This paper presents a new family of soft-switching resonant dc–dc converters. The proposed topologies include only one switch, two diodes and one high-frequency resonant LC tank. Zero-voltage switching condition is provided for the switch and thereby the converter power density and efficiency are enhanced considerably. Unlike quasi-resonant converters and soft-transition (ZVT/ZCT) converters, which have inherited a relatively large inductor from their PWM parents; in the proposed converters, only one small inductor is employed. The proposed family includes three step-down, three step-up, and three step-down/up converters. Complete analysis of the step-down converter is presented in this paper. Summarized key results of other topologies are also provided. Experimental results from a 100 W/445 kHz laboratory prototype are presented for verification.