High-Side Linear LED Driver Family with Thermal Shunt/Sharing

Lumissil Microsystems IIS32LT315x family of high-side linear LED drivers is a lineup designed to meet the harsh demands of automotive lighting applications. The family encompasses both single-channel (up to 450 mA) and triple-channel (3 × 150 mA) drivers, giving designers flexible options for powering tail lamps, brake lights, turn signals, and more. All IS32LT315x devices operate over a wide 4.5 V to 40 V input range and are AEC-Q100 temperature Grade 1 qualified (-40°C to +125°C ambient, up to +150°C junction).

Each driver uses an external resistor to set the constant-current output, and high-power applications can employ optional external shunt resistors to offload heat and reduce device thermal stress. Select models in the IS32LT315x series such as IS32LT3151A/C and IS32LT3153A/B/E provide an analog current control pin for LED thermal derating or dual-level brightness control via an NTC thermistor or external FET, as well as single-LED short detection for pinpoint fault diagnostics. All variants include built-in open/short fault detection at the LED string level and support “one-fail-all-off” functionality, a shared FAULTB output that can disable all connected drivers if any single string fails. With certain drivers of the family meeting ISO 26262 ASIL B functional safety criteria, the IS32LT315x enable safer and thermal smart automotive lighting designs. In compact thermally enhanced packages (SOP-8 EP for cost-optimized versions and eTSSOP for feature-rich versions), the IS32LT315x family delivers a comprehensive solution for exterior and interior automotive LED lighting, offering high output current, robust fault protection, and simplified thermal management in a single IC.