60V Synchronous 4-Switch Buck-Boost LED Controller with Spread Spectrum

The LT8391 is a synchronous 4-switch buck-boost LED controller that regulates LED current from input voltage above, below, or equal to the output voltage. The proprietary peak-buck peak-boost current mode control scheme allows adjustable and synchronizable 150kHz to 650kHz fixed frequency operation, or internal ±15% triangle spread spectrum operation for low EMI. With 4V to 60V input, 0V to 60V output, and seamless low noise transitions between operation regions, the LT8391 is ideal for LED driver and battery charger applications in automotive, industrial, and battery-powered systems.

The LT8391 provides both internal (up to 128:1) and external (up to 2000:1) LED current PWM dimming with a high-side PMOS switch. Two CTRL pins provide flexible 20:1 analog dimming with ±3% LED current accuracy at 100mV full scale. Fault protection is provided to detect an open or short LED condition, during which the LT8391 retries, latches off, or keeps running.

Switching Frequency

Max Output Power

LT8391

Adjustable 150kHz - 650kHz

450W+

LT8391A

2MHz

50W+

Applications

* Automotive Head Lamps/Running Lamps

* High Power LED Lighting

* 4-Switch Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT

* Synchronous Switching: Up to 98% Efficiency

* Proprietary Peak-Buck Peak-Boost Current Mode

* Wide VIN Range: 4V to 60V

* Wide VOUT Range: 0V to 60V (51V LED)

* ±3% LED Current Accuracy

* 2000:1 External and 128:1 Internal PWM Dimming

* High Side PMOS PWM Switch Driver