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:
Jun. 26, 2007
Filed:
Mar. 08, 2006
John O'dowd, County Limerick, IE;
Damien Mccartney, Limerick, IE;
Gabriel Banarie, Limerick, IE;
Analog Devices, Inc., Norwood, MA (US);
Abstract
A one terminal capacitor interface circuit for sensing the capacitance of a capacitor includes a differential integrating amplifier having an input common mode voltage and two summing nodes whose voltage is substantially equal to the input common mode voltage, a switching circuit for charging the capacitor to a first voltage level in a first phase, connecting, in a second phase, the capacitor to one of the summing nodes of the differential amplifier to provide a first output change substantially representative of the difference between the first voltage level and the input common mode voltage, and also representative of the capacitor; charging the capacitor to a second voltage level in a third phase, and connecting, in a fourth phase, the capacitor to the other summing node of the differential amplifier to provide a second output change substantially representative of the difference between the second voltage level and the input common mode voltage, and also representative of the capacitor; the combined first and second output changes representing the capacitance of the capacitor substantially independent of the input common mode voltage.