Title: Constant voltage power supply circuit and method of controlling the same
Application Number: 200610087650 Application Date: 2006.05.31
Publication Number: 1874104 Publication Date: 2006.12.06
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H02J1/00,G05F1/56
Applicant(s) Name: Ricoh KK Address:
Inventor(s) Name:
Attorney & Agent: lu xiaozhang shao yali
Abstract:
     A constant-voltage power supply circuit is disclosed that is able to prevent overshoot of an output voltage possibly occurring when changing a constant-voltage circuit in operation and is able to supply a constant output voltage. The constant-voltage power supply circuit includes a first constant-voltage circuit, having a first output transistor and a first output voltage controller, that generates a first reference voltage and generates a first proportional voltage in proportion to a voltage on an output terminal, and a second constant-voltage circuit having a second output transistor and a second output voltage controller that generates a second reference voltage and generates a second proportional voltage in proportion to the voltage on the output terminal. When the first output voltage controller or the second output voltage controller starts operations according to a control signal input from the outside, a rising edge of the first reference voltage or the second reference voltage is delayed so as to be later than a rising edge of the first proportional voltage or the second proportional voltage.
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