Electronic device case with inductive coupling features
A protective case includes a shell for receiving and at least partially covering an electronic device. The shell includes a first material and has a back portion and side portions extending from the back portion. The back portion is configured to be adjacent to the back surface of the electronic device when the electronic device is installed. The case also includes a core comprising a second material having a magnetic permeability substantially greater than a magnetic permeability of the first material. The core is affixed to the back portion of the shell at a location that coincides with a center region of the wireless charging coil of the wireless charging circuitry of the installed electronic device. The core increases magnetic coupling between the wireless charging coil of the installed electronic device and a source charging coil when the protective case is placed in proximity to the source charging coil.
1. A protective case for an electronic device, the electronic device having a housing and wireless charging circuitry and a wireless charging coil inside the housing proximate a back surface of the electronic device, the protective case comprising:
a shell for receiving and at least partially covering the electronic device, the shell comprising a first material and having a back portion and side portions extending from the back portion, the back portion of the shell configured to be adjacent to the back surface of the electronic device when the electronic device is installed in the protective case; and
a core comprising a second material that has a magnetic permeability substantially greater than a magnetic permeability of the first material, the core affixed to the back portion of the shell at a location on the back portion that coincides with a center region of the wireless charging coil of the wireless charging circuitry of the installed electronic device, the core to increase magnetic inductive coupling between the wireless charging coil of the installed electronic device and a source charging coil when the protective case with the installed electronic device is placed in proximity to the source charging coil.
2. The protective case of claim 1 wherein the shell comprises an outer structural layer and an inner cushion layer and wherein the inner cushion layer is adjacent to at least a portion of the back surface of the installed electronic device.
3. The protective case of claim 1 wherein the core is molded into the back portion of the shell.
4. The protective case of claim 1 wherein the core is attached to an inner surface of the back portion of the shell or is attached to an outer surface of the back portion of the shell.
5. The protective case of claim 1 wherein the core is embedded in an inner surface of the back portion of the shell or is embedded in an outer surface of the back portion of the shell.
6. The protective case of claim 1 wherein the second material comprises ferrite.
7. The protective case of claim 1 wherein the core extends to a periphery of the back portion of the shell.
8. The protective case of claim 7 wherein the core further extends from the periphery of the back portion of the shell into at least one of the side portions of the shell.
9. The protective case of claim 1 wherein the shell comprises two or more shell members.
10. The protective case of claim 1 wherein the electronic device is a smartphone and the source charging coil is associated with a wireless charging power source for wirelessly charging the smartphone.
11. The protective case of claim 1 , wherein the core has a primary plane that is substantially parallel to a primary plane of the wireless charging coil of the installed electronic device, the core being positioned between source charging coil and the wireless charging coil of the electronic device when the protective case with the installed electronic device is placed in proximity to the source charging coil.
12. The protective case of claim 1 , wherein at least part of the core is positioned on an interior surface of the protective case configured to be adjacent to at least a portion of the back surface of the electronic device when the electronic device is installed in the protective case.
13. A cover for an electronic device having a housing and wireless charging circuitry, the wireless charging circuitry including a wireless charging coil positioned inside the housing and proximate and substantially parallel with a back surface of the electronic device, the cover comprising:
a back portion configured to be adjacent to the back surface of the electronic device when the electronic device is installed in the cover, the back portion comprising a first material;
side portions extending from the back portion, the side portions for retaining the installed electronic device against the back portion of the cover, the back portion and the side portions at least partially covering the installed electronic device; and
a coupling region in the back portion of the cover, the coupling region comprising a high magnetic permeability material that is different than the material of the back portion of the cover, the coupling region located on the back portion of the cover to align with a center region of the wireless charging coil of the wireless charging circuitry of the installed electronic device and adapted to increase magnetic coupling between the wireless charging coil of the installed electronic device and an external coil.
14. The cover of claim 13 wherein the coupling region comprises a ferrite core attached to the back portion of the cover.
15. The cover of claim 13 wherein the high magnetic permeability material is molded into the first material of the back portion to form the coupling region.
16. The cover of claim 15 wherein the high magnetic permeability material is combined with the first material in the coupling region during a molding process.
17. The cover of claim 13 further comprising:
a power storage device disposed in a cavity of the back portion; and
electrical circuitry for transferring electrical power from the power storage device to the installed electronic device.
18. The cover of claim 17 wherein the electrical circuitry includes a coil for wirelessly transferring the electrical power from the power storage device to the installed electronic device.
19. A method of manufacturing a protective case for an electronic device having a housing, wireless charging circuitry, and a wireless charging coil positioned in the housing proximate a back surface of the electronic device, the method comprising:
molding a shell from a first material, the shell configured for receiving and at least partially covering the electronic device, the shell having a back portion and side portions extending from the back portion, the back portion of the shell configured to be adjacent to the back surface of the electronic device when the electronic device is installed in the protective case; and
embedding a core comprising a high magnetic permeability material in the back portion of the shell, the high magnetic permeability material being different than the first material, the core positioned in the back portion of the shell at a location on the back portion that coincides with a center region of the wireless charging coil of the wireless charging circuitry of the installed electronic device, the core to increase magnetic coupling between the wireless charging coil of the installed electronic device and an external coil.
20. The method of claim 19 wherein the embedding of the core occurs during the molding of the shell.
21. The method of claim 19 wherein the high magnetic permeability material comprises ferrite.