Patent ID: 7034605

Claim:
An internal step-down power supply circuit, comprising: an internal step-down power-supply output node that provides an internal step-down power supply potential; a driver that adjusts an external power-supply potential and provides an adjusted potential to the output node; a divider that divides a voltage that appears on the output node and provides a divided voltage therefrom; and a differential amplifier connected to the divider, the differential amplifier having a first transistor that provides a current responsive to a reference voltage, a second transistor that provides a current responsive to the divided voltage provided from the divider, a third transistor providing a first electrical current from the external power-supply potential to the first transistor, and a fourth transistor providing a second electrical current from the external power-supply potential to the second transistor, the differential amplifier comparing the divided voltage provided by the divider and the reference voltage, wherein a conductance of the first transistor is set to n times a conductance of the second transistor, wherein n is greater than 1 and wherein a conductance of the third transistor is set to n times a conductance of the fourth transistor.