CURRENT SENSING APPARATUS AND METHOD FOR A CAPACITANCE-SENSING DEVICE
First Claim
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1. An apparatus, comprising:
- a current-to-voltage converter having an input coupled to receive a current representing a capacitance of a sense element, wherein the current-to-voltage converter is configured to convert the current to an output voltage; and
an analog-to-digital converter (ADC) coupled to receive the output voltage of the current-to-voltage converter, wherein the ADC is configured to convert the output voltage to a digital value, and wherein the current-to-voltage converter is configured to maintain an approximately constant voltage at the input of the current-to-voltage converter.
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Abstract
A capacitance-sensing device including a current-to-voltage converter and an analog-to-digital converter is described. A sense element is coupled to an input of the current-to-voltage converter. The current-to-voltage converter is configured to convert current changes in the coupled sense element to an output voltage and to maintain a constant voltage at the input. The analog-to-digital converter is configured to convert the output voltage generated by the current-to-voltage converter to a digital value.
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Citations
20 Claims
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1. An apparatus, comprising:
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a current-to-voltage converter having an input coupled to receive a current representing a capacitance of a sense element, wherein the current-to-voltage converter is configured to convert the current to an output voltage; and an analog-to-digital converter (ADC) coupled to receive the output voltage of the current-to-voltage converter, wherein the ADC is configured to convert the output voltage to a digital value, and wherein the current-to-voltage converter is configured to maintain an approximately constant voltage at the input of the current-to-voltage converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method, comprising:
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sensing current changes in a sense element coupled to an input of a capacitance-sensing device; converting the sensed current changes to an output voltage by the capacitance-sensing device; and measuring capacitance changes of the sense element by converting the output voltage to a digital value. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. An apparatus, comprising:
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means for sensing current changes in a sense element coupled to an input of a capacitance-sensing device; means for converting the sensed current changes to an output voltage by the capacitance-sensing device; and means for measuring capacitance changes of the sense element by converting the output voltage to a digital value; and means for maintaining a constant voltage at the input of the capacitance-sensing device. - View Dependent Claims (20)
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Specification