A 20 MHz Low-Profile DC–DC Converter With Magnetic-Free Characteristics

This paper proposes a 20 MHz low-profile dc-dc converter with magnetic-free characteristics based on aircore planar inductors. The switch and diode of the proposed converter operate in soft-switching modes, which significantly reduces the switching loss. Furthermore, the parasitic capacitances are taken as part of corresponding resonant capacitors. A high-performance aircore inductor with a variable width and an optimal connecting angle is analyzed. The optimal parameters design method to achieve minimum winding resistance is derived in detail. The resonant driving method is adopted to reduce driving loss in a high-frequency condition. A 20 MHz prototype is built to verify the feasibility of the proposed converter.