High-current LED controller for automotive applications

DC-DC converter device offers upgraded performance and configuration options

Allegro MicroSystems: The new A6271 from Allegro MicroSystems Europe is a DC-DC converter controller which provides a programmable constant-current output for driving high-power LEDs in series in automotive applications.

The new AEC Q100 qualified device is based on a programmable fixed-frequency peak-current mode control architecture, and the DC-DC converter can be configured in a variety of different switching configurations including boost, buck-boost, SEPIC (single-ended primary inductor convertor) and buck (ground referenced switch). It is designed for automotive exterior lighting applications including high-power LED lighting systems, fog lights, reversing lights, daytime running lights, position lights and headlights.

The A6271 provides a cost-effective solution 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 accurately modulated using a current reference input for analogue control.

The A6271 has been carefully designed to minimise electromagnetic emissions through distributed decoupling and an externally programmable frequency dither circuit configured for the EMI specification CISPR 25. It is also possible to program the fundamental switching frequency below 150 kHz, where most EMI standards begin.

The device has a comprehensive set of integrated protection features to protect the IC, the LED driver system, and the LED string against faults. Fixed-output overvoltage protection ensures that no maximum voltage rating violations occur, even under a single point failure of the programmable output overvoltage protection circuit. Other protection features include LED overload (boost, SEPIC), output undervoltage (buck or buck-boost), input supply undervoltage, 5 V regulator output undervoltage, high-side supply (PWM PMOS) undervoltage, and thermal protection.

The A6271KLPTR-T is available in a 16-pin eTSSOP (suffix LP) package with exposed thermal pad for enhanced power dissipation.

About Allegro

Allegro MicroSystems, LLC is a leader in developing, manufacturing and marketing high-performance semiconductors. Allegro's innovative solutions serve high-growth applications within the automotive market, with additional focus on office automation, industrial, and consumer/communications solutions. Allegro is headquartered in Worcester, Massachusetts (USA) with design, applications, and sales support centers located worldwide. Further information about Allegro can be found at www.allegromicro.com

Allegro MicroSystems Europe, headquartered in Chertsey, United Kingdom, is the European sales and marketing operation, and operates a network of representatives and distributors throughout Europe.  Allegro also has an engineering design centre in Edinburgh in Scotland and an application and marketing centre in Annecy in France.