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:
Feb. 13, 2007
Filed:
May. 31, 2005
Hiroshi Usui, Niiza, JP;
Syohei Osaka, Niiza, JP;
Hiroshi Usui, Niiza, JP;
Syohei Osaka, Niiza, JP;
Sanken Electric Co., Ltd., , JP;
Abstract
A power factor corrector is connected to an AC power source, to provide a first DC voltage. A DC-DC converter supplies the first DC voltage from the power factor corrector to a primary winding of a transformer. A first rectifying/smoothing circuit rectifies and smoothes a voltage generated by a secondary winding of the transformer and supplies the rectified-and-smoothed voltage to a load. A second rectifying/smoothing circuit rectifies and smoothes a voltage generated by a control winding of the transformer. A light-load detector detects if an output ripple of the second rectifying/smoothing circuit is equal to or greater than a predetermined value, determines upon detection that the switching operation has decreased the frequency thereof or has shifted to an intermittent oscillation, and stops the power factor corrector.