LC series resonant converter based high power HBLED lamp driver with ZVS

In this paper, an efficient light emitting-diode (LED) lamp driver circuit for high power applications with a dimming feature is proposed. It consists of an LC series resonant converter in series with a DC bus. The idea is to supply the threshold voltage from a constant DC bus and control the voltage for regulating current with an LC series resonant converter. Since voltage responsible for current regulation is only processed by the converter, the conduction loss is less even if several LED stacks are connected to the same converter for high power applications. Resonant converter characterized by less EMI and switching losses, reduced component count, high efficiency, and removal of output electrolytic capacitor filter is expected to be an excellent alternative to be used in driving LED lamp for high power applications. The dimming property is versed through current amplitude modulation (AM) which is achieved by phase shift control. A 20W laboratory model is designed. The experimental and simulation results revealed that a high efficiency can be attained, even at high output power.