Auto LED Driver Eliminates MCU Or 555 For Dimming Control


Allegro announced two new single-chip switching regulators that provide constant-current output to drive high-power LEDs. The devices are combined with a host of safety and robust protection features making them ideal for automotive lighting applications.

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.

An internal 5V, 10 mA LDO provides added flexibility and cost savings for driving external loads if required by the system. User-selectable output current provides system design and application flexibility.


PWM as well as analog dimming capability provides precise LED current control, and automatic output voltage adjustment based on the number of LEDs in a single string ensures optimal system efficiency.

LED dimming is accomplished by a direct logic input pulse-width-modulation (PWM) signal at the enable pin. Alternatively, an analog 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 added capability to generate its own PWM dimming frequency and duty cycle in stand-alone mode that provides LED light dimming control without the need of a micro-controller or 555 timer.

The A6214 is provided in a compact 10-pin narrow SOIC package and the A6216 is available in a 16-pin TSSOP package.

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