System for and method of transferring charge to convert capacitance to voltage for touchscreen controllers
US8624870B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 7, 2011 |
| Grant date | Jan 7, 2014 |
| Priority date | — |
| Expiry date | Nov 8, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/96062
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A touchscreen controller system determines the actual locations of multiple simultaneous touches by eliminating mutual capacitance between adjacent rows and columns during self-capacitance measurements and selectively enabling mutual capacitance during mutual capacitance measurements. During the self-capacitance measurements, the controller system generates a set of candidate touch locations, which includes the locations of real and ghost touches. During the mutual capacitance measurements, only the locations in the candidate set are measured and, from these measurements, the actual touch locations are determined. By limiting the mutual capacitive measurements to only a small subset of the locations over the entire touch panel, real touch locations are determined on a linear order. Also, by using on-chip integration capacitors, embodiments of the invention are able to perform each measurement in a single cycle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.