An Interleaved Flyback-Typed LED Driver With ZVS and Energy Recovery of Leakage Inductance

Flyback converter has advantages of simple circuit configuration and easy control. However, it suffers two problems. One is the active switch is hard switching. The other is a very high voltage spike when the active switch is turned off. In order to solve these problems, this paper presents a novel dc-to-dc converter that mainly consists of two interleaved flyback converters. Both active switches can achieve zero-voltage switching on without the use of any active clamp circuit or snubber circuit. In addition, the leakage flux energy can be delivered to the output by using two added diodes. It helps to reduce the voltage spikes on the active switches and improve circuit efficiency. The steady-state analyses at different operation modes and the mathematical equations for parameters design are provided. Finally, a 200-W prototype circuit for driving high-brightness light-emitting diodes (LEDs) is built and tested to verify the feasibility of the proposed circuit. The LEDs are dimmed from 100% to 10% full power. Satisfactory performances are obtained from the experimental results.