportunity to measure the VFs of the LEDs. The test event is activated by a serial interface write,
and the result can be read through the serial interface during the next cycle. This feature can also be addressed
to measure the voltage on the VDD, VOUT, and INT pins. Typical example usage includes monitoring battery
voltage or using INT pin as a light sensor interface.
7.3.3 Energy Efficiency
When charge-pump automatic mode selection is enabled, the LP55231 monitors the voltage over the drivers of
D1 to D6 so that the device can select the best charge-pump gain and maintain good efficiency over the whole
operating voltage range. The red LED element of an RGB LED typically has a forward voltage of about 2 V. For
that reason, the outputs D7, D8, and D9 are internally powered by VDD, since battery voltage is high enough to
drive red LEDs over the whole operating voltage range. This allows the driving of three RGB LEDs with good
efficiency because the red LEDs do not load the charge pump. LP55231 is able to automatically enter powersave mode when LED outputs are not active, thus lowering idle current consumption down to 10 µA (typical).
Also, during the downtime of the PWM cycle (constant current output status is low), additional power savings can
be achieved when the PWM power-save feature is enabled.
7.3.4 Temperature Compensation
The luminance of an LED is typically a function of its temperature even though the current flowing through the
LED remains constant. Since luminance is temperature dependent, many LED applications require some form of
temperature compensation to decrease luminance and color purity variations due to temperature changes. The
LP55231 has a built-in temperature-sensing element, and PWM duty cycle of the LED drivers changes linearly in
relationship to changes in temperature. User can select the slope of the graph (31 slopes) based on the LED
characteristics (see Figure 13). This compensation can be done either constantly, or only right after the device
wakes up from powersave mode, to avoid error due to self-heating of the device. Linear compensation is
considered to be practical and accurate enough for most LED applications.
Compensation is effective over the temperature range −40°C to +90°C.
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Feature Description (continued)
100
MAXIMUM
SLOPE VALUE
PWM OUTPUT %
75
NO
COMP.
50
25
MINIMUM
SLOPE VALUE
0
-25
0
25
50
75
TEMPERATURE °C
Figure 13. Temperature Compensation Principle
7.3.5 Charge Pump Operational Description
7.3.5.1 Overview
The LP55231 includes a pre-regulated switched-capacitor charge pump with a programmable voltage
multiplication of 1 and 1.5×. In 1.5× mode, by combining the principles of a switched-capacitor charge pump and
a linear regulator, a regulated 4.5 V output is generated from the Li-Ion input voltage range. A two-phase nonoverlapping clock generated internally controls the operation of the charge pump. During the charge phase, both
flying capacitors (C1 and C2) are charged from input voltage. In the pump phase that follows, the flying
capacitors are discharged to output. A traditional switched-capacitor charge pump operating in this manner use
switches with very low on-resistance, ideally 0 Ω, to generate an output voltage that is 1.5× the input voltage.
The LP55231 regulates the output voltage by controlling the resistance of the input-connected pass-transistor
switches in the charge pump.
7.3.5.2 Output Resistance
At lower input voltages, the charge pump output voltage may degrade due to effective output resistance (ROUT) of
the charge pump. The expected voltage drop can be calculated by using a simple model for the charge pump
shown in Figure 14.
VIN
REG
V
, ROUT
,
1.5x
1.5 x V
VOUT
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Figure 14. Charge Pump Output Resistance Model
The model shows a linear pre-regulation block (REG), a voltage multiplier (1.5×), and an output resistance
(ROUT). Output resistance models the output voltage drop that is inherent to switched capacitor converters. The
output resistance is 3.5Ω (typ.), and it is a function of switching frequency, input voltage, flying capacitors’
capacitance value, internal resistances of the switches and ESR of the flying capacitors. When the output voltage
is in regulation, the regulator in the model controls the voltage V’ to keep the output voltage equal to 4.5 V
(typical).
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Feature Description (continued)
With increased output current, the voltage drop across ROUT increases. To prevent drop in output voltage, the
voltage drop across the regulator is reduced, V’ increases, and VOUT remains at 4.5 V. When the output current
increases to the point that there is zero voltage drop across the regulator, V’ equals the input voltage, and the
output voltage is on the edge of regulation. Additional output current causes the output voltage to fall out of
regulation, so that the operation is similar to a basic open-loop 1.5× charge pump. In this mode, output current
results in output voltage drop proportional to the output resistance of the charge pump. The out-of-regulation
output voltage can be approximated by: VOUT = 1.5 × VIN – IOUT × ROUT.
7.3.5.3 Controlling The Charge Pump
The charge pump is controlled with two CP_MODE bits in MISC register (address 36H). When both of the bits
are low, the charge pump is disabled, and output voltage is pulled down with an internal 300-kΩ (typical) resistor.
The charge pump can be forced to bypass mode, so the battery voltage is connected directly to the current
sources; in 1.5× mode output voltage is boosted to 4.5 V. In automatic mode, charge-pump operation mode is
determined by saturation of constant current drivers, as described in LED Forward Voltage Monitoring.
7.3.5.4 LED Forward Voltage Monitoring
When the charge-pump automatic mode selection is enabled, voltages over LED drivers D1 to D6 are monitored.
NOTE
Power input for current source outputs D7, D8, and D9 are internally connected to the
VDD pin.
If the D1 to D6 drivers do not have enough headroom, charge-pump gain is set to 1.5×. Driver saturation monitor
does not have a fixed voltage limit, since saturation voltage is a function of temperature and current. Charge
pump gain is set to 1×, when battery voltage is high enough to supply all LEDs.
In automatic gain change mode, the charge pump is switched to bypass mode (1×), when LEDs are inactive for
over 50 ms.
7.3.5.5 Gain Change Hysteresis
Charge pump gain control utilizes digital filtering to prevent supply voltage disturbances (for example, the
transient voltage on the power supply during the GSM burst) from triggering unnecessary gain changes.
Hysteresis is provided to prevent periodic gain changes (which could occur due to LED driver) and charge-pump
voltage drop in 1× mode. The hysteresis of the gain change is user-configurable; default setting is factoryprogrammable. Flexible configuration ensures that hysteresis can be minimized or set to desired level in each
application.
LED forward voltage monitoring and gain control block diagram is shown in Figure 15.
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Feature Description (continued)
MODE
CHARGE PUMP
VDD
VOUT
PWM
CURRENT
SOURCE
D1 TO
D6
VOFS
COMPARATOR
SATURATION
MONITOR
DIGITAL
FILTER
CONTROL
REGISTERS
PROGRAM
MEMORY
COMMAND
LOOK-AHEAD
MODE
CONTROL
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Figure 15. Forward Voltage Monitoring and Gain Control Block
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Feature Description (continued)
7.3.6 LED Driver Operational Description
7.3.6.1 Overview
LP55231 LED drivers are constant current sources. Output current can be programmed by control registers up to
25.5 mA. The overall maximum current is set by 8-bit output current control registers with 100-μA step size. Each
of the 9 LED drivers has a separate output current control register.
LED OUTPUT CURRENT
The LED luminance pattern (dimming) is controlled with PWM (pulse width modulation) technique, which has
internal resolution of 12 bits (8-bit control can be seen by user). PWM frequency is 312 Hz. See Figure 16.
PWM FREQUENCY = 312 Hz
12-BIT PWM
PATTERN
CONTROL
0% TO 100 %
8-BIT CURRENT
SETTING
0 mA TO 25.5 mA
TIME
Figure 16. LED Pattern and Current Control Principle
LED dimming is controlled according to a logarithmic or linear scale, see Figure 17. A logarithmic or linear
scheme can be set for both the program execution engine control and direct PWM control. Note: if the
temperature compensation is active, the maximum PWM duty cycle is limited to 50% at 25°C. This is required to
allow enough headroom for temperature compensation over the whole temperature range −30°C to +90°C.
100,0
100
PWM OUTPUT %
80,0
80
60
60,0
40,0
40
20,0
20
0
0,0
0,0
0
64,0
64
128,0
128
192,0
192
256,0
256
DIMMING CONTROL (DEC)
Figure 17. Logarithmic vs Linear Dimming
7.3.6.2 Powering LEDs
The LP55231 is very suitable for white LED and general purpose applications, and it is particularly well suited to
use with RGB LEDs. The LP55231 architecture is optimized for use with three RGB LEDs. Typically, the red
LEDs have forward voltages below 2 volts, thus red LEDs can be powered directly from VDD. In the LP55231 D7,
D8, and D9 drivers are powered from the battery voltage (VDD), not from the charge-pump output. D1 to D6
drivers are internally connected to the charge-pump output, and these outputs can be used for driving green and
blue (VF = 2.7 V to 3.7 V typical) or white LEDs. Of course, D7, D8, and D9 outputs can be used for green, blue
or white LEDs if the VDD voltage is high enough.
An RGB LED configuration example is given in the Typical Applications.
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Feature Description (continued)
7.3.6.3 Controlling The High-Side LED Drivers
1. Direct PWM Control: All LP55231 LED drivers, D1 to D9, can be controlled independently through the twowire serial I2C-compatible interface. For each high-side driver there is a PWM control register. Direct PWM
control is active by default.
2. Controlling by Program Execution Engines: Engine control is used when the user wants to create
programmed sequences. The program execution engine has a higher priority than direct control registers.
Therefore, if the user has set the PWM register to a certain value, it is automatically overridden when the
program execution engine controls the driver. LED control and program execution engine operation is
described in Control Register Details.
3. Master Fader Control: In addition to LED-by-LED PWM register control, the LP55231 is equipped with master
fader control, which allows the user to fade in or fade out multiple LEDs by writing to only one register. This
is a useful function to minimize serial bus traffic between the MCU and the LP55231. The LP55231 has three
master fader registers, so it is possible to form three master fader groups.
7.3.7 Automatic Power-Save Mode
Automatic power-save mode is enabled when POWERSAVE_EN bit in register address 36H is 1. Almost all
analog blocks are powered down in power save if an external clock signal is used. Only the charge-pump
protection circuits remain active. However, if the internal clock has been selected, only charge pump and LED
drivers are disabled during the power save; the digital part of the LED controller needs to stay active. In both
cases the charge pump enters the weak 1× mode. In this mode the charge pump utilizes a passive current
limited keep-alive switch, which keeps the output voltage at the battery level. During the program execution
LP55231 can enter power save if there is no PWM activity in any of the LED driver outputs. To prevent short
power-save sequences during program execution, LP55231 has an instruction look-ahead filter. During program
execution engine 1, engine 2, and engine 3 instructions are constantly analyzed, and if there are time intervals of
more than 50 ms in length with no PWM activity on LED driver outputs, the device enters power save. In powersave mode program execution continues uninterrupted. When an instruction that requires PWM activity is
executed, a fast internal start-up sequence is started automatically.
7.3.8 PWM Power-Save Mode
PWM cycle power-save mode is enabled when register 36 bit [2] PWM_PS_EN is set to 1. In PWM power-save
mode analog blocks are powered down during the down time of the PWM cycle. Which blocks are powered down
depends whether the external or internal clock is used. While the automatic power-save mode (see Automatic
Power-Save Mode) saves energy when there is no PWM activity at all, the PWM power-save mode saves energy
during PWM cycles. Like the automatic power-save mode, PWM power-save mode also works during program
execution. Figure 18 shows the principle of the PWM power-save technique. An LED on D9 output is driven at
50% PWM, 5-mA current (top waveform). After PWM power-save enable, the LED-current remains the same, but
the LP55231 input current drops down to about 50 µA when the LED is OFF, or to approximately 200 µA when
the charge-pump-powered output(s) are used.
CURRENT
LED CURRENT 5 mA/DIV
LP5523 INPUT
CURRENT 1 mA/DIV
PWM POWERSAVE
ENABLED
INPUT CURRENT ~50 éA
DURING PWM
POWERSAVE
TIME 1 ms/DIV
Figure 18. PWM Power-Save Principle
External Clock, VDD = 3.6 V
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7.4 Device Functional Modes
7.4.1 Modes Of Operation
RESET:
In the RESET mode all the internal registers are reset to the default values. Reset is always
entered if Reset Register (3DH) is written FFH or internal Power-On Reset is active. Power-On
Reset (POR) activate during the chip start-up or when the supply voltage VDD fall below 1.5 V
(typical). Once VDD rises above 1.5 V (typical), POR deactivate, and the chip continues to the
STANDBY mode. CHIP_EN control bit is low after POR by default.
STANDBY: The STANDBY mode is entered if the register bit CHIP_EN or EN pin is LOW and Reset is not
active. This is the low-power consumption mode, when all circuit functions are disabled. Most
registers can be written in this mode if EN pin is risen to high so that control bits are effective right
after the start-up (see Control Register Details).
START-UP: When CHIP_EN bit is written high, and EN pin is high, the INTERNAL START-UP SEQUENCE
powers up all the needed internal blocks (VREF, Bias, Oscillator etc.). Start-up delay is 500 μs. If
the chip temperature rises too high, the Thermal Shutdown (TSD) disables the chip operation, and
the chip waits in START-UP mode until no thermal shutdown event is present.
NORMAL:
During NORMAL mode the user controls the chip using the Control Registers.
POWER SAVE: In POWER-SAVE mode analog blocks are disabled to minimize power consumption. See
Automatic Power-Save Mode section for further information.
POR
RESET
Reset Register = FF
or
POR=H
STANDBY
EN=H (pin) and
CHIP_EN=H (bit)
EN=L (pin) or
CHIP_EN=L (bit)
INTERNAL
STARTUP
SEQUENCE
TSD = L
TSD = H
NORMAL MODE
Exit power save
Enter power save
POWER SAVE
Figure 19. Modes of Operation
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7.5 Programming
7.5.1 I2C-Compatible Control Interface
The I2C-compatible synchronous serial interface provides access to the programmable functions and registers on
the device. This protocol uses a two-wire interface for bidirectional communications between the ICs connected
to the bus. The two interface lines are the Serial Data Line (SDA) and the Serial Clock Line (SCL). Every device
on the bus is assigned a unique address and acts as either a Master or a Slave depending on whether it
generates or receives the serial clock SCL. The SCL and SDA lines should each have a pullup resistor placed
somewhere on the line and remain HIGH even when the bus is idle. Note: CLK pin is not used for serial bus data
transfer.
7.5.1.1 Data Validity
The data on SDA line must be stable during the HIGH period of the clock signal (SCL). In other words, state of
the data line can only be changed when clock signal is LOW.
SCL
SDA
data
change
allowed
data
valid
data
change
allowed
data
valid
data
change
allowed
Figure 20. Data Validity Diagram
7.5.1.2 Start And Stop Conditions
START and STOP conditions classify the beginning and the end of the data transfer session. A START condition
is defined as the SDA signal transitioning from HIGH to LOW while SCL line is HIGH. A STOP condition is
defined as the SDA transitioning from LOW to HIGH while SCL is HIGH. The bus master always generates
START and STOP conditions. The bus is considered to be busy after a START condition and free after a STOP
condition. During data transmission, the bus master can generate repeated START conditions. First START and
repeated START conditions are equivalent, function-wise.
7.5.1.3 Transferring Data
Every byte put on the SDA line must be eight bits long, with the most significant bit (MSB) being transferred first.
Each byte of data has to be followed by an acknowledge bit. The acknowledge related clock pulse is generated
by the master. The master releases the SDA line (HIGH) during the acknowledge clock pulse. The LP55231 pulls
down the SDA line during the 9th clock pulse, signifying an acknowledge. The LP55231 generates an
acknowledge after each byte has been received.
There is one exception to the acknowledge after every byte rule. When the master is the receiver, it must
indicate to the transmitter an end of data by not acknowledging (negative acknowledge) the last byte clocked out
of the slave. This negative acknowledge still includes the acknowledge clock pulse (generated by the master),
but the SDA line is not pulled down.
After the START condition, the bus master sends a chip address. This address is seven bits long followed by an
eighth bit which is a data direction bit (READ or WRITE). The LP55231 address is defined with ASEL0 and
ASEL1 pins, and it is 32h when ASEL1 and ASEL0 are connected to GND. For the eighth bit, a 0 indicates a
WRITE, and a 1 indicates a READ. The second byte selects the register to which the data is written. The third
byte contains data to write to the selected register.
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Programming (continued)
7.5.2 I2C-Compatible Chip Address
ASEL0 and ASEL1 pins configure the chip address for the LP55231 as shown in Table 1.
Table 1. LP55231 Chip Address Configuration
ASEL1
ASEL0
ADDRESS
8-BIT HEX ADDRESS
GND
GND
(HEX)
WRITE/READ
32
GND
64/65
VEN
33
66/67
VEN
GND
34
68/69
VEN
VEN
35
6A/6B
MSB
LSB
ADR6
bit7
ADR5
bit6
ADR4
bit5
ADR3
bit4
ADR2
bit3
ADR1
bit2
ADR0
bit1
0
1
1
0
0
1
0
R/W
bit0
2
I C Slave Address (chip address)
Figure 21. LP55231 Chip Address
ack from slave
ack from slave
ack from slave
start
MSB Chip Addr LSB
w
ack
MSB Register Addr LSB
ack
MSB
Data LSB
ack
stop
start
id = 32h
w
ack
addr = 40h
ack
address 40h data
ack
stop
SCL
SDA
Id = Chip Address = 32h For Lp55231. This data pattern writes temperature information to the temperature write
register (40h).
Figure 22. Write Cycle (W = Write; SDA = 0),
ack from slave
start
MSB Chip Addr LSB
w
ack from slave
MSB Register Addr LSB
repeated start
ack from slave data from slave nack from master
rs
MSB Chip Address LSB
rs
id = 32h
r
MSB
Data
LSB
stop
address 3Fh data
nack stop
SCL
SDA
start
id =32h
w ack
address = 3Fh
ack
r ack
Id = Chip Address = 32h For LP55231. This data pattern reads temperature information from the temperature read
register (3fh). when a read function is to be accomplished, a write function must precede the read function, as shown
above.
Figure 23. Read Cycle (R = Read; SDA = 1)
7.5.2.1 Control Register Write Cycle
• Master device generates start condition.
• Master device sends slave address (7 bits) and the data direction bit (r/w = 0).
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•
•
•
•
•
•
•
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Slave device sends acknowledge signal if the slave address is correct
Master sends control register address (8 bits).
Slave sends acknowledge signal.
Master sends data byte to be written to the addressed register.
Slave sends acknowledge signal.
If master sends further data bytes, the slave’s control register address is incremented by one after
acknowledge signal. In order to reduce program load time, the LP55231 supports address auto
incrementation. Register address is incremented after each 8 data bits. For example, the whole program
memory page can be written in one serial bus write sequence. Note: serial bus address auto increment is not
supported for register addresses from 16 to 1E.
Write cycle ends when the master creates stop condition.
7.5.2.2 Control Register Read Cycle
• Master device generates a start condition.
• Master device sends slave address (7 bits) and the data direction bit (r/w = 0).
• Slave device sends acknowledge signal if the slave address is correct
• Master sends control register address (8 bits).
• Slave sends acknowledge signal.
• Master device generates repeated start condition.
• Master sends the slave address (7 bits) and the data direction bit (r/w = 1).
• Slave sends acknowledge signal if the slave address is correct.
• Slave sends data byte from addressed register.
• If the master device sends an acknowledge signal, the control register address is incremented by one. Slave
device sends data byte from addressed register.
• Read cycle ends when the master does not generate acknowledge signal after data byte and generates stop
condition
7.5.2.3 Auto-Increment Feature
The auto-increment feature allows writing several consecutive registers within one transmission. Every time an 8bit word is sent to the LP55231, the internal address index counter is incremented by one, and the next register
is written. Table 2 shows writing sequence to two consecutive registers. Auto-increment feature is enabled by
writing EN_AUTO_INCR bit high in the MISC register (addr 36h). Note: serial bus address auto increment is not
supported for register addresses from 16 to 1E.
Table 2. Auto Increment Example
MASTER
START
CHIP
ADDR
=32H
REG
ADDR
WRITE
LP55231
ACK
DATA
ACK
DATA
ACK
STOP
ACK
7.6 Register Maps
7.6.1 Register Set
The LP55231 is controlled by a set of registers through the two-wire serial interface port. Some register bits are
reserved for future use. Table 3 below lists device registers, their addresses and their abbreviations. A more
detailed description is given in Control Register Details.
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Register Maps (continued)
Table 3. Control Register Map
HEX
ADDRESS
00
01
02
03
04
05
REGISTER NAME
ENABLE / ENGINE
CNTRL1
ENGINE CNTRL2
OUTPUT
DIRECT/RATIOMETRIC
MSB
OUTPUT
DIRECT/RATIOMETRIC
LSB
OUTPUT ON/OFF
CONTROL MSB
OUTPUT ON/OFF
CONTROL LSB
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
[6]
R/W
x0xxxxxx
CHIP_EN
0 = LP55231 not enabled
1 = LP55231 enabled
[5:4]
R/W
xx00xxxx
ENGINE1_EXEC
Engine 1 program execution control
[3:2]
R/W
xxxx00xx
ENGINE2_EXEC
Engine 2 program execution control
[1:0]
R/W
xxxxxx00
ENGINE3_EXEC
Engine 3 program execution control
[5:4]
R/W
xx00xxxx
ENGINE1_MODE
ENGINE 1 mode control
[3:2]
R/W
xxxx00xx
ENGINE2_MODE
ENGINE 2 mode control
[1:0]
R/W
xxxxxx00
ENGINE3_MODE
ENGINE 3 mode control
[0]
R/W
xxxxxxx0
D9_RATIO_EN
Enables ratiometric dimming for D9 output.
[7]
R/W
0xxxxxxx
D8_RATIO_EN
Enables ratiometric dimming for D8 output.
[6]
R/W
x0xxxxxx
D7_RATIO_EN
Enables ratiometric dimming for D7 output.
[5]
R/W
xx0xxxxx
D6_RATIO_EN
Enables ratiometric dimming for D6 output.
[4]
R/W
xxx0xxxx
D5_RATIO_EN
Enables ratiometric dimming for D5 output.
[3]
R/W
xxxx0xxx
D4_RATIO_EN
Enables ratiometric dimming for D4 output.
[2]
R/W
xxxxx0xx
D3_RATIO_EN
Enables ratiometric dimming for D3 output.
[1]
R/W
xxxxxx0x
D2_RATIO_EN
Enables ratiometric dimming for D2 output.
[0]
R/W
xxxxxxx0
D1_RATIO_EN
Enables ratiometric dimming for D1 output.
[0]
R/W
xxxxxxx1
D9_ON
ON/OFF Control for D9 output
[7]
R/W
1xxxxxxx
D8_ON
ON/OFF Control for D8 output
[6]
R/W
x1xxxxxx
D7_ON
ON/OFF Control for D7 output
[5]
R/W
xx1xxxxx
D6_ON
ON/OFF Control for D6 output
[4]
R/W
xxx1xxxx
D5_ON
ON/OFF Control for D5 output
[3]
R/W
xxxx1xxx
D4_ON
ON/OFF Control for D4 output
[2]
R/W
xxxxx1xx
D3_ON
ON/OFF Control for D3 output
[1]
R/W
xxxxxx1x
D2_ON
ON/OFF Control for D2 output
[0]
R/W
xxxxxxx1
D1_ON
ON/OFF Control for D1 output
BIT MNEMONIC AND DESCRIPTION
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Register Maps (continued)
Table 3. Control Register Map (continued)
HEX
ADDRESS
06
D1 CONTROL
07
D2 CONTROL
08
D3 CONTROL
09
D4 CONTROL
0A
0B
0C
0D
0E
0F TO 15
22
REGISTER NAME
D5 CONTROL
D6 CONTROL
D7 CONTROL
D8 CONTROL
D9 CONTROL
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
[7:6]
R/W
00xxxxxx
MAPPING
Mapping for D1 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D1
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D1 output
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D2 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D2 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D2 output
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D3 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D3 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D3 output
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D4 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D4 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D4 output
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D5 ouput
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D5 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D5
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D6 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D6 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D6 output
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D7 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D7 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D7 output
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D8 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D8 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D8 output
[7:6]
R/W
00xxxxxx
MAPPING Mapping for D9 output
[5]
R/W
xx0xxxxx
LOG_EN
Logarithmic dimming control for D9 output
[4:0]
R/W
xxx00000
TEMP COMP
Temperature compensation control for D9 output
BIT MNEMONIC AND DESCRIPTION
RESERVED
[7:0]
RESERVED FOR FUTURE USE
16
D1 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D1
17
D2 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D2
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Register Maps (continued)
Table 3. Control Register Map (continued)
HEX
ADDRESS
REGISTER NAME
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
BIT MNEMONIC AND DESCRIPTION
18
D3 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D3
19
D4 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D4
1A
D5 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D5
1B
D6 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D6
1C
D7 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D7
1D
D8 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D8
1E
D9 PWM
[7:0]
R/W
00000000
PWM
PWM duty cycle control for D9
RESERVED
[7:0]
26
D1 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D1 output current control register. Default 17.5 mA
(typ.)
27
D2 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D2 output current control register. Default 17.5 mA
(typ.)
28
D3 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D3 output current control register. Default 17.5 mA
(typ.)
29
D4 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D4 output current control register. Default current
is 17.5 mA (typ.)
2A
D5 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D5 output current control register. Default current
is 17.5 mA (typ.)
2B
D6 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D6 output current control register. Default current
is 17.5 mA (typ.)
2C
D7 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D7 output current control register. Default current
is 17.5 mA (typ.)
2D
D8 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D8 output current control register. Default current
is 17.5 mA (typ.)
2E
D9 CURRENT CONTROL
[7:0]
R/W
10101111
CURRENT
D9 output current control register. Default current
is 17.5 mA (typ.)
RESERVED FOR FUTURE
USE
[7:0]
1F TO 25
2F TO 35
RESERVED FOR FUTURE USE
RESERVED FOR FUTURE USE
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Register Maps (continued)
Table 3. Control Register Map (continued)
HEX
ADDRESS
36
MISC
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
[7]
R/W
0xxxxxxx
VARIABLE_D_SEL
Variable D source selection
[6]
R/W
x1xxxxxx
EN_AUTO_INCR
Serial bus address auto increment enable
[5]
R/W
xx0xxxxx
POWERSAVE_EN
Powersave mode enable
[4:3]
R/W
xxx00xxx
CP_MODE
Charge pump gain selection
[2]
R/W
xxxxx0xx
PWM_PS_EN
PWM cycle powersave enable
[1]
R/W
xxxxxx0x
CLK_DET_EN
External clock detection
[0]
R/W
xxxxxxx0
INT_CLK_EN
Clock source selection
BIT MNEMONIC AND DESCRIPTION
37
ENGINE1 PC
[6:0]
R/W
x0000000
PC
Program counter for engine 1
38
ENGINE2 PC
[6:0]
R/W
x0000000
PC
Program counter for engine 2
39
ENGINE3 PC
[6:0]
R/W
x0000000
PC
Program counter for engine 3
[7]
R
0xxxxxxx
LEDTEST_MEAS_DONE
Indicates when the LED test measurement is
done.
[6]
R
x1xxxxxx
MASK_BUSY
Mask bit for interrupts generated by STARTUP_BUSY or ENGINE_BUSY.
[5]
R
xx0xxxxx
START-UP_BUSY
This bit indicates that the start-up sequence is
running.
[4]
R
xxx0xxxx
ENGINE_BUSY
This bit indicates that a program execution engine
is clearing internal registers.
[3]
R
xxxx0xxx
EXT_CLK_USED
Indicates when external clock signal is in use.
[2]
R
xxxxx0xx
ENG1_INT
Interrupt bit for program execution engine 1
[1]
R
xxxxxx0x
ENG2_INT
Interrupt bit for program execution engine 2
[0]
R
xxxxxxx0
ENG3_INT
Interrupt bit for program execution engine 3
[2]
R/W
xxxxx0xx
INT_CONF
INT pin can be configured to function as a GPO
with this bit
[0]
R/W
xxxxxxx0
INT_GPO
GPO pin control for INT pin when INT_CONF is
set 1
3A
3B
24
REGISTER NAME
STATUS/INTERRUPT
INT/GPO
3C
VARIABLE
[7:0]
R/W
00000000
VARIABLE
Global 8-bit variable
3D
RESET
[7:0]
R/W
00000000
RESET
Writing 11111111 into this register resets the
LP55231
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Register Maps (continued)
Table 3. Control Register Map (continued)
HEX
ADDRESS
3E
REGISTER NAME
TEMP ADC CONTROL
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
[7]
R
0xxxxxxx
TEMP_MEAS_BUSY
Indicates when temperature measurement is
active
[2]
R/W
xxxxx0xx
EN_TEMP_SENSOR
Reads the internal temperature sensor once
[1]
R/W
xxxxxx0x
CONTINUOUS_CONV
Continuous temperature measurement selection
[0]
R/W
xxxxxxx0
SEL_EXT_TEMP
Internal/external temperature sensor selection
BIT MNEMONIC AND DESCRIPTION
3F
TEMPERATURE READ
[7:0]
R
00011001
TEMPERATURE
Bits for temperature information
40
TEMPERATURE WRITE
[7:0]
R/W
00000000
TEMPERATURE
Bits for temperature information
[7]
R/W
0xxxxxxx
EN_LED_TEST_ADC
[6]
R/W
x0xxxxxx
EN_LED_TEST_INT
[5]
R/W
xx0xxxxx
CONTINUOUS_CONV
Continuous LED test measurement selection
[4:0]
R/W
xxx00000
LED_TEST_CTRL
Control bits for LED test
R
N/A
41
LED TEST CONTROL
LED_TEST_ADC
LED test result
42
LED TEST ADC
[7:0]
43
RESERVED
[7:0]
44
RESERVED
[7:0]
45
ENGINE1 VARIABLE A
[7:0]
R
00000000
VARIABLE FOR ENGINE1
46
ENGINE2 VARIABLE A
[7:0]
R
00000000
VARIABLE FOR ENGINE2
47
ENGINE3 VARIABLE A
[7:0]
R
00000000
VARIABLE FOR ENGINE3
48
MASTER FADER1
[7:0]
R/W
00000000
MASTER FADER
49
MASTER FADER2
[7:0]
R/W
00000000
MASTER FADER
4A
MASTER FADER3
[7:0]
R/W
00000000
MASTER FADER
4B
RESERVED FOR FUTURE
USE
4C
ENG1 PROG START
ADDR
[6:0]
R/W
x0000000
ADDR
4D
ENG2 PROG START
ADDR
[6:0]
R/W
x0001000
ADDR
4E
ENG3 PROG START
ADDR
[6:0]
R/W
x0010000
ADDR
4F
PROG MEM PAGE SEL
[2:0]
R/W
xxxxx000
PAGE_SEL
RESERVED FOR FUTURE USE
RESERVED FOR FUTURE USE
RESERVED FOR FUTURE USE
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Register Maps (continued)
Table 3. Control Register Map (continued)
HEX
ADDRESS
REGISTER NAME
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
PROGRAM MEMORY
00H/10H/20H/30H/40H/50H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
01H/11H/21H/31H/41H/51H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
02H/12H/22H/32H/42H/52H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
03H/13H/23H/33H/43H/53H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
04H/14H/24H/34H/44H/54H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
05H/15H/25H/35H/45H/55H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
06H/16H/26H/36H/46H/56H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
07H/17H/27H/37H/47H/57H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
08H/18H/28H/38H/48H/58H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
09H/19H/29H/39H/49H/59H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
0AH/1AH/2AH/3AH/4AH/5A
H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
0BH/1BH/2BH/3BH/4BH/5B
H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
0CH/1CH/2CH/3CH/4CH/5
CH
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
0DH/1DH/2DH/36D/46D/5D
H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
PROGRAM MEMORY
0EH/1EH/2EH/3EH/4EH/5E
H
[15:8]
R/W
00000000
[7:0]
R/W
00000000
[15:8]
R/W
00000000
6F
PROGRAM MEMORY
0FH/1FH/2FH/3FH/4FH/5F
H
[7:0]
R/W
00000000
70
ENG1 MAPPING MSB
[0]
R
xxxxxxx0
50
51
52
53
54
55
56
57
58
59
5A
5B
5C
5D
5E
5F
60
61
62
63
64
65
66
67
68
69
6A
6B
6C
6D
6E
26
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BIT MNEMONIC AND DESCRIPTION
CMD
Every Instruction is 16-bit width.
The LP55231 can store 96 instructions. Each
instruction consists of 16 bits. Because one
register has only 8 bits, one instruction requires
two register addresses. In order to reduce
program load time the LP55231 supports address
auto-incrementation. Register address is
incremented after each 8 data bits. Thus the
whole program memory page can be written in
one serial bus write sequence.
D9
Engine 1 mapping information, D9 output
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Register Maps (continued)
Table 3. Control Register Map (continued)
HEX
ADDRESS
71
72
73
74
75
REGISTER NAME
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
[7]
R
0xxxxxxx
D8
Engine 1 mapping information, D8 output
[6]
R
x0xxxxxx
D7
Engine 1 mapping information, D7 output
[5]
R
xx0xxxxx
D6
Engine 1 mapping information, D6 output
[4]
R
xxx0xxxx
D5
Engine 1 mapping information, D5 output
[3]
R
xxxx0xxx
D4
Engine 1 mapping information, D4 output
[2]
R
xxxxx0xx
D3
Engine 1 mapping information, D3 output
[1]
R
xxxxxx0x
D2
Engine 1 mapping information, D2 output
[0]
R
xxxxxxx0
D1
Engine 1 mapping information, D1 output
[0]
R
xxxxxxx0
D9
Engine 2 mapping information, D9 output
[7]
R
0xxxxxxx
D8
Engine 2 mapping information, D8 output
[6]
R
x0xxxxxx
D7
Engine 2 mapping information, D7 output
[5]
R
xx0xxxxx
D6
Engine 2 mapping information, D6 output
[4]
R
xxx0xxxx
D5
Engine 2 mapping information, D5 output
[3]
R
xxxx0xxx
D4
Engine 2 mapping information, D4 output
[2]
R
xxxxx0xx
D3
Engine 2 mapping information, D3 output
[1]
R
xxxxxx0x
D2
Engine 2 mapping information, D2 output
[0]
R
xxxxxxx0
D1
Engine 2 mapping information, D1 output
[0]
R
xxxxxxx0
D9
Engine 3 mapping information, D9 output
[7]
R
0xxxxxxx
D8
Engine 3 mapping information, D8 output
[6]
R
x0xxxxxx
D7
Engine 3 mapping information, D7 output
[5]
R
xx0xxxxx
D6
Engine 3 mapping information, D6 output
[4]
R
xxx0xxxx
D5
Engine 3 mapping information, D5 output
[3]
R
xxxx0xxx
D4
Engine 3 mapping information, D4 output
[2]
R
xxxxx0xx
D3
Engine 3 mapping information, D3 output
[1]
R
xxxxxx0x
D2
Engine 3 mapping information, D2 output
[0]
R
xxxxxxx0
D1
Engine 3 mapping information, D1 output
ENG1 MAPPING LSB
ENG2 MAPPING MSB
ENG2 MAPPING LSB
ENG3 MAPPING MSB
ENG3 MAPPING LSB
BIT MNEMONIC AND DESCRIPTION
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Register Maps (continued)
Table 3. Control Register Map (continued)
HEX
ADDRESS
76
REGISTER NAME
GAIN CHANGE CTRL
BIT(s)
READ/
WRITE
DEFAULT VALUE
AFTER RESET
BIT MNEMONIC AND DESCRIPTION
[7:6]
R/W
00xxxxxx
THRESHOLD
Threshold voltage (typ.).
00 – 400mV
01 – 300mV
10 – 200mV
11 – 100mV
[5]
R/W
xx0xxxxx
ADAPTIVE_THRESH_EN
Activates adaptive threshold.
[4:3]
R/W
xxx00xxx
TIMER
00 – 5ms
01 – 10 ms
10 – 50 ms
11 – Infinite
[2]
R/W
xxxxx0xx
FORCE_1x
Activates 1.5x to 1x timer.
7.6.2 Control Register Details
00
•
•
•
•
•
•
•
•
•
•
•
•
•
01
•
•
•
•
28
ENABLE/ ENGINE CONTROL1
00 - Bit [6] CHIP_EN
1 = internal start-up sequence powers up all the needed internal blocks and the device enters normal mode.
0 = standby mode is entered. Control registers can still be written or read, excluding bits[5:0] in reg 00 (this
register), registers 16h to 1E (LED PWM registers) and 37h to 39h (program counters).
00 — Bits [5:4] ENGINE1_EXEC
Engine 1 program execution control. Execution register bits define how the program is executed. Program
start address can be programmed to Program Counter (PC) register 37H.
00 = hold: Hold causes the execution engine to finish the current instruction and then stop. Program counter
(PC) can be read or written only in this mode.
01 = step: Execute the instruction at the location pointed by the PC, increment the PC by one and then reset
ENG1_EXEC bits to 00 (that is, enter hold).
10 = free run: Start program execution from the location pointed by the PC.
11 = execute once: Execute the instruction pointed by the current PC value and reset ENG1_EXEC to 00
(that is, enter hold). The difference between step and execute once is that execute once does not increment
the PC.
00 — Bits [3:2] ENGINE2_EXEC
Engine 2 program execution control. Equivalent to above definition of control bits. Program start address can
be programmed to Program Counter (PC) register 38H.
00 — Bits [1:0] ENGINE3_EXEC
Engine 3 program execution control. Equivalent to engine 1 control bits. Program start address can be
programmed to Program Counter (PC) register 39H.
ENGINE CONTROL2
Operation modes are defined in this register.
Disabled: Engines can be configured to disabled mode each one separately.
Load program: Writing to program memory is allowed only when the engine is in load program operation
mode and engine busy bit (reg 3A) is not set. Serial bus master should check the busy bit before writing to
program memory or allow at least 1ms delay after entering to load mode before memory write, to ensure
initalization. All the three engines are in hold while one or more engines are in load program mode. PWM
values are frozen, also. Program execution continues when all the engines are out of load program mode.
Load program mode resets the program counter of the respective engine. Load program mode can be
entered from the disabled mode only. Entering load program mode from the run program mode is not allowed.
Run Program: Run program mode executes the instructions stored in the program memory. Execution
register (ENG1_EXEC etc.) bits define how the program is executed (hold, step, free run or execute once).
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•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
SNOSCR5D – MARCH 2013 – REVISED DECEMBER 2016
Program start address can be programmed to the Program Counter (PC) register. The Program Counter is
reset to zero when the PC’s upper limit value is reached.
Halt: Instruction execution aborts immediately and engine operation halts.
01 — Bit [5:4] ENGINE1_MODE
00 = disabled.
01 = load program to SRAM, reset engine 1 PC.
10 = run program as defined by ENGINE1_EXEC bits.
11 = halts the engine.
01 — Bits [3:2] ENGINE2_MODE
00 = disabled.
01 = load program to SRAM, reset engine 2 PC.
10 = run program as defined by ENGINE2_EXEC bits.
11 = halts the engine.
01 — Bits [3:2] ENGINE3_MODE
00 = disabled.
01 = load program to SRAM, reset engine 3 PC.
10 = run program as defined by ENGINE3_EXEC bits.
11 = halts the engine.
02 OUTPUT DIRECT/RATIOMETRIC MSB
• A particular feature of the LP55231 is the ratiometric up/down dimming of the RGB-LEDs. In other words, the
LED driver PWM output varies in a ratiometric manner. By a ratiometric approach the emitted color of an
RGB–LED remains the same regardless of the initial magnitudes of the R/G/B PWM outputs. For example, if
the PWM output of the red LED output is doubled, the output of green LED is doubled also.
• 02 — Bit [0] D9_RATIO_EN
• 1 = enables ratiometric diming for D9 output.
• 0 = disables ratiometric dimming for D9 output.
03
•
•
•
•
•
OUTPUT DIRECT/RATIOMETRIC LSB
03 — Bit [7] D8_RATIO_EN
1 = enables ratiometric diming for D8 output.
0 = disables ratiometric dimming for D8 output.
03 — Bit [0] D1_RATIO_EN to Bit [6] D7_RATIO_EN
The options for D1 output to D7 output are the same as above — see the “03 — Bit [7]” section.
04
•
•
•
•
OUTPUT ON/OFF CONTROL MSB
04 — Bit [0] D9_ON
1 = D9 output ON.
0 = D9 output OFF.
Note: Engine mapping overrides this control.
05
•
•
•
•
•
•
OUTPUT ON/OFF CONTROL MSB
05 — Bit [7] D8_ON
1 = D8 output ON.
0 = D8 output OFF.
Note: Engine mapping over rides this control.
05 — Bit [0] D1_ON to Bit [6] D7_ON
The options for D1 output to D7 output are the same as above — see the “05 — Bit [7]” section.
06 D1 CONTROL
• This is the register used to assign the D1 output to the MASTER FADER group 1, 2, or 3, or none of them.
Also, this register sets the correction factor for the D1 output temperature compensation and selects between
linear and logarithmic PWM brightness adjustment. By using logarithmic PWM-scale the visual effect looks
like linear. When the logarithmic adjustment is enabled, the chip handles internal PWM values with 12-bit
resolution. This allows very fine-grained PWM control at low PWM duty cycles.
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06 — Bit [7:6] MAPPING
00 = no master fader set, clears master fader set for D1. Default setting.
01 = MASTER FADER1 controls the D1 output.
10 = MASTER FADER2 controls the D1 output.
11 = MASTER FADER3 controls the D1 output.
The duty cycle on D1 output is D1 PWM register value (address 16H) multiplied with the value in the
MASTER FADER register.
06 — Bit [5] LOG_EN
0 = linear adjustment.
1 = logarithmic adjustment.
This bit is effective for both the program execution engine control and direct PWM control.
06 — Bit [4:0] TEMP_COMP
The reference temperature is 25°C (that is, the temperature at which the compensation has no effect) and the
correction factor (slope) can be set in 0.1% 1/°C steps to any value between −1.5% 1/°C and +1.5% 1/°C,
with a default to 0.0% 1/°C.
TEMP_COMP BITS
CORRECTION FACTOR (%)
00000
Not activated - default setting after reset.
11111
−1.5 1/°C
11110
−1.4 1/°C
...
...
10001
−0.1 1/°C
10000
0 1/°C
00001
0.1 1/°C
...
...
01110
1.4 1/°C
01111
1.5 1/°C
The PWM duty cycle at temperature T (in centigrade) can be obtained as follows: PWMF = [PWMS – (25 – T) ×
correction factor × PWMS] / 2, where PWMF is the final duty cycle at temperature T, PWMS is the set PWM duty
cycle (PWM duty cycle is set in registers 16H to 1EH) and the value of the correction factor is obtained from the
table above.
For example, if the set PWM duty cycle in register 16H is 90%, temperature T is −10°C and the chosen
correction factor is 1.5% 1/°C, the final duty-cycle PWMF for D1 output is [90% – (25°C − (−10°C) ) × 1.5% 1/°C
× 90%]/2 = [90% – 35 × 0.015 × 90%]/2 = 21.4%. Default setting 00000 means that the temperature
compensation is non-active and the PWM output (0 to 100%) is set solely by PWM registers D1 PWM to D9
PWM.
07 D2 CONTROL to 0E D9 CONTROL
• The control registers and control bits for D2 output to D9 output are similar to that given to D1, see the 06 –
Bit [5] and 06 – Bits [4:0] sections.
16 D1 PWM
• This is the PWM duty cycle control for D1 output. D1 PWM register is effective during direct control operation
- direct PWM control is active after power up by default. Note: serial bus address auto increment is not
supported for register addresses from 16 to 1E.
• 16 — Bits [7:0] PWM
• These bits set the D1 output PWM as shown in the figure below. Note: if the temperature compensation is
active, the maximum PWM duty cycle is 50% at 25°C. This is required to allow enough headroom for
temperature compensation over the temperature range −30°C to 90°C.
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100
PWM %
75
50
25
0
00000000
10000000
11111111
PWM Bits
Figure 24. Direct PWM Control Bits vs PWM Duty Cycle
17 D2 PWM to 1E D9 PWM
• PWM duty cycle control for outputs D2 to D9. The control registers and control bits for D2 output to D9 output
are similar to that given to D1.
26 D1 CURRENT CONTROL
• D1 LED driver output current control register. The resolution is 8-bits and step size is 100 μA.
CURRENT BITS
OUTPUT CURRENT (mA, typical)
00000000
0.0
00000001
0.1
00000010
0.2
...
...
10101111
17.5 (default setting)
....
....
11111110
25.4
11111111
25.5
27 D2 CURRENT CONTROL to 2E D9 CURRENT CONTROL
• The control registers and control bits for D2 output up to D9 output are similar to that given to D1 output.
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This register contains miscellaneous control bits.
36 — Bit [7] VARIABLE_D_SEL
Variable D source selection.
1 = variable D source is the LED test ADC output (LED TEST ADC). This allows, for example, program
execution control with analog signal.
0 = variable D source is the register 3C (VARIABLE).
36 — Bit [6] EN_AUTO_INCR
The automatic increment feature of the serial bus address enables a quick memory write of successive
registers within one transmission.
1 = serial bus address automatic increment is enabled.
0 = serial bus address automatic increment is disabled.
36 — Bit [5] POWERSAVE_EN
1 = power save mode is enabled.
0 = power save mode is disabled. See Automatic Power-Save Mode for further details.
36 — Bits [4:3] CP_MODE
Charge pump operation mode.
00 = OFF.
01 = forced to bypass mode (1x).
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10 = forced to 1.5× mode; output voltage is boosted to 4.5 V.
11 = automatic mode selection.
36 — Bit [2] PWM_PS_EN
Enables PWM powersave operation. Significant power savings can be achieved, for example, during ramp
instruction.
36 — Bits [1:0] CLK_DET_EN and INT_CLK_EN
Program execution is clocked with an internal 32.7-kHz clock or with external clock. Clocking is controlled
with bits INT_CLK_EN and CLK_DET_EN in the following way:
00 = forced external clock (CLK pin).
01 = forced internal clock.
10 = automatic selection.
11 = internal clock.
External clock can be used if a clock signal is present on CLK-pin. External clock frequency must be 32.7 kHz
for correct operation. If a higher or a lower frequency is used, it affects the program execution engine
operation speed. The detector block does not limit the maximum frequency. External clock status can be
checked with read only bit EXT_CLK_USED in register address 3A, when the external clock detection is
enabled (Bit [1] CLK_DET_EN = high).
If external clock is not used in the application, CLK pin must be connected to GND to avoid oscillation on this
pin and extra current consumption.
37 ENGINE1 PC
• Program counter starting value for program execution engine 1; A value from 0000000 to 1011111. The
maximum value depends on program memory allocation between the three program execution engines.
38 ENGINE2 PC
• 38 — Bits [6:0] PC
• Program counter starting value for program execution engine 2; A value from 0000000 to 1011111.
39 ENGINE3 PC
• 39 — Bits [6:0] PC
• Program counter starting value for program execution engine 3; A value from 0000000 to 1011111.
3A STATUS/INTERRUPT
• 3A — Bit [7] LEDTEST_MEAS_DONE
• This bit indicates when the LED test is done, and the result is written to the LED TEST ADC register.
Typically the conversion takes 2.7 milliseconds to complete.
• 1 = LED test done.
• 0 = LED test not done.
• This bit is a read-only bit, and it is cleared (to 0) automatically after a read operation.
• 3A — Bit [6] MASK_BUSY
• Mask bit for interrupts generated by START-UP_BUSY or ENGINE_BUSY.
• 1 = Interrupt events are masked; that is, no external interrupt is generated from START-UP_BUSY or
ENGINE_BUSY event (default).
• 0 = External interrupt is generated when START-UP_BUSY or ENGINE_BUSY condition is no longer true.
Reading the register 3A clears the status bits [5:4] and releases INT pin to high state.
• 3A — Bit [5] START-UP_BUSY
• A status bit which indicates that the device is running the internal start-up sequence. See Modes Of Operation
for details.
• 1 = internal start-up sequence running. Note: START-UP_BUSY = 1 always when CHIP_EN bit is 0.
• 0 = internal start-up sequence completed.
• 3A — Bit [4] ENGINE_BUSY
• A status bit which indicates that a program execution engine is clearing internal registers. Serial bus master
should not write or read program memory, or registers 00H, 37H to 39H or 4CH to 4EH, when this bit is set to
1.
• 1 = at least one of the engines is clearing internal registers.
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0 = engine ready.
3A — Bit [3] EXT_CLK_USED
1 = external clock detected.
0 = external clock not detected.
This bit is high when external clock signal on CLK pin is detected. CLK_DET_EN bit high in address 36
enables the clock detection.
3A — Bits [2:0] ENG1_INT, ENG2_INT, ENG3_INT
1 = interrupt set.
0 = interrupt unset/cleared.
Interrupt bits for program execution engine 1, 2, and 3, respectively. These bits are set by END or INT
instruction. Reading the interrupt bit clears the interrupt.
3B INT/GPO
• INT pin can be configured to function as a GPO by setting the bit INT_CONF. When INT is configured to
function as a GPO, output level is defined by the VDD voltage.
• 3B — Bit [2] INT_CONF
• 0 = INT pin is set to function as an interrupt pin (default).
• 1 = INT pin is configured to function as a GPO.
• 3B — Bit [0] INT_GPO
• 0 = INT pin state is low (if INT_CONF = 1).
• 1 = INT pin state is high (if INT_CONF = 1).
• When INT pin’s GPO function is disabled, it operates as an open drain pin. INT signal is active low; that is,
when interrupt signal is sent, the pin is pulled to GND. External pullup resistor is needed for proper
functionality.
3C VARIABLE
• 3C — Bits [7:0] VARIABLE
• These bits are used for storing a global 8-bit variable. Variable can be used to control program flow.
3D RESET
• 3D — Bits [7:0] RESET
• Writing 11111111 into this register resets the LP55231. Internal registers are reset to the default values.
Reading RESET register returns 00000000.
3E TEMP ADC CONTROL
• 3E — Bit [7] TEMP_MEAS_BUSY
• 1 = temperature measurement active.
• 0 = temperature measurement done or not activated.
• 3E — Bit [2] EN_TEMP_SENSOR
• 1 = enables internal temperature sensor. Every time when EN_TEMP_SENSOR is written high a new
measurement period is started. The length of the measurement period depends on temperature. At 25°C a
measurement takes 20 milliseconds. Temperature can be read from register 3F.
• 0 = temp sensor disabled.
• 3E — Bit [1] CONTINUOUS _CONV
• This bit is effective when EN_TEMP_SENSOR = 1.
• 1 = continuous temperature measurement. Not active when the device is in power save.
• 0 = new temperature measurement period initiated during start-up or after exit from power-save mode.
3E — Bit [0] SEL_EXT_TEMP
• 1 = temperature compensation source register addr 40H.
• 0 = temperature compensation source register addr 3FH.
3F TEMPERATURE READ
• 3F — Bits [7:0] TEMPERATURE
• These bits are used for storing an 8-bit temperature reading acquired from the internal temperature sensor.
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This register is a read-only register. Temperature reading is stored in 8-bit two's complement format.
TEMPERATURE READ BITS
TEMPERATURE INTERPRETATION (°C, typ.)
11010111
−41
11011000
−40
...
...
11111110
−2
11111111
−1
00000000
0
00000001
1
00000010
2
...
...
01011000
88
01011001
89
40 TEMPERATURE WRITE
• 40 — Bits [7:0] TEMPERATURE
• These bits are used for storing an 8-bit temperature reading acquired from an external sensor, if such a
sensor is used. Temperature reading is stored in 8-bit two's complement format, like in 3F TEMPERATURE
READ register.
• When writing temperature data outside the range of the temperature compensation: Values greater than 89°C
are set to 89°C; values less than −39°C are set to −39°C.
41
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LED TEST CONTROL
LED test control register
41 — Bit [7] EN_LEDTEST_ADC
Writing this bit high (1) fires single LED test conversion. LED test measurement cycle is 2.7 milliseconds.
41 — Bit [6] EN_LEDTEST_INT
1 = interrupt signal is sent to the INT pin when the LED test is accomplished.
0 = no interrupt signal is sent to the INT pin when the LED test is accomplished.
Interrupt can be cleared by reading STATUS/INTERRUPT register 3A.
41 — Bit [5] CONTINUOUS_CONV
1 = continuous LED test measurement. Not active in power-save mode.
0 = continuous conversion is disabled.
41 — Bits [4:0] LED__TEST_CTRL
These bits are used for choosing the LED driver output to be measured. VDD, INT pin and charge-pump
output voltage can be measured, also.
LED_TEST_CTRL BITS
MEASUREMENT
00000
D1
00001
D2
00010
D3
00011
D4
00100
D5
00101
D6
00110
D7
00111
D8
01000
D9
01001 to 01110
Reserved
01111
VOUT
10000
VDD
10001
INT-pin voltage
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LED_TEST_CTRL BITS
MEASUREMENT
10010 to 11111
N/A
42 LED TEST ADC
• 42 — Bits [7:0] LED_TEST_ADC
• This is used to store the LED test result. Read-only register. The LED test ADC's least significant bit
corresponds to 30 mV. The measured voltage V (typical) is calculated as follows: V = (RESULT(DEC) ×
0.03 – 1.478 V. For example, if the result is 10100110 = 166(DEC), the measured voltage is 3.5 V (typical).
See Figure 25 .
5
VOLTAGE (V)
4
3
2
1
0
40
90
140
190
RESULT (DEC)
Figure 25. LED Test Results vs Measured Voltage
45 ENGINE1 VARIABLE A
• 45 — Bits [7:0] VARIABLE FOR ENGINE1
• These bits are used for Engine 1 local variable. Read-only register.
46 ENGINE2 VARIABLE A
• 46 — Bits [7:0] VARIABLE FOR ENGINE2
• These bits are used for Engine 2 local variable. Read-only register.
47 ENGINE3 VARIABLE A
• 47 — Bits [7:0] VARIABLE FOR ENGINE3
• These bits are used for Engine 3 local variable. Read-only register.
48 MASTER FADER1
• 48 — Bits [7:0] MASTER_FADER
• An 8-bit register to control all the LED-drivers mapped to MASTER FADER1. Master fader allows the user to
control dimming of multiple LEDS with a single serial bus write. This is a faster method to control the dimming
of multiple LEDs compared to the dimming done with the PWM registers (address 16H to 1EH), which would
need multiple writes.
49 MASTER FADER2
• 49 — Bits [7:0] MASTER_FADER
• An 8-bit register to control all the LED-drivers mapped to MASTER FADER2. See MASTER FADER1
description.
4A MASTER FADER3
• 4A — Bits [7:0] MASTER_FADER
• An 8-bit register to control all the LED-drivers mapped to MASTER FADER3. See MASTER FADER1
description.
4C ENG1 PROG START ADDR
• Program memory allocation for program execution engines is defined with PROG START ADDR registers.
• 4C — Bits [6:0] — ADDR
• Engine 1 program start address.
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4D ENG2 PROG START ADDR
• 4D — Bits [6:0] — ADDR
• Engine 2 program start address.
4E ENG3 PROG START ADDR
• 4E — Bits [6:0] — ADDR
• Engine 3 program start address.
4F PROG MEM PAGE SELECT
• 4F — Bits [2:0] — PAGE_SEL
• These bits select the program memory page. The program memory is divided into six pages of 16
instructions; thus, the total amount of the program memory is 96 instructions.
70H ENG1 MAPPING MSB
• Valid engine 1-to-LED -mapping information can be read from ENG1 MAPPING register.
• 70H — Bit [0] D9
• 1 = D9 pin is mapped to the program execution engine 1.
• 0 = D9 pin non-mapped to the program execution engine 1.
71H ENG1 MAPPING LSB
• 71H — Bit [7] D8
• 1 = D8 pin is mapped to the program execution engine 1.
• 0 = D8 pin non-mapped to the program execution engine 1.
• 71H — Bit [6] D7
• 1 = D7 pin is mapped to the program execution engine 1.
• 0 = D7 pin non-mapped to the program execution engine 1.
• 71H — Bit [5] D6
• 1 = D6 pin is mapped to the program execution engine 1.
• 0 = D6 pin non-mapped to the program execution engine 1.
• 71H — Bit [4] D5
• 1 = D5 pin is mapped to the program execution engine 1.
• 0 = D5 pin non-mapped to the program execution engine 1.
• 71H — Bit [3] D4
• 1 = D4 pin is mapped to the program execution engine 1.
• 0 = D4 pin non-mapped to the program execution engine 1.
• 71H — Bit [2] D3
• 1 = D3 pin is mapped to the program execution engine 1.
• 0 = D3 pin non-mapped to the program execution engine 1.
• 71H — Bit [1] D2
• 1 = D2 pin is mapped to the program execution engine 1.
• 0 = D2 pin non-mapped to the program execution engine 1.
• 71H — Bit [0] D1
• 1 = D1 pin is mapped to the program execution engine 1.
• 0 = D1 pin non-mapped to the program execution engine 1.
72H ENG2 MAPPING MSB
• Valid engine 2-to-LED -mapping information can be read from ENG2 MAPPING register.
• 72H — Bit [0] D9
• See description above for ENG1 MAPPING register.
73H ENG2 MAPPING LSB
• 73H — Bit [7] D8 to Bit [0] D1
• See description above for ENG1 MAPPING register.
74H ENG3 MAPPING MSB
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Valid engine 3-to-LED -mapping information can be read from ENG3 MAPPING register.
74H — Bit [0] D9
See description above for ENG1 MAPPING register.
75H ENG3 MAPPING LSB
• 75H — Bit [7] D8 to Bit [0] D1
• See description above for ENG1 MAPPING register.
76H GAIN_CHANGE_CTRL
• With hysteresis and timer bits the user can optimize the charge pump performance to better meet the
requirements of the application at hand. Some applications need to be optimized for efficiency and others
need to be optimized for minimum EMI, for example.
• 76H - Bits[7:6] THRESHOLD
• Threshold voltage (typical) pre-setting. Bits set the threshold voltage at which the charge-pump gain changes
from 1.5× to 1×. The threshold voltage is defined as the voltage difference between highest voltage output
(D1 to D6) and input voltage VDD: VTHRESHOLD = VDD – MAX(voltage on D1 to D6).
• If VTHRESHOLD is larger than the set value (100 mV to 400 mV), the charge pump is in 1x mode.
• 00 = 400 mV
• 01 = 300 mV
• 10 = 200 mV
• 11 = 100 mV
• Values above are typical and should not be used as product specification.
• Writing to threshold [7:6] bits by the user overrides factory settings. Factory settings are not user accessible.
• 76H - Bit [5] ADAPTIVE_TRESH_EN
• 1 = Adaptive threshold enabled.
• 0 = Adaptive threshold disabled.
• Gain-change hysteresis prevents the mode from toggling back and forth (1× ≥ 1.5× ≥ 1×...) , which would
cause ripple on VIN and LED flicker. When the adaptive threshold is enabled, the width of the hysteresis
region depends on the choice of threshold bits (see above), saturation of the current sources, charge pump
load current, PWM overlap and temperature.
• 76H - Bits [4:3] TIMER
• A forced mode change from 1.5× to 1× is attempted at the interval specified with these bits. Mode change is
allowed if there is enough voltage over the LED drivers to ensure proper operation. Set FORCE_1x to 1 (see
below) to activate this feature.
• 00 = 5ms
• 01 = 10 ms
• 10 = 50 ms
• 11 = infinite. The charge pump switches gain from 1×mode to 1.5× mode only. The gain reset back to 1x is
enabled under certain conditions, for example in the powersave mode.
• 76H - Bit [2] FORCE_1×
• Activates forced mode change. In forced mode, charge pump mode change from 1.5× to 1× is attempted at
the constant interval specified with the TIMER bits.
• 1 = forced mode changes enabled.
• 0 = forced mode changes disabled.
7.6.3 Instruction Set
The LP55231 has three independent programmable execution engines. All the program execution engines have
their own program memory block allocated by the user. Note that in order to access program memory the
operation mode needs to be load program, at least for one of the three program execution engines. Program
execution is clocked with a 32.7-kHz clock. This clock can be generated internally or an external 32-kHz clock
can be connected to CLK pin. Using an external clock enables synchronization of LED timing to the external
clock signal.
Supported instruction set is listed in Table 4, Table 5, Table 6, and Table 7 below:
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Table 4. LP55231 LED Driver Instructions
Bit
[15]
Bit
[14]
ramp (1)
0
prescale
ramp (2)
1
0
0
0
0
1
0
0
0
1
0
0
0
0
0
0
)
1
0
0
0
0
1
0
0
0
wait
0
prescale
0
0
Inst.
set_pwm (1
)
set_pwm
(1)
(2)
Bit
[13]
Bit
[12]
Bit
[11]
Bit
[10]
Bit [9] Bit [8]
step time
sign
Bit
[7]
Bit [6] Bit [5] Bit [4] Bit [3] Bit [2] Bit [1] Bit [0]
# of increments
0
prescale
sign
1
1
0
0
0
step time
# of
increments
0
0
0
PWM value
0
0
0
0
0
Bit [2]
Bit
[1]
Bit [0]
PWM value
(2
time
This opcode is used with numerical operands.
This opcode is used with variables.
Table 5. LP55231 LED Mapping Instructions
Bit
[15]
Bit
[14]
Bit
[13]
Bit
[12]
Bit
[11]
Bit
[10]
Bit
[9]
Bit
[8]
Bit
[7]
mux_ld_start
1
0
0
1
1
1
1
0
0
mux_map_start
1
0
0
1
1
1
0
0
0
SRAM address 0-95
mux_ld_end
1
0
0
1
1
1
0
0
1
SRAM address 0 - 95
mux_sel
1
0
0
1
1
1
0
1
0
mux_clr
1
0
0
1
1
1
0
1
0
0
0
0
0
0
0
0
mux_map_next
1
0
0
1
1
1
0
1
1
0
0
0
0
0
0
0
mux_map_prev
1
0
0
1
1
1
0
1
1
1
0
0
0
0
0
0
mux_ld_next
1
0
0
1
1
1
0
1
1
0
0
0
0
0
0
1
mux_ld_prev
1
0
0
1
1
1
0
1
1
1
0
0
0
0
0
1
mux_ld_addr
1
0
0
1
1
1
1
1
0
SRAM address 0-95
mux_map_addr
1
0
0
1
1
1
1
1
1
SRAM address 0-95
Inst.
Bit
[6]
Bit
[5]
Bit [4]
Bit
[3]
SRAM address 0-95
LED select
Table 6. LP55231 Branch Instructions
Bit
[15]
Bit
[14]
Bit
[13]
Bit
[12]
Bit
[11]
rst
0
0
0
0
0
branch (1)
1
0
1
branch (2)
1
0
0
0
0
1
1
int
1
1
0
0
0
1
0
0
0
0
0
0
0
0
0
0
end
1
1
0
int
reset
0
0
0
0
0
0
0
0
0
0
0
trigger
1
1
1
ext.
trig
E1
ext.
trig
E2
E1
jne
1
0
0
0
1
0
0
Number of instructions to be skipped
if the operation returns true
variable
1
variable
2
jl
1
0
0
0
1
0
1
Number of instructions to be skipped
if the operation returns true
variable
1
variable
2
jge
1
0
0
0
1
1
0
Number of instructions to be skipped
if the operation returns true
variable
1
variable
2
je
1
0
0
0
1
1
1
Number of instructions to be skipped
if the operation returns true
variable
1
variable
2
Inst.
Bit
[10]
Bit
[9]
Bit [8]
Bit
[7]
0
0
0
0
0
0
38
0
loop count
X
(3)
X
(3)
E3
Bit [3] Bit [2] Bit [1] Bit [0]
0
0
0
0
step number
step number
wait for trigger
(1)
(2)
(3)
Bit
[4]
Bit [6] Bit [5]
loop count
send a trigger
E2
X
(3)
X (3)
E3
0
This opcode is used with numerical operands.
This opcode is used with variables.
X means do not care.
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Table 7. LP55231 Data Transfer and Arithmetic Instructions
Inst.
Bit
[15]
Bit
[14]
Bit
[13]
Bit
[12]
ld
1
0
0
1
add (1)
1
0
0
add (2)
1
0
sub (1)
1
sub (2)
1
(1)
(2)
Bit
[11]
Bit
[10]
Bit
[9]
Bit [8]
Bit
[7]
target
variable
0
0
8-bit value
1
target
variable
0
1
8-bit value
0
1
target
variable
1
1
0
0
1
target
variable
1
0
0
0
1
target
variable
1
1
Bit [6] Bit [5]
0
0
0
Bit
[4]
Bit [3] Bit [2] Bit [1] Bit [0]
0
variable
1
variable
2
8-bit value
0
0
0
1
variable
1
variable
2
This opcode is used with numerical operands.
This opcode is used with variables.
7.6.4 LED Driver Instructions
7.6.4.1 Ramp
This is the instruction useful for smoothly changing from one PWM value into another PWM value on the D1 to
D9 outputs; in other words, generating ramps (with a negative or positive slope). The LP55231 allows
programming very fast and very slow ramps.
Ramp instruction generates a PWM ramp, using the effective PWM value as a starting value. At each ramp step
the output is incremented/decremented by one unit, unless the number of increments is 0. Time span for one
ramp step is defined with prescale bit [14] and step time bits [13:9]. Prescale = 0 sets 0.49 ms cycle time and
prescale = 1 sets 15.6 ms cycle time; so the minimum time span for one step is 0.49 ms (prescale × step time
span = 0.49 ms × 1) and the maximum time span is 15.6 ms × 31 = 484 ms/step.
Number of increments value defines how many steps are taken during one ramp instruction; increment maximum
value is 255d, which corresponds increment from zero value to the maximum value. If PWM reaches
minimum/maximum value (0/255) during the ramp instruction, ramp instruction is executed to the end regardless
of saturation. This enables ramp instruction to be used as a combined ramp and wait instruction. Note: Ramp
instruction is wait instruction when the increment bits [7:0] are set to zero.
Programming ramps with variables is very similar to programming ramps with numerical operands. The only
difference is that step time and number of increments are captured from variable registers, when the instruction
execution is started. If the variables are updated after starting the instruction execution, it has no effect on
instruction execution. Again, at each ramp step the output is incremented/decremented by one unless increment
is 0. Time span for one step is defined with prescale and step time bits. Step time is defined with variable A, B, C
or D. Variables A, B and C are set with ld-instruction. Variable D is a global variable and can be set by writing the
VARIABLE register (address 3C). LED TEST ADC register (address 42) can be used as a source for the variable
D, as well. Note: Variable A is the only local variable which can be read throughout the serial bus. Of course, the
variable stored in 3CH can be read (and written), too.
Setting register 06H, 07H, or 08H bit LOG_EN high/low sets logarithmic (1) or linear ramp (0). By using the
logarithmic ramp setting the visual effect appears like a linear ramp, because the human eye behaves in a
logarithmic way.
Table 8. Ramp Instructions
NAME
prescale
sign
step time (1)
(1)
VALUE (d)
DESCRIPTION
0
Divides master clock (32.7 kHz) by 16 = 2048 Hz -> 0.488 ms cycle time
1
Divides master clock (32.7 kHz) by 512 = 64 Hz -> 15.625 ms cycle time
0
Increase PWM output
1
Decrease PWM output
1 - 31
One ramp increment done in (step time) x (prescale).
Valid for numerical operands.
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Table 8. Ramp Instructions (continued)
NAME
VALUE (d)
DESCRIPTION
0 - 255
The number of increment/decrement cycles. Note: Value 0 takes the same time as increment by 1, but
it is the wait instruction.
# of
increments (1)
One ramp increment done in (step time) x (prescale).
Step time is loaded with the value (5 LSB bits) of the variable defined below.
0 = local variable A
step time (2)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable D value, or register address 42H value.
The value of the variable should be from 00001b to 11111b (1d to 31d) for correct operation.
The number of increment/decrement cycles. Value is taken from variable defined below:
0 = local variable A
# of
increments (2)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable D value, or register address 42H value.
(2)
Valid for variables.
7.6.4.2 Ramp Instruction Application Example
Suppose that the LED dimming is controlled according to the linear scale and effective PWM value at the
moment t = 0 is 140d (approximately 55%), as shown in the figure below, and we want to reach a PWM value of
148d (approximately 58%) at the moment t = 1.5 s. The parameters for the RAMP instruction are:
• Prescale = 1 → 15.625 ms cycle time
• Step time = 12 → step time span is 12 × 15.625 ms = 187.5 ms
• Sign = 0 → increase PWM output
• # of increments = 8 → take 8 steps
DIMMING
CONTROL
148
147
STEP TIME
SPAN =
187.5ms
146
145
144
143
142
141
140
RAMP INSTRUCTION
375
750
1125
0
0
1
2
3
4
5
6
1500 TIME ELAPSED (ms)
7
8
STEP COUNT
Figure 26. Example Of Ramp Instruction
7.6.4.3 Set_PWM
This instruction is used for setting the PWM value on the outputs D1 to D9 without any ramps. Set PWM output
value from 0 to 255 with PWM value bits [7:0]. Instruction execution takes sixteen 32-kHz clock cycles (=488 µs).
NAME
PWM value (i) (1)
VALUE (d)
0 - 255
DESCRIPTION
PWM output duty cycle 0 - 100%
0 = local variable A
variable (ii) (1)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable D value, or register address 42H value.
(1)
40
(i) Valid for numerical operands. (ii) Valid for variables.
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7.6.4.4 Wait
When a wait instruction is executed, the engine is set in wait status, and the PWM values on the outputs are
frozen.
NAME
VALUE (d)
prescale
time
DESCRIPTION
0
Divide master clock (32.7 kHz) by 16 which means 0.488 ms cycle time.
1
Divide master clock (32 768 Hz) by 512 which means 15.625 ms cycle time.
1 - 31
Total wait time is = (time) × (prescale). Maximum 484 ms, minimum 0.488 ms.
7.6.5 LED Mapping Instructions
These instructions define the engine-to-LED mapping. The mapping information is stored in a table, which is
stored in the SRAM (program memory of the LP55231). LP55231 has three program execution engines which
can be mapped to 9 LED drivers. One engine can control one or multiple LED drivers. There are totally eleven
instructions for the engine-to-LED-driver control: mux_ld_start, mux_map_start, mux_ld_end, mux_sel, mux_clr,
mux_map_next, mux_map_prev, mux_ld_next, mux_ld_prev, mux_ld_addr and mux_map_addr.
7.6.5.1 MUX_LD_START; MUX_LD_END
Mux_ld_start and mux_ld_end define the mapping table location in the memory.
NAME
VALUE (d)
SRAM address
0-95
DESCRIPTION
Mapping table start/end address
7.6.5.2 MUX_MAP_START
Mux_map_start defines the mapping table start address in the memory, and the first row of the table is activated
(mapped) at the same time.
NAME
SRAM address
VALUE (d)
0-95
DESCRIPTION
Mapping table start address
7.6.5.3 MUX_SEL
With mux_sel instruction one, and only one, LED driver can be connected to a program execution engine.
Connecting multiple LEDs to one engine is done with the mapping table. After the mapping has been released
from an LED, PWM register value still controls the LED brightness.
NAME
VALUE (d)
DESCRIPTION
0 = no drivers selected
1 = LED1 selected
LED select
0-16
2 = LED2 selected
...
9 = LED9 selected
7.6.5.4 MUX_CLR
Mux_clr clears engine-to-driver mapping. After the mapping has been released from an LED, the PWM register
value still controls the LED brightness.
7.6.5.5 MUX_MAP_NEXT
This instruction sets the next row active in the mapping table each time it is called. For example, if the 2nd row is
active at this moment, after mux_map_next instruction call the 3rd row is active. If the mapping table end
address is reached, activation rolls to the mapping table start address next time when the mux_map_next
instruction is called. The engine does not push a new PWM value to the LED driver output before set_pwm or
ramp instruction is executed. If the mapping has been released from an LED, the value in the PWM register still
controls the LED brightness.
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7.6.5.6 MUX_LD_NEXT
Similar than the mux_map_next instruction, but only the index pointer is set to point to the next row; that is, no
mapping is set, and the engine-to-LED-driver connection is not e updated.
7.6.5.7 MUX_MAP_PREV
This instruction sets the previous row active in the mapping table each time it is called. For example, if the 3rd
row is active at this moment, after mux_map_prev instruction call the 2nd row is active. If the mapping table start
address is reached, activation rolls to the mapping table end address next time the mux_map_prev instruction is
called. Engine does not push a new PWM value to the LED driver output before set_pwm or ramp instruction is
executed. If the mapping has been released from an LED, the value in the PWM register still controls the LED
brightness.
7.6.5.8 MUX_LD_PREV
Similar than the mux_map_prev instruction, but only the index pointer is set to point to the previous row; that is,
no mapping is set, and the engine-to-LED-driver connection is not updated.
7.6.5.9 MUX_MAP_ADDR
Mux_map_addr sets the index pointer to point the mapping table row defined by bits [6:0] and sets the row
active. The engine does not push a new PWM value to the LED driver output before set_pwm or ramp instruction
is executed. If the mapping has been released from an LED, the value in the PWM register still controls the LED
brightness.
NAME
VALUE (d)
SRAM address
0-95
DESCRIPTION
Any SRAM address containing mapping data.
7.6.5.10 MUX_LD_ADDR
Mux_ld_addr sets the index pointer to point the mapping table row defined by bits [6:0], but the row is not set
active.
NAME
VALUE (d)
SRAM address
0-95
DESCRIPTION
Any SRAM address containing mapping data.
7.6.6 Branch Instructions
7.6.6.1 BRANCH
Branch instruction is mainly indented for repeating a portion of the program code several times. Branch
instruction loads step number value to program counter. Loop count parameter defines how many times the
instructions inside the loop are repeated. The LP55231 supports nested looping, that is, loop inside loop. The
number of nested loops is not limited. Instruction takes sixteen 32-kHz clock cycles.
NAME
ACCEPTED VALUE (d)
DESCRIPTION
loop count (i)
0-63
The number of loops to be done. 0 means an infinite loop.
step number
0-95
The step number to be loaded to program counter.
Selects the variable for loop count value. Loop count is loaded with the value of the
variable defined below.
0 = local variable A
loop count (ii)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable D value, or register address 42H value
42
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7.6.6.2 INT
Send interrupt to processor by pulling the INT pin down and setting corresponding status bit high. Interrupt can
be cleared by reading interrupt bits in STATUS/INTERRUPT register at address 3A.
NAME
int
reset
VALUE
DESCRIPTION
0
No interrupt is sent. PWM register valuesremain intact.
1
Reset program counter value to 0 and send interrupt to processor by pulling the INT pin down
and setting corresponding status bit high to notify that program has ended. PWM register
values remain intact. Interrupt can be cleared by reading interrupt bits in STATUS/INTERRUPT
register at address 3A.
0
Reset program counter value to 0 and hold. PWM register values remain intact.
1
Reset program counter value to 0 and hold. PWM register values of the non-mapped drivers
remain. PWM register values of the mapped drivers are set to 0000 0000.
On completion of int instruction with this bit set to 1 the master fader registers are set to zero
as follows: Program execution engine 1 sets MASTER FADER 1 (48H) to zero, engine 2 sets
MASTER FADER 2 (49H) to zero and engine 3 sets MASTER FADER 3 (4AH) to zero.
7.6.6.3 RST
Rst instruction resets Program Counter register (address 37H, 38H, or 39H) and continues executing the
program from the program start address defined in 4C-4E. Instruction takes sixteen 32-kHz clock cycles. Note
that default value for all program memory registers is 0000H, which is the rst instruction.
7.6.6.4 END
End program execution. Instruction takes sixteen 32-kHz clock cycles.
7.6.6.5 TRIGGER
Wait or send triggers can be used to, for example, synchronize operation between the program execution
engines. Send trigger instruction takes sixteen 32-kHz clock cycles and wait for trigger takes at least sixteen 32kHz clock cycles. The receiving engine stores the triggers which have been sent. Received triggers are cleared
by wait for trigger instruction. Wait for trigger instruction is executed until all the defined triggers have been
received. (Note: several triggers can be defined in the same instruction.)
External trigger input signal must stay low for at least two 32-kHz clock cycles to be executed. Trigger output
signal is three 32-kHz clock cycles long. External trigger signal is active low, for example, when trigger is
sent/received the pin is pulled to GND. Send external trigger is masked; that is, the device which has sent the
trigger does not recognize it. If send and wait external trigger are used on the same instruction, the send external
trigger is executed first, then the wait external trigger.
NAME
VALUE (d)
DESCRIPTION
wait for trigger
0 - 31
Wait for trigger from the engine(s). Several triggers can be defined in the same instruction.
Bit [7] engages engine 1, bit [8] engine 2, bit [9] engine 3 and bit [12] is for external trigger
I/O. Bits [10] and [11] are not in use.
send a trigger
0 - 31
Send a trigger to the engine(s). Several triggers can be defined in the same instruction. Bit
[1] engages engine 1, bit [2] engine 2, bit [3] engine 3 and bit [6] is for external trigger I/O.
Bits [4] and [5] are not in use.
The LP55231 instruction set includes the following conditional jump instructions: jne (jump if not equal); jge (jump
if greater or equal); jl (jump if less); je (jump if equal). If the condition is true, a certain number of instructions are
skipped (that is, the program jumps forward to a location relative to the present location). If condition is false, the
next instruction is executed.
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NAME
number of instructions to be
skipped if the operation returns
true.
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VALUE (d)
DESCRIPTION
0 - 31
The number of instructions to be skipped when the statement is true. Note:
value 0 means redundant code.
Defines the variable to be used in the test:
0 = local variable A
variable 1
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable, or register address 42H value.
Defines the variable to be used in the test:
0 = local variable A
variable 2
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable, or register address 42H value.
7.6.7 Arithmetic Instructions
7.6.7.1 LD
This instruction is used to assign a value into a variable; the previous value in that variable is overwritten. Each
of the engines have two local variables, called A and B. The variable C is a global variable.
NAME
VALUE (d)
DESCRIPTION
0 = variable A
target variable
0-2
1 = variable B
2 = variable C
8-bit value
0 - 255
Variable value
7.6.7.2 ADD
Operator either adds 8-bit value to the current value of the target variable, or adds the value of the variable 1 (A,
B, C or D) to the value of the variable 2 (A, B, C or D) and stores the result in the register of variable A, B or C.
Variables overflow from 255 to 0.
NAME
VALUE (d)
8-bit value (i)
0 - 255
target variable
0-2
DESCRIPTION
The value to be added.
0 = variable A
1 = variable B
2 = variable C
0 = local variable A
variable 1 (ii)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable, or register address 42H value.
0 = local variable A
variable 2 (ii)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable, or register address 42H value.
7.6.7.3 SUB
SUB Operator either subtracts 8-bit value from the current value of the target variable, or subtracts the value of
the variable 2 (A, B, C or D) from the value of the variable 1 (A, B, C or D) and stores the result in the register of
target variable (A, B or C). Variables overflow from 0 to 255.
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NAME
VALUE (d)
8-bit value (i)
0 - 255
target variable
0-2
DESCRIPTION
The value to be added.
0 = variable A
1 = variable B
2 = variable C
0 = local variable A
variable 1 (ii)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable, or register address 42H value.
0 = local variable A
variable 2 (ii)
0-3
1 = local variable B
2 = global variable C
3 = register address 3CH variable, or register address 42H value.
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LP55231 enables up to four parallel devices together, which can drive up to 12 RGB LEDs or 36 single
LEDs. Figure 27 shows the connections for two LP55231 devices for six RGB LEDs. Note that D7, D8, and D9
outputs are used for the red LEDs. The SCL and SDA lines must each have a pullup resistor placed somewhere
on the line (R3 and R4; the pullup resistors are normally located on the bus master.). In typical applications,
values of 1.8 kΩ to 4.7 kΩ are used, depending on the bus capacitance, I/O voltage, and the desired
communication speed. INT and TRIG are open-drain pins, which must have pullup resistors. Typical values for
R1 and R2 are from 120 kΩ to 180 kΩ for two devices.
8.2 Typical Applications
8.2.1 Using Two LP55231 in the Same Application
C1
C2
0.47 µF 0.47 µF
VIN = 2.7 V to 5.5 V
VDD
CIN1
VIO 1 µF
R1
COUT1
1 µF
C1+ C1- C2+ C2- VOUT
D1
D2
D7
B G
R
R2 R3 R4
D3
D4
SCL
SDA
D8
INT
MCU
TRIG
LP55231
R
G
B
G
EN
CLK
D5
ASEL0
ASEL1
GND
D6
D9
R
B G
C3
C4
0.47 µF 0.47 µF
VIN C1+ C1- C2+ C2- VOUT
CIN2
1 µF
VDD
SCL
SDA
INT
TRIG LP55231
COUT2
1 µF
D1
D2
D7
R
B G
R
B G
R
B
D3
D4
D8
EN
CLK
D5
VIO
ASEL0
ASEL1
GND
D6
D9
G
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Figure 27. LP55231 Typical Application
46
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Typical Applications (continued)
8.2.1.1 Design Requirements
DESIGN PARAMETER
EXAMPLE VALUE
Input voltage range
2.7 V to 5.5 V
LED VF (maximum)
3.6 V
LED current
25.5 mA maximum
Input capacitor
CIN1 = CIN2 = 1 μF
Output capacitor
COUT1 = COUT2 = 1 μF
Charge pump fly capacitors
C1 = C2 = C3 = C4 = 0.47 μF
Charge pump mode
1.5× or automatic
8.2.1.2 Detailed Design Procedure
The LP55231 requires 4 external capacitors for proper operation. Surface-mount multi-layer ceramic capacitors
are recommended. Tantalum and aluminium capacitors are not recommended because of their high ESR. For
the flying capacitors (C1 and C2) multi-layer ceramic capacitors must always be used. These capacitors are
small, inexpensive and have very low equivalent series resistance (ESR < 20 m typical). Ceramic capacitors with
X7R or X5R temperature characteristic are preferred for use with the LP55231. These capacitors have tight
capacitance tolerance (as good as ±10%) and hold their value over temperature (X7R: ±15% over −55°C to
+125°C; X5R: ±15% over −55°C to +85°C). Capacitors with Y5V or Z5U temperature characteristic are generally
not recommended for use with the LP55231. Capacitors with these temperature characteristics typically have
wide capacitance tolerance (80%, −20%) and vary significantly over temperature (Y5V: 22%, −82% over −30°C
to +85°C range; Z5U: 22%, −56% over 10°C to 85°C range). Under some conditions, a nominal 1-µF Y5V or Z5U
capacitor could have a capacitance of only 0.1 µF. Such detrimental deviation is likely to cause Y5V and Z5U
capacitors to fail to meet the minimum capacitance requirements of the LP55231.
For proper operation it is necessary to have at least 0.24 μF of effective capacitance for each of the flying
capacitors under all operating conditions. The output capacitor COUT directly affects the magnitude of the output
ripple voltage. In general, the higher the value of COUT, the lower the output ripples magnitude. For proper
operation it is recommended to have at least 0.50 μF of effective capacitance for CIN and COUT under all
operating conditions. The voltage rating of all four capacitors should be 6.3 V; 10 V is recommended.
Table 9 lists suitable external components from some leading ceramic capacitor manufacturers. TI strongly
recommends that the LP55231 circuit be thoroughly evaluated early in the design-in process with the massproduction capacitors of choice to help ensure that any variability in capacitance does not negatively impact
circuit performance.
Table 9. Suitable External Components
MODEL
TYPE
VENDOR
VOLTAGE RATING (V)
PACKAGE SIZE
1 µF for COUT and CIN
C1005X5R1A105K
Ceramic X5R
TDK
10
0402
LMK105BJ105KV-F
Ceramic X5R
Taiyo Yuden
10
0402
ECJ0EB1A105M
Ceramic X5R
Panasonic
10
0402
ECJUVBPA105M
Ceramic X5R , array of
two
Panasonic
10
0504
0.47 µF for C1 and C2
C1005X5R1A474K
Ceramic X5R
TDK
10
0402
LMK105BJ474KV-F
Ceramic X5R
Taiyo Yuden
10
0402
ECJ0EB0J474K
Ceramic X5R
Panasonic
6.3
0402
LEDs
User defined. Note that D7, D8, and D9 outputs are powered from VDD when
specifying the LEDs.
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8.2.1.3 Application Curves
3.6V
VDD
VOLTAGE (500 mV/DIV)
VOLTAGE (500 mV/DIV)
VDD
3.6V
2.8V
4.5V
4.2V
2.8V
4.2V
3.6V
VOUT
3.6V
VOUT
TIME (2 ms/DIV)
TIME (2 ms/DIV)
1.5× to 1×
1.5× To 1×
6 LEDs At 1 mA / 100% PWM
6 LEDs At 1 mA / 100% PWM
Figure 29. Line Transient and Charge Pump Automatic
Gain Change
Figure 28. Line Transient and Charge Pump Automatic
Gain Change
8.2.2 Driving Haptic Feedback with LP55231
Figure 30 depicts an example schematic for LP55231 driving a vibra motor. A vibra motor can be used for haptic
feedback with touch screens and also for normal vibra operation (call indication, and so forth). Battery-powered
D8 and D9 outputs are used for controlling the H-Driver (Microchip TC442x series or equivalent), which drives
the vibra motor. (The remaining outputs D1 to D7 can be used for LED driving.) With H-Driver the rotation
direction of the vibra motor can be changed. For vibra operation user can load several programs to the LP55231
program memory in order to get interesting vibration effects, with changing frequency, ramps, etc.
C1
C2
0.47 µF 0.47 µF
C1+ C1- C2+ C2-VOUT
COUT
1 µF
VIN
CIN
1 µF
VDD
D1
D2
SCL
SDA
EN
CLK
MCU
D3
D4
LP55231
TRIG FROM
SCREEN
CONTROLLER
D5
INT
D6
TRIG
ASEL0
ASEL1
GND
APPLICATION
PROCESSOR
CONTROL
(OPTIONAL)
{
D7
240R/100 MHz
FERRITE
100 kΩ
VDD
VIBRAP
OUTA
VIBRAN
OUTB
D8
INA
D9
INB
H-DRIVER
1 nF 1 nF
VIBRA
MOTOR
1 nF
M
100 kΩ
Copyright © 2016, Texas Instruments Incorporated
Figure 30. LP55231 Haptic Feedback Application
48
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If the application processor has controls for a vibra motor they can be connected to H-Driver INA and INB as
shown in Figure 30. In this case the vibra can be controlled directly with application processor and also with
LP55231. If application processor control is not needed, then connect the 100-kΩ resistors to GND.
A simple waveform for H-driver control is shown in Figure 31. At first the motor rotates in CW direction for 30 ms,
following a rotation of 30 ms in CCW direction. The sequence is started when the TRIG signal is pulled down
(active low signal). the TRIG signal is received from the touch screen controller. After the sequence is executed,
the LP55231 waits for another TRIG signal to start the sequence again. TRIG signal timing is not critical; it does
not have to be pulled down for the whole sequence duration like in the example. For call indication, etc. purposes
the program can be changed; for example, rotation times can be adjusted to get desired haptic reaction. Direct
control of D8 and D9 output is also possible through the control registers, if programming is not desired.
TRIG
TRIGGER SIGNAL
FROM TOUCH
SCREEN
CONTROLLER
30 ms
VIBRAP
CW
ROTATION
30 ms
VIBRAN
CCW
ROTATION
Figure 31. Control Waveform
8.2.2.1 Design Requirements
DESIGN PARAMETER
EXAMPLE VALUE
Input voltage range
2.7 V to 5.5 V
LED VF (maximum)
3.6 V
LED current
25.5 mA maximum
Input capacitor
CIN1 = 1 μF
Output capacitor
COUT = 1 μF
Charge pump fly capacitors
C1 = C2 = 0.47 μF
Charge pump mode
1.5× or Automatic
8.2.2.2 Detailed Design Procedure
External component selection follows the earlier example (see Detailed Design Procedure above). H-Bridge must
be selected to have high enough current capability for the vibra motor and control interface suitable for LP55231
LED outputs.
8.2.2.3 Application Curves
See Application Curves above.
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9 Power Supply Recommendations
The device is designed to operate from an input voltage supply range between 2.7 V and 5.5 V. In a typical
application this is from single Li-ion battery cell. This input supply must be well regulated and able to withstand
maximum input current and maintain stable voltage without voltage drop even at load transition condition (startup or rapid brightness change). The resistance of the input supply rail should be low enough that the input
current transient does not cause drop below a 2.7-V level in the LP55231 supply voltage.
10 Layout
10.1 Layout Guidelines
Place capacitors as close as possible to the LP55231 device to minimize the current loops. Example of LP55231
PCB layout and component placement is seen in Figure 32.
10.2 Layout Example
To LEDs
D7
D6
D5
D4
D3
D2
D1
D8
ASEL0
D9
ASEL1
TRIG
SCL
VOUT
Vias to GND plane
C2-
SDA
C1-
INT
Control signals
CLK
EN
GND
VDD
C1+
C2+
Input Voltage
Figure 32. Layout Example for LP55231
50
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11 Device and Documentation Support
11.1 Device Support
11.1.1 Third-Party Products Disclaimer
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.
11.2 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.3 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
11.4 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.5 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
11.6 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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51
PACKAGE OPTION ADDENDUM
www.ti.com
6-Feb-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
LP55231SQE/NOPB
ACTIVE
WQFN
RTW
24
250
Green (RoHS
& no Sb/Br)
SN
Level-1-260C-UNLIM
-30 to 85
LP55231
LP55231SQX/NOPB
ACTIVE
WQFN
RTW
24
4500
Green (RoHS
& no Sb/Br)
SN
Level-1-260C-UNLIM
-30 to 85
LP55231
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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