Semiconductor device and semiconductor device control method

A semiconductor device that operates at a first power source voltage and at a second power source voltage higher than the first power source voltage and that comprises:

• a first first-conductivity-type transistor supplied with the first power source voltage and controlled by an output signal of a first input inverter that inverts an input signal;
• a second first-conductivity-type transistor supplied with the first power source voltage and controlled by an output signal of a second input inverter that inverts the output signal of the first input inverter;
• a first second-conductivity-type transistor supplied with the second power source voltage;
• a second second-conductivity-type transistor supplied with the second power source voltage;
• and
• a third first-conductivity-type transistor and a fourth first-conductivity-type transistor that are connected in parallel either between the first first-conductivity-type transistor and the first second-conductivity-type transistor or between the second first-conductivity-type transistor and the second second-conductivity-type transistor, and that are configured to isolate either a first node connected to the first first-conductivity-type transistor or a second node connected to the second first-conductivity-type transistor from the second power source voltage in accordance with the first power source voltage;
• wherein:
• the output signal of the first input inverter is supplied to a gate of the third first-conductivity-type transistor;
• and
• the output signal of the second input inverter is supplied to a gate of the fourth first-conductivity-type transistor.