Offline Soft-Switched LED Driver Based on an Integrated Bridgeless Boost-Asymmetrical Half-Bridge Converter

• Published in: IEEE transactions on industry applications 2015-01, Vol.51 (1), p.761-769
• Main Authors: Almeida, Pedro S., Braga, Henrique A. C., Dalla Costa, Marco A., Alonso, J. Marcos
• Format: Article
• Language: English
• Subjects: Capacitance; Capacitors; Light emitting diodes; Reactive power; Rectifiers; Switches; Topology
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2014.2332066

This paper proposes an offline single-stage light-emitting diode (LED) driver based on a novel approach to reduce low-frequency ripple in LED arrays supplied from mains, while assuring high input power factor (PF). The proposal employs a series resonant dc-dc converter integrated into a bridgeless boost power factor correction (PFC) stage. The resonant stage works to reduce the low-frequency ripple transmitted from the output of the PFC stage to the LEDs with only small power losses. This solution achieves three main goals: 1) reduction of the bulk capacitance used at the dc bus, allowing for the use of long-life film capacitors; 2) increase in the overall efficiency of the LED driver owing to the low switching and conduction losses in the shared switching network; and 3) assuring high input PF. Experimental results of a driver without electrolytic capacitors for a 100-W street lighting LED luminaire are presented, showing overall efficiency in excess of 92%, input PF greater than 0.97, and line current harmonic content in compliance with the IEC 61000-3-2 standard.