Smart scanning for a capacitive sensing array
First Claim
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1. A method comprising:
- simultaneously driving a plurality of transmit electrodes in each of a plurality of scan groups in a capacitive sense array to generate a group receive signal for each of the plurality of scan groups corresponding to a mutual capacitance at sense elements of the capacitive sense array that form the scan group, wherein each of the plurality of scan groups comprises a plurality of sense elements;
determining, based on the group receive signals from the plurality of scan groups, a scan group where the generated receive signal is affected by a presence of a conductive object in proximity to the capacitive sense array, wherein each of a number of receive electrodes that form one of the plurality of scan groups share a single receive processing channel of a plurality of receive processing channels;
sequentially driving one or more of the plurality of transmit electrodes in an identified scan group with a transmit signal, where the generated receive signal corresponding to the identified scan group is affected by the presence of the conductive object in proximity to the capacitive sense array; and
determining, based on individual receive signals on each of the receive electrodes that form the identified scan group resulting from the sequential driving, a location of the conductive object, wherein each of the receive electrodes that form the identified scan group are coupled to a separate receive processing channel of the plurality of receive processing channels.
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Abstract
A method and apparatus scan a plurality of scan groups in a capacitive sense array to generate signals corresponding to a mutual capacitance between the electrodes. Each of the plurality of scan groups is formed from a subset of the plurality of electrodes. A processing device identifies a scan group where the generated signal is affected by a presence of a conductive object. The processing device individually scans the subset of the plurality of sense elements in the identified scan group to determine a location of the conductive object.
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Citations
14 Claims
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1. A method comprising:
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simultaneously driving a plurality of transmit electrodes in each of a plurality of scan groups in a capacitive sense array to generate a group receive signal for each of the plurality of scan groups corresponding to a mutual capacitance at sense elements of the capacitive sense array that form the scan group, wherein each of the plurality of scan groups comprises a plurality of sense elements; determining, based on the group receive signals from the plurality of scan groups, a scan group where the generated receive signal is affected by a presence of a conductive object in proximity to the capacitive sense array, wherein each of a number of receive electrodes that form one of the plurality of scan groups share a single receive processing channel of a plurality of receive processing channels; sequentially driving one or more of the plurality of transmit electrodes in an identified scan group with a transmit signal, where the generated receive signal corresponding to the identified scan group is affected by the presence of the conductive object in proximity to the capacitive sense array; and determining, based on individual receive signals on each of the receive electrodes that form the identified scan group resulting from the sequential driving, a location of the conductive object, wherein each of the receive electrodes that form the identified scan group are coupled to a separate receive processing channel of the plurality of receive processing channels. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus comprising:
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a capacitive sense array having a plurality of sense elements; and a processing device coupled to the capacitive sense array, the processing device to; simultaneously drive a plurality of transmit electrodes in each of a plurality of scan groups in the capacitive sense array to generate a group receive signal for each of the plurality of scan groups corresponding to a mutual capacitance at the sense elements that form the scan group, wherein each of the plurality of scan groups comprises a subset of the plurality of sense elements; determine, based on the group receive signals from the plurality of scan groups, a scan group where the generated receive signal is affected by a presence of a conductive object in proximity to the capacitive sense array, wherein each of a number of receive electrodes that form one of the plurality of scan groups share a single receive processing channel of a plurality of receive processing channels; sequentially drive one or more of the plurality of transmit electrodes in an identified scan group with a transmit signal, where the generated receive signal corresponding to the identified scan group is affected by the presence of the conductive object in proximity to the capacitive sense array; and determine, based on individual receive signals on each of the receive electrodes that form the identified scan group resulting from the sequential driving, a location of the conductive object, wherein each of the receive electrodes that form the identified scan group are coupled to a separate receive processing channel of the plurality of receive processing channels. - View Dependent Claims (7, 8, 9, 10)
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11. An apparatus comprising:
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a touch-sensor device, the touch-sensor device comprising an array of capacitive sense elements, the array comprising a plurality of transmit electrodes and a plurality of receive electrodes; a transmit selection circuit coupled to the touch-sensor device, the transmit selection circuit to selectively apply a transmit signal to one or more of the transmit electrodes; a receive selection circuit coupled to the touch-sensor device, the receive selection circuit to selectively measure a signal from one or more of the receive electrodes, wherein the measured signal corresponds to a mutual capacitance value between a transmit electrode and a receive electrode; and a processing device coupled to the touch-sensor device, the processing device to; simultaneously drive a plurality of transmit electrodes in a scan group of the capacitive sense array, wherein the scan group comprises the plurality of transmit electrodes and a plurality of receive electrodes; determine, based on a group receive signal from the scan group, if a conductive object is present on the touch-sensor device in an area corresponding to the scan group, wherein each of the plurality of receive electrodes that form the scan group share a single receive processing channel of a plurality of receive processing channels; if a conductive object is present on the touch-sensor device in the area corresponding to the scan group, sequentially drive one or more of the plurality of transmit electrodes in the scan group with a transmit signal; and determine, based on individual receive signals on each of the receive electrodes that form the scan group resulting from the sequential driving, a location of the conductive object, wherein each of the receive electrodes that form the identified scan group are coupled to a separate receive processing channel of the plurality of receive processing channels. - View Dependent Claims (12, 13, 14)
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Specification