Low power near-field communication devices
First Claim
1. A near-field communication device for detecting and reading external RFID tags, the device comprising:
- a resonant loop antenna circuit including an antenna and a variable component, the antenna having a target range of operation for near-field communication where the antenna inductance is susceptible to interference that can alter the target range, the antenna circuit being tunable by adjusting the variable component; and
an integrated circuit connected to the resonant loop antenna circuit, the integrated circuit comprising;
a controller for controlling transmitting and receiving near-field communications signals via the resonant loop antenna circuit,an inductance detection circuit to detect changes in the antenna inductance indicative of incidents of interference due to an external object located proximate to the device,an antenna tuning circuit to adjust the variable component of the resonant loop antenna circuit to compensate for changes in antenna inductance detected by the inductance detection circuit to maintain the target range of operation, anda wake-on circuit responsive to a sufficient change in antenna inductance being detected by the inductance detection circuit to transition the controller from a low power sleep mode to a communications mode where the wake-on circuit is only again responsive to the sufficient change in antenna inductance as referenced to the adjusted resonant loop antenna circuit.
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Accused Products
Abstract
Power consumption of near-field communication devices is regulated by waking the device for communications when a potential external near-field device is detected, and by adjusting the resonant antenna circuit to account for the detected change in antenna environment. Such near-field communication devices, which may be used to detect and read external RFID tags, include a resonant loop antenna circuit having an antenna and a variable component, the antenna circuit being tunable by adjusting the variable component. The antenna has a target range of operation for near-field communication, and an inductance that is susceptible to interference that can alter the target range. The resonant loop antenna circuit is connected to an integrated circuit that includes a controller for controlling near-field communications via the resonant loop antenna circuit, an inductance detection circuit to detect changes in the antenna inductance, a wake-on circuit responsive to a sufficient change in antenna inductance to transition the controller from a low power sleep mode to a communications mode, and an antenna tuning circuit to adjust the variable component of the resonant loop antenna circuit to compensate for changes in antenna inductance and to maintain the target range of operation.
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Citations
17 Claims
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1. A near-field communication device for detecting and reading external RFID tags, the device comprising:
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a resonant loop antenna circuit including an antenna and a variable component, the antenna having a target range of operation for near-field communication where the antenna inductance is susceptible to interference that can alter the target range, the antenna circuit being tunable by adjusting the variable component; and an integrated circuit connected to the resonant loop antenna circuit, the integrated circuit comprising; a controller for controlling transmitting and receiving near-field communications signals via the resonant loop antenna circuit, an inductance detection circuit to detect changes in the antenna inductance indicative of incidents of interference due to an external object located proximate to the device, an antenna tuning circuit to adjust the variable component of the resonant loop antenna circuit to compensate for changes in antenna inductance detected by the inductance detection circuit to maintain the target range of operation, and a wake-on circuit responsive to a sufficient change in antenna inductance being detected by the inductance detection circuit to transition the controller from a low power sleep mode to a communications mode where the wake-on circuit is only again responsive to the sufficient change in antenna inductance as referenced to the adjusted resonant loop antenna circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for use in a near-field communication device for detecting and reading external RFID tags using a resonant loop antenna circuit that includes an antenna and a variable component, the antenna having a target range of operation for near-field communication where the antenna inductance is susceptible to interference that can alter the target range, the antenna circuit being tunable by adjusting the variable component, and an integrated circuit connected to the resonant loop antenna circuit, the integrated circuit including a controller for controlling transmitting and receiving near-field communications signals via the resonant loop antenna circuit, the method comprising:
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detecting changes in the antenna inductance; responsive to detecting a sufficient change in antenna inductance, transitioning the integrated circuit controller from a low power sleep mode to a communications mode; adjusting the variable component of the resonant loop antenna circuit to compensate for the detected changes in antenna inductance to maintain the target range of operation; and upon adjusting the variable component of the resonant loop antenna circuit only transitioning the integrated circuit controller from a low power sleep mode to a communications mode again if the sufficient change in antenna inductance is detected as referenced to the adjusted antenna resonant loop antenna circuit. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification