Capacitive pressure sensing method and apparatus avoiding interelectrode capacitance by driving with in-phase excitation signals
US5942692A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 10, 1997 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | Apr 10, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive pressure sensor includes a chamber coupled to a region whose pressure is to be determined. The sensor includes a conductive flexible diaphragm and a pair of electrodes, each defining a capacitance with the diaphragm. Variations in pressure in the chamber cause deflection of the diaphragm which in turn causes variation in the capacitances. A processing circuit applies an excitation signal to the capacitances and couples the capacitances to inductive elements. A current through the inductive elements is detected to determine the difference in the sensor capacitances and, therefore, the deflection of the diaphragm and the pressure in the chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.