AAT3143

High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications General Description The AAT3143 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 AAT3143 can deliver current levels up to 80mA to drive white LEDs connected to the four current source outputs from a 2.7V to 5.5V input. The current source outputs may source up to 20mA each and 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 the AAT3143 ideally suited for small battery-powered applications. Output current, and therefore brightness, is controlled via externally applied Pulse Width Modulation (PWM) control. Typically, PWM frequencies of up to 50kHz can be applied. The AAT3143 has a thermal management system to protect the device in the event of a short-circuit condition at the voltage output pin. Built-in soft-startwww.DataSheet4U.com circuitry prevents excessive inrush current during startup. A high charge pump switching frequency allows the use of very small external capacitors. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1µA. The AAT3143 is available in a Pb-free, space-saving, 2.85x3.0mm 12-pin TSOPJW package. AAT3143 Features ...