Patent ID: 8081492

Claim:
A switching power supply comprising a smoothing circuit that is connected downstream of a plurality of rectifier circuits, wherein the smoothing circuit comprises: first and second choke coils one end of each of which is connected to one end of a capacitor; third and fourth choke coils one end of each of which is connected to the other end of the capacitor; a first core, around which the first and third choke coils are disposed; a second core, around which the second and fourth choke coils are disposed; and a common core, and wherein one annular magnetic path that passes within the first core and the common core is formed by currents that flow simultaneously trough the first and third choke coils and another magnetic path that passes within the second core and the common core is formed by currents that flow simultaneously through the second and fourth choke coils in synchronization with currents that flow simultaneously through the first and third choke coils.