Patent ID: 8421525

Claim:
A semiconductor circuit device comprising: a power line receiving a first voltage from an external power source; a set of internal circuits, each of the internal circuits having a plurality of operation modes, each of the internal circuits being provided with different operating voltages in accordance with each of the operation modes; a power supply circuit electrically connected with one of the set of internal circuits and the power line to provide a second voltage lower than or equal to the first voltage of the power line to the one of the set of internal circuits; and a control circuit controlling the power supply circuit in accordance with each of the plurality of operation modes, wherein when in the one of the set of internal circuits, a change of an operation mode is performed from one operation mode to another, if an operating voltage for an operation mode after the change of an operation mode is higher than an operating voltage for an operation mode before the change of an operation mode, firstly the control circuit controls the power supply circuit to supply the second voltage higher than the operating voltage for the operation mode after the change of an operation mode to the one of the set of internal circuits and secondly the control circuit controls the power supply circuit to supply the operation voltage for the operation mode after the change of an operation mode to the one of the set of internal circuits.