Patent ID: 7355469
Filing Date: 2008-04-08
Classification: G05F

Abstract:
1. A DC power supply voltage regulator circuit including an input terminal, an output terminal and a reference terminal, comprising: a first output transistor group with a current path having one end connected to the input terminal and the other end connected to the output terminal; a second output transistor group with a current path having one end connected to the input terminal, the second output transistor group having a lower current driving performance than the first output transistor group; a resistor element having one end connected to the other end of the current path of the second output transistor group, and the other end connected to the output terminal; a reference voltage generating circuit which is connected to the reference terminal and outputs a reference voltage; a voltage-dividing circuit which divides a voltage between the output terminal and the reference terminal; a resistive element having one end to which an output voltage from the voltage-dividing circuit is applied; an error amplifier having a first terminal connected to the other end of the resistive element and a second terminal connected to the reference voltage generating circuit, the error amplifier comparing a voltage which is applied to the first terminal and the reference voltage which is applied to the second terminal, and applying a control voltage to control terminals of the first and second output transistor groups, thereby controlling a resistance of the current path of each of the first and second output transistor groups; and a capacitive element having one end connected to the other end of the current path of the second output transistor group.