Noise cancellation technique for capacitive touchscreen controller using differential sensing
US8493356B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 7, 2011 |
| Grant date | Jul 23, 2013 |
| Priority date | — |
| Expiry date | Nov 16, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/96062
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A differential sensing scheme provides a means for detecting one or more touch events on a touch sensitive device in the presence of incident noise. Instead of sensing one touch sensitive channel, such as a row, column, or single touch sensor, multiple touch sensitive channels are sampled at a time. By sampling two nearby channels simultaneously and doing the measurement differentially, noise common to both channels is cancelled. The differential sensing scheme is implemented using simple switch-capacitor AFE circuitry. The originally sensed data on each individual channel is recovered free of common-mode noise. The recovered sensed data is used to determine the presence of one or more touch events and if present the location of each touch event on the touch sensitive device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.