RFID tag and transponder detection in wireless energy transfer systems

  • US 10,248,899 B2
  • Filed: 10/06/2016
  • Issued: 04/02/2019
  • Est. Priority Date: 10/06/2015
  • Status: Active Grant
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First Claim
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1. A wireless power transmitter configured to detect a radio frequency identification (RFID) tag, the transmitter comprising:

  • a transmitter resonator;

    a transmitter impedance matching network coupled to the transmitter resonator;

    an amplifier coupled to the transmitter impedance matching network;

    a detection subsystem connected to the transmitter resonator; and

    a controller coupled to the amplifier and to the detection subsystem and configured so that during operation of the transmitter, the controller is configured to control the transmitter resonator, the amplifier, and the impedance matching network to cycle the transmitter between a power transmission mode and a RFID tag detection mode,wherein in the power transmission mode;

    the RFID tag detection mode is interrupted; and

    the transmitter resonator generates a power magnetic field at a frequency fpower to transfer power to a wireless power receiver;

    wherein in the RFID tag detection mode;

    the power transmission mode is interrupted;

    the transmitter resonator generates at least one detection magnetic field at a frequency between f1 and f2 to excite a RFID tag;

    the detection subsystem measures a reflected impedance of the transmitter resonator at each frequency; and

    the controller determines whether a RFID tag is present in proximity to the transmitter based on the reflected impedance of the transmitter resonator; and

    wherein f1 and f2 are greater than fpower.

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