Capacitive multi-touch system and method of controlling the same
First Claim
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1. A capacitive multi-touch system, comprising:
- a touch sensor panel configured to generate a capacitance signal corresponding to a touch input;
a front-end circuit configured to convert the capacitance signal to a sensing channel signal; and
a digital signal processor configured to;
receive a common voltage (VCOM) from a display device, calculate a noise interval of two neighboring noise peaks of the common voltage, andperform a noise filtering operation on the sensing channel signal using a noise filter path,wherein the noise filter path is selected from a plurality of noise filter paths based on the noise interval, andwherein the noise interval is measured in a frequency domain of the common voltage.
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Abstract
A capacitive multi-touch system includes a touch sensor pane, a front-end circuit, and a digital signal processor. The touch sensor panel generates a capacitance signal corresponding to a touch input. The front-end circuit converts the capacitance signal to a sensing channel signal. The digital signal processor receives a common voltage (VCOM) from a display device, calculates a noise interval of two neighboring noise peaks of the common voltage, and performs a noise filtering operation on the sensing channel signal using a noise filter path. The noise filter path is selected from a plurality of noise filter paths based on the noise interval.
28 Citations
17 Claims
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1. A capacitive multi-touch system, comprising:
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a touch sensor panel configured to generate a capacitance signal corresponding to a touch input; a front-end circuit configured to convert the capacitance signal to a sensing channel signal; and a digital signal processor configured to; receive a common voltage (VCOM) from a display device, calculate a noise interval of two neighboring noise peaks of the common voltage, and perform a noise filtering operation on the sensing channel signal using a noise filter path, wherein the noise filter path is selected from a plurality of noise filter paths based on the noise interval, and wherein the noise interval is measured in a frequency domain of the common voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of controlling a capacitive multi-touch system, the method comprising:
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generating a capacitance signal corresponding to an input touch; converting the capacitance signal to a sensing channel signal; analyzing a noise spectrum of a common voltage (VCOM) to generate a filter selection signal; performing a filtering operation on the sensing channel signal using a noise filtering operation selected by the filter selection signal, wherein the analyzing of the noise spectrum further comprises; calculating a noise interval of the common voltage; comparing the noise interval to a bandwidth of a first filter; and generating the filter selection signal based on the comparison result. - View Dependent Claims (13, 14, 15)
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16. A capacitive multi-touch system, comprising:
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a display device configured to operate using a common voltage; a touch sensor panel disposed on the display device and configured to generate a sensing input signal corresponding to a touch input; and a digital signal processor configured to analyze noise characteristics of the common voltage and perform a noise filtering operation on the sensing input signal based on the noise characteristics, wherein the noise characteristics include a noise interval of two adjacent noise peaks of the common voltage, wherein the noise interval is measured in a frequency domain of the common voltage. - View Dependent Claims (17)
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Specification