Phase-tagged capacitance sensing circuit and electronic device using the same
US8305352B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 2009 |
| Grant date | Nov 6, 2012 |
| Priority date | — |
| Expiry date | Dec 10, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/04166
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An electronic device includes a touch panel, a driving circuit, and a sensing circuit. The driving circuit generates a driving signal, and superposes phase information on the driving signal. The touch panel includes multiple crossing conductors, for providing a sensing signal in response to a contact of an object on one of the sensing conductors and to a driving signal applied on the sensing element. The sensing circuit includes a signal extractor and a tag detector. The signal extractor generates a demodulation signal based on the period of the driving signal, width of the phase information, and for demodulating the sensing signal by using the demodulation signal to determine a sensing value. The tag detector enables the signal extractor as soon as a magnitude of the sensing signal is over a predetermined threshold. The signal demodulates the sensing signal by using a demodulation signal whose period is the same as the driving signal to determine the sensing value. The present electronic device can determine a touch position by processing of analog signal using the demodulation signal without phase compensation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.