AS3691

austriami crosyst ems

Product Brief

www.austriamicrosystems.com

Revision 1.2

1 - 3

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%

dissipation

1)

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

AS3691 dose not switch off the LED current

completely

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 (Single Module shown)

Product Brief

AS3691

4 Precision 400mA Current Sources for RGB and Single Color Leds

VSS

VSS

VDD

VDD

Ri1

Ri2

Ri3

Ri4

Rvdd

Cvdd

100nF

UV

UV

PW M

PW M

Ref

Overtemp

AS3691

T1

T2

T3

T4

D1

R1

R2

R3

R4

VREG

VSS

ON1

ON2

ON3

ON4

CURR1

CURR2

CURR3

CURR4

RES1

RES2

RES3

RES4

I1

UV1

Vc

UV2

UV3

UV4

I2

I3

I4

Vc

Vc

Vc

RFB1

RFB2

RFB3

RFB4

15

22

1

20

17

10

13

8

5

21,Pad

23

2 24

16

19

18

14

11

12

4

7

6

Csup

100nF