Patent ID: 8880922

Claim:
A computer comprising: a processor having a normal mode that operates at a first frequency and a power-saving mode that operates at a second frequency that is lower than the first frequency; a power-saving control unit; a power sensor unit that measures power consumption; and a path for supplying an interrupt signal from the power sensor unit to the power-saving control unit, wherein the power sensor unit compares a power consumption upper limit value defined by the power-saving control unit with measured power consumption, and outputs the interrupt signal directly to the processor and to the power-saving control unit if the measured power consumption exceeds the power consumption upper limit value, when the interrupt signal is inputted, the power saving control unit outputs to the processor a signal that is equivalent to the interrupt signal and outputs to the power sensor unit an instruction to the power sensor unit to deactivate the interrupt signal; when the interrupt signal or the signal that is equivalent to the interrupt signal is inputted, the processor switches from the normal mode to the power-saving mode, the power sensor unit: once the outputting of the interrupt signal is deactivated by the instruction to deactivate the interrupt signal, compares the power consumption upper limit value with a power consumption measured after outputting the interrupt signal; if the power consumption measured after outputting the interrupt signal exceeds the power consumption upper limit value, re-outputs the interrupt signal to the processor and to the power-saving control unit; if the power consumption measured after outputting the interrupt signal is at or below the power consumption upper limit value, does not re-output the interrupt signal to the processor and to the power-saving control unit; and the power-saving control unit, if the interrupt signal is not re-inputted from the power sensor unit after the instruction to deactivate the interrupt signal, deactivates the signal that is equivalent to the interrupt signal.