Patent ID: 7928796

Claim:
A constant voltage boost power supply comprising: a voltage-controlled variable frequency oscillator that produces and supplies a clock signal, and changes an oscillating frequency of the supplied clock signal according to a control voltage; a charge pump into which the clock signal is fed, the charge pump performing a pumping operation in synchronization with the clock signal to boost an input voltage and supply an output voltage in which the input voltage is boosted; a voltage dividing circuit that divides the output voltage of the charge pump to supply a monitor voltage; and a differential amplifier into which the monitor voltage and a reference voltage are fed, the differential amplifier amplifying a potential difference between the monitor voltage and the reference voltage to supply the control voltage, wherein the voltage-controlled variable frequency oscillator includes: a flip-flop that produces and supplies the clock signal; a delay circuit that delays the clock signal, fed back from the flip-flop, according to the control signal; and an oscillation control unit that controls a start and a stop of oscillation of the flip-flop based on a signal supplied from the delay circuit and an oscillation enable signal for permitting the oscillation of the clock signal.