LT3799-1 Datasheet | Linear Technology

LT3799-1 Offline Isolated Flyback LED Controller with Active PFC Features n n n n n n n n DESCRIPTION The LT®3799-1 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. Isolated PFC LED Driver with Minimum Number of External ponents VIN and VOUT Limited Only by External ponents 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 APPLICATIONS n n Offline 4W to 100W+ LED Applications High DC VIN LED Applications L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Patents pending. TYPICAL APPLICATION 20W LED Driver 1.20 1.15 LED Current vs Input Voltage 90V TO 150V AC 100k 0.22μF 499k 499k VIN VIN_SENSE 6.34k VREF 100k 32.4k 40.2k CTRL3 CTRL2 100k NTC 15.8k FAULT CTRL1 LT3799-1 100k 20Ω 4:1:1 ILED (A) 1.10 1.05 4.7p F 10μF 2k DCM FB 4.99k 100k...