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. 26, 1988
Filed:
Mar. 21, 1986
Applicant:
Inventors:
Shigeru Sugayama, Hitachi, JP;
Tatsuo Shimura, Hitachi, JP;
Tadaaki Kariya, Ibaraki, JP;
Sigeo Tomita, Hitachi, JP;
Assignees:
Hitachi, Ltd., Tokyo, JP;
Hitachi Haramachi Semi-Conductor, Ltd., Hitachi, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03K / ;
U.S. Cl.
CPC ...
307633 ; 307637 ; 307646 ; 307305 ; 361 93 ; 361 98 ;
Abstract
A voltage across a resistor of a small value connected in series with the cathode or anode of a thyristor is used as a signal source for overcurrent detection. When an overcurrent is generated, the voltage across the resistor increases in excess of the built-in voltage between the base and emitter of a transistor, thereby turning on the transistor. A transistor to take out a current from the gate of the thyristor is turned on. Thus, the self-turn off operation of the thyristor is executed.