Patent ID: 8654551

Claim:
A power-supply device comprising: an AC-DC converter including a first buck converter and a second buck converter, the first and second buck converters sharing a coupling inductor, the coupling inductor including a first inductor and a second inductor that are electromagnetically-coupled with each other; wherein the first buck converter includes: the first inductor of the coupling inductor, a first power semiconductor switching element configured to intermittently switch on and off a current flowing into the first inductor, a first diode configured to circulate a current which flows out of the first inductor, when the first power semiconductor switching element is kept off, an output capacitor, a second diode configured to limit a reflex path of a current, when the first power semiconductor switching element is kept on, and a second body diode connected in parallel with a second power semiconductor switching element, wherein the second buck converter includes: the second inductor of the coupling inductor, a second power semiconductor switching element configured to intermittently switch on and off a current flowing into the second inductor, the second diode configured to circulate a current which flows out of the second inductor, when the second power semiconductor switching element is kept off, the output capacitor, the first diode configured to limit a reflex path of a current, when the second power semiconductor switching element is kept on, and a first body diode connected in parallel with the first power semiconductor switching element; and wherein one end of the first inductor and one end of the second inductor are electrically connected with each other through a common junction point with which one end of the output capacitor electrically connected, and each of a current flowing through the first inductor and a current flowing through the second inductor flows through the common junction point to the output capacitor.