Abstract: There is provided a source voltage control circuit including a reference voltage generating circuit with a negative feedback circuit, a source voltage level sensing circuit for increasing the internal source voltage when the external voltage exceeds a given voltage, a first differential amplifying circuit for active operation, and a second differential amplifying circuit for stand-by operation, whereby a stable internal source voltage is produced and the slope of the internal source voltage is readily adjusted when the external source voltage exceeds the given value. The first differential amplifying circuit receives the reference voltage and the internal source voltage, controlled by a first control signal and the output of the source voltage level sensing circuit. The second differential amplifying circuit receives the reference voltage and the internal source voltage, controlled by a second control signal.