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. 06, 2002
Filed:
Apr. 27, 2001
Fujitsu Denso Ltd., Kanagawa, JP;
Abstract
A primary side of a transformer has a switching transistor to on-off control the current flowing in a primary winding on a primary side. A secondary side of the transformer has a commutating side FET to be turned on by applying the induced voltage of a tertiary winding on a secondary side of a current transformer, and a flywheel side FET with the primary winding on the primary side of the current transformer connected thereto in series. The current transformation ratio of the current transformer is small in the initial period when the flywheel side FET is turned on, and then, the current transformation ratio is increased by current controlling means comprising a saturable reactor, a diode or the like.