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:
Oct. 25, 2011
Filed:
Mar. 13, 2009
Yohichi Sakai, Toyonaka, JP;
Shinichi Kojima, Osaka, JP;
Yohichi Sakai, Toyonaka, JP;
Shinichi Kojima, Osaka, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
In a power supply device, a synchronous rectifier step-down converter alternately turns on and off a switch and a synchronous rectifier switch. A reference voltage generator generates a predetermined reference voltage. An error amplifier outputs an error voltage such that an output voltage of the step-down converter approaches the predetermined reference voltage. A pulse-width signal generator generates a pulse-width signal controlling turning on and off the switch and the synchronous rectifier switch based on the error voltage. A driver circuit controls turning on and off the switch and the synchronous rectifier switch based on the pulse-width signal. An inductor is connected in series with output of the step-down converter. A bypass switch short-circuits an output terminal of the step-down converter to an input terminal of the step-down converter. A mode controller controls turning on and off the bypass switch.