Patent ID: 8395423

Claim:
A switching control circuit configured to perform switching so as to cause a first transistor to be turned on and kept on for a predetermined time period, in order to generate an output voltage of a target level out of an input voltage, the first transistor having an input electrode to be applied with the input voltage and an output electrode connected to an inductor and a diode, the switching control circuit comprising: a comparison circuit configured to compare a feedback voltage corresponding to the output voltage with a reference voltage; a detecting circuit configured to detect whether a switching period of the first transistor is longer than a predetermined period; and a driving circuit configured to turn off a second transistor connected in parallel to the diode as well as turn on the first transistor to be kept on for the predetermined time period, and thereafter, turn off the first transistor and the second transistor, when the feedback voltage becomes lower than the reference voltage, and turn off the first transistor as well as turn on the second transistor, when the switching period becomes longer than the predetermined period.