General Description

The AAT3151B is a low noise, constant frequency charge pump DC/DC converter that uses a dual mode load switch (1X) and fractional (1.5X) charge pump conversion to maximize efficiency for white LED applications. The AAT3151B is capable of driving four white 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 AAT3151B ideally suited for small battery-powered applications.

特性 Features

? 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 (50μA) for Low-Current Mode

? Dual Mode 1X and 1.5X Charge Pump for Maximum Efficiency and VF Coverage

? Drives Four Channels of LEDs

? 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

? TDFN33-12 Package

Applications

? Color (RGB) Lighting

? Programmable Current Sinks

? White LED Backlighting

? White Photo Flash for Digital Still Cameras