60V, Synchronous, Quad-Switch Buck-Boost LED Driver with Spread Spectrum

Milpitas, CA – April 6, 2016 – Linear Technology CorporaTIon introduces the LT8391, a synchronous buck-boost DC/DC LED controller that can be input Adjust the LED current when the voltage is above, below or equal to the output voltage. With an input voltage range of 4V to 60V, it is ideal for a wide range of applications in automotive, industrial and architectural lighting. Similarly, its output voltage can be set from 0V to 60V, enabling the drive of multiple LEDs in a single string. The LT8391's internal 4-switch buck-boost controller is combined with four external N-channel MOSFETs to achieve LED power from 10W to over 100W. The device's buck-boost feature makes it ideal for applications such as automotive applications where input voltages can change dramatically during stop/start, cold start and dump. The transition between buck, pass-through, and boost modes of operation is seamless, providing a stable output even with large variations in supply voltage. The LT8391 uses an external high-side PMOS switch to provide both internal (128:1) and external (2000:1) LED current PWM dimming. Available in a 28-lead 4mm x 5mm QFN or thermally enhanced TSSOP package, it provides a very compact solution pin layout.

The LT8391 uses four external N-channel MOSFETs to deliver up to 100W of continuous LED power and up to 98% efficiency. ±3% LED current accuracy guarantees stable brightness. The dedicated peak buck, peak boost current mode control method supports adjustable and synchronizable 150kHz to 650kHz fixed frequency operation, or internal spread spectrum operation to achieve lower EMI. Additional features include integrated bootstrap diodes and open and shorted LED protection, as well as fault condition reporting.

The LT8391EFE is available in a 28-lead thermally enhanced TSSOP package. The LT8391EUFD is available in a 28-lead 4mm x 5mm QFN package. The industrial grade versions of the LT8391IFE and LT8391IUFD are also available. The 1,000-piece purchase price is $4.65 per piece. All versions are available from stock.

Photo Caption: 60V Input/Output, Synchronous Buck-Boost LED Driver Delivers Up to 100W LED Power

Performance Summary: LT8391

· Four-switch single inductor architecture allows VIN to be above, below or equal to VOUT

· Synchronous switch: 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 diode

· No upper MOSFET refresh noise in buck or boost

· Adjustable and synchronizable frequency range: 150kHz to 650kHz

· Flicker-free spread spectrum for low EMI

· Open and shorted LED protection with fault reporting

· Available in 28-pin TSSOP package with exposed pad and 28-pin 4mm x 5mm QFN package

1 High conversion efficiency gives superior Power output performance
2 Outstanding Power output even in low light or high temperature conditions
3 Optimized design for ease of soldering and lamination
4 Long-term stability, reliability and performance
5 Low breakage rate
6 Uniform color