LT3799: Offline Isolated Flyback LED Controller with Active PFC
The LT®3799 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.
- Offline 4W to 100W+ LED Applications
- High DC VIN LED Applications
- 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
Demonstration circuit 1744A is an off-line isolated flyback converter featuring the LT®3799. The demo board is designed to drive a single LED from an input voltage range of 90V AC to 270V AC. It is also designed to comply with IEC 61000-3-2 Class C harmonics standard and EN55015B conducted EMI standard.
Demonstration circuit 1595A is an off-line isolated flyback converter featuring LT3799. The demo board is designed to drive a 20V nominal LED string at 1A from an input voltage range of 90VAC to 270VAC. It is also designed to comply with IEC 61000-3-2 Class C harmonics standard and EN55015B conducted EMI standard.
Demonstration circuit 1775A is an off-line isolated flyback LED driver featuring the LT®3799. The demo board provides a constant-current output of 0.5A over an LED string voltage of 20V and 30V. It is optimized to operate over a wide AC input voltage range (90VAC to 270VAC).
|Part Number||# of Outputs||Current||Voltage In||Voltage Out|
|LT3799||1||1000||90V - 150V||20V|