AAT3140

AAT3140 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications General Description The AAT3140 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 device produces current levels up to 30mA on each of its four current source outputs to drive various arrangements of LEDs from a 2.7V to 5.5V input. Outputs 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 CP) make the AAT3140 ideally suited for small battery-powered applications. The AAT3140 is equipped with AnalogicTech’s unique AutoBias™ technology which allows individual LEDs to be powered either by charge pump or battery input, determined internally and automatically to maximize the power efficiency even with a large difference in LED forward voltage. Features ChargePump™ VIN Range: 2.7V to 5.5V Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum Efficiency and VF Coverage Drives Low-VF and High-VF Type LEDs Up to Four 30mA Outputs 32-Position Logarithmic Scale with Digital Control Low Noise Constant Frequency Operation 1MHz Switching Frequency AutoBias Technology Small Application Circuit Regulated Output Current Automatic Soft Start No Inductors IQ < 1µA in Shutdown 12-Pin TSOPJW Package AnalogicTech's Simple Seri...