AS3691
Datasheet
Datasheet
AS3691
4 Precision 400mA Current Sources for RGB and Single Color Leds
1 General Description
The AS3691 (AS3691A and AS3691B) features four
high precision current sources for lighting of up to
four LED strings (RGB or single color leds). Each
of the four currents sources can be controlled
independently by PWM inputs. The full scale
current value is set by external resistors.
Very wide output voltage current source
voltage compliance
−
Down to 0.41V
2)
−
Up to 15V
Integrated overtemperature protection
Separate sense pads (Rfb1-Rfb4) for easy and
precise PCB Layout
Package
−
DIE
−
QFN24 4x4mm
−
eP-TSSOP
2)
2 Key Features
4 x up to 0.4A constant current outputs
Programmable with external resistors
4 independent PWM inputs
Absolute current accuracy +/-0.5%
’
Automatic Supply Regulation’ to reduce power
dissipation
1)
1)
15V is sufficient for most applications as the
AS3691 dose not switch off the LED current
completely
Patent Pending
3 Applications
General Lighting
Backlighting
RGB Backlighting for LCD TV/Monitors with
White Color Balancing
4 Application Diagrams
Figure
1 – Application Diagram of AS3691 for Single Color Lighting
VDD
Csup
100nF
Rvdd
Cvdd
100nF
UV
VREG
UV1
CURR1
UV2
CURR2
UV3
CURR3
UV4
CURR4
UV
VDD
AS3691
D1
Ref
Vc
Vc
Vc
Vc
T1
I1
R1
R2
T2
I2
R3
T3
I3
R4
T4
I4
Overtemp
Pad VSS
ON1
RFB1
RES1 ON2
RFB2
RES2 ON3
RFB3
RES3 ON4
RFB4
RES4
Ri1
VSS
PWM
Ri2
Ri3
Ri4
VSS
PWM
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