Differential capacitance measurement
US6949937B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 13, 2004 |
| Grant date | Sep 27, 2005 |
| Priority date | — |
| Expiry date | Feb 17, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A circuit and method are given, which realizes a stable yet sensitive differential capacitance measuring device with good RF-suppression and with very acceptable noise features for use in capacitive sensor evaluation systems. By evaluating the difference of capacitor values only—with the help of a switched capacitor front-end—large spreads of transducer capacitor values are tolerable. Furthermore a mode of operation can be set up, where no essential galvanic connection between sensor input and the active read-out input at any given time is existing. The solution found exhibits a highly symmetrical construction. Using the intrinsic advantages of that solution the circuit of the invention is manufactured as an integrated circuit with standard CMOS technology at low cost.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.