Features and Benefits
- 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)
- AEC-Q100 Qualified for Automotive Applications
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+|
- Automotive Head Lamps/Running Lamps
- High Power LED Lighting
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Demonstration circuit 2345A is a 60V synchronous 4-switch buck-boost LED controller with spread spectrum featuring the LT8391 LED driver. It accepts an input voltage from 4V to 60V and drives a single string of LEDs up to 25V at 2A. DC2345A runs at 400kHz switching frequency without spread spectrum, but spread spectrum frequency modulation (SSFM) can be enabled with a simple jumper. SSFM spreads the switching frequency to fsw ±15% for reduced EMI.
Documentation & Resources
R570 Reliability Data3/23/2018415 K
DC2345A - Demo Manual5/9/2016748K
60V Synchronous Buck-Boost LED Driver7/28/2016893K
Automotive LED Driver Power Conversion Topology Guide6/1/2022 Analog Dialogue
Buck-Boost LED Driver Reaches 98% Efficiency, Features Internal PWM Dimming and Spread Spectrum without Flicker2/1/2016 LT Journal
Tools & Simulations
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LT8391 Companion Parts
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