A Novel Expandable Reverse Polarity Buck Converter With Zero Voltage Switching

In this paper, a novel inverting buck converter is proposed. The introduction of coupled inductor not only helps realize the ZVS of all switches, but also reduces voltage stress on the synchronous rectifier. Therefore, switches with lower on-resistance can be selected to reduce the conduction loss, thus improving efficiency. In addition, the converter can further improve the voltage conversion ratio and expand the phase number by changing the turns ratio and designing matrix coupled inductor, which is suitable for high-current-output applications. In order to verify the correctness of the theoretical analysis, a prototype was built to achieve −48V input, 12V/300W output. The peak efficiency of the prototype was measured to be 96.7%, and the full load efficiency was 96.3%.