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. 02, 1992

Filed:

Jul. 26, 1989
Applicant:
Inventor:

Hiroshi Ikeuchi, Kanagawa, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02H / ; H02H / ;
U.S. Cl.
CPC ...
361 18 ; 315411 ; 361 57 ; 363 56 ;
Abstract

A protection circuit against an excessive current in a flyback transformer which supplies a high voltage to a CRT. A fuse and current detecting resistor are inserted on the line which supplies a current to the primary winding of the flyback transformer. The intermediate point of the primary winding and the node of the fuse and current detecting resistor are connected by a semiconductor switching element which becomes conductive when the voltage across the current detecting resistor reaches a certain high voltage. Accordingly, if an excessive current flows in the flyback transformer, the thyristor turns on, causing the fuse to be blown by the large current, whereby the current supply to the flyback transformer can be shut off.


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