AAT1274

1.5A Single Flash LED Driver IC

DATA SHEET

9

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201981A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 21, 2012

Functional Description

The AAT1274 is a boost converter with a current regu-

lated output designed to drive high current white LED

used in camera flash applications. The AAT1274 has a

constant current sink channel to accurately regulate the

current flow through a high current, high intensity white

flash LED. The AAT1274 has two basic operating modes;

a flash mode controlled by the FLEN pin and the movie/

face.

Flash Mode

A flash pulse may be initiated by pulling the FLEN input

pin from a logic low-to-high state, which initiates a flash

pulse. The maximum flash current in the AAT1274 is set

and the maximum movie-mode current.

In mobile GSM systems where the phone remains in

constant contact with the base station by regular com-

munication, a FLINH pin is provided to prevent both the

camera flash and PA transmission pulses from occurring

simultaneously. This avoids potential dips to the Li-ion

battery voltage below the system’s undervoltage lockout

threshold (UVLO). During a flash event, strobing the

FLINH pin low-to-high reduces the LED current to the

default movie-mode current level for the duration of

FLINH. Strobing FLINH high-to-low instructs the AAT1274

to revert the flash LED current to its maximum level,

assuming that the FLEN pin is still active (high).

Movie (Torch) Mode

The movie / torch mode current level, and the flash to

maximum movie mode current ratio are programmed by

rent level can be adjusted to one of 16 steps using a

logarithmic scale where each code level is 1dB below the

previous code. The flash to maximum movie mode cur-

rent ratio can be set from 1:2 to 1:30 with respect to the

resistor. The manual FLEN signal has priority over movie-

mode operation.

Functional Block Diagram

System Control Enable

OUT (to Flash LED)

FL

FLGND

RSET

PGND

AGND

FLEN

EN/SET

IN

SW

FLINH