Patent ID: 8278901

Claim:
A switching regulator that converts a voltage input to an input terminal thereof to a predetermined constant voltage and outputs an output voltage from an output terminal, the switching regulator comprising: a switching element configured to switch between on and off according to a control signal; an inductor configured to be charged with the input voltage by switching of the switching element; a rectification element configured to discharge the inductor when the switching element is off and charging the inductor is stopped; a differential amplifier configured to amplify a difference between a voltage proportional to the output voltage and a predetermined reference voltage; a voltage change detection circuit configured to detect changes in the output voltage; a control circuit configured to control a time period during which the switching element is on or off by causing the switching element to switch between on and off in a predetermined cycle depending on a voltage output from the differential amplifier, the control circuit configured to turn on the switching element regardless of the predetermined cycle when the voltage change detection circuit detects that a decrease in the output voltage exceeds a predetermined first reference value; and an ancillary circuit that causes the switching element to turn on by adjusting the voltage output from the differential amplifier when the voltage change detection circuit detects that the decrease in the output voltage exceeds the first reference value, wherein the voltage change detection circuit comprises: a signal amplifier unit configured to amplify a signal output from the differential amplifier and output the amplified signal; and a binarization unit configured to binarize the amplified signal output the signal amplifier unit, and wherein the ancillary circuit comprises: a constant current source configured to supply a constant electrical current; and a switch member connected in series to the constant current source and configured to output the constant electrical current supplied from the constant current source to an output terminal of the differential amplifier according to a signal output from the voltage change detection circuit, wherein when the voltage change detection circuit inputs a signal indicating that the decrease in the output voltage exceeds the first reference value thereto, the switch member causes the constant current source to output the constant electrical current to the output terminal of the differential amplifier, and the constant current supplied by the constant current source of the ancillary circuit has a current value corresponding to a voltage output from the signal amplifier unit of the voltage change detection circuit.