Computer system which is operative to change from a normal operating state to a suspend state when a power supply thereof detects that an external source is no longer providing power to said power supply at a predetermined level

摘要

Described is a personal computer system which includes a central processing unit (CPU) and power management circuitry (PMC) in circuit communication with the CPU. A switch is coupled to the PMC. A power supply is coupled to the CPU, PMC and the switch and includes circuitry for selectively providing system power to the computer system and auxiliary power to the PMC (1) from an external source or (2) from an internal source. When the system is in a normal operating state and the external source stops providing power at a predetermined level (e.g., blackout or brownout) to the power supply, the power supply is operative to change to its internal power and generate a control signal to the switch. The control signal causes the switch to activate a closure event and generate another control signal. In response to the activation of the latter control signal, the power management circuitry is operative to cause the system to change to the suspend state wherein the entire state of the system is safely saved to a non-volatile storage device.