Features

• 4-Switch Single Inductor Architecture Allows V_IN Above, Below or Equal to V_OUT
• Synchronous Switching: Up to 98% Efficiency
• Proprietary Peak-Buck Peak-Boost Current Mode
• Wide V_IN Range: 4V to 60V
• Wide V_OUT 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
• Integrated Bootstrap Diodes
• No Top MOSFET Refresh Noise in Buck or Boost
• Adjustable and Synchronizable: 150kHz to 650kHz
• Flicker-Free Spread Spectrum for Low EMI
• Open and Short LED Protection with Fault Reporting
• Available in 28-Lead TSSOP with Exposed Pad and 28-Lead QFN (4mm × 5mm)

Typical Application

Description

The LT®8391 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.