AS3691 Datasheet, PDF (1/3 Pages) ams AG – 4 Precision 400mA Current Sources for RGB and Single Color Leds

AS3691
Product Brief
austriamicrosystems
Product Brief
AS3691
4 Precision 400mA Current Sources for RGB and Single Color Leds
1 General Description
The AS3691 features four high precision current
sources for driving 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
4 x 400mA 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)_{Patent Pending}
4 Application Diagrams
Very wide output voltage current source voltage
compliance
− Down to 0.41V
− Up to 15V ²⁾
Integrated overtemperature protection
Separate sense pads (Rfb1-Rfb4) for easy and
precise PCB Layout
Package
− DIE
− QFN24 4x4mm
2) _{15V is sufficient for most applications as the}
AS3691 dose not switch off the LED current
completely
3 Applications
General Lighting
Backlighting
RGB Backlighting for LCD TV/Monitors with
White Color Balancing
Figure 1 – Application Diagram of AS3691 for Single Color Lighting (Single Module shown)
VDD
UV
Csup
100nF
Cvdd
100nF
Rvdd
VREG
UV1
15
22
AS3691
D1
Ref
CURR1
1
Vc
UV2
20
T1
CURR2
17
Vc
UV3
10
T2
CURR3
13
Vc
UV4
8
T3
CURR4
5
Vc
T4
Overtemp
I1
I2
I3
I4
R1
R2
R3
R4
21,Pad
VSS
23
ON1
2 24
19
RFB1 RES1 ON2
16 18
11
RFB2 RES2 ON3
14 12
7
RFB3 RES3 ON4
46
RFB4 RES4
VDD
UV
VSS
PW M
Ri1
Ri2
Ri3
Ri4
VSS
PWM
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Revision 1.2
1-3