Patent ID: 7928759

Claim:
A semiconductor device comprising: a plurality of blocks each having a plurality logic circuits constructed of an insulated gate field effect transistor having a first gate insulation film and processing a received signal; a plurality of switching circuits, arranged corresponding to the respective circuit blocks, each including a first switching transistor and a second switching transistor having a second gate insulation film greater in thickness than said first gate insulation film; and a switch control circuit for setting a switch control signal to a switching circuit arranged for a respective circuit block among said plurality of circuit blocks set into operating state to an active state to turn said first switching transistor and said second switching transistor conductive, wherein said first switching transistor is rendered selectively conductive to electrically couple a first power source node supplied a first power supply voltage and a first power node of a corresponding logic circuit in response to a corresponding switch control signal wherein said second switching transistor is rendered selectively conductive to electrically couple a second power source node supplied a second power supply voltage lower than said first power supply voltage and a second power node of a corresponding logic circuit in response to said corresponding switch control signal.