Evaluation circuit for a capacitive sensor, capacitive sensor, and actuator in a motor vehicle
US10684142B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 14, 2016 |
| Grant date | Jun 16, 2020 |
| Priority date | — |
| Expiry date | Jan 2, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/960745
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An evaluation circuit for a capacitive sensor for detecting the distance, speed, or position of an object, comprises a reference capacitance and a measuring capacitance. A square wave voltage is applied to the reference capacitance and the measuring capacitance via a resistor, and a pulse which has a variable duration is obtained with the aid of a logic linking unit. The reference capacitance is connected to a first switching stage and the measuring capacitance is connected to a further switching stage. A single measuring capacitance has a capacitive coupling to an auxiliary electrode, and the switching stages are part of a logic linking unit. An output of the logic linking unit is connected to an integration stage. A charging capacitor (Ca) is charged or discharged via an output of the integration stage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.