The LT3799-1 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 LT3799-1 typically achieves power factors of 0.97. The FAULT pin provides notification of open and short LED conditions. The LT3799-1 offers improved line regulation over the LT3799, but is not designed for use with a TRIAC dimmer. The LT3799-1 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. Triac Dimmable LED Current Regulator LT3799 Yes ± 10% LT3799-1 No ± 5% Applications * Offline 4W to 100W+ LED Applications * High DC VIN LED Applications * Isolated PFC LED Driver with Minimum Number of External Components* VIN and VOUT Limited Only by External Components* Active Power Factor Correction (Typical PFC > 0.97)* Low Harmonic Content https://elecena.pl/product/2490555/offline-isolated-flyback-led-controller-with-active-pfc 2012-02-05 https://elecena.pl/product/2490555/offline-isolated-flyback-led-controller-with-active-pfc 2017-10-09 https://elecena.pl/product/2490555/offline-isolated-flyback-led-controller-with-active-pfc 2025-01-19