AAT3141

AAT3141 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications General Description The AAT3141 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 AAT3141 ideally suited for small battery-powered applications. The AAT3141 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. AnalogicTech's Advanced Simple Serial Control™ (AS2Cwire™) digital input is used to enable, disable, and set the LED drive current with a 32-level logarithmic scale LED brightness control. The AAT3141 has a thermal management system to protect the device in the event of a short-circuit condition at an output pin. Built-in soft-start circuitry prevents excessive inrush current during start-up. A high charge pump switching frequency enables the use of very small external capacitors. In shutdown mode, the device disconnects the load from VIN and reduces quiescent current to less than 1µA. The AAT3141 is available in the very small, Pb-free 12-pin TSOPJW package. 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 AS2Cwire Independent 3+1 Output Addressing 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