A Single-Stage LED Driver With High-Performance Primary-Side-Regulated Characteristic

Abstract

A traditional flyback LED driver is limited by its low performance, which usually does not meet the power factor (PF) and total harmonic distortion requirements according to Energy Star or IEC61000-3-2. The control loop from the secondary side to the primary side has low reliability and employs more components, which reduces the power density of the system and increases the cost. In this brief, based on single-stage single ended primary inductor converter (SEPIC) and flyback converter, a primary-side-regulated LED driver is proposed to improve the performance of the system. Working in DCM, the SEPIC circuit realizes the PF correction naturally. For the flyback converter, the proposed primary-side-regulated method improves the power density and guarantees accurate control of the output current. A 100-W prototype based on SEPIC-flyback was built to verify the analysis and the experimental results coincided with the analysis results satisfactorily.