LED Driver Integrates Dynamic Headroom Control

Sculpted for automotive LCD backlight applications, the LM3492 LED driver with dynamic headroom control drives current to two independently dimmable strings of LEDs. Its headroom control feature dynamically adjusts the LED supply voltage through the boost converter feedback to the lowest level required to provide optimal system efficiency. The device integrates a boost converter and a two-channel current regulator to deliver a maximum power of 15W and an output voltage up to 65V. Integrated fast slew rate current regulators allow high frequency and narrow pulse width dimming signals to achieve a contrast ratio of 1,000:1. LED current is programmable from 50 mA to 200 mA via a single resistor. Available in a 20-pin, thermally-enhanced TSSOP, price for the LM3492 is $1.75 each/1,000. NATIONAL SEMICONDUCTOR CORP., Santa Clara, CA. (800) 272-9959.