Abstract: An improved power management system provides a dual mode power supply that supplies normal voltages and standby voltages. When the computer is placed in a power saving mode, the power supply is controlled to cease supplying the normal voltages to conserve power. While the computer is in the power saving mode, the standby power is supplied to specific devices that may be involved in waking the computer. When an I/O device or another device detects computer activity while in the power saving mode, a wake signal is generated and input to a power management device. The power management device then controls the power supply to supply the normal voltages to wake the computer.

Abstract: A circuit disables an on-board voltage regulator when an upgrade voltage regulator is installed. The system including the voltage regulator disable circuit of the preferred embodiment comprises an on-board voltage regulator circuit, a receptacle, coupled to the on-board voltage regulator circuit, for receiving an upgrade voltage regulator module, and a disable circuit coupled to the on-board voltage regulator circuit and the receptacle, the disable circuit being activated upon insertion of the upgrade voltage regulator module to disable an output of the on-board voltage regulator circuit.