An electronic device includes: a DC power source which supplies a first DC supply voltage; a DC voltage converter which is enabled or disabled in response to a first control signal, and which converts the first DC supply voltage into a second DC supply voltage different from the first DC supply voltage, when the DC voltage converter is enabled; a switch which selects and supplies either the first DC supply voltage or the second DC supply voltage as an output in response to a second control signal; a DC voltage regulator which is enabled or disabled in response to a third control signal, and which converts the DC supply voltage selected by the switch into a third supply voltage lower than the selected DC supply voltage when said DC voltage regulator is enabled; a control unit which provides the second control signal to the switch; and a loading which utilizes the third DC supply voltage. While the loading is operating intermittently, the control unit provides to the DC voltage converter the first control signal for disabling the DC voltage converter, provides to the switch the second control signal for selecting the first DC supply voltage, and provides to the DC voltage regulator the third control signal for enabling the DC voltage regulator.