© 2006 Semtech Corp.

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

18

Application Examples (Cont.)

Main Backlight Plus Sub-Backlight Plus Flash

D1

LED

C2

1u

434mA Max (500ms)

D2

LED

D3

LED

D4

LED

D5

LED

102mA Max

102mA Max

102mA Max

102mA 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

SDA

EN

SDIM

SCL

FL

MDIM

VBAT

R1

Pull-up

VLOGIC

R2

Pull-up

Note: R1 and R2

pull-up resistors are a

requirement of the I2C

specification

MAIN BACKLIGHT

SUB BACKLIGHT

102mA Max

102mA Max

102mA Max

D6

LED

D7

LED

R3

Balance

R4

Balance

FLASH

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 2 LED sub-backlight with up to 32mA per LED using resistor current balancing

•

PWM dimming of sub-backlight using SDIM pin

•

Up to 204mA flash capability controlled by FL pin

Register Settings (20mA backlight currents and 200mA flash current used as an example):

0x00: set to 0x7F to enable all 7 current sinks for use

0x01 through 0x04: set to 0x32 for 20mA per current sink

0x05: set to 0x64 for 40mA for this current sink (20mA per LED)

0x06 and 0x07: set to 0xFA for 100mA per current sink, 200mA total

0x08: set to 0x44 for Flash Mode enabled, 250kHz charge pump frequency, FL pin controls S2/FL2 and S3/FL1