Switching power supply device

Abstract

A switching power supply device includes a power conversion circuit including input and output capacitors, a switching element, and an inductor, and a common-mode choke coil that is between a DC power supply and the power conversion circuit and includes a core material around which first and second windings are linearly wound and aligned by being turned in one direction. The power conversion circuit and the common-mode choke coil constitute a noise equalization circuit that is an electric closed circuit including a low-frequency band blocking filter including an input capacitor and a mutual inductance of the common-mode choke coil, and a high-frequency band blocking filter including the mutual inductance and a stray capacitance of the common-mode choke coil. The noise equalization circuit cancels out noise generated by a switching operation of the switching element in each of a low-frequency band and a high-frequency band different from the low-frequency band.

Dependencies are inferred from the claim text.