AAT3151(2004) View Datasheet(PDF) - Analog Technology Inc

Part Name

Description

MFG CO.

AAT3151
(Rev.:2004)

High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications

Analog Technology Inc 

AAT3151

High Efficiency 1X/1.5X/2X Charge Pump

For White LED Applications

General Description

The AAT3151 is a low noise, constant frequency

charge pump DC/DC converter that uses a tri-mode

load switch (1X), fractional (1.5X), and doubling (2X)

conversion to maximize efficiency for white LED

applications. The AAT3151 is capable of driving

four-channel LEDs at a total of 120mA from a 2.7V

to 5.5V input. The current sinks may be operated

individually or in parallel for driving higher-current

LEDs. A low external parts count (two 1µF flying

capacitors and two small 1µF capacitors at VIN and

VOUT) makes the AAT3151 ideally suited for small

battery-powered applications.

AnalogicTech's AS2Cwire™ (Advanced Simple

Serial Control™) serial digital input is used to

enable, disable, and set current for each LED with

a 16-level logarithmic scale plus four low-current

settings down to 50µA for optimized efficiency, with

a low housekeeping current of only 40µA.

Each output of the AAT3151 is equipped with built-

in protection for VOUT short-circuit and auto-disable

for LED failure condition. Built-in soft-start circuitry

prevents excessive inrush current during start-up.

A low-current shutdown feature disconnects the

load from VIN and reduces quiescent current to less

than 1µA.

The AAT3151 is available in a space-saving, ther-

mally-enhanced, 12-pin 3x3mm DFN package.

Features

ChargePump™

• VIN Range: 2.7V to 5.5V

• Fully Programmable Current with Single Wire

• 16-Step Logarithmic Scale

• 15/20/30mA Max Current

• Four Low Current Settings Down to 50µA

• Low IQ (40µA) for Low Current Mode

• Tri-Mode 1X, 1.5X, and 2X Charge Pump for

Maximum Efficiency and VF Coverage

• Drives Four Channels of LEDs

• Individual Main/Sub-Group Control

• No Inductors, Low Noise Operation

• 1MHz Constant Switching Frequency

• Small Application Circuit

• Built-In Thermal Protection

• Built-In Auto-Disable for Short-Circuit

• Automatic Soft-Start

• IQ <1µA in Shutdown

• Thermally Enhanced 3x3mm 12-Pin DFN

Package

Applications

• Color (RGB) Lighting

• Programmable Current Sinks

• White LED Backlighting

• White Photo-Flash for DSCs

Typical Application

2.7V to 5.5V

VIN

C1+

CIN

1µF

C1-

C2+

AAT3151

C2-

VOUT

EN/SET

EN/SET

D1

D2

D3

D4

GND

C1

1µF

C2

1µF

D1 D2 D3 D4

COUT

1µF

3151.2004.10.0.6

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