A Novel Single-Switch Single-Stage LED Driver with Power Factor Correction and Current Balancing Capability

A novel single-switch single-stage high power factor LED driver is proposed by integrating a flyback converter, buck–boost converter and current balance circuit. Only an active switch corresponding control circuit are used. The can be adjusted the scheme of pulse–width modulation (PWM). performs function correction (PFC), which operated at discontinuous-current mode (DCM) to achieve unity low total harmonic distortion (THDi). regulates dc-link voltage obtain smooth dc for LED. current–balance applies principle ampere-second capacitors equal in each string. steady-state analyses different operation modes provided, mathematical equations designing component parameters conducted. Finally, 90-W prototype with three strings was built tested. Experimental results show that string indeed consistent. High THDi achieved. regulated from 100% 25% rated power. Satisfactory performance has proved feasibility this