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:
Mar. 28, 1989
Filed:
Jan. 25, 1988
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
Inverter circuits are provided with bridge arms which, for example, including series-connected transistors (T1l , T2l ) with one freewheeling diode (D1, D2) each transistor. A critical operating state occurs when the recovery current is switched off by one of the diodes (D1, D2), so that the other transistor (T1l , T2l ) is cut in. The return current, which passes through this diode, can assume such high values, when rapidly cutting in the transistor, that the 'dynamic' blocking capability of the diode is exceeded, and the diode is burnt out. The load current and the control current are thus reversed, so that the transistor is switched on more slowly and temporarily takes over part of the voltage which is normally applied to the diode.