Linearized capacitance sensor system
US5194819A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 10, 1990 |
| Grant date | Mar 16, 1993 |
| Priority date | — |
| Expiry date | Aug 10, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive sensing circuit and system includes a variable capacitance sensing element as an active element in a circuit to measure changes in capacitance of the sensing element. A switching network in alternate cycles energizes a capacitor to develop a charge which effectively linearizes the sensor's capacitance response. In a push-pull circuit with two active sensing elements, a multi-channel switching network energizes two fixed correction capacitors to provide third or higher order correction, significantly extending the effective scale of the sensor. In a preferred embodiment, a single feedback signal is applied to all capacitors in different switching cycles. Examples include weight and pressure sensing systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.