PURPOSE: To reduce power consumption when boosting operation is not carried out by stopping oscillation of a switching regulator when the output is higher than a predetermined level.

CONSTITUTION: When the voltage at an input terminal 1 is lower than a set voltage at an output terminal 2, output from an error amplifier 3 goes High and a control transistor 6 is turned ON, OFF with the frequency in an oscillation circuit 4 thus starting boosting operation. If the input voltage is higher than the set voltage at the output terminal 2, output from the error amplifier 3 goes Low and the control transistor 6 stops oscillation. At the same time, output from a comparator 13 goes High and the oscillation circuit stops oscillation.