PURPOSE: To save wasteful power consumption while stabilizing the operation of integrated circuit by a method wherein oscillating output from an oscillator is introduced as one input into a differential amplifier while a divided output from a resistor dividing circuit is introduced as the other reference input to supply an output pulse from the differential amplifier for a charge.pump circuit.

CONSTITUTION: An oscillator 21, a differential amplifier 22, a charge.pump circuit 23 and a voltage dividing resistor circuit 24 are formed on the same chip and an oscillating output from the oscillator 21 is introduced into one input terminal of the differential amplifier 22 while a divided output from the voltage dividing resistor circuit 24 is introduced into the other input terminal of the differential amplifier 22 as a reference voltage to supply an output from the differential amplifier 22 for the charge.pump circuit 23. The oscillator 21 and the differential amplifier 22 are supplied with VCC power supply. On the other hand, the voltage dividing resistor circuit 24 composed of a resistor net comprising fuse elements to be connected or disconnected by irradiation by laser beams between VCC power supply and VSS power supply.