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:
Aug. 01, 1989
Filed:
Aug. 10, 1987
Michael Peppel, Weinheim, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
For maintaining the current-blocking switching state of a thyristor that can be turned off, a low-resistance shunt is added between the gate and cathode terminal of the thyristor in the event of a fault, i.e., in case of a failure of the blocking negative gate- cathode voltage. The shunt preferably is a self-conducting field-effect transistor which is kept in the cut-off state, at least with the thyristor turned off by the negative thyristor gate-cathode voltage itself or indirectly by a supply voltage causing this voltage. The drain-source path of the transistor is connected in series with a diode having a low forward voltage in order to prevent undesirable inverse operation of the transistor.