SENSING CIRCUIT FOR CAPACITIVE TOUCH PANEL
First Claim
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1. A sensing circuit for a capacitive touch panel, comprising:
- a sensing signal part for generating a sensing signal according to a capacitance of the capacitive touch panel and a noise which is received by the sensing signal part, wherein the capacitance of the capacitive touch panel at a touched condition is different from the capacitance of the capacitive touch panel at an untouched condition;
a reference signal part for receiving the noise and outputting a reference signal, the reference signal part having the same electrical conditions as the sensing signal part; and
an integrator for receiving the sensing signal and the reference signal, subtracting the reference signal from the sensing signal to generate an output signal.
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Abstract
A sensing circuit for a capacitive touch panel is disclosed. By adding a path for a noise to pass through, the noise is differentially processed through two paths which have the same electrical conditions with each other. The noise is then decreased significantly, and a sensing signal can be detected correctly.
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Citations
20 Claims
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1. A sensing circuit for a capacitive touch panel, comprising:
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a sensing signal part for generating a sensing signal according to a capacitance of the capacitive touch panel and a noise which is received by the sensing signal part, wherein the capacitance of the capacitive touch panel at a touched condition is different from the capacitance of the capacitive touch panel at an untouched condition; a reference signal part for receiving the noise and outputting a reference signal, the reference signal part having the same electrical conditions as the sensing signal part; and an integrator for receiving the sensing signal and the reference signal, subtracting the reference signal from the sensing signal to generate an output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A sensing circuit for a capacitive touch panel, comprising:
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a sensing signal path for generating a sensing signal according to a capacitance of the capacitive touch panel and a noise which is received by the sensing signal path, wherein the capacitance of the capacitive touch panel at a touched condition is different from the capacitance of the capacitive touch panel at an untouched condition; a reference signal path for receiving the noise and outputting a reference signal, the reference signal path having the same electrical conditions as the sensing signal path; and a first differential amplifier for receiving the sensing signal and the reference signal, subtracting the reference signal from the sensing signal to generate an output signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification