A semiconductor device including a display driving circuit that drives a display panel, a touch detection signal driving circuit that applies a touch detection signal to a touch sensor, and a touch state detection circuit that receives a signal obtained by observing the touch sensor is configured as follows. A connection switching circuit that switches connection between a terminal and an internal circuit is included therein. The connection switching circuit switches connection with the terminal by selecting one of at least two of the display driving circuit, the touch detection signal driving circuit and the touch state detection circuit. A protection circuit which is capable of changing a protection voltage level is connected to the terminal, and the protection voltage level varies depending on the signal amplitude of the circuit selected by the connection switching circuit.