AL3159

HIGH EFFICIENCY 1x/2x CHARGE PUMP

FOR WHITE LED APPLICATIONS

AL3159

Document number: DS35048 Rev. 2 - 2

1 of 10

www.diodes.com

January 2011

© Diodes Incorporated

Description

The AL3159 is a low noise, constant frequency charge pump

DC/DC converter that uses a Dual mode load switch (1x), and (2x)

conversion for white LED applications. The AL3159 is capable of

driving nine LED channels at 20mA from a 2.7V to 5.5V input. The

current sinks may be operated using three simple logic control

inputs individually or in parallel for driving higher-current LEDs. Low

external

part

counts

(one

1µF

flying

capacitor

and

two

small, battery-powered applications.

AL3159

digital

inputs

are

used

to

enable

or

disable

the

LED channels with a fixed default current settings at 20mA or other

factory programming options available.

Each output of the AL3159 is equipped with built-in protection for

soft-start circuitry prevents excessive inrush current during start-up

and mode switching. A low-current shutdown feature disconnects

The AL3159 is available in a lead-free, space-saving, thermally

enhanced 20-pin 3 x 3mm QFN package.

Features

• V

• Up to 93% Max Power Efficiency

• 1% Current Matching Accuracy Between Channels

• Drives up to 9 configurable Channels of LEDs

• Three simple logic decoding LED On/Off control inputs

• Low transition threshold voltage typical 150 mV

• Dual-Mode 1x and 2x Charge Pump

• 1.2 MHz Constant Switching Frequency

•

• Soft Start for reducing inrush current

• I

• Thermally-Enhanced QFN3030-20 Package: Available in

“Green” Molding Compound (No Br, Sb)

• Lead Free Finish/ RoHS Compliant (Note 1)

Pin Assignments

Applications

• Mobile Phone White LED Backlighting and Indicators

• PDA White LED backlighting

• Battery-operated Phone Main and Sub Screen White LED

Backlighting

Notes:

http://www.diodes.com/products/lead_free.html

Typical Application Circuit