Charge balancing converter using a passive integrator circuit
First Claim
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1. A method comprising:
- at a capacitance-sensing circuit electrically coupled to a capacitive sense array of electrodes and including a current generator;
performing capacitance sensing of an electrode of the capacitive sense array of electrodes, including;
configuring a passive integrator circuit to include a first capacitor associated with a self-capacitance of the electrode, wherein the first capacitor is formed between the electrode and a ground;
balancing by the current generator charge integrated on the passive integrator circuit; and
sensing the charge integrated on the passive integrator circuit, wherein the sensed charge is indicative of a sensed capacitance associated with at least one of the self-capacitance and a mutual capacitance of the electrode; and
converting the sensed charge indicative of the sensed capacitance of the electrode into a digital value, wherein the digital value corresponds to a length of time for balancing the charge integrated on the passive integrator circuit and associated with the sensed capacitance of the electrode.
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Abstract
A method, apparatus, and system are described to perform, by a capacitance-sensing circuit, capacitance sensing of an electrode of a capacitive sense array of electrodes. Performing the capacitance sensing includes integrating, on a passive integrator circuit, charge from a sensed capacitance of the electrode of the capacitive sense array. The passive integrator circuit integrates the charge on a self-capacitance of the electrode as part of the integrating. The capacitance-sensing circuit converts the charge from the sensed capacitance of the electrode into a digital value representing the sensed capacitance of the electrode.
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Citations
20 Claims
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1. A method comprising:
at a capacitance-sensing circuit electrically coupled to a capacitive sense array of electrodes and including a current generator; performing capacitance sensing of an electrode of the capacitive sense array of electrodes, including; configuring a passive integrator circuit to include a first capacitor associated with a self-capacitance of the electrode, wherein the first capacitor is formed between the electrode and a ground; balancing by the current generator charge integrated on the passive integrator circuit; and sensing the charge integrated on the passive integrator circuit, wherein the sensed charge is indicative of a sensed capacitance associated with at least one of the self-capacitance and a mutual capacitance of the electrode; and converting the sensed charge indicative of the sensed capacitance of the electrode into a digital value, wherein the digital value corresponds to a length of time for balancing the charge integrated on the passive integrator circuit and associated with the sensed capacitance of the electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus comprising
a capacitance-sensing circuit electrically coupled to capacitive sense array of electrodes and including a current generator, wherein the capacitance-sensing circuit is configured to: -
perform capacitance sensing of an electrode of the capacitive sense array of electrodes, including; configuring a passive integrator circuit to include a first capacitor associated with a self-capacitance of the electrode, wherein the first capacitor is formed between the electrode and a ground; balancing by the current generator charge integrated on the passive integrator circuit; and sensing the charge, integrated on the passive integrator circuit, wherein the sensed charge is indicative of a sensed capacitance associated with at least one of the self-capacitance and a mutual capacitance of the electrode; and convert the sensed charge indicative of the sensed capacitance of the electrode into a digital value, wherein the digital value corresponds to a length of time for balancing the charge integrated on the passive integrator circuit and associated with the sensed capacitance of the electrode. - View Dependent Claims (18)
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19. A system comprising:
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a capacitive sense array, the capacitive sense array comprising a plurality of electrodes, wherein a first capacitor is formed between an electrode of the plurality of electrodes and a ground, associated with a self-capacitance of the electrode, and configured to become part of a passive integrator circuit, and wherein the passive integrator circuit is used to integrate charge indicative of a sensed capacitance associated with at least one of the self-capacitance and a mutual capacitance of the electrode; and a capacitance-sensing circuit coupled to the capacitive sense array and including a current generator, wherein the capacitance-sensing circuit is configured to; balance by the current generator the charge integrated on the passive integrator circuit, sense the integrated charge on the passive integrator circuit, and convert the integrated charge into a digital value, wherein the digital value corresponds to a length of time for balancing the charge integrated on the passive integrator circuit and associated with the sensed capacitance of the electrode. - View Dependent Claims (20)
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Specification