Semiconductor device

A semiconductor device comprising:

• a shared pad to which a plurality of circuits is coupled;
• a regulator circuit that includes a driving transistor coupled between the shared pad and an internal logic circuit and a driving control circuit that drives the driving transistor on the basis of the voltage of a wire coupling the driving transistor and the internal logic circuit to each other;
• and
• an interface circuit coupled to the shared pad,
• wherein the driving control circuit has, at least, two operation modes among a first operation mode in which an internal power supply generated by lowering a power supply applied to the shared pad using the regulator circuit is supplied to the internal logic circuit, a second operation mode in which the interface circuit uses the shared pad to transmit and receive signals, and a third operation mode in which the shared pad and the internal logic circuit are coupled to each other as a wire,
• wherein a control signal that keeps the voltage of the internal power supply constant is applied to the driving transistor in the first operation mode,
• wherein a control signal of a first logic level is applied to the driving transistor to turn the driving transistor to a disconnected state in the second operation mode, and
• wherein a control signal of a second logic level that is a logic level opposite to the first logic level is applied to the driving transistor in the third operation mode.