Patent ID: 7582987

Claim:
A double power sources switching circuit, positioned between a computer system and a peripheral device, comprising: a power output terminal, used for outputting power to said electronic product; a first power input terminal, used for inputting power to said power output terminal; a second power input terminal, used for inputting power to said power output terminal; a detection unit, used for detecting whether a voltage of said first power input terminal is lower than a preset switching value to allow a transition to be output; and a power source switching circuit, switching said second power input terminal to be electrically connected to said power output terminal to transmit power to said electronic product depending on an output of said detection unit; wherein, if a voltage of said first power input terminal is lower than said preset switching value of said detection unit in a continuous discharge state after said computer system is in a sleep or power-down mode, said power source switching circuit then switches said second power input terminal to provide electricity to said electronic product.