To provide a semiconductor device that generates a stable negative potential with high accuracy and achieves lower power consumption. The semiconductor device includes a voltage conversion circuit, a comparator, a logic circuit, a transistor, and a capacitor. The voltage conversion circuit has a function of outputting, as a second signal, a signal obtained by conversion of a voltage of an input first signal in response to a clock signal output from the logic circuit. The comparator has a function of being controlled to be supplied with or not supplied with a power supply voltage in response to a power gating signal. The transistor has a function of holding an output voltage of the comparator in the capacitor in a period during which the transistor is in an off state. The logic circuit has a function of switching between supply and stop of the clock signal on the basis of the voltage held in the capacitor in a period during which the power supply voltage to the comparator is stopped.