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:
Jan. 24, 2012
Filed:
Apr. 23, 2009
Yuancheng Ren, Hangzhou, CN;
Junming Zhang, Hangzhou, CN;
Lei Miao, Hangzhou, CN;
Zhaoqi Mao, Hangzhou, CN;
Yuancheng Ren, Hangzhou, CN;
Junming Zhang, Hangzhou, CN;
Lei Miao, Hangzhou, CN;
Zhaoqi Mao, Hangzhou, CN;
Monolithic Power Systems, Inc., San Jose, CA (US);
Abstract
The present invention discloses a smart driving method for a secondary synchronous rectifier of an isolated converter and its apparatus thereof. The apparatus comprises: a main circuit having a secondary synchronous rectifier Q; a differentiation filter circuit, filtering the drain-source voltage Vds of the secondary synchronous rectifier, comprising a capacitor and at least one resistor connected in series and outputting a filtered voltage Vf from either between said capacitor and said at least one resistor or between said at least one resistor; a smart driver, receiving Vf and Vds and putting out a driving signal to the gate of the secondary synchronous rectifier. The control approach is fulfilled by comparing Vds to a reference voltage Vthrand comparing the absolute value of Vf to another reference voltage Vthr. When Vds<Vthrand |Vf|>Vthr, Qis turned on. When Vds>Vthr, Qis turned off, where Vthris a predetermined reference voltage. The driving is reliable with an additional differentiation filter circuit to eliminate error trigger.