Driving circuit for high-brightness LED lamps

Abstract

This paper proposes a high efficiency driving circuit for multiple high-brightness light emitting diode (HB-LED) lamps with dimming feature. A high-frequency half-bridge series resonant inverter is adopted as a current driver. By appropriately controlling the frequency of the active switches and the resonant tank, the lamp currents can be regulated effectively. On the other hand, the LED lamps can be dimmed individually by the integral cycle control. The tactful circuit ensures high circuit efficiency owing to the advantages of less conducting losses and zero-voltage switching (ZVS) operation of the active power switches and zero current switching (ZCS) operation of the dimming switches. A prototype circuit designed for three white light HB-LED lamps was built and tested to verify the analytical predictions.