Linearity enhancement for capacitive sensors
US7078916B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 2004 |
| Grant date | Jul 18, 2006 |
| Priority date | — |
| Expiry date | Apr 26, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P15/125
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for enhancing the linearity of a differential capacitive sensor as a function of beam displacement. An ac-modulated feedback connection from a sensor output terminal to a movable beam electrode is provided through a fix-up capacitor. The output terminal signal is inverted in the feedback connection so that the fix-up capacitor reduces the capacitance from the fixed electrodes to the beam electrode. When the fix-up capacitor value is chosen approximately equal to the fixed capacitance of the differential capacitor, the feedback circuit compensates for the effect of this fixed capacitance. The linearity of the output as a function of the displacement of the beam is improved. Thus, the signal-to-noise ratio of devices such as accelerometers may be increased by allowing sensors to employ a large displacement range. The invention may be used in differential accelerometers and in other types of differential capacitive sensors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.