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. 19, 1994
Filed:
Jul. 14, 1992
Herbert Heitzer, Kuemmersbruck, DE;
Gerhard Rumold, Bubenreuth, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
An input stage for programmable controllers in which a Schmitt trigger and a two-terminal configuration having a negative resistance characteristic are combined in an integrated circuit. A first resistor supplementing this bipolar configuration to form a constant-current sink is connected externally of the integrated circuit in parallel with the bipolar configuration. A power loss mainly develops in the first resistor which is external of the integrated circuit so that multi-channel input stages are able to be realized cost-effectively without requiring a supply of cooling air to cool the integrated circuit. A second resistor may be connected external of the integrated circuit in series with the two-terminal configuration to further reduce power loss within the integrated circuit and to limit the current flowing into the integrated circuit.