Conventional boost converters, while having a high level of simplicity and robustness, are known to have poor efficiency at high step-up regime. More complicated topologies have been extensively explored to increase the step-up ratio while keeping a high-efficiency, however, an efficient regulated dc-dc power conversion at high step-up regime still remains a challenge. In this work we demonstrate fully soft-switched operation of boost converters based on impulse rectification, which results in an efficient power conversion at very high step-up regime. Contrary to the conventional analysis of boost converters which seeks to minimize conduction and switching losses, our approach considers reactive power as the key parameter limiting efficiency. A theoretical basis for this operation mode enabled an appropriate design resulting in power conversion efficiencies above 90% for voltage gain values of 5, 10, 25, and 50, with a peak efficiency of 97%. The guidelines to design boost converters based on the proposed approach are discussed. The simplicity and high performance of this approach opens new avenues in designing regulated dc-dc converters with a high step-up.