In this study, an improved passive lossless snubber cell for the non-isolated pulse-width modulation direct-current (DC)–DC converter family is proposed. The proposed snubber cell provides soft switching for all semiconductor power devices in the converter under wide-input voltage–current and output load ranges. Detailed theoretical analysis is carried out and verified with the implementation of a continuous conduction mode power-factor correction boost converter having 220- input, 400- output, 50-kHz switching frequency, and 1-kW output power. The overall efficiency of the proposed converter at full load increased from 85% in hard-switching conditions to 97.5%, thanks to the proposed lossless passive snubber cell. The application of the proposed snubber cell to other DC–DC converters is also presented.