POWER MANAGEMENT

1

SC628A

LED Flash Driver

Charge Pump with 1000mA Flash Mode,

Features

Input supply voltage range — 3.0V to 5.5V

Charge pump modes — 1x, 1.5x and 2x

Flash LED — 1000mA max in flash mode, 275mA max

continuous for spotlight

Charge pump frequency — 250kHz

External flash control pin to sync with camera

One second flash time out with disable feature

Q

= 100μA

Low shutdown current — 0.1μA (typical)

Ultra-thin package — 3mm x 3mm x 0.6mm

Fully WEEE and RoHS compliant

Applications

Cellular phone flash

PDA flash

Description

The SC628A is a high efficiency charge pump LED driver

using Semtech’s proprietary charge pump technology.

Performance is optimized for use in single-cell Li-ion

battery applications. The load

and supply conditions

determine whether the charge pump operates in 1x, 1.5x,

or 2x mode.

The charge pump provides continuous spotlight mode

current or pulsed flash mode current to an LED using a

dedicated current sink. In flash mode, a flash-timeout

feature turns off the flash if active for longer than 1 second.

In spotlight mode, the timeout feature is disabled to allow

continuous operation of the LED.

the flash mode or the spotlight mode current. The flash/

a dedicated flash enable pin (FLEN).

In sleep mode, the device reduces quiescent current to

100μA while continuing to monitor the serial interface.

SC628A

IN

SDA

FLEN

AGND

PGND

OUT

FL

4.7μF

1

C+ C1- C2+ C2-

Flash Control

Enable Control

SCL

EN

C1

2.2μF

C2

2.2μF

4.7μF

FLASH

US Patents: 6,504,422; 6,794,926

Typical Application Circuit

July 14, 2009