© 2006 Semtech Corp.

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

17

POWER MANAGEMENT

Application Examples (Cont.)

Main Backlight Plus Sub-Backlight

D1

LED

C2

1u

434mA Max (500ms)

D2

LED

D3

LED

D4

LED

D5

LED

32mA Max

32mA Max

32mA Max

32mA Max

C1

2u2

C3 1u

C4 1u

VIN

11

VIN

17

EN

2

SDA

7

SCL

8

ASEL

5

SDIM

3

MDIM

4

FL

6

VOUT

9

VOUT

16

M1

1

M2

24

M3

23

M4

22

S1/FL3

20

S2/FL2

19

S3/FL1

18

GND

12

GND

21

U1

SC614

EN

SCL

SDA

FL

SDIM

MDIM

VBAT

R1

Pull-up

R2

Pull-up

VLOGIC

Note: R1 and R2

pull-up resistors are a

requirement of the I2C

specification

SUB BACKLIGHT

MAIN BACKLIGHT

102mA Max

102mA Max

102mA Max

D6

LED

D7

LED

328mA Max Continuous

Features:

•

Up to 4 LED main backlight with up to 32mA per LED

•

PWM dimming of main backlight using MDIM pin

•

Up to 3 LED sub-backlight with up to 32mA per LED

•

PWM dimming of sub-backlight using SDIM pin

Register Settings (20mA backlight currents used as an example):

0x00: set to 0x7F to enable all 7 current sinks for use (or as needed if less)

0x01 through 0x07: set to 0x32 for 20mA per current sink

0x08: set to 0x00 for Flash Mode disabled (FL pin inactive) and 250kHz charge pump frequency