Single-stage AC/DC dual inductor BCM current-fed push-pull for HB-LED lighting applications

Abstract

A single-stage, AC/DC driver for High Brightness Light-Emitting Diodes (HB-LED) with galvanic isolation is presented in this paper. The driver is based on a Dual Inductor Current-fed Push-Pull (DICPP) converter with each inductor operating in Boundary Conduction Mode (BCM). The interleaving between the two inductors makes possible for the converter to reduce the high input current ripple of a BCM. Moreover, it is fully compliant with IEC 1000-3-2 Class C, and it is also able to achieve high Power Factor (PF). Moreover, the low component count, simplicity and overall outstanding characteristics make this topology suitable for medium power range HB-LED drivers in low cost applications. Finally, the proposed topology has been tested on a 90W prototype for the full range of the US single-phase line voltage, feeding several strings of HB-LED, with an output voltage of 48V at full load. The prototype achieves a maximum efficiency of 92% with 0.99 power factor, 8% THD at full load and guarantees good quality light.