Constant-current 3 A buck regulator IC for driving high-power LEDs

September 18, 2012 // By Christoph Hammerschmidt
The A6211 from Allegro MicroSystems Europe is a switching buck regulator IC that provides a constant-current output of 3 A for driving high-power LEDs.

The new device is designed for use in consumer, industrial and architectural lighting applications, including MR16 bulb replacements and light bars for scanners and multifunction printers. It has significant fault protection advantages including design techniques to address pin-pin shorts, pin-ground shorts and open or shorted external components.

With a wide input supply voltage from 6 to 48 V, the new device integrates a high-side N-channel MOSFET switch for DC-to-DC step-down conversion. A true average current is produced using a cycle-by-cycle controlled "on" time method.

The LED current is user-configurable with an external current sense resistor, allowing the output voltage to be set to optimise constant-current supply for a wide variety of LED configurations including multiple LEDs in series, in a single string or in parallel.

LED dimming is accomplished by a direct logic input pulse-width-modulation (PWM) signal at the "enable" pin. This pin is also designed to accommodate connection to the input voltage supply to allow simple on/off operation without a separate "enable" signal.

The A6211GLJTR-T is supplied in a compact 8-pin narrow SOIC package (suffix LJ) with exposed pad for enhanced thermal dissipation. It is lead (Pb) free,with 100% matt tin leadframe plating.

Please click here to download a copy of the data sheet:

http://www.allegromicro.com/en/Products/Regulators-And-Lighting/LED-Drivers-For-Lighting/A6211.asp