High-current LED driver IC features automotive qualification

August 22, 2012 // By Christoph Hammerschmidt
The A6268 from Allegro MicroSystems Europe is an automotive-grade high-current LED driver IC for applications such as LED headlights, daytime running lights and fog lights. The device has full AEC-Q100 Grade 0 automotive qualification.

This new LED driver IC is based on a DC-DC converter controller which provides a programmable constant current output for driving high-power LEDs in series.

The A6268 operates from a wide input voltage range from 5 to 50 V, making it ideal for start/stop designs as well as handling double-battery and load-dump conditions. It provides a cost-effective solution in configurations using an external logic-level MOSFET and minimum additional external components.

The maximum LED current is set with a single external sense resistor, and can be modified using a current reference input. Direct PWM (pulse width modulation) control is possible via the “enable” input, which also provides a shutdown mode.

The DC-DC converter can be configured als either a ground-referenced boost converter or a supply-referenced boost converter providing buck-boost capability. The buck-boost topology used ensures that there is no leakage path through the LEDs when in shutdown mode and no inrush current at power-up. A programmable switching frequency between 100 and 700 kHz offers flexibility to minimise EMI/EMC effects and AM band interference.

Integrated diagnostics and two fault outputs give indication of input and output undervoltage, chip overtemperature, output open circuit, LED short circuit and LED undercurrent, and can be configured to provide short-circuit to supply and short-circuit to ground protection for the LED connections, LED overcurrent and short-circuited LED string protection. A unique feature of the A6268 is the ability to detect one or more short-circuited LEDs.

The A6268KLPTR-T is available in a 16-pin TSSOP package with exposed pad (suffix LP) for enhanced thermal performance.

For more information, visit  http://www.allegromicro.com/en/Products/Regulators-And-Lighting/LED-Driv...