NFC or RFID device RF detuning detection and driver output power regulation
First Claim
1. A method for detuning detection and transmitter (TX) current regulation, the method comprising:
- monitoring, by a sensor within a transmitter in a transmitter reader mode of a radio frequency (RF) device, a transmitter (TX) current and/or voltage at a maximum predetermined transmitter power level that corresponds to a first operational gear associated with a first corresponding specific register configuration, wherein the TX current and/or voltage is output by an output driver of the transmitter to drive an antenna and matching circuit of the RF device;
detecting a change in the TX current and/or voltage as output by the output driver, andin response to the detected change, detecting an initial detuning of the antenna and matching circuit arising from a load change on the antenna resulting from interaction with a further resonant circuit; and
in response to detection of the initial detuning, reducing the TX current to match inductance between the antenna and matching circuit and the further resonant circuit by shifting the transmitter power level to one of a plurality of lower discrete gears based on a comparison between a predicted TX current and a plurality of TX current thresholds, wherein each lower discrete gear is associated with a different specific register configuration, and a discrete, predetermined transmitter power level that is below the maximum predetermined transmitter power level, and further wherein the transmitter is configured to initiate reading in highest gear and only shift to a lower gear to match inductance between the antenna and matching circuit and the further resonant circuit.
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Accused Products
Abstract
A near field communication (NFC) or Radio Frequency Identification (RFID) reader device for contact-less communication includes a transmitter block connected to an antenna via a matching circuitry. An electromagnetic carrier signal and modulated data information are emitted via this main antenna. Any secondary object brought into the vicinity of the main antenna influences the primary resonant circuit resulting in a load change seen by the transmitter. This detuning can cause increased power consumption, RF (Radio Frequency) standard incompliance, and device damage. The present disclosure describes devices and methods on how to detect detuning and how to regulate the transmitter'"'"'s output.
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Citations
19 Claims
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1. A method for detuning detection and transmitter (TX) current regulation, the method comprising:
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monitoring, by a sensor within a transmitter in a transmitter reader mode of a radio frequency (RF) device, a transmitter (TX) current and/or voltage at a maximum predetermined transmitter power level that corresponds to a first operational gear associated with a first corresponding specific register configuration, wherein the TX current and/or voltage is output by an output driver of the transmitter to drive an antenna and matching circuit of the RF device; detecting a change in the TX current and/or voltage as output by the output driver, and in response to the detected change, detecting an initial detuning of the antenna and matching circuit arising from a load change on the antenna resulting from interaction with a further resonant circuit; and in response to detection of the initial detuning, reducing the TX current to match inductance between the antenna and matching circuit and the further resonant circuit by shifting the transmitter power level to one of a plurality of lower discrete gears based on a comparison between a predicted TX current and a plurality of TX current thresholds, wherein each lower discrete gear is associated with a different specific register configuration, and a discrete, predetermined transmitter power level that is below the maximum predetermined transmitter power level, and further wherein the transmitter is configured to initiate reading in highest gear and only shift to a lower gear to match inductance between the antenna and matching circuit and the further resonant circuit. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for detuning detection and transmitter (TX) current regulation, the method comprising:
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monitoring, by a sensor within a transmitter of a radio frequency (RF) device, a transmitter (TX) voltage and/or current as output by an output driver of the transmitter to drive an antenna and matching circuit of the RF device, wherein the antenna and matching circuit is in a transmitter reader mode at a maximum predetermined transmitter power level that corresponds to a first operational gear associated with a first corresponding specific register configuration; detecting a change in the TX voltage and/or current using the sensor; detecting, in response to the detected change, an initial detuning of the antenna and matching circuit arising from a load change on the antenna resulting from interaction with a further resonant circuit; and in response to detection of the initial detuning, reducing the transmitter (TX) current to match inductance between the antenna and matching circuit and the further resonant circuit by shifting the transmitter power level to one of a plurality of lower gears based on a comparison between a predicted TX current and a plurality of TX current thresholds, wherein each lower gear is associated with a different specific corresponding register configuration, and a discrete, predetermined transmitter power level that is below the maximum predetermined transmitter power level, and further wherein the transmitter is configured to initiate reading in highest gear and only shift to a lower gear to match inductance between the antenna and matching circuit and the further resonant circuit. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A device for detuning detection and transmitter (TX) current regulation, the device comprising:
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a transmitter circuit including; an active attenuator configured to generate a transmitter (TX) voltage; a first sensor; a second sensor; an output driver configured and arranged to output an TX current and/or voltage; and a control unit; and an antenna and matching circuit configured to be driven by the TX current corresponding to the TX voltage as output by the output driver, wherein the first sensor is configured to monitor the TX current and/or voltage; the second sensor is configured to monitor a voltage or current of the antenna and matching circuit; and the control unit, including circuitry, configured to; detect a change in the TX current and/or voltage as output by the output driver and a change in the voltage or current of the antenna and matching circuit; detect, in response to the detected change in the TX current and/or voltage and the detected change in the voltage or current of the antenna and matching circuit, an initial detuning of the antenna and matching circuit arising from a load change on the antenna resulting from interaction with a further resonant circuit, and in response to detection of the initial detuning, reduce the TX current to match inductance between the antenna and matching circuit and the further resonant circuit, wherein the device is configured to initially operate at a maximum predetermined transmitter power level that corresponds to a first operational gear associated with a first corresponding specific register configuration, and further wherein inductance is matched between the antenna and matching circuit and the further resonant circuit by shifting the transmitter power level to one of a plurality of lower gears based on a comparison between a predicted TX current and a plurality of TX current thresholds, wherein each lower gear is associated with a different specific corresponding register configuration, and a discrete, predetermined transmitter power level that is below the maximum predetermined transmitter power level. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification