A new prototype of a secondary-side phase shifted (SPS) soft-switching PWM dc-dc converter is presented in this paper. In the proposed dc-dc converter, soft-switching operations are achievable from full to no loads by utilizing the parasitic inductances of the high frequency (HF) transformer. Beside that, no circulating current occurs in both of the primary and secondary side full-bridge circuits, consequently the related idling power can be minimized. The wide-range soft-switching principle is described in details by actual performances oriented the circuit description. The essential performances, steady-state and switching characteristics of the proposed dc-dc converter are originally demonstrated in experiments by a 1kW-50 kHz prototype, and its practical effectiveness is verified.