A modified ZVZCS phase-shift full-bridge circuit

MA Xiao-lin
（Limited Hangzhou Branch， Acbel Electronic Company， Hangzhou 310013， China）

Abstract： Aiming at the existing problems of phase-shift full bridge circuit，an improved circuit was proposed by adding a group of bridge arm（CLC）based on the traditional phase-shift full bridge circuit. The bridge arm is connected to the lagging arm to provide the switching current for the lagging arm. Therefore，it is more easy to achieve zero voltage switching for lagging arm. In addition，the bridge arm also provides current to output rectifier diode by a transformer to achieve the zero current switching. The circuit working process and the waveforms of key components were provided in detail and the key parameters of components in the circuit were given. Finally，the prototype of 1 200 W was demonstrated for a communication power supply with output voltage range of 40 V~60 V and the maximum output current of 20 A. Results show that the withstand voltage of the diode and electromagnetic interference is reduced rapidly，the proposed circuit can achieve the desired demand and high efficiency of 96.3%.
Key words： phase-shifted full bridge； ZVS； ZCS； high efficiency； low electromagnetic interference（EMI）