LT3799 Offline Isolated Flyback LED Controller with Active PFC FEATURES DESCRIPTION n Isolated PFC LED Driver with Minimum Number of The LT 3799 is an isolated flyback controller with power External Components factor correction specifically designed for driving LEDs. n TRIAC Dimmable The controller operates using critical conduction mode n V and V Limited Only by External Components allowing the use of a small transformer. Using a novel IN OUT n Active Power Factor Correction (Typical PFC > 0.97) current sensing scheme, the controller is able to deliver a n Low Harmonic Content well regulated current to the secondary side without using n No Opto-Coupler Required an opto-coupler. A strong gate driver is included to drive n Accurate Regulated LED Current (5% Typical) an external high voltage MOSFET. Utilizing an onboard n Open LED and Shorted LED Protection multiplier, the LT3799 typically achieves power factors n Thermally Enhanced 16-Lead MSOP Package of 0.97. The FAULT pin provides notification of open and short LED conditions. APPLICATIONS The LT3799 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third n Offline 4W to 100W+ LED Applications winding to provide power to the part. An internal LDO n High DC V LED Applications IN provides a well regulated supply for the parts internal L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and circuitry and gate driver. True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Patents pending. TYPICAL APPLICATION TRIAC Dimmable 20W LED Driver LED Current vs Input Voltage 1.20 1.15 90V 100k 20 0.22F TO 150V 4:1:1 1.10 0.1F 499k AC 100k 4.7pF 1.05 200 10F 499k 2k 1.00 1A 100k V DCM IN 0.95 V FB IN SENSE 0.90 4.99k 560F 6.34k LT3799 2 0.85 V 0.80 REF 20W 20 90 100 110 120 130 140 150 100k CTRL3 GATE LED 32.4k 40.2k V (V ) IN AC POWER 3799 TA01b CTRL2 SENSE INTV CTRL1 CC 0.05 100k 4.7F NTC 16.2k 2.2nF GND + FAULT FAULT CT COMP COMP 3799 TA01a 0.1F 0.1F 3799fb 1 For more information www.linear.com/LT3799 I (A) LEDLT3799 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , FAULT .................................................................32V IN CTRL1 1 16 V IN SENSE CTRL2 2 15 GATE, INTV ...........................................................12V SENSE CC CTRL3 3 14 GATE V CTRL1, CTRL2, CTRL3, V , COMP ................4V 4 17 13 REF INTV IN SENSE CC FAULT 5 GND 12 NC + FB, CT, V COMP , ...................................................3V 6 REF, CT 11 V IN + COMP 7 10 DCM SENSE ......................................................................0.4V COMP 8 9 FB DCM .......................................................................3mA MSE PACKAGE 16-LEAD PLASTIC MSOP Maximum Junction Temperature .......................... 125C = 50C/W, = 10C/W JA JC Operating Temperature Range (Note 2) EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB LT3799E ............................................ 40C to 125C LT3799I ............................................. 40C to 125C Storage Temperature Range .................. 65C to 150C ORDER INFORMATION (