Phase-tagged capacitance sensing circuit and electronic device using the same
First Claim
1. An electronic device comprising:
- a touch panel comprising a plurality of sensing conductors;
a driving circuit for sending a square waveform driving signal which is modulated with a predetermined period and superposing phase information on it, the driving circuit comprising;
a signal generator for generating the driving signal; and
a tag generator coupled to the signal generator, for generating the phase information and for superposing the phase information on a rising edge or a falling edge of the driving signal, so that an amplitude of the rising edge of the driving signal plus the phase information pulse is lower than a minimum amplitude of the square waveform, or an amplitude of the falling edge of the driving signal plus the phase information is above a maximum amplitude of the square waveform; and
a sensing circuit for accepting sensing signal and determining a sensing value based on the phase information and the same period of the driving signal.
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Accused Products
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.
15 Citations
16 Claims
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1. An electronic device comprising:
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a touch panel comprising a plurality of sensing conductors; a driving circuit for sending a square waveform driving signal which is modulated with a predetermined period and superposing phase information on it, the driving circuit comprising; a signal generator for generating the driving signal; and a tag generator coupled to the signal generator, for generating the phase information and for superposing the phase information on a rising edge or a falling edge of the driving signal, so that an amplitude of the rising edge of the driving signal plus the phase information pulse is lower than a minimum amplitude of the square waveform, or an amplitude of the falling edge of the driving signal plus the phase information is above a maximum amplitude of the square waveform; and a sensing circuit for accepting sensing signal and determining a sensing value based on the phase information and the same period of the driving signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of processing information on an electronic device, the electronic device comprising a touch panel comprising a plurality of sensing conductors, the method comprising:
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providing a driving signal with a period; superposing phase information on the driving signal, and driving the driving signal to the plurality of conductors of the touch panel, wherein the phase information is superposed on a rising edge or a falling edge of the driving signal, so that an amplitude of the rising edge of the driving signal plus the phase information pulse is lower than a minimum amplitude of the square waveform, or an amplitude of the falling edge of the driving signal plus the phase information is above a maximum amplitude of the square waveform; generating a sensing signal in response to a contact of an object on one of the sensing conductor; performing peak detection to detect the phase information tagging in the sensing signal, and generating the start point for demodulation; and generating a demodulation signal based on the phase information and the period of driving signal, and demodulating the sensing signal by using the demodulation signal to determine a touch position of the touch panel. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification