Implementation of a single-stage LED driver using resonant controller

This paper proposes the implementation of a singlestage AC-DC converter using a high voltage resonant controller IC L6598 for driving a street lighting system. The converter is formed by integrating two boost circuits and a half-bridge type LLC resonant circuit. Both boost circuits work in boundary conduction mode (BCM) satisfying the natural function of power factor correction (PFC) of the converter. The soft-switching characteristics of LLC resonant circuit assures the primary side switches to work in zero-voltage-switching (ZVS) mode and the secondary side diodes to work in zero-current-switching (ZCS) mode. This significantly reduces the switching losses and indeed improves the system efficiency. The input voltage is divided by two capacitors resulting in low bus voltage which is allowing the converter to perform well under high-input-voltage. Simulation and experimental results obtained from a 100-W, 240-V AC input laboratory prototype are presented. The result demonstrate that the power factor (PF) of the converter is higher than 0.95, the total harmonics distortion (THD) is lower than 20.5%, and the efficiency is 92.6% at full load.