MILPITAS, Calif., October 11, 2021 -- Lumissil Microsystems, a division of Integrated Silicon Solution, Inc. (ISSI),announced today an LED driver to further expand its portfolio of automotive exterior lighting solutions. TheIS32LT3959 is a single inductor, multi-topology controller with constant on-time for driving a ground referencedhigh-voltage LED string. This single channel switching LED driver integrates a PWM engine with external controlto achieve dual brightness capability for Rear Combination Lamp (RCL), Daytime Running Lamp (DRL) andheadlights.

The IS32LT3959 switching LED driver supports advanced features such as ultra-low 1.5µA shutdown current toconserve battery power, 3% output current accuracy for optimal LED brightness control, programmable PulseWidth Modulation (PWM) engine for standalone LED dimming capability and spread spectrum to minimize thedevice EMI profile. Other key features are programmable single LED short detection, both analog and digitaldimming, LED current monitoring pins, device and LED temperature monitoring, single inductor requirement forall switching topologies and comes in a thermally enhanced eTSSOP-28 package. It operates from a wide 4.5 to55V supply voltage and is guaranteed to meet specifications over the -40°C ~ +150°C operating temperaturerange.

“The IS32LT3959 is our latest automotive-compliant, AEC-Q100 LED driver designed to meet the demands ofnext generation exterior vehicle lighting designs.” Said Ven Shan, Vice President of Marketing. “This driverincorporates the latest features in a compact 28-pin package to provide power and space savings; while at thesame time lowering the overall system costs due to its many integrated functions.”

The integrated PWM engine can be configured to operate up to 2kHz with a 5 to 95% duty cycle. A single pinwill enable or disable the PWM engine so that when enabled the LED current level is subject to the PWM dutycycle and when disabled the maximum current is output to the LED string. This support for two LED currentlevels enables cost effective lighting systems since the same LEDs can be used for both tail and brake lamps.This dual brightness capability can also be used with DRL for higher brightness during the daytime and a lowerbrightness level at nighttime.

Availability and pricing

The IS32LT3959 is available now in production quantities, with AEC-Q100 qualification and supporting PPAPdocumentation. The device comes in a thermally enhanced 28-pin TSSOP package is priced at $0.95 each in 10kpcs quantities.