Automotive integrated buck LED driver, with PWM dimming

January 20, 2016 // By Graham Prophet
Removing the need for a local microcontroller or timer-based PWM dimming control, Allegro MicroSystems’ single-IC switching regulators provide constant-current output to drive high-power LEDs in automotive applications. These devices are the first to allow LED dimming without the need for local microcontroller or timer-based PWM dimming control.

Allegro’s A6214 and A6216 devices integrate a high-side N-channel DMOS switch for DC-to-DC step-down (buck) conversion. A true average current is output using a cycle-by-cycle, controlled on-time method. Combined with automotive-grade quality, a host of safety and robust protection features suits the A6214 and A6216 devices for automotive lighting where high quality and reliability are essential.

User-selectable output current provides system design and application flexibility, and automatic output voltage adjustment based on the number of LEDs in a single string ensures optimal system efficiency. An internal 5V, 10 mA LDO provides added flexibility and system cost savings for driving local circuitry if required.

LED dimming is accomplished by a direct logic input pulse-width-modulation (PWM) signal at the enable pin. An analogue dimming input can be used to calibrate the LED current, or implement thermal foldback in conjunction with an external NTC thermistor. The A6216 has the capability to generate its own PWM dimming frequency and duty cycle in stand-alone mode that provides LED light dimming control.

A6214 is provided in a 10-pin narrow SOIC package (suffix LK). The A6216 is available in a 16-pin TSSOP package (suffix LP), both with exposed pad for enhanced thermal dissipation.

Click here to download a copy of the A6214 and A6216 Integrated buck LED driver data sheet.

Allegro MicroSystems;