Patent ID: 8395440

Claim:
An integrated circuit comprising: a block of components; power gating circuitry configured to receive a source voltage supply, and to provide an internal voltage supply to said block of components, in a first mode of operation the internal voltage supply being derived from the source voltage supply, and in a power saving mode of operation the power gating circuitry being configured to isolate the internal voltage supply from the source voltage supply; voltage regulator circuitry configured to provide a control voltage to said power gating circuitry during said power saving mode of operation, the control voltage being settable to any of a plurality of predetermined voltage levels; an adaptive controller configured to receive operating parameter data from at least one of the block components and the power gating circuitry, the operating parameter data being indicative of leakage current within the power gating circuitry, and the adaptive controller being configured to issue a feedback control signal to the voltage regulator circuitry whose value is dependent on the received operating parameter data; the voltage regulator circuitry being responsive to the feedback control signal to change the control voltage between said plurality of predetermined voltage levels until the operating parameter data indicates a desired leakage current has been obtained within the power gating circuitry, wherein: the power gating circuitry comprises at least one PMOS transistor whose gate is driven by the control voltage during said power saving mode of operation; the control voltage is set to exceed the source voltage supply by an overdrive voltage, the overdrive voltage being variable so as to enable any of said plurality of predetermined voltage levels to be set as said control voltage; when the operating parameter data indicates that the leakage current is exceeding the desired leakage current, the adaptive controller is configured to set the feedback control signal to a value that causes the voltage regulator circuitry to increase the overdrive voltage provided a maximum predetermined voltage level has not been reached; and when the operating parameter data indicates that the leakage current is below the desired leakage current, the adaptive controller is configured to set the feedback control signal to a value that causes the voltage regulator circuitry to decrease the overdrive voltage provided a minimum predetermined voltage level has not been reached.