Modulating a reference voltage to preform capacitive sensing
First Claim
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1. An input device, comprising:
- a plurality of sensor electrodes; and
a processing system, comprising;
a reference voltage modulator configured to modulate a reference voltage used to provide power to a plurality of power supplies;
a central receiver electrically coupled to the plurality of sensor electrodes, wherein the central receiver is configured to, when the reference voltage is being modulated, acquire first resulting signals from the plurality of sensor electrodes simultaneously, wherein the central receiver comprises circuitry configured to output, using the first resulting signals, a first capacitive measurement representing a total capacitance of the plurality of sensor electrodes; and
a plurality of local receivers each coupled to a respective one of the plurality of sensor electrodes, wherein the plurality of local receivers is configured to acquire second resulting signals from the plurality of sensor electrodes, wherein each of the plurality of local receivers comprises circuitry, different from the circuity in the central receiver, configured to output, using at least a portion of the second resulting signals, a second capacitive measurement representing a localized capacitance value for a portion of a sensing region comprising the respective one of the plurality of sensor electrodes coupled to a respective one of the plurality of local receivers,wherein the processing system is configured to mitigate an effect a grounding condition has on the second capacitive measurements outputted by the plurality of local receivers using the first capacitive measurement outputted by the central receiver.
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Abstract
This disclosure generally provides an input device modulates a reference voltage used to provide power to a plurality of power supplies and acquires, while modulating the reference voltage, first resulting signals from a plurality of sensor electrodes simultaneously at a central receiver. In input device also acquires second resulting signals from the sensor electrodes at a plurality of local receivers and mitigates an effect a grounding condition has on the second resulting signal using the first resulting signals.
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Citations
19 Claims
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1. An input device, comprising:
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a plurality of sensor electrodes; and a processing system, comprising; a reference voltage modulator configured to modulate a reference voltage used to provide power to a plurality of power supplies; a central receiver electrically coupled to the plurality of sensor electrodes, wherein the central receiver is configured to, when the reference voltage is being modulated, acquire first resulting signals from the plurality of sensor electrodes simultaneously, wherein the central receiver comprises circuitry configured to output, using the first resulting signals, a first capacitive measurement representing a total capacitance of the plurality of sensor electrodes; and a plurality of local receivers each coupled to a respective one of the plurality of sensor electrodes, wherein the plurality of local receivers is configured to acquire second resulting signals from the plurality of sensor electrodes, wherein each of the plurality of local receivers comprises circuitry, different from the circuity in the central receiver, configured to output, using at least a portion of the second resulting signals, a second capacitive measurement representing a localized capacitance value for a portion of a sensing region comprising the respective one of the plurality of sensor electrodes coupled to a respective one of the plurality of local receivers, wherein the processing system is configured to mitigate an effect a grounding condition has on the second capacitive measurements outputted by the plurality of local receivers using the first capacitive measurement outputted by the central receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A processing system, comprising:
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a reference voltage modulator configured to modulate a reference voltage used to provide power to a plurality of power supplies; a central receiver electrically coupled to a plurality of sensor electrodes, wherein the central receiver is configured to, when the reference voltage is being modulated, acquire first resulting signals from the plurality of sensor electrodes simultaneously, wherein the central receiver comprises circuitry configured to output, using the first resulting signals, a first capacitive measurement representing a total capacitance of the plurality of sensor electrodes; and a plurality of local receivers each coupled to a respective one of the plurality of sensor electrodes, wherein the plurality of local receivers is configured to acquire second resulting signals from the plurality of sensor electrodes, wherein each of the plurality of local receivers comprises circuitry, different from the circuitry in the central receiver, configured to output, using at least a portion of the second resulting signals, a second capacitive measurement representing a localized capacitance value for a portion of a sensing region comprising the respective one of the plurality of sensor electrodes coupled to a respective one of the plurality of local receivers, wherein the processing system is configured to mitigate an effect a grounding condition has on the second capacitive measurements outputted by the plurality of local receivers using the first capacitive measurement outputted by the central receiver. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method comprising:
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modulating a reference voltage used to provide power to a plurality of power supplies; acquiring, while modulating the reference voltage, first resulting signals from a plurality of sensor electrodes simultaneously at a central receiver electrically coupled to the plurality of sensor electrodes, wherein the central receiver comprises circuitry that outputs, using the first resulting signals, a first capacitive measurement representing total capacitance of the plurality of sensor electrodes; acquiring second resulting signals from the plurality of sensor electrodes at a plurality of local receivers, wherein each of the plurality of local receivers is coupled to a respective one of the plurality of sensor electrodes, wherein each of the plurality of local receivers comprises circuitry, different from the circuitry in the central receiver, that outputs, using at least a portion of the second resulting signals, a second capacitive measurement representing a localized capacitance value for a portion of a sensing region comprising the respective one of the plurality of sensor electrodes coupled to a respective one of the plurality of local receivers; and mitigating an effect a grounding condition has on the second capacitive measurements outputted by the plurality of local receivers using the first capacitive measurement outputted by the central receiver. - View Dependent Claims (17, 18, 19)
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Specification