Patent ID: 7859235

Claim:
A constant voltage power supply circuit comprising: a first output transistor connected between an input terminal and an output terminal, the first output transistor forming a first current path between the input and output terminals, the first output transistor having a first control terminal applied with a first control signal to control a current flow through the first current path; a second output transistor connected between the output terminal and a ground terminal, the second output transistor forming a second current path between the output and ground terminals, the second output transistor having a second control terminal applied with a second control signal to control a current flow through the second current path; a first comparator outputting the first control signal to decrease an ON-resistance of the first output transistor when an output voltage from the output terminal reaches a predetermined value or less; a second comparator outputting the second control signal to render the second output transistor conductive to decrease the output voltage when the output voltage reaches a predetermined value or more; an acceleration circuit accelerating charging of the first control terminal of the first output transistor to a predetermined potential; and an inhibition circuit inhibiting the acceleration circuit operation according to a change of the second control signal.