| 摘要 |
<p>A computer has a power supply unit (19) comprising a main power supply for receiving AC power and an auxiliary power supply arranged to provide computer power in the event of an AC power failure. The computer has a detector for detecting failure of AC power and for generating in response to such a failure an AC fail signal which causes switch over from the main power supply to the auxiliary power supply. The computer has a use operable switch (17) which is coupled to a microprocessor (16), the microprocessor (16) being arranged to generate 'power-on' and 'power-off' logic control signals in response to 'on' and 'off' signals received from the user operable switch (17). The 'power-on' and 'power-off' signals are transmitted to a logic controlled switch for turning the power supply unit on and off. The microprocessor (16) is also coupled to the detector to receive therefrom said AC fail signal and to generate in response a 'power-off' signal for transmission to the logic controlled switch to turn off the power supply unit (19). The microprocessor (16) is arranged to transfer data held in volatile memory into non-volatile memory following receipt of an AC fail signal or an 'off' logic control signal prior to transmission of a 'power-off' signal to the power supply unit for the purpose of preserving 'working' data.</p> |
