In order to match voltages between the fuel cell stacks and the DC link bus of fuel cell vehicles, a single-switch Boost dc–dc converter with diode-capacitor modules is proposed in this paper. The capacitors are charged in parallel and discharged in series. The wide voltage-gain range can be obtained by using a simple structure. In addition, the basic operating principles, the extended stages, the fault tolerant operation, and steady-state characteristics of the converter are analyzed and presented in this paper, and the small-signal model is also derived. A 400 V, 1.6 kW experimental prototype is developed, and the wide voltage-gain range (3.3 ∼ 8) is demonstrated with a maximum efficiency at 97.25%. The experimental results validate the effectiveness and feasibility of the proposed converter and its suitability as a power interface for fuel cell vehicles.