This paper presents the detailed analysis and design of a soft-switching DC-DC converter called clamped-resonant interleaved boost converter(CRIB). This topology, thanks to a resonant L-C tank connected between the drain terminals of the switches of two interleaved boost cells, achieves zero-voltage and zero current commutations of all devices, independently of the load current, with a reduced dv/dt across the switches, making the converter suitable for high-frequency operation. Moreover, a proper no-load operation is proved, whenever the minimum voltage gain is higher than a given threshold. Differently from previous works on current-fed resonant converters, the presented theoretical analysis includes the effect of the input filter inductors, allowing to derive a simple design procedure to meet the given specifications. According to the outlined design steps, an experimental prototype was built, rated at 42~54 V to 400 V~300 W. Measurements confirm the theoretical predictions, showing an efficiency above 96% at the nominal power in the whole input voltage range. Finally, the possibility to reduce the overall magnetic volume by coupling the two input inductors is demonstrated.