Patent ID: 8253481

Claim:
A semiconductor integrated circuit device comprising: a first power wire to receive a power supply voltage; a second power wire to receive a reference voltage; a third power wire to receive a reference potential; a power supply switch to connect the second power wire and the third power wire; a power region coupled between the first and second power wires and controllable to operate in different low-power consumption modes, including a low-speed mode and a standby mode; a reference voltage regulator to supply the reference voltage to the second power wire; a power switch control unit to control the power supply switch based on a connection control signal; and a power consumption control unit to determine an operation state of the power region and to control the reference voltage regulator and the power switch control unit, wherein, in the low-speed mode, the power consumption control unit controls the reference voltage regulator to supply the reference voltage to the second power wire and controls the power switch control unit to turn off the power supply switch so as to make the power region operating in the low-speed mode operate between the power supply voltage and the reference voltage, wherein, in the standby mode, the power consumption control unit stops operation of the reference voltage regulator, and controls the power switch control unit to turn off the power supply switch to interrupt supply of the reference voltage and the reference potential to the power region operating in the standby mode, and wherein, in a normal operation mode, the power consumption control unit stops operation of the reference voltage regulator, controls the power switch control unit to turn on the power supply switch, and makes the power region operating in the normal operation mode operate between the power supply voltage and the reference potential.