Single Stage Single Switch LED Driver with Improved Power Factor Correction and Soft Switching

Light Emitting Diodes (LEDs) with their current performances have been proved to be the most suitable solution for street lighting applications. Nowadays, a topic of interest in this context is the design for electronic driver in order to take the advantage of LEDs performances. However, requirements such as high power factor, long life time, accurate current control and high efficiency pose challenges to the design of LED driver circuits. A novel high-powerfactor single-stage single-switch light-emitting diodes (LEDs) driver for street lighting system is proposed in this paper. By integrating the single-ended primary-inductor converter (SEPIC) power factor correction circuit and Class-E resonant dc/dc converter, the proposed converter exhibits extreme simplicity and high reliability, as there is only one active power switch. The LED driver could achieve nearly a unit power factor by operating the SEPIC circuit at discontinuous conduction mode. With careful parameters design of a single Class-E resonant converter, the proposed converter can achieve soft-switching characteristics, which could significantly reduce the switching losses and greatly improve the system efficiency. Operational principle, analytical results, and design considerations are presented, and a based on the circuit topology, the simulation process of the proposed LED Driver using MATLAB software is presented to verify the theoretical analysis.