Capacitive physical quantity sensor and diagnosis method
US7525322B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 18, 2007 |
| Grant date | Apr 28, 2009 |
| Priority date | — |
| Expiry date | Sep 5, 2027 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB81B2201/0235
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive sensor for detecting a physical quantity includes a sensor element and a detecting circuit. The sensor element includes a movable electrode and a fixed electrode. A periodic voltage is applied to the fixed electrode. A high-voltage generating circuit applies a diagnostic voltage to an input side of a C-V conversion circuit so as to diagnose a sticking of a foreign object between the movable electrode and the fixed electrode. The C-V conversion circuit includes a diagnostic switch, which is opened in a diagnostic mode. The periodic voltage in the diagnostic mode is larger than the periodic voltage in a normal measuring mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.