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:
May. 26, 2009
Filed:
Oct. 23, 2006
Yusuke Minakuchi, Nara, JP;
Yoshiki Takagi, Hyogo, JP;
Yusuke Minakuchi, Nara, JP;
Yoshiki Takagi, Hyogo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Analog Research Limited, Nara, JP;
Abstract
A constant-voltage circuit in which a response speed for a sudden change of an input voltage or a sudden change of a load current can be fast are disclosed. In normal operating conditions, a first control circuit (error amplifier circuit) having an excellent direct-current characteristic controls operations of an output voltage control transistor and an output voltage is made a constant voltage. When the output voltage is suddenly decreased, before the first control circuit controls the operations of the output voltage control transistor by responding to the sudden decrease of the output voltage, an amplifier circuit having a high-speed response characteristic amplifies the change of the output voltage, and when the amplified voltage obtained by the amplification is suddenly decreased, a second control circuit controls the operations of the output voltage control transistor for a predetermined period. With this, the output voltage can be a constant voltage.