A single-stage power factor corrected LED driver with dual half-wave rectifier

In this paper, an architecture of a single-stage power factor corrected AC-DC converter controlled by a high voltage resonant controller IC L6598 is proposed as LED street lighting driver. The converter is formed by the integration of two boundary conduction mode (BCM) boost circuits and a half-bridge LLC resonant circuit. The converter adapts dual half-wave rectifiers at the output side that supply same voltage and current value to two separate LED strings. The bus voltage capacitance is greatly reduced and film capacitor is chosen instead of electrolytic capacitors to realize a long lifetime LED driver. With suitable switching frequency, the soft-switching characteristics of LLC resonant circuit assure the zero-voltage-switching (ZVS) of power switches and zero-current-switching (ZCS) of output diodes. This greatly reduces the switching losses and enhances the efficiency of the system. Although the bus voltage is a little bit higher than the input peak voltage, the result obtained from a 140-W laboratory prototype demonstrated that the power factor (PF) is as high as 0.99, the total harmonics distortion (THD) is 15.6%, and the efficiency is 89.4% at 240-V AC input.