Sensing circuit and method for a capacitive touch panel
US8593429B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 2010 |
| Grant date | Nov 26, 2013 |
| Priority date | — |
| Expiry date | Oct 25, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0446
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A sensing method and circuit for a capacitive touch panel sense the capacitance variation of a lateral capacitor formed at the intersection of two traces of the capacitive touch panel, to distinguish a real point from a ghost point. A sensing cycle includes two non-overlapping clock phases. In the first clock phase, the voltages across the lateral capacitor and across a sensing capacitor are set. In the second clock phase, the voltage at a first terminal of the lateral capacitor is changed, and a second terminal of the lateral capacitor is connected to a first terminal of the sensing capacitor, causing a voltage variation at a second terminal of the sensing capacitor. This voltage variation is used to determine whether the intersection is touched. The sensing method and circuit reflect the status of the lateral capacitor in real-time and prevent the location of the touch point from being misjudged.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.