Patent ID: 7639068

Claim:
A semiconductor integrated circuit device, comprising: a circuit block; a first MOS transistor; a first power line; a second power line; a third power line; and a drive circuit; wherein the MOS transistor is connected between the first power line and the second power line, wherein the circuit block is connected between the second power line and the third power line, wherein the drive circuit controls a voltage supplied to a gate of the first MOS transistor, wherein the MOS transistor is off in a standby state, wherein the MOS transistor is on in an operation state, wherein during a shift from the standby state to the operation state, the drive circuit changes the voltage supplied to the gate of the first MOS transistor at a first rate, and then, changes the voltage supplied to the gate of the first MOS transistor at a second rate faster than the first rage, wherein the drive circuit includes a first drive circuit and a second drive circuit, wherein a driving performance of the first drive circuit is smaller than a driving performance of the second drive circuit, and wherein an output of the first drive circuit and an output of the second drive circuit are commonly connected to the gate the first MOS transistor.