Date: 20/03/2011

Charge pump based LED driver for portable devices

Diodes Incorporated has released AL3157, a LED driver for LCD backlighting, flashlight or camera flash circuits. Provided in the compact 12-pin 3mm x 3mm DFN package and needing the support of only three external capacitors, the device is well suited to portable, battery powered products such as ruggedized mobile phones.

Operating from a regular 2.7V to 5.5V supply, this 93% efficient charge pump drives 3 channels at up to 30mA for small LCD screen backlighting and a separate channel at up to 210mA for LED flashlight or LED camera flash.

Simple to control, the AL3157 uses only 2 enable pins to enable and disable the associated LCD backlighting and camera flash output channels and to dim the LED current delivered using pulse width modulation. To maximize reliability, all output channels incorporate short-circuit, thermal and under-voltage lockout protection. For further information, visit www.diodes.com.