ADM8845

Preliminary Technical Data FEATURES ADM8845 drives 6 LEDs from a 2.6 V to 5.5 V (li-ion) input supply 1x/1.5x/2x Fractional Charge Pump to maximise power efficiency 1% Max LED Current Matching Up to 88% Power Efficiency over Li-ion Range Powers Main and Sub Display LEDs with individual shutdown Package footprint only 9mm2 (3mm x 3mm) Package height only 0.9mm Low power shutdown mode Shutdown Function Soft-start limiting inrush current Charge Pump Driver for LCD White LED Backlights ADM8845 GENERAL DESCRIPTION The ADM8845 provides the power required to drive up to six LEDs, using charge pump technology. The LEDs are used for backlighting a color LCD display, with up to four LEDs in the main display and up to two LEDs in the sub display, with regulated constant current for uniform brightness intensity. Two digital input control pins, CTRL1 and CTRL2 control the shutdown operation and the brightness of the main and sub displays. To maximize power efficiency, a charge pump that can operate in either of a 1x, 1.5x or 2x mode is used. The charge pump automatically switches between 1x/1.5x/2x modes based on the input voltage, to maintain sufficient drive for the LED anodes at the highest power efficiency. Improved brightness matching of the LEDs is achieved by the use of a feedback pin to sense individual LED current with a maximum matching accuracy of 1%. APPLICATIONS Mobile phones with Main and Sub Displays White LED Backlighting Camera Flash/Strobes and Movie Light Applications...