The present disclosure relates to a circuit arrangement which comprises one high-efficiency fully soft-switching single-stage 3-level power amplifier with dual auxiliary networks. The primary-side passive auxiliary network is formed by one inductor and two capacitors to extend soft switching ranges and avoid switching loss. The secondary-side active auxiliary network is constituted of four switches, three capacitors and two inductors which not only removes or maximally reduces otherwise occurring disruptive spikes but also assists zero voltage switching (ZVS) for switches of active auxiliary network. A predictive gate drive method for driving power switches is presented to guarantee ZVS turn-on. The proposed circuit achieves high level of integration without bulky dc link capacitor, and high-efficiency by single-stage conversion and ZVS for all the switches under different operating conditions.