OVERVIEW

The SM8132A is a charge pump DC/DC converter that switches between ×1and ×1.5 automatically. The SM8132A switches between ×1 and ×1.5 according to detected LED drive current, so that the battery life can be prolonged to the fullest extent. Since the connected LED are all detected for the switching, the SM8132A can respond to the variation of LED forward voltage. 4-channel of LED drive current control circuit is built-in, the SM8132A can control 1 to 4 lights of white LED, which are connected in parallel. The LED drive current per channel is set up by external resistor. Besides, the input signal controlling of EN pin allows ON/OFF and dimming.

FEATURES

■ Battery life extension by automatic charge pump switch between ×1 and ×1.5 according to the

detection of the LED drive current

■ Controlling 1 to 4 lights of white LED connected in parallel

■ Set up LED drive current value by external resistor (5k?:5mA/ch, 15k?:15mA/ch, 0k?:20mA/ch)

■ 1-wire input controlling

■ ON/OFF and brightness control by input signal controlling of EN pin

■ Soft start circuit built-in

■ Thermal shut down circuit built-in

■ Supply voltage range

? No-load current (IOUT=0mA): 2.7 to 4.6V

? Load current (IOUT=80mA): 3.3 to 4.6V

■ Maximum output voltage: 4.2V (typ)

■ Maximum output current: 80mA (typ)

■ Quiescent current

? Not-switching (×1 mode): 0.3mA (typ)

? Switching (×1.5 mode): 1.0mA (typ)

■ Standby current (Power save mode): 0.01μA (typ)

■ Operating frequency (×1.5 mode): 750kHz (typ)

■ LED drive current matching (RSET =20k?): ± 3

■ Package: 16-pin QFN WL-CSP (under development)

APPLICATIONS

■ Cellular phone

■ PDA

■ Portable games

■ Handy terminal

■ Digital still camera

■ Digital video camera

■ LCD back light

■ White LED driving