Patent ID: 7531995

Claim:
An electronic device comprising: 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 when said DC voltage converter is enabled, said second DC supply voltage being different from the first DC supply voltage; 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 when said DC voltage regulator is enabled, said third supply voltage being lower than the selected DC supply voltage; a control unit which provides the second control signal to the switch; and a loading which utilizes the third DC supply voltage, wherein, while said loading is operating intermittently, said control unit provides to said DC voltage converter the first control signal for disabling said DC voltage converter, provides to said switch the second control signal for selecting the first DC supply voltage, and provides to said DC voltage regulator the third control signal for enabling said DC voltage regulator.