Charge Pump Supports White LED Backlights

Supporting both white LED backlight and camera-flash applications, the AAT2801 multi-function charge pump drives up to four LEDs and delivers up to 30 mA on each current-source output. To maximize efficiency, the device operates at a switching frequency of 1 MHz and in 1x, 1.5x, and 2x modes. The company's AutoBias technology allows the device to automatically select the appropriate voltage rail for each LED by comparing the forward voltage with the input voltage. An S2Cwire interface provides drive-current control with a 32-level logarithmic brightness scale. For flash applications, the AAT2801 integrates a charge pump with a regulated output voltage and delivers up to 120 mA of continuous current for movie mode or up to 300 mA of pulsed current for camera flash. Other features include an enable pin, a thermal management circuit and an operating temperature range from -40°C to 85°C. Available in a lead-free, 16-pin TDFN44 package, price is $1.82 each/1,000. ANALOGIC TECHNOLOGIES INC., Sunnyvale, CA. (408) 737-4600.