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:
Jul. 07, 2009
Filed:
Aug. 05, 2004
Applicant:
Masami Yakabe, Tokyo, JP;
Inventor:
Masami Yakabe, Tokyo, JP;
Assignee:
Tokyo Electron Limited, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 27/26 (2006.01);
U.S. Cl.
CPC ...
Abstract
A capacitance detection circuit containing an input protection circuit and having high sensitivity is provided. A capacitance detection circuit for detecting the capacitance of a capacitive sensor, comprising a buffer amplifier connected to the capacitive sensor via a signal wire and having a voltage gain of 1; diodes connected in series between the signal wire and a positive power supply; diodes connected in series between the signal wire and a negative power supply, wherein an output terminal of the buffer amplifier is connected to a junction point of the diodes and to a junction point of the diodes.