General Description

The AAT3156 is a low noise, constant frequency charge pump DC/DC converter that uses a trimode load switch (1X), fractional (1.5X), and doubling (2X) conversion to maximize efficiency for white LED applications. The AAT3156 is capable of driving six-channel LEDs at a total of 180mA 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) make this part 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

? Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum Efficiency and VF Coverage

? Drives Six 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 Open Circuit

? Automatic Soft-Start

? IQ <1μA in Shutdown

? Thermally-Enhanced QFN44-16 Package

Applications

? Color (RGB) Lighting

? Programmable Current Sinks

? White LED Backlighting

? White Photo Flash for DSCs