| CPC H01F 27/24 (2013.01) [H01F 38/14 (2013.01); H02J 7/02 (2013.01); H02J 50/12 (2016.02); H02J 50/90 (2016.02)] | 20 Claims |

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1. An accessory for an electronic device, wherein the electronic device has a first coil configured to transmit first wireless power signals and a second coil configured to receive second wireless power signals from a wireless power transmitting device, the accessory comprising:
a coil configured to receive the first wireless power signals from the first coil in the electronic device when the accessory is coupled to the electronic device; and
a ferrimagnetic core overlapping the coil, wherein the ferrimagnetic core operates in:
a first state when the accessory and the electronic device are inductively coupled to the wireless power transmitting device, wherein the ferrimagnetic core has a first magnetic reluctance in the first state; and
a second state when the accessory and the electronic device are not inductively coupled to a wireless power transmitting device, wherein the ferrimagnetic core has a second magnetic reluctance that is less than the first magnetic reluctance in the second state.
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