A novel single-stage high power LEDs driver

The conventional two-stage driver for high-power light-emitting-diodes (LEDs) is composed of a power-factor-correction (PFC) converter with a buck converter or a flyback converter for adjusting the voltage/current for supplying LEDs. However, large numbers of circuit components are required and the total efficiency is limited due to two-stage power conversion. This paper proposes a single-stage dimmable driver for high-power-rated LEDs. The presented circuit combines a buck-boost PFC converter with a flyback converter into a single-stage power-conversion circuit. The proposed driver offers high power factor, high efficiency, cost-effectiveness and a constant-output-voltage control scheme. Finally, a prototype driver is developed and tested in order to supply 100W LEDs with universal utility-line input voltages. Operational analysis, design equations, a design example, and experimental results demonstrate the feasibility of the proposed circuit.