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:
Apr. 23, 2002
Filed:
Feb. 21, 2001
Xue Fei Xie, Hong Kong, HK;
Ngai Kit Poon, Kowloon, HK;
Pong Liu, Kwai Hing, HK;
Hay Pong, Ap Lei Chau, HK;
University of Hong Kong, Hong Kong, HK;
Abstract
A synchronous rectifier is disclosed, which makes use of gate charge retention technique. In a forward converter after the main transformer is reset its secondary voltage diminishes to zero. For self-driven synchronous rectifiers the driving voltage is lost and current is forced to go through body diode with high conduction loss. Active clamp is a method to get around the problem but it requires an active switch on the primary side. The present invention introduces gate charge retention method by, which no additional active switch is required on the primary side. Synchronous rectifiers are kept on even after the main transformer is reset and secondary voltage diminished to zero. This synchronous rectifier avoids effect of leakage inductance in converter transformer windings and operates at high efficiency. This synchronous rectifier can operate in a number of circuit topologies.