Wide dynamic range capacitive transducer
US6151967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 10, 1998 |
| Grant date | Nov 28, 2000 |
| Priority date | — |
| Expiry date | Mar 10, 2018 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB81B2203/0392
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A variable area capacitor with a flexible electrode responsive to a physical effect and a rigid electrode with a predetermined surface contour. The surface contour is dimensioned to provide a specific change in capacitance with deflection of the flexible electrode. A thin dielectric layer maintains a substantially fixed spacing between the two electrodes. Preferred embodiments include a pressure sensor, microphone and accelerometer. A differential transconductance amplifier detects changes of the variable capacitor in a low-impedance, bridge-like circuit and feeds back current to balance the bridge. The voltage that controls the feedback current is proportional to capacitance over a wide dynamic range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.