Active integrator for a capacitive sense array
First Claim
Patent Images
1. A circuit comprising:
- an active integrator configured to measure a capacitance of a touch sense array, wherein the active integrator is configured to receive from the touch sense array a response signal comprising a positive portion and a negative portion, wherein the response signal is representative of a presence or an absence of a conductive object proximate to the touch sense array, the active integrator comprisinga first integrating capacitor, anda second integrating capacitor, wherein the first integrating capacitor or the second integrating capacitor are configured to be alternately coupled in a feedback configuration between an output terminal of the active integrator and a first input terminal of the active integrator, the first integrating capacitor in the feedback configuration to integrate the positive portion of the response signal and the second integrating capacitor in the feedback configuration to integrate the negative portion of the response signal.
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Abstract
An active integrator for sensing capacitance of a touch sense array is disclosed. The active integrator is configured to receive from the touch sense array a response signal having a positive portion and a negative portion. The response signal is representative of a presence or an absence of a conductive object on the touch sense array. The active integrator is configured to continuously integrate the response signal.
322 Citations
20 Claims
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1. A circuit comprising:
an active integrator configured to measure a capacitance of a touch sense array, wherein the active integrator is configured to receive from the touch sense array a response signal comprising a positive portion and a negative portion, wherein the response signal is representative of a presence or an absence of a conductive object proximate to the touch sense array, the active integrator comprising a first integrating capacitor, and a second integrating capacitor, wherein the first integrating capacitor or the second integrating capacitor are configured to be alternately coupled in a feedback configuration between an output terminal of the active integrator and a first input terminal of the active integrator, the first integrating capacitor in the feedback configuration to integrate the positive portion of the response signal and the second integrating capacitor in the feedback configuration to integrate the negative portion of the response signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method, comprising:
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receiving a response signal at an active integrator from a touch sense array, the response signal comprising a positive portion and a negative portion, wherein the response signal is representative of a presence or an absence of a conductive object proximate to the touch sense array; and alternately integrating, by a first integrating capacitor or a second integrating capacitor of the active integrator, the positive portion or the negative portion of the response signal, wherein the first integrating capacitor or the second integrating capacitor are configured to be alternately coupled in a feedback configuration between an output terminal of the active integrator and a first input terminal of the active integrator, the first integrating capacitor in the feedback configuration to integrate the positive portion of the response signal and the second integrating capacitor in the feedback configuration to integrate the negative portion of the response signal continuously integrating the response signal includes integrating at least a portion of the response signal while sample-and-holding an output of the active integrator, wherein sample-and-holding the output of the active integrator includes sample-and-holding the output corresponding to the positive portion during a first period and sample-and-holding the output corresponding to the negative portion during a second period. - View Dependent Claims (15, 16, 17, 18)
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19. An apparatus, comprising:
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a touch sense array; and an active integrator configured to measure a capacitance of the touch sense array, wherein the active integrator is configured to receive from the touch sense array a response signal comprising a positive portion and a negative portion, wherein the response signal is representative of a presence or an absence of a conductive object proximate to the touch sense array, the active integrator comprising a first integrating capacitor, and a second integrating capacitor, wherein the first integrating capacitor or the second integrating capacitor are configured to be alternately coupled in a feedback configuration between an output terminal of the active integrator and a first input terminal, the first integrating capacitor in the feedback configuration to integrate the positive portion of the response signal and the second integrating capacitor in the feedback configuration to integrate the negative portion of the response signal. - View Dependent Claims (20)
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Specification