RELATING TO DIAGNOSTICS OF A CAPACITIVE SENSOR
First Claim
1. A detector circuit for detecting the presence of a remote capacitive sensor having at least two terminals connected via a protection circuit that includes one or more capacitors, the detector circuit comprising:
- a voltage supply for changing the charge on the sensor and the protection circuit;
a detector for measuring the voltage on one or more of the terminals;
wherein the presence of the sensor is determined by causing the terminals to ground and then by causing a change of charge on one terminal in a predetermined manner such that the detector can detect the presence of the sensor by measuring a voltage variation of one or more terminals where the voltage variation is larger when the sensor is present than when the sensor is absent.
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Accused Products
Abstract
A detector circuit for detecting the presence of a remote capacitive sensor having at least two terminals connected via a protection circuit that includes one or more capacitors, the detector circuit comprising: a current supply for changing the charge on the sensor and the protection circuit, a detector for measuring the voltage on one or more of the terminals; wherein the presence of the sensor is determined by changing the charge on the capacitive sensor and the one or more capacitors of the protection circuit in a predetermined manner such that the voltage measurement on the one or more terminals when the sensor is present is significantly different than when the sensor is absent.
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Citations
20 Claims
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1. A detector circuit for detecting the presence of a remote capacitive sensor having at least two terminals connected via a protection circuit that includes one or more capacitors, the detector circuit comprising:
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a voltage supply for changing the charge on the sensor and the protection circuit; a detector for measuring the voltage on one or more of the terminals; wherein the presence of the sensor is determined by causing the terminals to ground and then by causing a change of charge on one terminal in a predetermined manner such that the detector can detect the presence of the sensor by measuring a voltage variation of one or more terminals where the voltage variation is larger when the sensor is present than when the sensor is absent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20)
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15. A method for detecting the presence of a remote capacitive sensor having at least two terminals connected via a protection circuit that includes one or more capacitors, the method comprising:
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changing the charge on the sensor and the protection circuit, measuring the voltage on one or more of the terminals; wherein the presence of the sensor is determined by causing the terminals to ground and then by causing a change of charge on one terminal in a predetermined manner such that the detector can detect the presence of the sensor by measuring a voltage variation of one or more terminals where the voltage variation is larger when the sensor is present than when the sensor is absent.
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Specification