Multi-Mode Wireless Charging

• US 20150115723A1
• Filed: 10/28/2013
• Published: 04/30/2015
• Est. Priority Date: 10/28/2013
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: MUURINEN, Jari Juhani, LEVO, Sakari Johannes
• Granted Patent: US 9,672,976 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 2003/106 Magnetic circuits using combinations of different magnetic materials
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: Y10T 29/49073 by assembling coil and core

Abstract

A device may include a multiple inductive coils arranged concentrically for operating according multiple modes of wireless power transfer. The device may include multiple layers of magnetic shields to protect device components from the effects of the magnetic field used for power transfer. Construction and material of multiple layers of shields may be based on addressing individually the different parameters of the multiple modes of operation and based on the combined effect of the layers in each mode of operation. In some examples, the device may include first and second ferrite shields each having different magnetic properties.

Claims

1. An apparatus comprising:

a first inductive coil tuned to operate in one or more first modes of inductive wireless power transfer;

a second inductive coil positioned concentrically with the first inductive coil and tuned to operate in one or more second modes of inductive wireless power transfer;

a first magnetic shield comprising a first material having a first magnetic permeability configured to shield an apparatus component when operating in the one or more first modes; and

a second magnetic shield comprising a second material having a second magnetic permeability configured to shield the apparatus component when operating in the one or more second modes.

2. The apparatus of claim 1, wherein first magnetic shield is positioned in-between the second magnetic shield and the first inductive coil.

3. The apparatus of claim 1, wherein the first magnetic shield and the second magnetic shield are positioned with a common plane and the second magnetic shield encompasses a perimeter of the first magnetic shield.

4. The apparatus of claim 3, wherein a first thickness of the first magnetic shield differs from a second thickness of the second magnetic shield.

5. The apparatus of claim 1, wherein the first magnetic permeability is below 50μ

and the second magnetic permeability is above 100μ

.

6. The apparatus of claim 1, wherein the one or more first modes of inductive wireless power transfer include a tightly coupled mode, and the one or more second modes of inductive wireless power transfer include a resonant mode.

7. The apparatus of claim 6, wherein the one or more first modes of inductive wireless power transfer include a second tightly coupled mode.

8. The apparatus of claim 1, further comprising a portable electronic device configured to receive power wirelessly via the first inductive coil and the second inductive coil.

9. The apparatus of claim 8, wherein the portable electronic device includes one of a cellular phone, a smartphone, and a tablet computer.

10. The apparatus of claim 1, further comprising a removable cover of a portable electronic device, wherein the first inductive coil, the second inductive coil, the first magnetic shield, and the second magnetic shield are attached to the removable cover.

11. A method comprising:

providing a first magnetic shield having a first magnetic permeability;

providing a second magnetic shield having a second magnetic permeability; and

assembling the first magnetic shield, the second magnetic shield, a first inductive coil, and a second inductive coil into a multi-mode wireless power transfer assembly.

12. The method of claim 11, further comprising positioning the first magnetic shield in-between the second magnetic shield and the first inductive coil.

13. The method of claim 11, further comprising positioning the first magnetic shield and the second magnetic shield within a common plane such that a perimeter the first magnetic shield is encompassed by the second magnetic shield.

14. The method of claim 13, further comprising creating the first magnetic shield and the second magnetic shield with different thicknesses.

15. The method of claim 11, wherein the first magnetic permeability is below 50μ

and the second magnetic permeability is above 100μ

.

16. The method of claim 11, wherein the assembly is operable in one or more first modes of inductive wireless power transfer using the first inductive coil, and operable in one or more second modes of inductive wireless power transfer using the second inductive coil.

17. The method of claim 16, wherein the one or more first modes of inductive wireless power transfer include a tightly coupled mode, and the one or more second modes of inductive wireless power transfer include a resonant mode.

18. The method of claim 11, further comprising integrating the assembly into a portable electronic device.

19. An electronic device comprising:

one or more internal electronic components;

first and second inductive coils tuned to operate respectively in first and second modes of inductive wireless power transfer;

a power conversion circuit configured to power the one or more internal electronic components with electric currents induced in the first and second inductive coils; and

first and second magnetic shields respectively comprising a first permeability and a second permeability, the first and second magnetic shields configured to shield the one or more internal electronic components from magnetic fields that induce the electric currents in the first and second inductive coils.

20. The portable electronic device of claim 19, wherein the first mode of inductive wireless power transfer includes a tightly coupled mode, and the second mode of inductive wireless power transfer includes a resonant mode.