Method and apparatus for reduced power integrated circuit operation

A battery-powered electronic system in which ICs of low and high voltage specifications can be operated simultaneously by a single low voltage power supply, wherein prolongation of battery life, miniaturization of the housing size and reduction of manufacturing costs are achieved. The present invention comprises a monolithically integrated charge pump circuit for boosting a power supply voltage so as to output a voltage greater than that of the power supply voltage, and a power supply multiplexor for selecting between the output of the charge pump circuit and the power supply voltage in accordance with a power supply select control signal. The output of the multiplexor is used as a supply voltage, for at least one other IC in the system. The voltage selection process is dynamically determined based on the time-varying requirements of system operation. A voltage regulation circuit may be used to provide control over the charge pump circuit output. Circuitry is disclosed for disabling charge pump operation, when such operation is unnecessary, to reduce power consumption.