Automotive LED driver incorporates hysteretic control and high-side current sensing

August 31, 2011 // By Christoph Hammerschmidt
US-based chipmaker Supertex, Inc., has introduced an LED lamp driver IC, designed specifically for solid-state lighting applications in automobiles, such as head lights, tail lights, brake indicator lights, dome lights, and panel backlights. The AT9919 is AEC-Q100 compliant, and drives LEDs using a buck topology.

The chip comes in a compact eight-lead DFN package. Because of the c function of the IC, a constant output current to the LED string is maintained at all times, thereby improving the reliability and lifetime of the LEDs. LED brightness is achieved through a PWM control signal. The IC drives loads of up to 1.0 A at over 90% efficiency from input voltages ranging from 4.5 to 40 V.

According to Supertex, the LED driver chip provides a constant current to LEDs in automotive applications, thus ensuring consistent brightness and prolonged LED lifetimes. Its high switching frequency reduces the need for many external components, which helps to shrink the size and reduce the cost of the assembly. The AT9919 is RoHS compliant. Samples are available from stock. Pricing is US$0.98 each for the AT9919K7-G in 1K quantities.

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