Multi-mode capacitive sensing device and method with current conveyor
First Claim
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1. A capacitance sensing device, comprising:
- a first plurality of sensor elements;
a second plurality of sensor elements;
a capacitance sensing circuit coupled to the first and second pluralities of sensor elements, the capacitance sensing circuit configured to generate a first current representative of a self capacitance of at least one of the first plurality of sensor elements and configured to generate a second current representative of a mutual capacitance of at least one of the second plurality of sensor elements; and
a conversion circuit configured to convert the first current to a first digital value and the second current to a second digital value,wherein the capacitance sensing circuit is configured to generate the first current and the second current in response to a signal from a mode selection circuit.
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Abstract
An apparatus for and a method of sensing capacitance of one or more sensor elements in multiple capacitance sensing modes, including a self-capacitance sensing mode and a mutual capacitance sensing mode.
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Citations
18 Claims
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1. A capacitance sensing device, comprising:
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a first plurality of sensor elements; a second plurality of sensor elements; a capacitance sensing circuit coupled to the first and second pluralities of sensor elements, the capacitance sensing circuit configured to generate a first current representative of a self capacitance of at least one of the first plurality of sensor elements and configured to generate a second current representative of a mutual capacitance of at least one of the second plurality of sensor elements; and a conversion circuit configured to convert the first current to a first digital value and the second current to a second digital value, wherein the capacitance sensing circuit is configured to generate the first current and the second current in response to a signal from a mode selection circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method comprising:
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generating a first current representative of a self capacitance of one of a plurality of self capacitance sensor elements in a first mode; generating a second current representative of a mutual capacitance of one of a plurality of mutual capacitance sensor elements in a second mode; and selecting between the first mode and the second mode based on an output of a mode selection circuit coupled to a first voltage input of a conversion circuit. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A two-dimensional user interface comprising:
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a first plurality of row sensor elements; a second plurality of column sensor elements; a capacitance sensing circuit coupled to the first and second pluralities of sensor elements, the capacitance sensing circuit configured to generate a first current representative of a self capacitance of at least one of the first plurality of sensor elements and configured to generate a second current representative of a mutual capacitance of at least one of the second plurality of sensor elements; and a conversion circuit configured to convert the first current to a first digital value and the second current to a second digital value, wherein the capacitance sensing circuit is configured to generate the first current and the second current in response to a signal from a mode selection circuit. - View Dependent Claims (16, 17, 18)
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Specification