Patent ID: 7368896

Claim:
A constant voltage circuit that converts an input voltage received at an input terminal into a predetermined constant voltage and outputs the predetermined constant voltage from an output terminal, the constant voltage circuit comprising: an output voltage control transistor that receives an input control signal from the input terminal and outputs a current according to the input control signal to the output terminal; a reference voltage generating circuit unit that generates and outputs a predetermined reference voltage; an output voltage detection circuit unit that detects an output voltage from the output terminal, and generates and outputs a proportional voltage that is proportional to the detected output voltage; a bias current adjusting circuit unit that adjusts a bias current according to the output voltage; and an error amplifying circuit unit that conducts operation control of the output voltage control transistor to adjust the proportional voltage to correspond to the reference voltage, wherein the error amplifying circuit unit includes a first error amplifier and a second error amplifier that have differing characteristics and are configured to conduct the operation control of the output voltage control transistor at the same time, and wherein the first and second error amplifier each receive: the reference voltage from the reference voltage generating circuit unit, and a dedicated bias current from the bias current adjusting circuit.