The AAT3175 is a low-noise, high-frequency, current-mode charge pump that's designed for white LED flash applications. The dedicated fractional/doubler charge pump can drive up to three flash LEDs at 300 mA total current with current sharing from a 2.7- to 5.5-V source.
Developed by Advanced Analogic Technologies, the tri-mode device maximizes efficiency by combining a load switch (1X), fractional (1.5X), and doubling (2X) capability with an internal sensing circuit to match output to LED requirements. The charge pump is also completely programmable using the company's Simple Serial Control digital interface. The single wire interconnect is used to enable, disable, and set current for all LEDs across 16 current levels, capable of controlling movie-mode lighting or camera flash.
With four current sink channels, the AAT3175 can accommodate single, two-in-one or three-in-one LEDs with high-precision current matching. Operating at a 1-MHz switching frequency, the AAT3175 requires just two 1-ΜF flying capacitors and two small 1ΜF capacitors at Vin and Vout. Available in a lead-free, thermally-enhanced, 12-pin, 3- by 3-mm TDFN package, the device sells for $1.22 in 1000-piece quantities. For more information, visit the AnalogicTech website at www.analogictech.com.