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:
Sep. 20, 1983
Filed:
Mar. 03, 1980
Applicant:
Inventors:
Frederick G Wall, Garland, TX (US);
Stephen C Kwan, Plano, TX (US);
Assignee:
Texas Instruments Incorporated, Dallas, TX (US);
Primary Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
3403 / ; 200D / ; 307115 ; 3403 / ;
Abstract
Current sensing circuits especially adapted for use with either capacitive touch plate or mechanical switch keys. The circuits include a transistor whose base is connected to a constant voltage source and whose emitter-collector circuit is connected between the touch plate or switch keys and an input to a comparator. A second transistor and a capacitor are interconnected with the first transistor to provide transient surge protection. The circuits distinguish between differing values of current and activate the comparator which produces a signal indicative of the existing condition.