Capacitive proximity sensor with enabled touch detection
First Claim
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1. A capacitive proximity sensing circuit, comprising:
- one or more guard electrodes;
first capacitive sensor circuitry configured to sense a first capacitance and produce a first capacitive sensor reading responsive to the sensed first capacitance and indicative of detection of a user proximate to the first capacitive sensor, wherein the first capacitive sensor circuitry includes a first capacitive sensor coupled to a first side of at least one of the one or more guard electrodes;
second capacitive sensor circuitry configured to sense a second capacitance and produce a second capacitive sensor reading responsive to the sensed second capacitance and indicative of detection of the user proximate to the second capacitive sensor, wherein the second capacitive sensor circuitry includes a second capacitive sensor coupled to a second side of at least one of the one or more guard electrodes; and
output circuitry configured to receive and compare the first and second capacitive sensor readings and produce an output signal to indicate detection of the user proximate to the first capacitive sensor when the first capacitive sensor reading is greater than the second capacitive sensor reading.
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Abstract
A capacitive proximity sensor circuit capable of distinguishing between instances of detected user proximity includes one or more guard electrodes, a first sensor, and a second sensor. The capacitive proximity sensor is installed in a device such that a first sensor faces a first component of the device, and the second sensor faces a second component of the device. The first and second sensors measure a capacitance to detect proximity of a user relative to the respective sensor. The guard electrode is provided to mitigate stray capacitance to reduce error in the capacitance measurements obtained by the first and second sensors.
65 Citations
24 Claims
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1. A capacitive proximity sensing circuit, comprising:
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one or more guard electrodes; first capacitive sensor circuitry configured to sense a first capacitance and produce a first capacitive sensor reading responsive to the sensed first capacitance and indicative of detection of a user proximate to the first capacitive sensor, wherein the first capacitive sensor circuitry includes a first capacitive sensor coupled to a first side of at least one of the one or more guard electrodes; second capacitive sensor circuitry configured to sense a second capacitance and produce a second capacitive sensor reading responsive to the sensed second capacitance and indicative of detection of the user proximate to the second capacitive sensor, wherein the second capacitive sensor circuitry includes a second capacitive sensor coupled to a second side of at least one of the one or more guard electrodes; and output circuitry configured to receive and compare the first and second capacitive sensor readings and produce an output signal to indicate detection of the user proximate to the first capacitive sensor when the first capacitive sensor reading is greater than the second capacitive sensor reading. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A capacitive proximity sensing circuit for use with a mobile device, comprising:
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one or more guard electrodes; a first sensor coupled to a first side of at least one of the one or more guard electrodes; a second sensor coupled to a second side of at least one of the one or more guard electrodes; first capacitive sensor circuitry coupled to the first sensor, the first capacitive sensor circuitry configured to sense user proximity to the mobile device with respect to the first sensor and to produce a first capacitive sensor reading responsive to the sensed user proximity with respect to the first sensor and indicative of the user proximate to the first sensor; second capacitive sensor circuitry coupled to the second sensor, the second capacitive sensor circuitry configured to sense user proximity to the mobile device with respect to the second sensor and to produce a second capacitive sensor reading responsive to the sensed user proximity with respect to the second sensor and indicative of the user proximate to the second sensor; and output circuitry configured to receive and compare the first and second capacitive sensor readings and produce an output signal to indicate detection of the user proximate to the first capacitive sensor when the first capacitive sensor reading is greater than the second capacitive sensor reading. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification