Abstract: A power supply circuit for supplying electric power to a portable computer includes a main battery, a first control circuit, a backup battery and a second control circuit. The main battery includes a first output terminal and a second output terminal shorter than the first output terminal. When the main battery is drawn out of the portable computer, a disconnection between the second output terminal and the portable computer occurs earlier than a disconnection between the first output terminal and the portable computer to from a time difference between the two disconnections. During this time difference, the main battery is controlled by the first control circuit to change from supplying electric power to the portable computer to not supplying electric power to the portable computer, and the backup battery is controlled by the second control circuit to supply electric power to the portable computer instead of the main battery.

Abstract: A power supply circuit for supplying electric power to a portable computer includes a main battery, a first control circuit, a backup battery and a second control circuit. The main battery includes a first output terminal and a second output terminal shorter than the first output terminal. When the main battery is drawn out of the portable computer, a disconnection between the second output terminal and the portable computer occurs earlier than a disconnection between the first output terminal and the portable computer to from a time difference between the two disconnections. During this time difference, the main battery is controlled by the first control circuit to change from supplying electric power to the portable computer to not supplying electric power to the portable computer, and the backup battery is controlled by the second control circuit to supply electric power to the portable computer instead of the main battery.

Abstract: A double network physical isolation circuit includes a north bridge chip, a bus switch circuit, a first memory, and a second memory. The bus switch circuit includes a first and a second bus switch chip. The first and second memories are connected to different networks. The north bridge chip is connected to the first and second memory. When the bus switch circuit receives a high level signal, the first input pin of the first bus switch chip is in electrical communication with the first output pin of the first bus switch chip, and the first memory is activated. The second memory is grounded through the second bus switch chip. When the bus switch circuit receives a low level signal, the second input pin is in electrical communication with the second output pin of the first bus switch chip, and the second memory is activated. The first memory is grounded through the second bus switch chip.

Abstract: A double network physical isolation circuit includes a north bridge chip, a bus switch circuit, a first memory, and a second memory. The bus switch circuit includes a first and a second bus switch chip. The first and second memories are connected to different networks. The north bridge chip is connected to the first and second memory. When the bus switch circuit receives a high level signal, the first input pin of the first bus switch chip is in electrical communication with the first output pin of the first bus switch chip, and the first memory is activated. The second memory is grounded through the second bus switch chip. When the bus switch circuit receives a low level signal, the second input pin is in electrical communication with the second output pin of the first bus switch chip, and the second memory is activated. The first memory is grounded through the second bus switch chip.