Supply voltage switching circuit

A supply voltage switching circuit for a computer, the supply voltage switching circuit comprising:

• a first MOSFET, a gate of the first MOSFET receiving a first system voltage, a source of the first MOSFET receiving a second system voltage;
• a second MOSFET having a contrary polarity of the first MOSFET, a gate and a source of the second MOSFET respectively receiving a first standby voltage, and a drain of the second MOSFET connected to a drain of the first MOSFET, a node between the drains of the first MOSFET and the second MOSFET outputting a voltage to the computer;
• a first transistor having a first end receiving the first system voltage and connected to the gate of the first MOSFET, a second end receiving a second standby voltage, and a third end receiving a control signal from the computer;
• and
• a second transistor having a first end receiving the first standby voltage and connected to the gate of the second MOSFET, a second end receiving the second standby voltage, and a third end receiving the control signal from the computer.

A method to establish a switching circuit for supplying at least two different power sources to an electronic device, comprising the steps of:

• electrically connecting at least two different power sources to a chipset capable of switching between said at least two power sources to provide a selective one of said at least two power sources to an electronic device;
• electrically connecting said chipset to each of a plurality of control powers different from each other via a switch so as to correspond said each of said plurality of control powers to each of said at least two different power sources;
• and
• controllably providing a control signal from said electronic device indicating a current mode of said electronic device to said switch so as to allow said switch providing said each of said plurality of control powers to said chipset in response to said control signal and to control provision of said selective one of said at least two power sources to said electronic device via said chipset.