AAT3194

High Efficiency 1.5X Fractional Charge Pump For White LED Applications General Description The AAT3194 is a low noise, constant frequency charge pump DC/DC converters that use fractional (1.5X) conversion to increase efficiency in white LED applications. The devices can be used to produce current levels up to 20mA for each output from a 2.7V to 5.5V input. A low external parts count (two 1µF flying capacitors and two small bypass capacitors at IN and OUT) makes these devices ideally suited for small, battery-powered applications. AnalogicTech’s Simple Serial Control™ (S2Cwire™) interface is used to enable, disable, and set the LED drive current for 32-level logarithmic scale LED brightness control. The AAT3194 has a thermal management system for protection in the event of a short-circuit condition on any of the output pins. Built-in soft-start circuitry prevents excessive inrush current during start-up. A high switching frequency enables the use of small external capacitors. A lowcurrent shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1µA. The AAT3194 is available in a Pb-free 12-pin TSOPJW package. AAT3194 Features ChargePump™ VIN Range: 2.7V to 5.5V 20mA Full-Scale Current Simple Serial Control (S2Cwire) Interface — 32-Position Logarithmic Scale with Digital Control Low Noise Constant Frequency Operation 33% Less Input Current Than Doubler Charge Pump High Accuracy Brightness Matching Small Applicatio...