Systems and methods for detecting wireless power receivers and other objects at a near-field charging pad

  • US 10,615,647 B2
  • Filed: 07/25/2018
  • Issued: 04/07/2020
  • Est. Priority Date: 02/02/2018
  • Status: Active Grant
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First Claim
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1. A method of operating a near-field charging pad, comprising:

  • at a near-field charging pad that includes one or more processors and a plurality of power-transfer zones that each respectively includes at least one power-transferring element and a signature-signal receiving circuit, wherein the one or more processors of the near-field charging pad are in communication with a data source that includes predefined signature signals, the predefined signature signals including a first predefined signature signal that identifies a wireless power receiver, a second predefined signature signal that identifies an object other than a wireless power receiver, and a third predefined signature signal that identifies a combination of a wireless power receiver and an object other than a wireless power receiver;

    sending, by a respective power-transferring element included in a first power-transfer zone of the plurality of power-transfer zones, a plurality of test radio-frequency (RF) power transmission signals with first values for a first set of transmission characteristics;

    in conjunction with sending each of the plurality of test RF power transmission signals, detecting, using the signature-signal receiving circuit, respective amounts of reflected power at the first power-transfer zone, wherein the respective amounts of reflected power correspond to energy from the test RF power transmission signals of the plurality of test RF power transmission signals that was reflected outside of the near-field charging pad and returned to the first power-transfer zone;

    generating, using the signature-signal-receiving circuit and based on variations in the respective amounts of reflected power, a signature signal;

    comparing the signature signal with the predefined signature signals that each identify an object among a plurality of objects;

    based at least in part on the comparison of the signature signal with the predefined signature signals, determining whether (i) an authorized wireless power receiver is present on a surface of the near-field charging pad that is adjacent to the first power-transfer zone and/or (ii) an object other than a wireless power receiver is present on the surface of the near-field charging pad that is adjacent to the first power-transfer zone.

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