A Single-Stage LED Driver Based on BCM Boost Circuit and <tex-math notation="LaTeX">$LLC$</tex-math> Converter for Street Lighting System

In this paper, a single-stage LED driver is proposed for a street lighting system. Two boost circuits that share a single inductor are formed by integrating the switches of a half-bridge LLC resonant converter. Both boost circuits operate in the boundary conduction mode, which realizes a power-factor correction function. Because the input voltage of the LED driver is divided by two capacitors, the bus voltage is considerably reduced to almost the input peak voltage, rendering the novel single-stage LED driver to work suitably under high-input-voltage conditions. The soft-switching characteristics of the half-bridge LLC resonant circuit are not affected by the integration of the switches; thus, the converter has a low cost and a high efficiency. A 100-W prototype was developed, and the efficiency was determined to be as high as 91.1% in a full-load state under a 220-V ac input.