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.

Date of Patent:
Jun. 13, 2000

Filed:

Apr. 30, 1998
Applicant:
Inventors:

Yasuhiro Shin, Tokyo, JP;

Teruyuki Fujii, Tokyo, JP;

Assignee:
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03K / ;
U.S. Cl.
CPC ...
327 74 ; 327403 ; 327407 ;
Abstract

A static key interface circuit has an input terminal coupled to N key switches, where N is an integer greater than one. The N key switches are biased at different potentials, which are supplied to the input terminal when the key switches are closed. A multilevel detector in the key interface circuit detects the potential of the input terminal and generates corresponding result data. A dynamic key interface circuit has an input terminal coupled to P rows of N key switches each and scans the P rows in turn, using a similar multilevel detector. The multilevel detector increases the number of key switches connectable to a single input terminal by a factor of N.


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