AnalogicTech, AAT3174

High current charge pump simplifies designs for multi-function LED flash applications

News Release from: Advanced Analogic Technologies Inc., Europe
27/03/2006

AnalogicTech has introduced a high current, high efficiency charge pump for multi-function LED applications. Recognising that a serial bus is a powerful tool for driving LEDs, the AAT3174 helps designers who want to quickly and easily develop a solution that supports both flash and movie mode operation and, importantly, can move between the two modes using a simple on/off toggle switch.

The device simplifies the design of applications supporting both flash and movie modes by allowing designers to control the LEDs via either AnalogicTech’s Simple Serial Control? (S2Cwire?) interface or by the RSET pin. This capability also allows designers to support current levels as high as 800mA with an external resistor.

The AAT3174 also helps maximise power efficiency during extended torch mode operations by using a tri-mode charge pump that combines 1X, 1.5X, and 2X operation modes with an internal sensing circuit. This allows the AAT3174 to deliver power more efficiently than a simple voltage doubling (2X) charge pump.

Designed for small-footprint portable applications, the AAT3174 requires only four external capacitors (two 1µF flying capacitors and two small bypass capacitors on VIN and VOUT), plus a resistor to program the maximum regulated output current. The device also offers extensive protection circuitry, including a thermal management system which protects the AAT3174 in the event of a short-circuit condition at the output pin. In addition, integrated soft-start circuitry protects the device from excessive inrush current during start-up by disconnecting the load from VIN and reducing quiescent current to less than 1µA.

Specified over the -40 to +85 degrees C temperature range, the AAT3174 is available in a Pb-free, 12-pin 3x3mm TDFN package.