Automotive buck LED drivers drive single and multiple LED strings

By Gina Roos, editor-in-chief

Diodes Inc. launched its AL8843Q  and AL8862Q  automotive-compliant DC/DC buck converters, designed for driving single LEDs and multiple LED strings for interior and exterior LED lamps. Applications include daytime running lights (DRLs), fog lights, turn lights, and brake/stop lights.

The AL8843Q, with a supply voltage from 4.5 V to 40 V, and the AL8862Q buck converters, with a supply voltage from 5 V to 55 V, can withstand even severe voltage variations, such as load dumps during low cranking or stop-start operation, without suffering any degradation in the LED drive current, said the company.

The DC/DC buck converters support full-scale (0% to 100%) PWM dimming, controlled with either an analog input between 0.4 V and 2.5 V or a PWM signal generated by an external microcontroller or host processor. Both parts feature an integrated power MOSFET: 40 V/0.2 Ω for the AL8843Q and 55 V/0.4 Ω for the AL8862Q. They also feature hysteretic-mode buck LED driver control, which simplifies the feedback loop, enabling engineers to realize highly stable buck converter designs using only four external components.

Safety features include overtemperature protection as well as LED short- and open-circuit protection. The AL8862Q also incorporates an open-drain fault indication pin.

The AL8843Q and AL8862Q in SO-8EP packages are qualified to AEC-Q100 Grade 1, support PPAP documents, and are manufactured in IATF16949-certified facilities.