Linear LED Drivers Conserve Space in Portables
Fri, 08/06/2010 - 11:11am
Fairchild Semiconductor’s FAN5622/24/26 linear LED drivers tout a design that reduces overall component count by eliminating additional passive components used in charge pumps and series boost LED drivers. They feature an easy-to-use control interface and a minimal amount of components. These two-, four-, and six-channel current-sink linear LED drivers are suitable for backlighting the main LCD displays or keypads in mobile electronics. With a very low dropout voltage of 50 mV, the FAN5622/24/26 facilitates driving LEDs without an inductor or flyback capacitors. The brightness levels of the LED outputs are programmed through a single-wire control interface. The user can program 32 linear dimming steps and turn on and off the LEDs through this interface by applying digital pulses. This allows for greater dimming resolution using a simple methodology to control this functionality. These LED drivers also have a high peak efficiency (92 percent) thus extending battery life in portable applications. Additional features include a wide input voltage range (2.7 to 5.5V), short-circuit, under-voltage and thermal protection and less than 1µA shut-down current.