Analysis and experimentation on a new high power factor off-line LED driver based on interleaved integrated buck flyback converter

This paper presents a high power factor (PF), low total harmonic distortion (THD) light-emitting diode (LED) driver implemented by using an interleaved capacitor technique. Also, the driver presents dimming capability; in addition, the proposed technique ensures a high PF and low THD at all dimming range. An interleaved capacitor is placed between the rectifier and the integrated buck flyback converter (IBFC) operating in discontinuous conduction mode (DCM), in order to boost the conduction angle, and in return increase the PF and decrease the THD. Analyzing the operation of the proposed converter it is found that one diode of the conventional IBFC will not conduct and could be removed, which provides a reduction in the number of components. Furthermore the proposed technique offers a significant reduction in the output ripple of the converter, thus output capacitance reduction is achieved. The paper presents a prototype for the proposed converter supplying an LED luminaire of 37 V/ 0.7 A. The prototype shows a high PF equal to 0.997, very small THD of 2.5%, output current ripple of 6 %, and efficiency of 80 %.