Features

• Isolated PFC LED Driver with Minimum Number of External Components
• TRIAC Dimmable
• V_IN and V_OUT Limited Only by External Components
• Active Power Factor Correction (Typical PFC > 0.97)
• Low Harmonic Content
• No Opto-Coupler Required
• Accurate Regulated LED Current (±5% Typical)
• Open LED and Shorted LED Protection
• Thermally Enhanced 16-lead MSOP Package

Typical Application

Description

The LT3799 is an isolated flyback controller with power factor correction specifically designed for driving LEDs. The controller operates using critical conduction mode allowing the use of a small transformer. Using a novel current sensing scheme, the controller is able to deliver a well regulated current to the secondary side without using an opto-coupler. A strong gate driver is included to drive an external high voltage MOSFET. Utilizing an onboard multiplier, the LT3799 typically achieves power factors of 0.97. The FAULT pin provides notification of open and short LED conditions.

The LT3799 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third winding to provide power to the part. An internal LDO provides a well regulated supply for the part’s internal circuitry and gate driver.