Capacitive sensor system with noise reduction
US8941394B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2010 |
| Grant date | Jan 27, 2015 |
| Priority date | — |
| Expiry date | Nov 14, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system for reducing noise when detecting the capacitance value of a capacitor in a touch display that operates in a potentially noisy environment. A capacitance sensor is provided for determining the size of the capacitor in the touch screen display and includes a charging circuit that charges the capacitor and a discharge circuit that resets the charge of the capacitor to substantially zero. A control circuit controls the capacitance sensor and the operation of the charge and discharge circuits in accordance with a predetermined charging/discharging algorithm to resolve the value of the capacitor and output such value in a sampling operation. The operation of the control circuit and the charging/discharging algorithm is subject to errors as a function of the noisy environment, which errors will be reflected in the output value. A noise reduction circuit is provided to modify the operation of the control circuit to reduce noise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.