Capacitance to frequency converter
First Claim
1. A method of converting a capacitance value to a frequency value, the method comprising:
- reciprocally transferring charge between a first capacitor having the capacitance value and a second capacitor;
selectively modulating a frequency of a generated signal in response to the charge transferred between the first capacitor and the second capacitor; and
selectively transferring the charge relative to the second capacitor in response to the generated signal.
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Accused Products
Abstract
A capacitance to frequency converter includes a switching capacitor circuit, a charge dissipation circuit, a comparator, and a signal generator. The switching capacitor circuit charges a sensing capacitor and transfers charge from the sensing capacitor to a circuit node of the charge dissipation circuit. The comparator is coupled to the charge dissipation circuit to compare a potential at the circuit node to a reference voltage. The signal generator is coupled to an output of the comparator and to the charge dissipation circuit. The signal generator is responsive to the output of the comparator to generate a signal fed back to control the charge dissipation circuit. A frequency of the signal is proportional to a capacitance of the sensing capacitor.
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Citations
20 Claims
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1. A method of converting a capacitance value to a frequency value, the method comprising:
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reciprocally transferring charge between a first capacitor having the capacitance value and a second capacitor; selectively modulating a frequency of a generated signal in response to the charge transferred between the first capacitor and the second capacitor; and selectively transferring the charge relative to the second capacitor in response to the generated signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A capacitance to frequency converter comprising:
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a switching capacitor circuit to transfer charge between a first capacitor having the capacitance and a second capacitor; a modulator coupled to the switching capacitor to selectively modulate a frequency of a generated signal in response to the charge transferred between the first capacitor and the second capacitor; and a charge dissipation circuit coupled to the modulator to selectively transfer the charge relative to the second capacitor in response to the generated signal. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An apparatus comprising:
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a switching capacitor circuit to transfer charge between a first capacitor having the capacitance and a second capacitor; a comparator coupled to the second capacitor to compare a potential on the second capacitor to a first voltage and to generate a modulation signal; a pulse generator coupled to the comparator to receive the modulation signal and to generate a feedback signal responsive to the modulation signal; and a charge dissipation circuit coupled to the pulse generator to selectively transfer the charge relative to the second capacitor in response to the feedback signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification