The main goal of many power electronics circuits is to ensure transfer of electrical energy with high efficiency and with a good power density, i.e., the ratio between power and volume occupied. Typical converters, based on PWM, cannot achieve high efficiency at high frequency because they work in hard-switching mode. In fact, during switch’s transitions there is an overlap between the voltage across the power switch and the current through it, which causes the largest part of converter losses. In many times, these converters are replaced by resonant soft-switching converters. As a matter of fact, these converters are capable of a better efficiency at high frequency since they can avoid the overlap between current and voltage.