A single-stage DC/DC converter for LED automobile headlight

This paper presents a novel single-stage DC/DC converter with high voltage gain for LED automobile headlight. The converter is integrated by a boost cell and double LLC cell. Because the components of system are reduced by integrating the switches, the cost decreases. The boost circuit works in continuous conduction mode(CCM) with double voltage gain, the double LLC cell connected in series can also realize high voltage gain. Here the LLC resonant converter is chosen, which makes sure that the switches in the primary side can work in zero-voltage-switching (ZVS) condition and the diodes in the secondary side can work in zero-current-switching (ZCS) condition. A 30W prototype is proposed in the lab, with 30 high-brightness LEDs connected in series. The experimental results well confirm the theoretical prediction, and the efficiency is as high as 92%.