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PIN DESCRIPTION
PIN NO. NAME FUNCTION
1 VD 3.3V low drop out voltage
2 CCH Constant current high limit voltage
3 CCL Constant current low limit voltage
4 CCO LED current cut-off voltage
5 PWM PWM input pin
6 N/C No connection
7 GND Ground
8 COM PWM pulse filter pin
9 SWO Open drain output of the comparator for LED current cut-off function
10 N/C No connection
11 PHO Open drain output of the two internal operational amplifier for photo coupler
12 VSEN Current sense pin
13 FB Voltage sense pin
14 VCC Power supply pin
1
2
3
4
14
SOP-14
VA
CCH
CCL
CCD
5
6
7
PWM
NC
VG
20
19
18
16
15
17
VCC
FB
VSEN
PHO
NC
SWO
COM
FUNCTION BLOCK DIAGRAM
BG LDO VD
VSEN
CCV(200mV)
FB
CVV(2.5/1.2)
CCL
CCH
BiasVCC
PHO
GND
DimCCO
PWM
COM
SWO
Function Description • CC / CV Controller • PWM / Linear Dimming • LED Current Cut-Off Function • High Accuracy Internal
Reference Voltage • Built-in 3.3V LDO
PIN DETAIL DESCRIPTION – PWM PIN & COM PIN
1000 PWM Duty (%)
COM
3.2V
50
1.6V
Level Shifter &
FilterPWM COM
PWM Duty Change to DC Level
Duty 100%~0%
3.2V~0V
PIN DETAIL DESCRIPTION – CCH / CCL / CCD
CCH Constant current high limit voltage CCL Constant current low limit voltage CCO LED Current Cut Off Voltage SWO Open drain output of the comparator for LED current cut-off function For VSENSE Reference Voltage COM > CCH VSENSE Reference Voltage = CCH / 16 CCH ≧ COM ≧ CCL VSENSE Reference Voltage = COM / 16 CCL > COM VSENSE Reference Voltage = CCL/ 16 For FB Reference Voltage COM & CCH > CCO FB Reference Voltage = 2.5V COM or CCH < CCO FB Reference Voltage = 1.2V
SWO FUNCTION @ LINEAR DIMMING
CH1Vout CH2SWO CH3PWM CH4Iout
COM & CCH > CCO SWO Pull High COM or CCH < CCO SWO Pull Low
CCO = 150mV (about 4.5%) PWM = 10% 0% CCH = VD (3.3V) SWO= H L
CCO = 150mV (about 4.5%) PWM = 0% 10% CCH = VD (3.3V) SWO= L H
SWO FUNCTION @ LINEAR DIMMING
CH1Vout CH2SWO CH3CCH CH4Iout
COM & CCH > CCO SWO Pull High COM or CCH < CCO SWO Pull Low
CCO = 150mV PWM = VD (3.3V) CCH = 200mV 0mV SWO= H L
CCO = 150mV PWM = VD (3.3V) CCH = 0mV 200mV SWO= L H
LED OPEN TEST
PWM Duty = 100% LED Open Iout = 200mA 0mA
WM Duty = 10% LED Open Iout = 200mA 0mA
CH1Vout CH2SWO CH3PWM CH4Iout
VCC
GND
FB VSEN
PWMCCL
PHO
Flyback or LLC or ...
CCOVD CCH
Photo coupler
SWO COM
3.3V LDOFor
MCU/CCH/CCL/CCO
Level
Photo coupler
For special function
CCHLevel
or VD
CCLLevel
or GND
CCOLevel
or GND
MCU
PWM InputDuty 0%~100%
VLED
VCC
PWMDimming
Secondary SidePrimary Side
APPLICATION CIRCUIT DIAGRAM – PWM DIM
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCH=VD=3.3V
PWMDimming
CCO=GND=0V
CCL=GND=0V
PWM DIMMING CURVE – EXAMPLE 1
1000 PWM Duty (%)
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
0 3.2 COM (V)
LED Dimming Curve
CCH / CCL / CCO Setting
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCH=VD=3.3V
CCL=3.2V x 10%
PWMDimming
CCO=GND=0V
1000 PWM Duty (%)
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
0 3.2 COM (V)
20mV / 10%
CCL = 3.2V x 90%
LED Dimming Curve
PWM DIMMING CURVE – EXAMPLE 2
CCH / CCL / CCO Setting
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCH=VD=3.3V
PWMDimming
CCO=3.2V x 3%
CCL=GND=0V
1000 PWM Duty (%)
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
0 3.2 COM (V)
6mV / 3%
LED Dimming Curve
CCO = 3.2V x 3%
PWM DIMMING CURVE – EXAMPLE 3
CCH / CCL / CCO Setting
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCH=3.2V x 90%
PWMDimming
CCO=3.2V x 3%
CCL=3.2V x 10%
1000 PWM Duty (%)
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
0 3.2 COM (V)
180mV / 90%
20mV / 10%
CCH = 3.2V x 90%CCL = 3.2V x 90%
LED Dimming Curve
CCO = 3.2V x 3%
PWM DIMMING CURVE – EXAMPLE 4
CCH / CCL / CCO Setting
PWM DIMMING CURVE – REAL DESIGN 1
CCH / CCL / CCO Setting
0
40
80
120
160
200
0 20 40 60 80 100
ILED
(m
A)
PWM Duty(%)
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCH=VD=3.3V
PWMDimming
CCO=GND=0V
CCL=GND=0V
PWM Dimming Frequency = 1KHz
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCH=3.0V
PWMDimming
CCO=147mV
CCL=300mV
0
40
80
120
160
200
0 20 40 60 80 100
ILED
(m
A)
PWM Duty(%)
PWM DIMMING CURVE – REAL DESIGN 2
CCH / CCL / CCO Setting
PWM Dimming Frequency = 1KHz
APPLICATION CIRCUIT DIAGRAM – LINEAR DIM
Photo coupler
3.3V LDOFor
MCU/CCL/CCO
Level
Secondary Side
For special function
CCLLevel
or GND
CCOLevel
or GND
VD
VLED
VCC
Analog Input3.2V~0V
MCUorVR
LinearDimming
Flyback or LLC or ...
Photo coupler
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
Primary Side
0 CCH (V)
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
3.2Linear Dimming
LED Dimming Curve
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCO=GND=0V
CCL=GND=0V
VD=3.3VLinearDimming3.2V~0V
LINEAR DIMMING CURVE – EXAMPLE 1
CCH / CCL / CCO Setting
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCO=GND=0V
VD=3.3VLinearDimming3.2V~0V
CCL=3.2V x 10%
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
0 3.2
20mV / 10%
CCL = 3.2V x 90%
LED Dimming Curve
CCH (V)Linear Dimming
LINEAR DIMMING CURVE – EXAMPLE 2
CCH / CCL / CCO Setting
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
VD=3.3VLinearDimming3.2V~0V
CCL=GND=0V
CCO=3.2V x 3%
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
6mV / 3%
LED Dimming Curve
CCO = 3.2V x 3%
0 3.2 CCH (V)Linear Dimming
LINEAR DIMMING CURVE – EXAMPLE 3
CCH / CCL / CCO Setting
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
VD=3.3VLinearDimming3.2V~0V CCO
=3.2V x 3%
CCL=3.2V x 10%
VSEN Reference Voltage / LED Current Ratio
200mV / 100%
180mV / 90%
20mV / 10%
CCL = 3.2V x 90%
LED Dimming Curve
CCO = 3.2V x 3%
0 3.2 CCH (V)Linear Dimming
LINEAR DIMMING CURVE – EXAMPLE 4
CCH / CCL / CCO Setting
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
CCO=GND=0V
CCL=GND=0V
VD=3.3VLinearDimming3.2V~0V
LINEAR DIMMING CURVE – REAL DESIGN 1
Linear Dimming Voltage = 3.2V~0V
CCH / CCL / CCO Setting
0
40
80
120
160
200
0 0.5 1 1.5 2 2.5 3
ILED
(m
A)
CCH Linear Dimming (V)
VCC
GND
FB VSEN
PWMCCL
PHO
CCOVD CCH
SWO COM
VD=3.3VLinearDimming3.2V~0V CCO
=507mV
CCL=1030mV
LINEAR DIMMING CURVE – REAL DESIGN 1
Linear Dimming Voltage = 3.2V~0V
CCH / CCL / CCO Setting
0
40
80
120
160
200
0 0.5 1 1.5 2 2.5 3
ILED
(m
A)
CCH Linear Dimming (V)
Recommended