Switching power planes of external device interfaces in a computing system in response to connection status

摘要

A computing system includes a motherboard including one or more connection subsystems, each of which includes a port connector and a device interface circuit conditioning signals transmitted or received through the port connector. The port connector includes a connection-sensing terminal, which is connected to ground through a cable, and which is allowed to float to a voltage supplied through a pull-up resistor when the cable is disconnected. The motherboard also includes a main voltage plane supplying electrical power to a separate voltage plane for each device interface circuit only when a cable is connected to the port connector which is also connected to the device interface circuit.