Internal step-down power supply circuit

摘要

An internal step-down power supply circuit has an internal step-down power-supply output node, a driver, a divider circuit and a current mirror circuit. The internal node provides an internal step-down power supply potential. The driver adjusts an external power-supply potential and provides an adjusted external power-supply potential to the internal node. The divider circuit divides a voltage that appears on the internal node and provides a divided voltage. The current mirror circuit is connected to the divider circuit. The current mirror circuit compares the voltage provided by the divider circuit and a reference voltage. The current mirror circuit sets the conductance of a first transistor feeding a current in response to the reference voltage to n times of the conductance of a second transistor feeding a current in response to the voltage provided from the divider circuit, wherein n is greater than 1.