Method of reading a capacitive sensor and related integrated circuit
US7755683B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 2001 |
| Grant date | Jul 13, 2010 |
| Priority date | — |
| Expiry date | Jan 11, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The method is for reading a capacitive sensor and may be implemented by a circuit for biasing and reading capacitances that includes circuits for selecting a column line and a row line, and a charge amplifier producing an output voltage representing the capacitance of the selected capacitor intercepted by the selected column and row lines. The method includes preliminarily resetting the output voltage of the charge amplifier, connecting all the deselected row and column plates of the array to a reference voltage and connecting a feedback capacitor and the selected capacitor to an inverting input of the amplifier, applying a step voltage on the capacitor that is connected to the inverting input of the amplifier, and reading the output voltage at steady-state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.