Inductive module

Patent metadata

Field	Value
Publication number	US-10084349-B2
Application number	US-201715701237-A
Country	US
Kind code	B2
Filing date	Sep 11, 2017
Priority date	Feb 15, 2017
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

Embodiments describe a wireless power receiving module to receive magnetic flux for wireless power transfer. The wireless power receiving module includes a receiver coil comprising a single length of wire wound into a plurality of turns, an electromagnetic receiver shield coupled to a first side of the receiver coil, a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency, and a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, and where the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil.

First claim

What is claimed is:

1. A wireless power receiving module to receive magnetic flux for wireless power transfer, the module comprising:
a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields;
an electromagnetic receiver shield that is a passive component and coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil;
a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and
a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, wherein the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil.

2. The wireless power receiving module of claim 1 , wherein the electromagnetic receiver shield is grounded to discharge voltage generated by the plurality of electric fields.

3. The wireless power receiving module of claim 1 , wherein the electromagnetic receiver shield comprises silver.

4. The wireless power receiving module of claim 1 , wherein the receiver coil comprises copper wire having plated layers of nickel and immersion gold formed over the copper wire.

5. The wireless power receiving module of claim 1 , wherein the thermally conductive layer comprises graphite and the electrically conductive layer comprises copper.

6. The wireless power receiving module of claim 1 , further comprising a flex circuit formed of a flexible dielectric layer having first and second opposing sides, wherein the receiver coil is disposed on the first side and the electromagnetic receiver shield is disposed on the second side.

7. The wireless power receiving module of claim 1 , wherein the receiver coil is directly attached to the ferrite layer.

8. The wireless power receiving module of claim 1 , wherein the receiver coil has a trace width-to-gap ratio of 70 to 30.

9. The wireless power receiving module of claim 1 , wherein each turn of the plurality of turns have a wire width that is different than other turns of the plurality of turns.

10. An electronic device configured to receive magnetic flux for wireless power transfer, the electronic device comprising:
a housing having a charging surface;
a battery positioned within the housing;
a wireless power receiving module positioned within the housing adjacent to the charging surface to receive magnetic flux for wireless power transfer during a charging event, the wireless power receiving module comprising:
a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields;
an electromagnetic receiver shield that is a passive component and coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil;
a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and
a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, wherein the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil.

11. The electronic device of claim 10 , wherein the electromagnetic receiver shield is grounded to discharge voltage generated by the plurality of electric fields.

12. The electronic device of claim 10 , wherein the electromagnetic receiver shield comprises silver.

13. The electronic device of claim 10 , wherein the receiver coil comprises copper wire having plated layers of nickel and immersion gold formed over the copper wire.

14. The electronic device of claim 10 , wherein the thermally conductive layer comprises graphite and the electrically conductive layer comprises copper.

15. A wireless charging system comprising:
a wireless charging device including a transmitter coil configured to generate a magnetic flux across a charging surface and a transmitter shield positioned between the charging surface and the transmitter coil, the transmitter shield made from material that enables the transmitter shield to intercept some electric fields generated during a charging event and directed away from the transmitter coil and allow the magnetic flux to pass through the transmitter shield;
an electronic device configured to receive the magnetic flux generated by the wireless charging device during a charging event, the electronic device comprising: a housing having a charging surface; a battery positioned within the housing; and a wireless power receiving module positioned within the housing adjacent to the charging surface to receive magnetic flux for wireless power transfer during a charging event, the wireless power receiving module comprising:
a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields;
an electromagnetic receiver shield that is a passive component and coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil;
a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and
a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, wherein the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil.

16. The wireless charging system of claim 15 , wherein the electromagnetic receiver shield is grounded to discharge voltage generated by the plurality of electric fields.

17. The wireless charging system of claim 15 , wherein the electromagnetic receiver shield comprises silver.

18. The wireless charging system of claim 15 , wherein the receiver coil comprises copper wire having plated layers of nickel and immersion gold formed over the copper wire.

19. The wi

Assignees

• Apple Inc

Inventors

• Larsson Karl Ruben F
• Jol Eric S
• Graham Christopher S
• Oro Aaron A

Classifications

• H05K9/0058

  specially adapted for optoelectronic applications · CPC title

• H01F27/24

  Magnetic cores · CPC title

• H01F38/14 Primary

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• H01F27/28

  Coils; Windings; Conductive connections · CPC title

• H01F27/36

  Electric or magnetic shields or screens (movable for varying inductance H01F21/10) · CPC title