Patent ID: 7629712

Claim:
An electronic apparatus comprising: a DC power source for supplying a first DC supply voltage; a first DC voltage converter for converting the first DC supply voltage into a second DC supply voltage which is lower than the first DC supply voltage; a second DC voltage converter for converting either the first DC supply voltage or the second DC supply voltage at an input voltage terminal thereof into a third DC supply voltage which is lower than the second DC supply voltage; a switch for selecting and supplying one of the first DC supply voltage of said DC power source and the second DC supply voltage of said first DC voltage converter to the input voltage terminal of said second DC voltage converter, in accordance with a control signal; a switching controller for providing to said switch said control signal for supplying said first DC supply voltage to said input voltage terminal of said second DC voltage converter when operation stages of the components receiving the third DC supply voltage correspond substantially to a high loading state, and for providing to said switch and control signal for supplying said second DC supply voltage to said input voltage terminal of said second DC voltage converter when operational states of the components receiving the third DC supply voltage correspond substantially to a low loading state; and a plurality of components, ones of said components receiving the second DC supply voltage, ones of said components receiving the third DC supply voltage.