LT3799 - Offline Isolated Flyback LED Controller with Active PFC

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.

Features
  • Isolated PFC LED Driver with Minimum Number of External Components
  • TRIAC Dimmable
  • VIN and VOUT 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

Applications
  • Offline 4W to 100W+ LED Applications
  • High DC VIN LED Applications
Packaging
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT3799EMSE#PBFMS-16EE$3.22$2.25
LT3799EMSE#TRPBFMS-16EE$2.31
LT3799IMSE#PBFMS-16EI$3.70$2.59
LT3799IMSE#TRPBFMS-16EI$2.65
Demo Boards
Part NumberDescriptionPrice
DC1595ALT3799 Demo Board - Offline Isolated Flyback Controller with PFC - Universal Input, VOUT(NOM) = 20V, I LED = 1A$150.00
DC1744ALT3799EMSE Demo Board u 90V VIN 270V, VOUT= 1A at ~ 4V$150.00
DC1775ALT3799 Demo Board - Offline Isolated Flyback Controller with PFC - Universal Input, VOUT(NOM) = 28V, I LED = 0.5A$175.00
Datasheet
Design Note
Reliability Data
Press Release
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LT3799 Footprints and Symbols
Isolated LED Current Control with Active PFC
LT3799 Demo Circuit - Offline Isolated Flyback LED Controller with Active PFC (120VAC to 1A @ 20V)