The LT8391 from Analog Devices is a Synchronous 4-switch Buck-Boost LED Controller designed for automotive headlamps, running lamps, and high-power LED lighting applications. It supports a wide input voltage range of 4-60 V and regulates LED current from input voltages above, below, or equal to the output voltage, which ranges from 0-60 V. This AEC-Q100-qualified LED driver uses a proprietary peak-buck peak-boost current mode control scheme, enabling adjustable and synchronizable fixed-frequency operation from 150 kHz to 650 kHz, or internal ±15% triangle spread spectrum mode for reduced EMI. It provides both internal (up to 128:1) and external (up to 2000:1) PWM dimming with ±3% LED current accuracy, and includes a high-side PMOS PWM switch driver with integrated bootstrap diodes.
The LT8391 offers flicker-free spread spectrum switching, low-noise transitions between buck and boost regions, and fault protection with open/short LED detection and reporting. It is available in a surface-mount package that measures 4 mm × 5 mm.