A current-fed DC-DC converter with zero-current switching (ZCS) is presented in this paper. The front stage, which is a DC-DC buck converter, is used to regulate the output voltage by utilizing pulse-width modulation. The rear stage, which is a push-pull DC-DC converter by using the current-fed technique, is used to transfer energy from low voltage side to high voltage side for high voltage applications. Moreover, the stray components of the transformer are integrated as the resonant tank to achieve ZCS on the active switches and to avoid the unpredictable resonant phenomenon. The operating principles and the steady-state analysis of the proposed converter are discussed. Finally, a prototype circuit of the proposed converter with 400-V input and 5-kV/200-mA output is implemented to verify the performance.