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. 04, 2003
Filed:
Aug. 21, 2001
Reinhard Kögel, Brigachtal, DE;
Jean-Paul Louvel, Villingen-Schwenningen, DE;
Thomson Licensing, S.A., Boulogne-Billancourt, FR;
Abstract
A switched-mode power supply has a storage capacitor, a transformer with a primary winding and at least one secondary winding, and also a switching transistor which is connected in series with the primary winding. The primary winding is subdivided into sub-windings with at least one tap. A capacitance is disposed in parallel with each sub-winding, as a damping network. The numbers of windings of the sub-windings and the values of the capacitors disposed in parallel with the sub-windings are selected in such a way that the oscillations occurring when the switching transistor becomes blocked have different resonant frequencies and thereby partially cancel each other. This results in an effective damping of the resonant voltage over the switching transistor. Since the capacitors are connected in series, the effective total capacitance is low, so that the resulting discharge current at the time when the switching transistor becomes conductive is comparably low.