The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 28, 2012
Filed:
Dec. 04, 2008
Kohji Yoshii, Hyogo, JP;
Kohji Yoshii, Hyogo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A disclosed constant voltage circuit is configured to become active or inactive and convert an input voltage applied to an input terminal into a predetermined constant voltage for output from an output terminal. The circuit includes an output transistor for supplying, from the input terminal to the output terminal, an output current, an error amplifier circuit unit for controlling operations of the output transistor to make a first proportional voltage, which is proportional to the output voltage from the output terminal, equal to a predetermined reference voltage, a ramp voltage generating circuit unit for generating and outputting a ramp voltage whose voltage level increases at a predetermined speed from start-up, and an amplifier circuit unit for amplifying the voltage difference between the ramp voltage and a second proportional voltage, which is proportional to the output voltage, and outputting the amplified voltage difference to a control electrode of the output transistor.