Dimmable LED drive for automotive lighting designs

November 16, 2016 // By Graham Prophet
Allegro’s A6217 is an automotive, AEC-Q100 qualified single IC switching regulator that provides constant-current output to drive high-power LEDs. It integrates a high-side N-channel DMOS switch for DC-to-DC step-down (buck) conversion and has integrated frequency dithering for low EMI. A true average current is output using a cycle-by-cycle, controlled on-time method.

This LED driver is targeted at the automotive lighting market, for daytime running lights, front and rear fog lights, turn/stop lights, map lights, and dimmable interior lights. Output current is user-selectable by an external current sense resistor. Output voltage is automatically adjusted to drive various numbers of LEDs in a single string, ensuring optimal system efficiency. LED dimming can be accomplished by logic-level or "chopped battery" PWM, as well as analogue dimming capability.


The A6217 is an enhanced version of the A6213 and is available in a pinout-equivalent eSOIC-8 package (LJ), or a more compact 3 x 3 mm wettable flank DFN-10 (EJ). Both packages have an exposed pad for enhanced thermal dissipation.


Allegro MicroSystems; www.allegromicro.com