An integrated circuit comprises a block of components to be power gated and power gating circuitry for selectively isolating the components from the source voltage supply to achieve such power gating. A voltage regulator provides a control voltage to the power gating circuitry when performing power gating operations. The control voltage may be set to any of a plurality of predetermined voltage levels. An adaptive controller receives operating parameter data from either or both of the block of components and the power gating circuitry, that operating parameter data being indicative of leakage current. The adaptive controller issues a feedback signal to the voltage regulator whose value depends on the received operating parameter data. The voltage regulator responds to the feedback signal to change the control voltage between the predetermined voltage levels until the operating parameter data indicates that a desired leakage current is obtained within the power gating circuitry.