Power: Six-Channel White LED Driver Targets Main And Sub Displays

When backlighting large-panel display and dual-LCD systems, the 90% efficient CAT3606 white LED driver replaces the inductor boost circuits traditionally used in applications requiring high-brightness backlighting. A unique fractional charge-pump topology that automatically switches from 1x LDO mode to 1.5x boost mode ensures flicker-free LED current over the life of the battery. The CAT3606 also can be used to drive a main plus sub cell-phone display or a main display plus low-power camera flash. Independent control of each LED bank enables pulse-width-modulation dimming and standby mode of the four-LED main and two-LED sub displays. To reduce battery drain, the device features a complete system shutdown enable that consumes less than 1 µA. A flexible digital interface accommodates a variety of brightness control circuits. The low-noise, 1-MHz fixed-frequency-control scheme allows the use of small external capacitors, reducing cost and board layout. The CAT3606 costs $1.48 in 1000-piece quantities.