austriamicrosystems
AS3693B
AS3696
Product specification
4 channel white LED controller for general lighting
applications
General Description
The AS3696 is a 4 channels precision LED controller
with PWM inputs or internal PWM generator for driving
external FETs in precise lighting applications. Build in
safety features include thermal shutdown as well as
open and short LED detection.
2x2 Channel LED driver
Output current only limited by external FET
Build in shunt regulator
Absolute current accuracy +/- 1%
Channel to channel accuracy +/- 1%
Normal Mode
Linear current control with external voltage
Digital PWM control with PWM input
Build in PWM-generator with analog duty cycle
control
Current Boost Mode
Linear current control with external voltage
Digital PWM control with 2 PWM inputs
Open LED detection and auto-turnoff
Short LED detection and auto-turnoff
Temperature shutdown
2x automatic supply regulation feedback
Package QFN 32pin 5x5mm, 0.5mm pitch
Package TQFP 32pin 7x7mm, 0.8mm pitch
Applications
Commercial, industrial and retail lighting
Streetlights
Large panel LED backlighting
1 Block Diagram
Vsupply
VDD
xFAULT
FB12
FB34
V2_5
S1 G1
D1
S2 G2
D2
S3 G3
D3
S4 G4
D4
SMPS
feedback
Rosc
Cosc
Fault detectors
Oscillator
AS3696
Vduty
CB_PWM12
CB_PWM34
CB_MODE
PWM control
Reference
xPD
PWM
SEL
EPAD
VSS
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Vshort
Vfb
Vref
Vset2
Vset1
Sel_PPTrim
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AS3696
2 Typical Application
R2
SMPS2
R2
SMPS1
Rfb
Rfb
R1
R1
24V
G4
S4
D4
S3
D3
G3
S2
G2
D2
V DD
G1
S1
Cvdd
2.2uF
D1
Rvdd
Vduty
PWM
SEL
CB_PWM12
Precision current sink
AS3696
PWM
controller
CB_PWM34
CB_MODE
FB12
Safety features
FB34
Supply feedback
xPD
xFault
Vref
Vset1 Vset2
Vref
Vfb
Vshort
V2_5
VSS
Epad
Cfb
1uf-10uF
Oscillator
Rosc
Cosc
Cfb
1uf-10uF
Sel_PPTrim
2.2uF
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austriamicrosystems
AS3696
3 Electrical Characteristics
3.1
Absolute Maximum Ratings
Stresses beyond those listed may cause permanent damage to the device. These are stress ratings
only and functional operation of the device at these or any other conditions beyond those indicated in
Section “Electrical Characteristics” is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Symbol
Parameter
Min
Max
Unit
Note
VDDMAX
Supply voltage
-0.3
5.4
V
Voltage limit due to internal shunt
regulator.
VIN_2.5V
Maximum voltage
-0.3
V2_5
+0.3V
V
Applicable for 2.5V pins
VIN_5V
Maximum voltage
-0.3
VDD
+0.3V
V
Applicable for 5V pins
VIN_50V
Maximum voltage
-0.3
50
V
Applicable for 50V pins
Ilatch
Latch-Up immunity
-100
+100
mA Norm: EIA/JESD78
TSTRG
Storage Temperature Range
-55
150
C
Maximum Junction Temperature
Humidity
5
85
%
Non condensing
VESD_LV
Electrostatic Discharge on all pins
( except D1...D4 )
-2000
2000
V
Norm: MIL 883 E Method 3015
Human body model
VESD_HV
Electrostatic Discharge on pins
D1 ... D4
-4000
4000
V
Norm: MIL 883 E Method 3015
Human body model
TBODY
Body Temperature during
Soldering
260
C
according to IPC/JEDEC J-STD020C
Note:
3.2
(1)
(2)
(3)
(1) Pins: V2_5, Vfb
(2) Pins: All pins except V2_5, D1-D4, Vfb
(3) Pins: D1 – D4
Operating Conditions
3.2.1 General
Symbol
Parameter
Conditions
Min
Typ
Max
Rthja
Thermal resistance
junction – ambient
QFN32
PDERATE
PT Derating Factor
QFN32
Tamb
Ambient Temperature
-30
85
°C
Tj
Junction Temperature
-30
115
°C
30
Unit
°C/W
mW/
C
33
3.2.2 Power supply
Symbol
Parameter
Conditions
VDDint
Shunt regulator operation. Supply current has
Supply Voltage VDD
to be limited between 10mA and 30mA by
shunt regulator operation
external resistor
IDDmax
Maximum shunt regulator
current
VDDext
Supply Voltage VDD
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no shunt regulator operation. No external
current limiting resistor needed
Rev 2.1 / 2012-11-29
Min
Typ
Max
Unit
5.0
5.2
5.5
V
30
mA
4.9
V
4.0
4.5
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AS3696
Symbol
Parameter
Conditions
Min
VDD_POR
Power on reset level
Circuit stays in power down until VDD_POR is
reached. G1 – G4 is pulled to GND during
power down
2.4
IDD_q
Quiescent current
VDD= 5V, Default setting, PWM = 0
1
IDD_r
Supply current
VDD = 5V, PWM = 240Hz, Duty = 50%
2.5
10
mA
V2_5
V2_5 regulator output
2.5
2.6
V
I2_5
V2_5 output current
1
mA
Vref
Reference voltage
1.26
V
Rvref
Output resistance Vref
2.4
1.24
Typ
1.25
Max
Unit
3.0
V
mA
Ω
300
3.2.3 Current outputs
Symbol
Parameter
Vdx
Output voltage pins Dx
Rdx
Input resistance in Dx
PWM = 0 U_DX=16V
PWM = 1
1
0.1
Vgx
Max output voltage pin Gx
Igx = 1mA
VDD0.5
Igx
Max output current pin Gx
Rsx
Input resistance pin Sx
Iled_250
Ich_250
Conditions
Min
Typ
Max
Unit
50
V
MΩ
MΩ
VDD
V
1
mA
1
MΩ
Current accuracy
Trimmed during production
ILED =100mA, Temp = 25°C,
external NMOS-Transistor used,
Vset1 = 250mV
(excluding error of external Rset)
-1.0
+1.0
%
Channel to channel
Current accuracy
Trimmed during production
ILED =100mA, Temp = 25°C,
external NMOS-Transistor used,
Vset1 = 250mV
(excluding error of external Rset)
-1.0
+1.0
%
Tjunction = -20°C to +100°C
(1)
Vset1 = 200mV to 500mV
Iled_all
Current accuracy
-2.0
+2.0
%
external NMOS-Transistor used,
(excluding error of external Rset)
Note:
(1) It is not recommended to use Vset < 200mV in order to minimize influences from PCB-layout and
noise.
3.2.4 Feedback circuit, fault detectors
Symbol
Parameter
Conditions
Min
Typ
IFBmax
Feedback current
maximum
RFBmin
Minim output resistance
VDx = 0.3V
300
IFB_g
FB transconductance
IFB_g = ΔIFB/ ΔVDx
-3
Vfb
Feedback voltage trip
point
Vshort
Short LED detector
Voltage
Tovtemp
300
Unit
uA
1000
Ω
mA/V
Trip voltage at Pins Dx
0
3
V
Short LED detection level voltage
Short will be detected if:
0
2
V
150
°C
((V_Dx -VsetX) /5 + VsetX) > Vshort
Over temperature limit
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Max
130
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140
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AS3696
Symbol
Parameter
Conditions
Min
Over termperature
hysteresis
Thyst
Typ
Max
10
Unit
°C
3.2.5 PWM-inputs
Symbol
Parameter
Conditions
Min
fPWM
PWM-input frequency
Pins: PWM, CB_PWM12, CB_PWM34
0
Conditions
Min
Typ
Max
Unit
1
kHz
Typ
Max
Unit
3.2.6 Oscillator
Symbol
Parameter
UrefH
Reference Voltage high
3.1
3.2
3.3
V
UrefL
Reference Voltage low
0.0
0.1
0.2
V
3.2.7 Digital pins
Symbol
Parameter
Min
VIH
High Level Input voltage
VIL
Max
Unit
1.3
VDD
V
Low Level Input voltage
-0.3
0.8
V
VoH
High Level output voltage
VDD0.3
VoL
Low Level output voltage
VoL_PD
Low level output voltage open
drain outputs
R_pu
Input resistance PullUp inputs
300
kΩ
R_pd
Input resistance PullDown inputs
300
kΩ
3.3
Typ
Note
V
I=mA
VDD0.3
V
I=mA
VDD0.3
V
I=mA
Pins equivalent circuit
VDD
VDD
7V
GND
VDD
Digital inputs
7V
GND
VDD
Digital inputs Pull up
7V
GND
VDD
Digital inputs Pull Down
7V
GND
VDD
Digital outputs push/pull
7V
GND
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AS3696
VDD
Digital output open drain
7V
GND
4 Detailed Block description
4.1
Current outputs
Optional:
Vshort
For proper detection the PWM high time has to be longer than 500us.
4.2
PWM controller
The PWM controller can operate in normal mode or current boost mode. Depending on the mode
different output currents can be set.
“3DMode”
0
“SEL”
Mode
Comment
Vref_INT
0
External PWM is used as PWM_INT
Vset1
0
1
Normal
PWM external
Normal
PWM internal
Vset1
1
X
PWM-frequency is generated by internal oscillator
PWM-duty cycle is set by voltage on pin “Vduty”
Vduty can either be an external voltage ( PWM=0 )
or can be derived from the PWM signal by filtering
with an ext capacitor
CB_PWM12 is used for driving Channels 1 and 2
CB_PWM34 is used for driving Channels 3 and 4
Current boost
mode
Vset2
Cosc
Rosc
Oscillator
Vduty
100k
PWM
Sel
P WM_INT Ch1/Ch2
CB_PWM12
P WM_INT Ch3/Ch4
CB_PWM34
Vset1
Vset2
Vref _INT
CB_Mode
4.3
Oscillator
The build in oscillator can be used to generate internal PWM frequencies. The external Capacitor is
charged with the current 1.24V/Rosc and discharged with the current 1.24V*10/Rosc.
1*Iosc
UrefH
UrefL
UrefH
3.2V
10*Iosc
Iosc = 1.24V/Rosc
Rosc
Rosc
1.24V
Ud
Cosc
UrefL
0.1V
Cosc
,
T2
,
The Oscillator frequency can be calculated:
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T1
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[Hz]
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AS3696
4.4
Power supply
The device has a build in electronic Zener-diode at pin VDD for building a shunt regulator. To obtain a
5.2V regulated supply, a series resistor Rvdd has to be connected in series to the internal zener diode.
An external capacitor Cvdd is used to filter the supply on the pin VDD.
Vsupply
Rvdd
VDD
Cvdd
2.2uF
Shunt
Regulator
5.2V
GND
The external resistor Rvdd has to be calculated according to the following formula:
Vsupply...Minimum Supply voltage
Power dissipation of Rvdd;
(
)
To ensure proper operation the minimum supply voltage should be choosen as Vsupply.
If a stable supply voltage between 4V and 5V is available in the system this supply can also be used for
VDD. In that case there is no need for the series resistor Rvdd.
4.5
Safety features
4.5.1
Temperature shutdown
If the die temperature reaches 140°C all outputs are turned off. If the die temperature goes below 130°C
the outputs are turned on again.
4.5.2
xPD input
In addition to the build in power on reset circuit there is an external power down input “xPD” available.
This gives the possibility to keep the outputs turned off until all blocks of the LED-driver circuits are fully
working ( DCDC, MCU ... )
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austriamicrosystems
AS3696
4.6
Reference circuit
Temp
POR
4.0V to 5.2V analog supply
VDD
2.5V digital supply
LDO
Shunt
Regulator
5.2V
Voltage Ref
GND
V2_5
Vref
The reference circuit generates an internal supply voltage of 2.5V for the digital logic.
4.7
Dynamic feedback control
The output of pins “FB12” and “FB34” can be used to control any external power supply for best power efficiency.
Every power supply senses its output voltage with a resistive voltage divider. This voltage divider can be modified
to set the output voltage between a minimum output voltage VMIN and a maximum output voltage VMAX. The
design of the dynamic feedback control is done in 3 steps.
Step 1: Set the resistors R1,R2 in the power supply according to the minimum output voltage
Vdcdc_MIN
R1
SMPS
sense
R2
(
)
Step 2: Add the Resistors R3 in the power supply according to the maximum output voltage
Vdcdc_MAX
R1
SMPS
sense
R2
R3
(
)
Step 3: Connect R3 to the feedback pin “FBxx”.
C1 should be chosen according to the speed requirements of the feedback loop.
Vdcdc_MIN to Vdcdc_MAX
R1
SMPS
sense
R2
R3
Current
Into
FB-pin
300R
300uA
AS369x
-3mA/V
FB
C1
1uF-10uF
Feedback speed
V_FB-0.1v
V_FB
Voltage Dx
The characteristic of the feedback function can be seen in the diagram. The final output voltage of is determined
by the setting of VFB and the current that is drawn from the external voltage divider.
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austriamicrosystems
AS3696
5 Pinout and Packaging
5.1
Pinout QFN32, TQFP32
Pin
Nr
Pin
Name
QFN Package
Pin
Name
TQFP package
Pin
Type
Description
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
EP
D1
G1
V2_5
Vfb
Vduty
FB12
FB34
Vref
Vset1
Vset2
Rosc
Cosc
PWM
CB_Mode
CB_PWM12
CB_PWM34
SEL
SEL_PPtrim
xFAULT
xPD
Vshort
VDD
G4
D4
S4
S3
D3
G3
G2
D2
S2
S1
VSS
D1
G1
V2_5
Vfb
Vduty
FB12
FB34
VSS
Vset1
Vset2
Rosc
Cosc
PWM
CB_Mode
CB_PWM12
CB_PWM34
SEL
SEL_PPtrim
xFAULT
xPD
Vshort
VDD
G4
D4
S4
S3
D3
G3
G2
D2
S2
S1
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
Connect to Drain of external Transistor
Connect to Gate of external Transistor
Supply output. Connect 2.2uF bypass capacitor to GND
Trip point voltage for outputs D1 – D4
Analog duty cycle control input
Power supply feedback output1 and output2
Power supply feedback output3 and output4
Reference voltage output (QFN ), VSS ( TQFP )
Reference voltage input in normal mode
Reference voltage input in 3D mode
Resistor of RC-oscillator
Capacitor of RC-oscillator
PWM input
Mode select input
PWM input in Current Boost Mode for channel1 and channel2
PWM input in Current Boost Mode for channel3 and channel4
PWM input select in normal mode
Connect to VSS. This pin is used for factory trimming.
Fault output. Active low
Power down input. Active low
Short LED detection threshold voltage
Shunt voltage regulator input.
Connect to Gate of external Transistor
Connect to Drain of external Transistor
Connect to Source of External Transistor and to Resistor RSET
Connect to Source of External Transistor and to Resistor RSET
Connect to Drain of external Transistor
Connect to Gate of external Transistor
Connect to Gate of external Transistor
Connect to Drain of external Transistor
Connect to Source of External Transistor and to Resistor RSET
Connect to Source of External Transistor and to Resistor RSET
Exposed PAD. Connect to VSS ( QFN )
DI-PD
DI-PD
DI-PD
DI-PD
DI-PD
DI-PD
DO-OD
DI-PU
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
AIO
Analog Pin
DI
Digital input
DI-PU
Digital input with pull up resistor
DI-PD
Digital input with pull down resistor
DO
Digital output
DO-OD
Digital output open drain
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AS3696
5.2
Package Drawing QFN32
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AS3696
5.3
Package Drawing TQFP32
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AS3696
6 Ordering information
Part Number
Marking
Package Type
Delivery Form
AS3696-ZQFT
AS3696
QFN32
Tape and Reel
in Dry Pack
AS3696-ZTQT
AS3696
TQFP32
Tape and Reel
in Dry Pack
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Description
Package size = 5x5mm, Pitch = 0.5mm,
Pb-free;
Package size = 7x7mm, Pitch = 0.8mm,
Pb-free;
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AS3696
Copyright
Copyright © 1997-2009, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten,
Austria-Europe. Trademarks Registered ®. All rights reserved. The material herein may not be
reproduced, adapted, merged, translated, stored, or used without the prior written consent of the
copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective
companies.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification
provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express,
statutory, implied, or by description regarding the information set forth herein or regarding the freedom
of the described devices from patent infringement. Austriamicrosystems AG reserves the right to change
specifications and prices at any time and without notice. Therefore, prior to designing this product into a
system, it is necessary to check with austriamicrosystems AG for current information.
This product is intended for use in normal commercial applications. Applications requiring extended
temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical lifesupport or life-sustaining equipment are specifically not recommended without additional processing by
austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing
flow might show deviations from the standard production flow, such as test flow or test location.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate.
However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages,
including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of
business or indirect, special, incidental or consequential damages, of any kind, in connection with or
arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to
recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or
other services.
Contact Information
Headquarters
austriamicrosystems AG
A-8141 Schloss Premstätten, Austria
T. +43 (0) 3136 500 0
F. +43 (0) 3136 5692
For Sales Offices, Distributors and Representatives, please visit:
http://www.austriamicrosystems.com/contact
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