Diodes' Versatile 9-Channel LED Drivers Improve LCD Backlighting Performance with 93% Efficiency and 1% Channel Matching



Diodes Incorporated announces two, 9-channel LED drivers with internal charge-pumps for backlighting of small-LCD screens, keypads and LED lights. Working from 2.7V to 5.5V and driving 20mA, the applications include mobile phones and other portable consumer devices. Driving three groups of three LED channels and its three independent PWM dimmable control inputs the AL3158 provides a simple drive for RGB LEDs. The AL3159 with its versatile 3-wire logic decoding of LED current control simplifies the driving of 9-LEDs for illuminating LCD screens and LED indicator control. The inductor-less solution requires only three external capacitors to complete the driver circuit. High levels of functional integration coupled with thin QFN packages mean that these devices save board space and reduce manufacturing costs. The devices offer up to 93% power efficiency maximizing battery life, and feature 1% current matching accuracy between channels to deliver an extremely even, consistent screen image. LED open and short-circuit protection, thermal and under-voltage lockout and over voltage protection are provided on all channel outputs to maximize reliability. A soft start function reduces power supply inrush current to maximize battery-operating life. Both drivers are available in a lead-free, thermally enhanced, 20-pin 3mm x 3mm 0.6mm height QFN package. The AL3158 and AL3159 cost $0.25 each at 1k volumes. Further information at: www.diodes.com