Analog Devices LT8391A

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 andbattery-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.

Features

• 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
• 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 applications

• Automotive Head Lamps/Running Lamps
• High Power LED Lighting

More information

• Datasheet
• IC product information