CAPACITIVE TOUCH SENSING SYSTEM
First Claim
1. A capacitive touch sensing system, comprising:
- a touch panel comprising a plurality of driving electrodes intersecting with a plurality of sensing electrodes;
a differential unit calculating a difference between sensing signals outputted by two adjacent sensing electrodes to output a differential signal;
a downconversion unit configured to demodulate the differential signal to generate a dc signal and to accumulate the dc signal; and
an AD converter configured to convert the accumulated dc signal to a digital signal.
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Abstract
There is provided a capacitive touch sensing system including a touch panel, a plurality of amplification units, an analog signal processing unit and an AD converter. The touch panel includes a plurality of driving electrodes intersecting with a plurality of sensing electrodes. Each of the amplification units is coupled to one of the sensing electrodes so as to output an amplified sensing signal. The analog signal processing unit demodulates a differential signal of the amplified sensing signals outputted by two adjacent amplification units or demodulates the amplified sensing signal outputted by the amplification units to generate a dc signal. The AD converter converts the dc signal to a digital signal.
100 Citations
20 Claims
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1. A capacitive touch sensing system, comprising:
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a touch panel comprising a plurality of driving electrodes intersecting with a plurality of sensing electrodes; a differential unit calculating a difference between sensing signals outputted by two adjacent sensing electrodes to output a differential signal; a downconversion unit configured to demodulate the differential signal to generate a dc signal and to accumulate the dc signal; and an AD converter configured to convert the accumulated dc signal to a digital signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A capacitive touch sensing system, comprising:
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a touch panel comprising a plurality of driving electrodes intersecting with a plurality of sensing electrodes; a driving circuit sequentially inputting a driving signal having a driving frequency to the driving electrodes; a downconversion unit configured to demodulate sensing signals outputted by each of the sensing electrodes with an operating frequency of 4 times of the driving frequency to generate a dc signal and to accumulate the dc signal; and an AD converter configured to convert the accumulated dc signal to a digital signal. - View Dependent Claims (12, 13, 14, 15)
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16. A capacitive touch sensing system, comprising:
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a touch panel comprising a plurality of driving electrodes intersecting with a plurality of sensing electrodes; a plurality of amplification units respectively coupled to the sensing electrodes for amplifying sensing signals outputted by the sensing electrodes; a differential unit calculating a difference between amplified sensing signals outputted by two adjacent amplification units to output a differential signal; and an AD converter configured to convert the differential signal to a digital signal. - View Dependent Claims (17, 18, 19, 20)
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Specification