Patent ID: 8749152

Claim:
A switching power supply comprising: a first inductor; a first switching element that supplies a power supply voltage to the first inductor and allows a current to flow when the first switching element is on; a rectifying element that is connected in series to the first switching element, and allows a current of the first inductor to flow when the first switching element is turned off; and a second inductor electromagnetically coupled to the first inductor, in which a potential to turn on the first switching element is induced when the current of the first inductor increases, a potential to turn off the first switching element is induced when the current of the first inductor decreases, and the induced potential is supplied to a control terminal of the first switching element, wherein the rectifying element includes a diode having a withstand voltage lower than that of the first switching element, and a second switching element that is connected in series to a cathode of the diode and includes a control terminal connected to an anode of the diode.