AAT3152

AAT3152 High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications General Description The AAT3152 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 AAT3152 is capable of driving four-channel LEDs 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 this part ideally suited for small, battery-powered applications. AnalogicTech's S2Cwire™ (Simple Serial Control™) serial digital input is used to enable, disable, and set current for each LED with eight settings (20mA down to 50µA) including main/sub-display group control. The AAT3152 consumes extremely low current internally (50µA typical) at light load for optimized efficiency. Each output of the AAT3152 is equipped with builtin protection for VOUT short-circuit and auto-disable for load short-circuit conditions. Built-in soft-start circuitry prevents excessive inrush current during start-up. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1µA. The AAT3152 is available in a Pb-free, space-saving, thermally-enhanced 12-pin 3x3mm TDFN package. Features • • ChargePump™ • • • • • • • • • • VIN Range: 2.7V to 5.5V Fully Programmable Current with Single Wire — Eight-Step Current: 20mA to 50µA — Individual Main-Sub Group Control — Low IQ (50µA) at Light Load Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum Efficiency and VF Coverage Drives 1-4 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