**Bor-Ren Lin**

Depart. of Electrical Engineering, National Yunlin University of Science and Technology (NYUST), Yunlin 640, Taiwan; linbr@yuntech.edu.tw; Tel.: +886-912312281

Received: 6 April 2019; Accepted: 15 April 2019; Published: 17 April 2019

**Abstract:** A dc/dc pulse width modulation (PWM) circuit was investigated to realize the functions of reduced primary current loss and balanced voltage and current distribution. In the presented dc/dc converter, two full bridge pulse width modulation circuits were used with the series/parallel connection on the high-voltage/low-voltage side. The flying capacitor was adopted on the input side to achieve voltage balance on input split capacitors. The magnetic coupling element was employed to achieve current sharing between two parallel circuits. A capacitor-diode passive circuit was adopted to lessen the primary current at the commutated interval. The phase-shifted duty cycle control approach was employed to regulate load voltage and implement soft switching characteristics of power metal-oxide-semiconductor field-e ffect transistors (MOSFETs). Finally, the experimental results using a 1.68 kW prototype converter were obtained to confirm the performance and feasibility of the studied circuit topology.

**Keywords:** dc converter; full bridge converter; zero voltage operation
