US 12,407,195 B2
Method and device for performing a presence check for wireless charging listener devices
Markus Wobak, Graz (AT); Erich Merlin, Gratkorn (AT); and Ulrich Neffe, Albersdorf-Prebuch (AT)
Assigned to NXP B.V., Eindhoven (NL)
Filed by NXP B.V., Eindhoven (NL)
Filed on Sep. 30, 2022, as Appl. No. 17/936,926.
Prior Publication US 2024/0113564 A1, Apr. 4, 2024
Int. Cl. H02J 50/80 (2016.01); H01F 38/14 (2006.01); H02J 50/20 (2016.01)
CPC H02J 50/80 (2016.02) [H01F 38/14 (2013.01); H02J 50/20 (2016.02)] 21 Claims
OG exemplary drawing
 
1. A method for performing a presence check of a wireless charging (WLC) listener device by a WLC poller device, the method comprising:
transmitting a radio frequency (RF) presence check signal at an antenna of the WLC poller device;
sampling a input signal from the antenna by the WLC poller device concurrently with the transmission of the RF presence check signal;
measuring a rate of change of a magnitude of the input signal during the transmission of the presence check signal;
determining a difference between the input signal and an expected input signal; and detecting a presence of the WLC listener device if the measured rate of change of the input signal is above a threshold rate of change, and the difference between the input signal and the expected input signal is within a predetermined range.