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TPS61050, TPS61052
SLUS525A – MARCH 2007 – REVISED SEPTEMBER 2015
TPS6105x 1.2-A High-Power White LED Driver
2-MHz Synchronous Boost Converter With I2C Compatible Interface
1 Features
3 Description
•
The TPS6105x device is based on a high-frequency
synchronous-boost topology with constant current
sink to drive single white LEDs. The device uses an
inductive fixed-frequency PWM control scheme using
small external components, minimizing input ripple
current.
Four Operational Modes
– Torch and Flash up to ILED = 1200 mA
– Voltage-Regulated Boost Converter: 4.5 V, 5
V, and 5.25 V
– Shutdown: 0.3 μA (Typical)
Total Solution Circuit Area < 25 mm2
Up to 96% Efficiency
I2C-Compatible Interface up to 400 kbps
Integrated LED Turnon Safety Timer
Zero Latency TX-Masking Input (TPS61050)
Hardware Voltage Mode Selection Input
(TPS61052)
Integrated ADC for LED VF Monitoring
Integrated Low Light Dimming Mode
LED Disconnect During Shutdown
Open and Shorted LED Protection
Overtemperature Protection
Available in a 12-Pin NanoFree™ (CSP) and
10-Pin QFN Packaging
1
•
•
•
•
•
•
•
•
•
•
•
•
2 Applications
•
Camera White LED Torch/Flash for Cell Phones,
Smart-Phones and PDAs
Audio Amplifier Power Supply
•
The 2-MHz switching frequency allows the use of
small and low profile 2.2-μH inductors. To optimize
overall efficiency, the device operates with only a
250-mV LED feedback voltage.
The TPS6105x device not only operates as a
regulated current source, but also as a standard
voltage-boost regulator. This additional operating
mode can be useful to supply other high-power
devices in the system, such as a hands-free audio
power amplifier, or any other component requiring a
supply voltage higher than the battery voltage (refer
to TPS61052).
For highest flexibility, the LED current or the desired
output voltage can be programmed through an I2C
compatible
interface.
To
simplify
flash
synchronization with the camera module, the device
offers a trigger pin (FLASH_SYNC) for fast LED
turnon time.
When the TPS6105x is not in use, it can be put into
shutdown mode through the I2C-compatible interface,
reducing the input current to 0.3 μA (typical). During
shutdown, the LED pin is high impedance to avoid
leakage current through the LED.
Typical Application Schematic
Device Information(1)
TPS61050
L
2.2 mH
SW
SW
PART NUMBER
VOUT
COUT
10 mF
P
AVIN
CIN
P
P
TPS61050
TPS61052
PACKAGE
BODY SIZE (NOM)
VSON (10)
3.00 mm × 3.00 mm
DSBGA (12)
1.96 mm × 1.46 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
LED
I 2C I/F
SCL
SDA
GPIO
FLASH_SYNC
AGND
PGND
PGND
P
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.
TPS61050, TPS61052
SLUS525A – MARCH 2007 – REVISED SEPTEMBER 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
6.7
4
4
4
4
5
6
8
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
I2C Interface Timing Characteristics ........................
Typical Characteristics ..............................................
Detailed Description ............................................ 11
7.1
7.2
7.3
7.4
Overview .................................................................
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
11
12
14
15
7.5 Programming........................................................... 20
7.6 Register Maps ......................................................... 24
8
Application and Implementation ........................ 29
8.1 Application Information............................................ 29
8.2 Typical Applications ................................................ 29
9 Power Supply Recommendations...................... 38
10 Layout................................................................... 38
10.1 Layout Guidelines ................................................. 38
10.2 Layout Example .................................................... 38
10.3 Thermal Considerations ........................................ 38
11 Device and Documentation Support ................. 40
11.1
11.2
11.3
11.4
11.5
Device Support......................................................
Related Links ........................................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
40
40
40
40
40
12 Mechanical, Packaging, and Orderable
Information ........................................................... 40
12.1 Package Summary................................................ 40
4 Revision History
Changes from Original (March 2007) to Revision A
Page
•
Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional
Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device
and Documentation Support section, and Mechanical, Packaging, and Orderable Information section .............................. 1
•
Updated names of the pinout drawings to reflect the new standards .................................................................................... 3
•
Deleted Dissipation Ratings table........................................................................................................................................... 4
2
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Copyright © 2007–2015, Texas Instruments Incorporated
Product Folder Links: TPS61050 TPS61052
TPS61050, TPS61052
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SLUS525A – MARCH 2007 – REVISED SEPTEMBER 2015
5 Pin Configuration and Functions
DRC Package
10-Pin VSON
Top View
YZG Package
12-Pin DSBGA
Top View
YZG Package
12-Pin DSBGA
Bottom View
Pin Functions
PIN
NAME
I/O
DESCRIPTION
VSON
DSBGA
AVIN
5
D3
I
This is the input voltage pin of the device. Connect directly to the input bypass capacitor.
VOUT
9
A2
O
Boost converter output.
LED
6
D2
I
LED return input. This feedback pin regulates the LED current through the internal sense
resistor by regulating the voltage across it. The regulation operates with typically 250 mV
dropout voltage. Connect to the cathode of the LED.
Flash strobe pulse synchronization input.
FLASH_SYNC
10
A1
I
FLASH_SYNC = LOW (GND): The device is operating and regulating the LED current to the
torch current level (TC).
FLASH_SYNC = HIGH (VIN): The device is operating and regulating the LED current to the
flash current level (FC).
SCL
2
B3
I
SDA
1
A3
I/O
Serial interface clock line. This pin must not be left floating and must be terminated.
Serial interface address/data line. This pin must not be left floating and must be terminated.
GPIO
3
C3
I/O
General purpose input/output (refer to REGISTER2). This pin can either be configured as a
logic input or as an open-drain output (TPS61050).
ENVM
3
C3
I
SW
8
B1, B2
I/O
Inductor connection. Drain of the internal power MOSFET. Connect to the switched side of
the inductor. SW is high impedance during shutdown.
PGND
7
C1, C2
—
Power ground. Connect to AGND underneath IC.
AGND
4
D1
—
Analog ground.
PowerPAD™
—
—
—
Internally connected to PGND.
Enable pin for voltage mode boost converter (TPS61052).
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
Voltage on AVIN, VOUT, SW, LED
(2)
Voltage on SCL, SDA, FLASH_SYNC, GPIO, ENVM
(2)
MIN
MAX
UNIT
–0.3
7
V
–0.3
7
V
25
mA
85
°C
150
°C
150
°C
Input current on GPIO
TA
TJ
Operating ambient temperature
(MAX)
Tstg
(1)
(2)
(3)
(3)
–40
Maximum operating junction temperature
Storage temperature
–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 values are with respect to network ground terminal.
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)), 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 (θJA), as given by the following equation: TA(max)= TJ(max)–(θJA × PD(max)).
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
±1000
Machine model (MM)
±200
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)
MIN
NOM
MAX
Input voltage range
2.5
3.6
6
Output voltage range in Current regulator mode
VIN
5.5
Output voltage range in Voltage regulator mode
4.5
5.25
L
Inductance effective value range
1.3
CIN
Input capacitance range
COUT
Output capacitance effective value range
TJ
Operating junction temperature
VIN
VOUT
2.2
2.9
10
3
UNIT
V
V
V
µH
10
50
–40
µF
125
6.4 Thermal Information
TPS6105x
THERMAL METRIC (1)
DRC (VSON)
YZG (DSBGA)
10 PINS
12 PINS
UNIT
RθJA
Junction-to-ambient thermal resistance
48.5
82
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
67.4
0.6
°C/W
RθJB
Junction-to-board thermal resistance
23
35
°C/W
ψJT
Junction-to-top characterization parameter
1.8
2.6
°C/W
ψJB
Junction-to-board characterization parameter
23.1
19.1
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
5.3
N/A
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
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TPS61050, TPS61052
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SLUS525A – MARCH 2007 – REVISED SEPTEMBER 2015
6.5 Electrical Characteristics
Unless otherwise noted the specification applies for VIN = 3.6 V over an operating junction temp. of –40°C ≤ TJ ≤ 125°C.
Typical values are for TA = 25°C.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
SUPPLY CURRENT
Input voltage
VIN
2.5
6
Minimum input voltage for start-up
MODE_CTRL[1:0] = 11, OV[1:0] = 01, RL = 10 Ω
IQ
Operating quiescent current into AVIN
MODE_CTRL[1:0] = 01, ILED = 0 mA
8.5
Shutdown current into AVIN
MODE_CTRL[1:0] = 00, OV[1:0] ≠ 11
–40°C ≤ TJ ≤ 85°C
0.3
ISD
MODE_CTRL[1:0] = 00, OV[1:0] = 11
–40°C ≤ TJ ≤ 85°C
140
VIN falling
2.3
VUVLO
Undervoltage lockout threshold
2.5
V
V
mA
3
μA
μA
2.4
V
OUTPUT
VOUT
Output voltage
OVP Output overvoltage protection
OVP
Current regulator mode
VIN
5.5
Voltage regulator mode
4.5
5.25
VOUT rising
5.7
Output overvoltage protection hysterisis
D
Minimum duty cycle
LED current accuracy
6.25
V
V
7.5%
(1)
0.25 V ≤ VLED ≤ 2 V,
50 mA ≤ ILED ≤ 250 mA, TJ = 50°C
–15%
15%
0.25 V ≤ VLED ≤ 2 V,
200 mA ≤ ILED ≤ 1200 mA, TJ = 50°C
–12%
12%
LED current temperature coefficient
VLED
6
0.15
V
0.08
DC output voltage accuracy
2.5 V ≤ VIN ≤ 0.9 VOUT, PWM operation
LED sense voltage
ILED = 1200 mA
250
LED input leakage current
VLED = VOUT = 5 V, –40°C ≤ TJ ≤ 85°C
0.1
–3%
%/°C
3%
mV
1
μA
POWER SWITCH
rDS(on)
Ilkg(SW)
Switch MOSFET on-resistance
80
VOUT = VGS = 3.6 V
Rectifier MOSFET on-resistance
Switch MOSFET leakage
VDS = 6 V, –40°C ≤ TJ ≤ 85°C
Rectifier MOSFET leakage
2.5 V ≤ VIN ≤ 6 V, ILIM bits = 00
Ilim
2.5 V ≤ VIN ≤ 6 V, ILIM bits = 01, 10 (1)
Switch current limit
2.5 V ≤ VIN ≤ 6 V, ILIM bits = 11
mΩ
80
(1)
Thermal shutdown (1)
0.1
1
0.1
1
μA
850
1000
1150
1275
1500
1725
1700
2000
2300
140
160
°C
20
°C
Thermal shutdown hysteresis (1)
mA
OSCILLATOR
fSW
Oscillator frequency
1.8
2
2.2
MHz
±0.25
±1
LSB
ADC
Resolution
3
Total error (1)
VLED = 0.25 V, assured monotonic by design
Bits
SDA, SCL, GPIO, ENVM, FLASH_SYNC
V(IH)
High-level input voltage
V(IL)
Low-level input voltage
V(OL)
I(LKG)
(1)
1.2
V
0.4
V
Low-level output voltage (SDA)
IOL = 8 mA
0.3
Low-level output voltage (GPIO)
DIR = 1, IOL = 8 mA
0.3
Logic input leakage current
Input connected to VIN or GND, –40°C ≤ TJ ≤ 85°C
0.01
GPIO pulldown resistance
DIR = 0, GPIO ≤ 0.4 V (TPS61050)
400
kΩ
ENVM pulldown resitance
ENVM ≤ 0.4 V (TPS61052)
400
kΩ
FLASH_SYNC pulldown resistance
FLASH_SYNC ≤ 0.4 V
400
kΩ
0.1
V
μA
Assured by design. Not tested in production.
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Electrical Characteristics (continued)
Unless otherwise noted the specification applies for VIN = 3.6 V over an operating junction temp. of –40°C ≤ TJ ≤ 125°C.
Typical values are for TA = 25°C.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
TIMING
Start-up time
(2)
LED current settling time triggered by
rising edge on FLASH_SYNC
LED current settling time
TX mask
(2)
(2)
triggered by
From shutdown into torch mode ILED = 75 mA
1.2
ms
From shutdown into voltage mode through ENVM
IOUT = 0 mA
650
μs
MODE_CTRL[1:0] = 10,
ILED = from 0 mA to 900 mA
400
μs
20
μs
MODE_CTRL[1:0] = 10,
ILED = 900 mA to 150 mA
Settling time to ±15% of the target value
6.6 I2C Interface Timing Characteristics (1)
MIN
fSCL
SCL clock frequency
tBUF
Bus free time between a STOP and START condition
tHD; tSTA
Hold time (repeated) START condition
tLOW
LOW period of the SCL clock
tHIGH
HIGH period of the SCL clock
tSU; tSTA
Setup time for a repeated START condition
tHD; tDAT
Data hold time
tRCL
Rise time of SCL signal
tRCL1
Rise time of SCL signal after a repeated START condition
and after an acknowledge bit
tFCL
Fall time of SCL signal
tRDA
Rise time of SDA signal
tFDA
Fall time of SDA signal
tSU; tSTO
Setup time for STOP condition
CB
Capacitive load for SDA and SCL
(1)
6
100
Fast mode
400
Standard mode
4.7
Fast mode
1.3
UNIT
kHz
μs
4
μs
Fast mode
600
ns
Standard mode
4.7
Fast mode
1.3
Standard mode
μs
4
μs
600
ns
Standard mode
4.7
μs
Fast mode
600
ns
Standard mode
250
Fast mode
100
Fast mode
Data setup time
MAX
Standard mode
Standard mode
tSU; tDAT
TYP
ns
Standard mode
0
3.45
Fast mode
0
0.9
Standard mode
20 + 0.1CB
1000
Fast mode
20 + 0.1CB
300
Standard mode
20 + 0.1CB
1000
Fast mode
20 + 0.1CB
1000
Standard mode
20 + 0.1CB
300
Fast mode
20 + 0.1CB
300
Standard mode
20 + 0.1CB
1000
Fast mode
20 + 0.1CB
300
Standard mode
20 + 0.1CB
300
Fast mode
20 + 0.1CB
300
Standard mode
Fast mode
μs
ns
ns
ns
ns
ns
μs
4
600
ns
400
pF
Assured by design. Not tested in production.
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SLUS525A – MARCH 2007 – REVISED SEPTEMBER 2015
SDA
tf
tLOW
tr
tsu;DAT
tf
tBUF
tr
thd;STA
SCL
S
thd;STA
thd;DAT
tsu;STA
HIGH
tsu;STO
Sr
P
S
Figure 1. Serial Interface Timing For F/S-Mode
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6.7 Typical Characteristics
Table 1. Table of Graphs
GRAPH TITLE
FIGURE
LED Power Efficiency
vs Input Voltage
Figure 2, Figure 3
DC Input Current
vs Input Voltage
Figure 4
LED Current
vs LED Pin Headroom Voltage
LED Current
vs LED Current Digital Code
Voltage Mode Efficiency
vs Output Current
Figure 9
DC Output Voltage
vs Load Current
Figure 10
DC Output Voltage
vs Input Voltage
Figure 11
Quiescent Current
vs Input Voltage
Figure 12
Shutdown Current
vs Input Voltage
Figure 13
Junction Temperature
vs GPIO Voltage
Figure 14
Figure 5
Figure 6, Figure 7, Figure 8
100
ILED = 150 mA
80
ILED = 100 mA
70
ILED = 50 mA
60
50
40
30
20
ILIM = 2000 mA
10
0
2.5
2.9
3.3
3.7
4.1
4.5
VI - Input Voltage - V
4.9
2500
5.3 5.5
ILED = 300 mA
70
ILED = 500 mA
60
ILED = 700 mA
50
ILED = 900 mA
40
30
20
ILIM =2000 mA
2.9
1400
ILIM = 2000 mA
4.9
5.3 5.5
ILED = 1200 mA
ILED = 1200 mA
1500
1250
1000
750
1000
ILED = 900 mA
800
ILED = 700 mA
600
ILED = 500 mA
400
ILED = 150 mA
500
200
250
ILED = 500 mA
2.9
3.3
ILED = 300 mA
3.7
4.1
4.5
VI - Input Voltage - V
4.9
5.3 5.5
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0
250
350
450
550
ILED = 75 mA
650
750
850
950
1050
LED Pin Headroom Voltage - mV
Figure 4. DC Input Current vs Input Voltage
8
3.7
4.1
4.5
VI - Input Voltage - V
1200
ILED = 900 mA
1750
0
2.5
3.3
Figure 3. LED Power Efficiency vs Input Voltage
ILED = 700 mA
2000
80
0
2.5
ILIM = 2000 mA
2250
ILED = 1200 mA
90
10
Figure 2. LED Power Efficiency vs Input Voltage
DC Input Current - mA
LED Power Efficiency (PLED/PIN) - %
ILED = 250 mA
90
LED Current - mA
LED Power Efficiency (PLED/PIN) - %
100
Figure 5. LED Current vs LED Pin Headroom Voltage
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SLUS525A – MARCH 2007 – REVISED SEPTEMBER 2015
1300
300
ILIM = 2000 mA
280
240
VIN = 4.5 V
1100
VIN = 3.6 V
VIN = 3.6 V
1000
220
200
180
160
900
LED Current - mA
LED Current - mA
ILIM = 2000 mA
1200
VIN = 4.5 V
260
VIN = 2.5 V
140
120
VIN = 2.5 V
800
700
600
500
100
400
80
300
60
200
40
20
0
0
100
0
40
80
120 160
200
240
LED Current Digital Code - mA
ILIM = 2000 mA
1200
200
400
600
800
1000
1200 1300
LED Current Digital Code - mA
Figure 6. LED Current vs LED Current Digital Code
1300
0
280 300
Figure 7. LED Current vs LED Current Digital Code
100
TA = 85°C
VIN = 4.2 V
90
1100
80
1000
TA = 25°C
800
700
TA = -40°C
600
500
Efficiency - %
LED Current - mA
VIN = 3.6 V
70
900
400
VIN = 3 V
VIN = 2.5 V
60
50
40
30
300
20
200
VOUT = 5 V,
ILIM = 2000 mA
10
100
0
0
0
200
Figure 8. LED Current vs LED Current Digital Code
5.15
0
400
600
800
1000 1200 1300
LED Current Digital Code - mA
5.60
5.50
5.05
VIN = 4.2 V
5
VIN = 3.6 V
VIN = 3 V
DC Output Voltage - V
DC Output Voltage - V
5.10
10000
VOUT = 5 V,
ILIM = 2000 mA
IOUT = 0 mA
IOUT = 100 mA
5.40
5.30
IOUT = 1000 mA
5.20
5.10
5
VIN = 2.5 V
4.90
4.85
0.1
10
100
1000
IO - Output Current - mA
Figure 9. Voltage Mode Efficiency vs Load Current
VOUT = 5 V,
ILIM = 2000 mA
4.95
1
4.90
4.80
1
10
100
1000
IO - Output Current - mA
10000
Figure 10. DC Output Voltage vs Output Current
2.5
2.9
3.3
3.7
4.1
4.9
4.5
VI - Input Voltage - V
5.3 5.5
Figure 11. DC Output Voltage vs Input Voltage
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15
1.40
Voltage Mode Regulation,
VO = 5 V
14
13
TA = 85°C
1.20
Shutdown Current - mA
Quiescent Current - mA
12
11
10
9
8
7
6
5
1
0.80
0.60
TA = 25°C
0.40
4
3
2
1
0
2.5
TA = -40°C
0.20
2.9
3.3
3.7
4.1
4.5
VI - Input Voltage - V
4.9
0
2.5
5.3 5.5
Figure 12. Quiescent Current vs Input Voltage
2.9
3.3
3.7
4.1
4.5
4.9
VI - Input Voltage - V
5.3 5.5
Figure 13. Shutdown Current vs Input Voltage
200
GPIO = Input,
IGPIO = -100 mA
150
125
100
75
50
25
GPIO
Input Buffer
0
VGPIO
TJ - Junction Temperature - °C
175
-25
-50
-0.50
-0.45
-0.40
-0.35
-0.30
100 mA
-0.25
-0.20
GPIO Voltage - V
Figure 14. Junction Temperature vs GPIO Voltage
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7 Detailed Description
7.1 Overview
The TPS6105x family employs a 2-MHz constant-frequency, current-mode PWM converter to generate the
output voltage required to drive high-power LEDs. The device integrates a power stage based on an NMOS
switch and a synchronous NMOS rectifier. The device also implements a linear low-side current regulator to
control the LED current when the battery voltage is higher than the diode forward voltage.
In boost mode, the duty cycle of the converter is set by the error amplifier and the saw-tooth ramp applied to the
comparator. Because the control architecture is based on a current-mode control, a compensation ramp is added
to allow stable operation at duty cycles larger than 50%. The converter is a fully-integrated synchronous-boost
converter, always operating in continuous-conduction mode. This allows low-noise operation, and avoids ringing
on the switch pin, which would be seen on a converter when entering discontinuous-conduction mode.
The TPS6105x device not only operates as a regulated current source but also as a standard voltage-boost
regulator. In the TPS61052 device, the voltage-mode operation can be activated either by a software command
or by means of a hardware signal (ENVM). This additional operating mode can be useful to properly synchronize
the converter when supplying other high-power devices in the system, such as a hands-free audio power
amplifier, or any other component requiring a supply voltage higher than the battery voltage.
The TPS6105x integrates an I2C-compatible interface, allowing transfers up to 400 kbps. This communication
interface can be used to
• set the operating mode (shutdown, constant output current mode vs. constant output voltage mode).
• control the brightness of the external LED (torch and flash modes).
• adjust the output voltage (4.5 V / 5 V / 5.25 V) or to program the safety timer.
For more details, refer to the I2C Register Description section.
The torch and flash functions can be controlled by the I2C interface. To simplify flash synchronization with the
camera module, the device offers a FLASH_SYNC strobe input pin to switch (with zero latency) the LED current
from flash to torch light. The maximum duration of the flash pulse can be limited by means of an internal userprogrammable safety timer (STIM).
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7.2 Functional Block Diagram
SW
AVIN
Undervoltage
Lockout
Bias Supply
VREF = 1.22 V
Ramp
Compensation
Bandgap
REF
OVP
COMPARATOR
VOUT
S
ERROR
AMPLIFIER
Control
Logic
VREF
P
COMPARATOR
CURRENT
REGULATION
VOLTAGE
REGULATION
2 MHz
Oscillator
D = k*(VOUT-LED)
3-bit +
ADC -
SENSE FB
SCL
ON/OFF
Max tON Timer
I2C I/F
SDA
FLASH_SYNC
Control
Logic
LED
DAC
CURRENT
CONTROL
P
LED Current Regulator
GPIO or ENVM
P
AGND
PGND
Figure 15. Functional Block Diagram
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Functional Block Diagram (continued)
TX -OFF
ILED
0
0
Torch Current
0
1
Torch Current
1
0
Flash Current
1
1
Torch Current
LED CURRENT CONTROL
(GPIO Bit)
0: Input
1: Output
Port Direction
(DIR)
GPIO
400 kW
(GPIO Bit)
CURRENT REGULATOR MODE - TORCH/FLASH ACTIVE
MODE 0 = LOW
MODE 1 = HIGH
0
1
0
TX -OFF
Flash Blanking
(Tx-MASK)
MODE 0
MODE 1
FLASH_SYNC
1
0
1
400 kW
Safety Timer Trigger
(STT)
Edge Detect
LED CURRENT CONTROL
0: TORCH CURRENT LEVEL
1: FLASH CURRENT LEVEL
Start
Flash/Timer
(SFT)
Start
tSTIM
30.5 Hz
2 MHz CLOCK
16-bit Prescaler
Safety Timer
Time-Out (TO)
Dimming
(DIM)
122 Hz
Timer
Value
(STIM)
Timer
Value
(DCTIM
LED ON/OFF CONTROL
Duty-Cycle Generator (0.8% . . . 8.6%)
0: LED OFF
1: TORCH CURRENT LEVEL
Figure 16. Timer Block Diagram (TPS61050)
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Functional Block Diagram (continued)
Enable Voltage Mode
CURRENT REGULATOR MODE - TORCH/FLASH ACTIVE
MODE 0 = LOW
MODE 1 = HIGH
ENVM
400 kW
MODE 0
MODE 1
FLASH_SYNC
1
400 kW
0
1
Safety Timer Trigger
(STT)
Edge Detect
LED CURRENT CONTROL
0: TORCH CURRENT LEVEL
1: FLASH CURRENT LEVEL
Start
FLASH/Timer
(SFT)
Start
tSTIM
2 MHz CLOCK
16-bit Prescaler
30.5 Hz
Safety Timer
Time-Out (TO)
Dimming
(DIM)
122 Hz
Timer
Value
(STIM)
Timer
Value
(DCTIM)
LED ON/OFF CONTROL
Duty-Cycle Generator (0.8% . . . 8.6%)
0: LED OFF
1: TORCH CURRENT LEVEL
Figure 17. Timer Block Diagram (TPS61052)
7.3 Feature Description
7.3.1 Efficiency
The sense voltage has a direct effect on the converter’s efficiency. Because the voltage across the low-side
current regulator does not contribute to the output power (LED brightness), the lower the sense voltage, the
higher the efficiency will be.
When running in boost mode (VF(LED) > VIN), the voltage present at the LED pin of the low-side current regulator
is typically 250 mV, which contributes to high power-conversion efficiency.
When running in the linear down-converter mode (VF(LED) < VIN), the low-side current regulator drops the voltage
difference between the input voltage and the LED forward voltage. Depending on the input voltage and the LED
forward voltage characteristic, the converter displays efficiency of approximately 80% to 90%.
7.3.2 Soft-Start
Because the output capacitor always remains biased to the input voltage, the TPS6105x can immediately start
switching once it has been enabled through the I2C-compatible interface (refer to MODE_CTRL[1:0] bits). The
device starts-up by smoothly ramping up its internal reference voltage, thus limiting the inrush current.
7.3.3 Shutdown
The MODE_CTRL[1:0] bits are low, the device is forced into shutdown. Depending on the setting of OV[1:0] the
device can enter different shutdown modes. In shutdown mode, the regulator stops switching and the LED pin is
high impedance thus eliminating any DC conduction path.
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Feature Description (continued)
If OV[1:0] ≠ 11, the internal switch and rectifier MOSFET are turned off. VOUT is one body-diode drop below the
input voltage and the device consumes only a shutdown current of 0.3 μA (typical). The output capacitor remains
biased to the input voltage.
If OV[1:0] = 11, the internal switch MOSFET is turned off and the rectifier MOSFET is turned on. In this shutdown
mode there is almost no dropout voltage between the converter’s input and output. The shutdown current is 150
μA (typical).
7.3.4 LED Failure Modes
If the LED fails as a short circuit, the low-side current regulator limits the maximum output current and the LED
FAILURE (LF) flag will be set.
If the LED fails as an open circuit, the control loop initially attempts to regulate off of its low-side current regulator
feedback signal. This drives VOUT higher. Because the open-circuited LED will never accept its programmed
current, VOUT must be voltage-limited by means of a secondary control loop. In this failure mode, the TPS6105x
limits VOUT to 6 V (typical) and sets the LED FAILURE (LF) flag.
7.3.5 Undervoltage Lockout
The undervoltage lockout circuit prevents the device from misoperation at low input voltages. It prevents the
converter from turning on the switch or rectifier MOSFET under undefined conditions.
7.3.6 Thermal Shutdown
As soon as the junction temperature, TJ, exceeds 160°C typical, the device goes into thermal shutdown. In this
mode, the boost power stage and the low-side current regulator are turned off, the MODE_CTRL[1:0] bits are
reset, the OVERTEMP bit is set and can only be reset by a readout.
7.4 Device Functional Modes
7.4.1 Operating Modes: Torch and Flash
The device operation is more easily understood by referring to the timer block diagram. Depending on the
settings of MODE_CTRL[1:0] bits the device can enter 4 different operating modes:
• MODE_CTRL[1:0] = 00: The device is in shutdown mode.
• MODE_CTRL[1:0] = 01: The device is regulating the LED current to the torch current level (TC bits)
regardless of the FLASH_SYNC input and START_FLASH/TIMER (SFT) bit. The safety timer is disabled in
this operating mode.
• MODE_CTRL[1:0] = 11: The device is regulating a constant output voltage according to OV[1:0] bits settings.
The low-side LED current regulator is disabled and the LED is disconnected from the output. In this operating
mode, the safety timer is disabled and the general purpose timer (DCTIM) can be used to generate a
software time-out (TO) flag. DCTIM start is triggered on the rising edge of START_FLASH/TIMER (SFT).
• MODE_CTRL[1:0] = 10: The flash pulse can be either trigger by a hardware signal (FLASH_SYNC) or by a
software bit (SFT).
Flash strobe is level sensitive (STT = 0): LED strobe pulse follows FLASH_SYNC
• FLASH_SYNC and (SFT) = 0: LED operation is set to the torch current level and the safety timer is disabled.
• FLASH_SYNC or (SFT) = 1: The LED is driven at the flash current level and the safety timer is running.
The maximum duration of the flash pulse is defined in the STIM register.
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Device Functional Modes (continued)
Figure 18. Torch Mode Operation
IFLASH
LED Current
FLASH_SYNC
I2 C Bus
Free
Free
DC/DC Turn-On Command
DC/DC Turn-Off Command
TC[2:0] = 000
MODE_CTRL[1:0] = 10
MODE_CTRL[1:0] = 00
Figure 19. Synchronized Flash Strobe
FLASH_SYNC or (SFT)
STIM
TIMER
IFLASH
LED CONTROL
TIME-OUT
RESET (SF)
TORCH
Figure 20. Level Sensitive Safety Timer (Time-Out)
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Device Functional Modes (continued)
FLASH_SYNC or (SFT)
STIM
TIMER
FLASH
TIME-OUT
RESET (SF)
TORCH
LED CONTROL
Figure 21. Level Sensitive Safety Timer (Normal Operation + Time-Out)
The safety timer is started by:
• a rising edge of FLASH_SYNC signal.
• a rising edge of START_FLASH/TIMER (SFT) bit.
The safety timer is stopped by:
• a low level of FLASH_SYNC signal or START_FLASH/TIMER (SFT) bit.
• a time-out signal (TO).
The START-FLASH/TIMER (SFT) bit is reset by the time-out (TO) signal.
The Flash strobe is edge sensitive (STT = 1): The LED strobe pulse is triggered by a rising edge
When FLASH_SYNC and START_FLASH/TIMER (SFT) are both low, the LED operation is set to the torch
current level without time-out.
The duration of the flash pulse is defined in the STIM register. The flash strobe is started by:
• a rising edge of FLASH_SYNC signal.
• a rising edge of START_FLASH/TIMER (SFT) bit.
Once running, the timer ignores any triggering signal, and only stops after a time-out (TO). The STARTFLASH/TIMER (SFT) bit is reset by the time-out (TO) signal.
FLASH_SYNC or (SFT)
STIM
TIMER
IFLASH
LED CONTROL
RESET (SF)
ITORCH
Figure 22. Edge Sensitive Timer (Single Trigger Event)
FLASH_SYNC or (SFT)
STIM
TIMER
IFLASH
LED CONTROL
RESET (SFT)
ITORCH
Figure 23. Edge Sensitive Timer (Single Trigger Event)
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Device Functional Modes (continued)
FLASH_SYNC or (SFT)
STIM
TIMER
IFLASH
LED CONTROL
RESET (SFT)
ITORCH
Figure 24. Edge Sensitive Timer (Multiple Trigger Events)
7.4.2 Mode of Operation: Flash Blanking (TPS61050)
The TPS61050 device also integrates a general purpose I/O pin (GPIO) that can be configured either as a
standard logic input/output or as a flash masking input (Tx-MASK). This blanking function turns the LED from
flash to torch light, thereby reducing almost instantaneously the peak current loading from the battery. The TxMASK function has no influence on the safety timer duration.
IFLASH
LED Current
ITORCH
FLASH_SYNC
GPIO (Tx-MASK)
I 2C Bus
Free
LED Turn-On
Command
Free
Free
LED Turn-Off
Command
Figure 25. Synchronized Flash With Blanking Periods
7.4.3 Hardware Voltage Mode Selection (TPS61052)
The TPS61052 device integrates a logic input (ENVM) that can be used to force the converter to run in voltage
mode regulation. This additional operating mode can be useful to supply other high power consumption devices
in the system (for example, hands-free audio power amplifier) or any other component requiring a supply voltage
higher than the battery voltage.
Table 2 gives an overview of the different mode of operation of TPS61052.
Table 2. TPS61052 Operating Modes
INTERNAL REGISTER
SETTINGS MODE_CTRL[1:0]
ENVM
00
0
Power stage is in shutdown. The output is either connected directly to the battery
(OV[1:0]=11, rectifier is bypassed) or through the rectifer’s body diode (OV[1:0]=01). In both
case the power stage LC filter is connected in series between the battery and the output.
01
0
LED is turned-on for DC light operation. The converter is operating in the current regulation
mode (CM). The output voltage is controlled by the forward voltage characteristic of the LED.
10
0
LED is turned-on for flash operation. The converter is operating in the current regulation
mode (CM). The output voltage is controlled by the forward voltage characteristic of the LED.
11
0
LED is turned-off and the converter is operating in the voltage regulation mode (VM). The
output voltage is set through the register OV[1:0].
00
1
LED is turned-off and the converter is operating in the voltage regulation mode (VM). The
output voltage is set through the register OV[1:0].
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OPERATING MODES
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Device Functional Modes (continued)
Table 2. TPS61052 Operating Modes (continued)
INTERNAL REGISTER
SETTINGS MODE_CTRL[1:0]
ENVM
01
1
The converter is operating in the voltage regulation mode (VM) and it’s output voltage is set
through the register OV[1:0]. The LED is turned-on for torch operation according to the
register TC[2:0]. The LED current is regulated by the means of the low-side current sink.
10
1
The converter is operating in the voltage regulation mode (VM) and it’s output voltage is set
through the register OV[1:0]. The LED is turned-on for flash operation according to the
register FC[2:0]. The LED current is regulated by the means of the low-side current sink.
11
1
LED is turned-off and the converter is operating in the voltage regulation mode (VM). The
output voltage is set through the register OV[1:0].
OPERATING MODES
7.4.4 Low Light Dimming Mode
The TPS6105x device features white LED drive capability at very low light intensity. To generate a reduced LED
average current, the device employs a 122-Hz fixed frequency PWM modulation scheme. Operation is
understood best by referring to the timer block diagram.
The torch current is modulated with a duty cycle defined by the DCTIM[2:0] bits. The low light dimming mode can
only be activated in the torch only mode, MODE_CTRL[1:0] = 01.
PWM Dimming Steps (DCTIM)
0.8%, 1.6%, 2.3%, 3.1%, 3.9%, 4.7%, 6.3%, 8.6%
I TORCH
Torch Current Steps (TC)
50mA, 75mA, 100mA, 150mA, 200mA, 250mA
0
I LED(DC) = I TORCH x DCTIM
Figure 26. PWM Dimming Principle
White LED blinking can be achieved by turning on/off periodically the LED dimmer through the (DIM) bit, see
Figure 27.
LED OFF
LED ON with Reduced Current
ITORCH
ITORCH
PWM Dimming Steps = 0.8%, 1.6%, 2.3%, 3.1%, 3.9%, 4.7%, 6.3%, 8.6%
I 2 C Bus
FREE
TC[2:0] = ITORCH
DIM = 1
FREE
FREE
FREE
TC[2:0] = 000
DIM = 0
FREE
TC[2:0] = ITORCH
DIM = 1
FREE
TC[2:0] = 000
DIM = 0
Figure 27. White LED Blinking Control
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7.5 Programming
7.5.1 3-Bit ADC
The TPS6105x device integrates a 3 bit A/D converter to measure the differential voltage across the output and
the low-side current regulator. To get a proper settling of the LED forward voltage, the data acquisition is done
approximately 10 ms after the start of the flash sequence.
When running in the linear down-mode (VF(LED) < VIN), the low-side current regulator drops the voltage difference
between the input voltage and the LED forward voltage. This may result in thermal limitations (especially for
CSP-12 packaging) when running high LED current under high battery conditions (VIN ≥ 4.5 V) with low forward
voltage LEDs and/or high ambient temperature.
The LED forward voltage measurement can be started either by a START FLASH event (FLASH_SYNC or SFT
bit) or by setting ADC[2:0] bits (whilst MODE_CTRL[1:0]=01 or 10).
L
VOUT
VBAT
CIN
P
C OUT
P
P
P
ADC Digital Output Coding, ADC [2:0]
VOUT-LED
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