Patent ID: 7030686

Claim:
A constant-voltage circuit for converting an input voltage provided to an input terminal of said constant-voltage circuit into a predetermined constant voltage, and for providing said constant voltage to a load, comprising: a reference voltage generating circuit unit for generating and outputting a predetermined reference voltage; an output voltage detecting unit for detecting said constant voltage, and generating and outputting a voltage that is proportional to said detected voltage; an output transistor for outputting a current provided from said input terminal to said load according to a control signal; an error amplifying circuit unit for providing said control signal for controlling operations of said output transistor so that said proportional voltage becomes equal to said reference voltage; an output current detecting unit for detecting said current output from said output transistor, and generating and outputting a proportional current that is proportional to the detected current; a first resistance connected to said output voltage detecting unit; a proportional current supply circuit unit for supplying said proportional current, which is proportional to the output current, from said output current detecting unit to said first resistance; a second resistance connected between said output transistor and said load; and a capacitor connected to a junction where said second resistance and said load are connected; wherein said second resistance and said capacitor constitute a phase compensating circuit unit for carrying out phase compensation for said error amplifying circuit unit.