Low Cost Drive Circuit and Control IC Design for AC-Direct LED Lamps-Doctoral Thesis Yoo-Chae Chung (정 유 채) Department of Electrical Engineering Pohang University of Science and Technology

Low Cost Drive Circuit and Control IC Design for AC-Direct LED Lamps-Doctoral Thesis Yoo-Chae Chung (정 유 채) Department of Electrical Engineering Pohang University of Science and Technology

 Abstract
This paper proposes a drive circuit for ac-direct LED lamps and its custom IC design. The proposed circuit consists only of a line filter, an LED bridge, a load inductor, a bi-directional switch, and a switch-control circuit. The switch connects the LED bridge to the power line directly. Each leg of the LED bridge consists of LEDs and a protection diode, all connected in series. The load inductor limits the bridge current. The switch operates at a zero current switching condition, so the circuit has high power efficiency PE. The circuit can operate at a free-volt input condition (85 < Vin,rms < 265 V). For all input voltage conditions the circuit had PE > 89%, luminous efficiency ~ 90 lm/W, power factor > 0.9 and 120 Hz flicker index ~ 0.3. The circuit satisfies the IEC 61000-3-2 Class C and the EN 55015 regulations. The proposed LED driver is wellsuited for use in household LED lamps.
LINK
https://www.mediafire.com/file/9g9cnq4x5nsm7ch/Low_Cost_Drive_Circuit_and_Control_IC_Design_for_AC-Direct_LED.pdf/file