White LED drivers

Micrel has launched a family of efficient white LED drivers that extends mobile handset talk time by up to 32%.

The family targets a wide variety of mobile devices including portable display backlights, keypad backlighting and camera flash in mobile handsets, smart phones, portable media/MP3 players, portable navigation devices and other portable devices — all applications where saving battery power is needed.

The series is designed to drive two to six WLEDs. Each IC features a linear charging scheme that saves the normally used switching components.

This saves up to 62% of board space. The family ensures uniform display illumination through a dynamic average matching technique that provides better than 1.5% current matching and accuracy. Brightness is controlled through an ultra-fast PWM or single-wire digital 32-step interface. This allows control of a wide range of frequencies from 200 Hz to 500 kHz and dimming down to less than 1% duty cycle.