Patent ID: 7843084
Filing Date: 2010-11-30
Classification: H02J

Abstract:
1. An electronic device capable of automatically selecting a power source, comprising: a battery compartment configured for receiving a battery module; a first power port configured to connect to a first external power source which provides power with a voltage higher than a voltage of the battery module; a second power port configured to connect to a second external power source which provides power with a voltage lower than the voltage of the battery module; a DC/DC converter configured for converting power from the battery module, the first external power source, or the second external power source to a required voltage to power the electronic device; at least three unidirectional switches, wherein a first one of the at least three unidirectional switches is configured for conducting the power from the first power port to the DC/DC converter when being forward biased between the first power port and the DC/DC converter; a second one of the at least three unidirectional switches is configured for conducting the power from the second power port to the DC/DC converter when being forward biased between the second power port and the DC/DC converter; and a third one of the at least three unidirectional switches is configured for conducting the power from the battery module to the DC/DC converter when being forward biased between the battery compartment and the DC/DC converter; a path switch connected between the battery compartment and the third unidirectional switch, for maintaining or cutting off power from the battery module to the third one of the at least three unidirectional switches; a power selection module connected to the battery compartment, the second power port, and the path switch, wherein the power selection module controls the path switch to switch off if the second power port is connected to the second external power source, cutting off power from the battery module to the third of the at least three unidirectional switches.