Patent ID: 7683584

Claim:
A power source switching apparatus, comprising: a battery storing charges received from an external power source and outputting a voltage corresponding to the stored charges; a voltage adjuster outputting a first power source voltage during an external power source mode where the battery is being charged, the first power source voltage based at least in part on the external power source and the output voltage of the battery; a controller outputting a first control signal and a second control signal, the first control signal enabled if the battery is operating in the external power source mode and the second control signal is enabled if the battery is not operating in the external power source mode; a first switch outputting the first power source voltage if the first control signal is enabled; and a second switch outputting the output voltage of the battery if the second control signal is enabled, wherein the first power source voltage has the same level as that of the output voltage of the battery and the level of the first power source voltage increases corresponding to the level of output voltage of the battery while the battery is being charged, and wherein the controller further outputs a third control signal, the third control signal enabled if the battery is operating in an external power source mode, the voltage adjuster outputting the first power source voltage further based on the third control signal.