US 12,113,373 B2
Wireless power system with charging alerts
Arash Mehrabi, Menlo Park, CA (US); and Dmitry Berdnikov, San Jose, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Oct. 20, 2021, as Appl. No. 17/506,285.
Claims priority of provisional application 63/127,022, filed on Dec. 17, 2020.
Prior Publication US 2022/0200362 A1, Jun. 23, 2022
Int. Cl. H02J 7/00 (2006.01); H02J 50/10 (2016.01); H02J 50/40 (2016.01); H02J 50/80 (2016.01)
CPC H02J 50/80 (2016.02) [H02J 50/10 (2016.02); H02J 50/402 (2020.01); H02J 2207/20 (2020.01)] 21 Claims
OG exemplary drawing
 
1. A removable battery case configured to attach to a cellular telephone, comprising:
wireless power receiving circuitry configure to receive wireless power signals from the cellular telephone using a wireless power coil, wherein the wireless power receiving circuitry has a rectifier that produces a rectifier output voltage using power wirelessly received using the wireless power coil;
a battery;
a ballast load;
measurement circuitry configured to measure the rectifier output voltage;
control circuitry configured to:
cause current from the rectifier to flow through the ballast load;
measure the rectifier output voltage with the measurement circuitry while the current from the rectifier is flowing through the ballast load; and
charge the battery using current from the rectifier.