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.

Date of Patent:
Jun. 01, 2004

Filed:

Dec. 27, 2002
Applicant:
Inventors:

Ta-yung Yang, Milpitas, CA (US);

Jenn-yu G. Lin, Taipei, TW;

Chern-Lin Chen, Taipei, TW;

Assignee:

System General Corp., Taipei Hsien, TW;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02M 3/24 ;
U.S. Cl.
CPC ...
H02M 3/24 ;
Abstract

A pulse width modulated soft-switching power converter, having a pair of main switches and a pair of auxiliary switches coupled to the primary winding of the transformer. The main switches and auxiliary switches intermittently conduct an input voltage source to the primary winding to operate the soft-switching power converter in four operation stages in each switching cycle. The main switches conduct the input voltage source to the transformer in a first operation stage. In a second operation stage, the conduction is cut off. The transformer operates as an inductor with the auxiliary switches switched on under zero-voltage or zero-current switching mode in a third operation stage. In the fourth operation stage, the auxiliary switches are switched off, whereby the flyback energy achieves the zero-voltage transition. A zero-voltage-detection is employed to optimize the zero-voltage switching. The switching frequency is decreased in response to the decrease of the load. Furthermore, the auxiliary switching is restricted in accordance with the decrease of the load. Therefore reducing the power consumption in the light load and no load conditions.


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