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:
Nov. 03, 1987
Filed:
Dec. 17, 1984
Robert Bosch GmbH, Stuttgart, DE;
Abstract
To protect electrical equipment against excessive applied input signals which, for example, may be analog signals, excessive with respect to positive or negative excess voltage in relation to an upper reference level (U.sub.Ref) and/or a lower reference level (GND), collector current control of the transistor (12) at the input (3) of the protective circuit by three transistors (11, 13, 14) holds the voltage level at the input (3) at the reference voltage level when a driving or signal supply circuit provides an excess voltage. The input transistors, and the further transistors, are connected in the form of a current mirror. The circuit can be constructed in dual form (11-14; 21-24) to provide for protection against negative over-voltage as well. Due to the symmetrical circuit structure, excellent temperature compensation is obtained. The circuit can easily be constructed in the form of an integrated circuit.