Circuit and method for sensing a differential capacitance
US9267976B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 2014 |
| Grant date | Feb 23, 2016 |
| Priority date | — |
| Expiry date | Sep 24, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A circuit for sensing a differential capacitance includes a charge-storing circuit to generate a first output voltage and a second output voltage related to capacitances at two terminals of the differential capacitance, respectively, an operational amplifier to amplify the difference between the first and second output voltages to generate a sensing value, a first sampling capacitor having one terminal connected to the negative input terminal and the other terminal receiving the first or second output voltage, and a second sampling capacitor having one terminal connected to the negative input terminal and the other terminal switched to the output terminal of the operational amplifier. The second sampling capacitor stores a non-ideal error value to offset the non-ideal effect of the operational amplifier imparted on the sensing value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.