Capacitive touch sense architecture having a correlator for demodulating a measured capacitance from an excitation signal
US9846186B2 · kind B2 · utility
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12Claims
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Key dates
| Filing date | Nov 3, 2014 |
| Grant date | Dec 19, 2017 |
| Priority date | — |
| Expiry date | Mar 17, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An analog front end circuit utilizes coherent detection within a capacitance measurement application. The analog front end circuit uses coherent detection to measure capacitance of a touch screen display. An analog excitation signal is modulated by a capacitor to be measured. The modulated signal is synchronously demodulated using a correlator, which includes a discrete mixer and a discrete integrator. The excitation signal is also input to the mixer such that the modulated signal is multiplied by the excitation signal. The excitation signal is an analog signal having a sine wave function or other waveform.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.