A semiconductor device includes a reference voltage generation circuit, an amplifier circuit, and a voltage dropping circuit. The reference voltage generation circuit includes a negative feedback circuit to generate a reference voltage controlled by an output signal from the negative feedback circuit. The amplifier circuit amplifies the output signal from the negative feedback circuit at the leading edge of an external power supply voltage or the input time of an external signal. The voltage dropping circuit drops the external power supply voltage in accordance with the reference voltage output from the reference voltage generation circuit to generate an internal power supply voltage.