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:
Feb. 09, 1982
Filed:
Oct. 05, 1979
Ichiro Ohhinata, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A PNPN switch has a transistor for protecting the switch from the dv/dt effect, which is so connected as to shortcircuit one outermost PN junction PN of the switch. The transistor is driven by a drive circuit and not through the outer outermost PN junction of the switch by a drive circuit. The drive circuit is so designed that, in a transient mode, it operates as a transistor element and a capacitive element and, in a DC mode, it operates solely as a capacitive element. To this end, a transistor is used as the drive circuit. A level shift element is connected in series with the emitter-base junction of the drive transistor. The series circuit of the level shift element and the emitter-base junction is connected across the other PN junction and the collector of the drive transistor is connected to the base of the dv/dt protective transistor.