AS3691_1 Datasheet, PDF (1/22 Pages) ams AG – 4 Precision 400mA Current Sources for RGB and Single Color Leds

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.
2 Key Features
ƒ 4 x up to 0.4A constant current outputs
ƒ Programmable with external resistors
ƒ 4 independent PWM inputs
ƒ Absolute current accuracy +/-0.5%
ƒ ^’Automatic Supply Regulation’ to reduce power
dissipation¹⁾
1) _{Patent Pending}
4 Application Diagrams
ƒ Very wide output voltage current source
voltage compliance
− Down to 0.41V
− Up to 15V ²⁾
ƒ Integrated overtemperature protection
ƒ Separate sense pads (Rfb1-Rfb4) for easy and
precise PCB Layout
ƒ Package
− DIE
− QFN24 4x4mm
− eP-TSSOP
2) _{15V is sufficient for most applications as the}
AS3691 dose not switch off the LED current
completely
3 Applications
ƒ General Lighting
ƒ Backlighting
ƒ RGB Backlighting for LCD TV/Monitors with
White Color Balancing
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
VDD
UV
AS3691
D1
Ref
Overtemp
Vc
T1
I1
R1
Vc
T2
I2
R2
Vc
T3
I3
R3
Vc
T4
I4
R4
VSS
PWM
Pad VSS ON1 RFB1 RES1 ON2 RFB2 RES2 ON3 RFB3 RES3 ON4 RFB4 RES4
Ri1
Ri2
Ri3
Ri4
VSS
PWM
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Revision 2.3
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