IP Library › Granted Patent US 11,444,485

Granted Patent B2

US 11,444,485 · App. 16/782,214 · Granted Sep 13, 2022

Inductive charging system with charging electronics physically separated from charging coil

Inventor: Afshin Partovi (Palo Alto, CA)

Assignee: MOJO MOBILITY, INC.

H02J50/005 H01F5/003 H01F38/14 H02J50/12 H02J50/70 H02J2310/48

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Quick Facts

Patent No.: US 11,444,485
App. No.: 16/782,214
Granted: Sep 13, 2022
Kind: B2

External Links

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Abstract

An inductive charger where the charging surface or coil is separated from the drive or control electronics is described.

Claims (76)

1. An inductive charger for transmitting power to an inductive receivers of an electronic device for charging the electronic device, the inductive charger comprising:

a metallic first enclosure having a non-metallic charging surface, the first enclosure comprising:

an inductive charging coil comprising a spiral-shaped metallic Litz wire conductor that defines two charging coil terminals,

wherein the inductive charging coil has a first side that faces the charging surface and a second side that faces away from the charging surface opposite the first side, and

wherein the inductive charging coil is configured to transmit electromagnetic power by inductive power transfer through the charging surface of the enclosure with an alternating magnetic field at an operating frequency within a frequency range of 100 kHz to 1 MHz when an electronic device is positioned in proximity to the charging surface; and

a soft magnetic shielding material positioned proximate the second side of the charging coil away from the charging surface;

a metallic second enclosure physically separated from the first enclosure, the second enclosure comprising:

a drive circuit and a resonant capacitor electrically coupled to the inductive charging coil in the first enclosure to drive the inductive charging coil with an alternating current; and

a microcontroller electrically coupled to the drive circuit, wherein the microcontroller is configured to:

detect a received communication of information in a current or voltage modulation of the inductive charger coil by the inductive receiver; and

control the transmission of power during inductive power transfer; and

an electrical cable that electrically couples the first enclosure and the second enclosure,

wherein the cable comprises only two sets of twisted wires coupled to the two electrical terminals of the inductive charging coil to provide power and communication between the inductive charging coil in the first enclosure and the drive circuit and the microcontroller in the second enclosure, each set of twisted wires comprising multiple electrical wires to reduce electrical loss,

wherein the cable further comprises a metallic electromagnetic shield coupled to an

electrical ground that covers the two sets of twisted wires, and

wherein the cable is at least ten centimeters in length.

2. The inductive charger of claim 1 , wherein the charging surface comprises a polymer and a thermally conductive additive to increase the polymer's thermal conductivity.

3. The inductive charger of claim 1 , further comprising a first shield having a thermally conductive carbon-based layer positioned between the first side of the inductive charging coil and the charging surface of the first metallic enclosure such that the first shield covers the inductive charging coil and wherein the transmission of electromagnetic power through the first shield is allowed in the frequency range for inductive power transfer.

4. The inductive charger of claim 3 , wherein the thermally conductive layer comprises graphite.

5. The inductive charger of claim 1 , further comprising a second shield having an electrically conductive metal layer positioned between the first side of the inductive charging coil and the charging surface of the first metallic enclosure such that the second shield covers the inductive charging coil, wherein the metal layer has a periodic pattern and wherein the transmission of electromagnetic power through the second shield is allowed in the frequency range for inductive power transfer.

6. The inductive charger of claim 5 , wherein the second shield further comprises a non-metallic thermally conductive layer.

7. The inductive charger of claim 6 , wherein the thermally conductive layer comprises graphite.

8. The inductive charger of claim 1 , wherein the cable comprises a metal foil layer and a metal coated polymer covering the two sets of twisted wires.

9. The inductive charger of claim 8 , wherein the cable has a length greater than or equal to one meter.

10. The inductive charger of claim 9 , wherein the two sets of twisted wires are Litz wires selected for low loss transmission of current at the operating frequency.

11. The inductive charger of claim 1 , further comprising a far-field charger system and a far-field antenna for far-field power transfer frequency of over 1 GHz to provide power to an electronic device positioned at a distance from the charging surface of the inductive charger.

12. An inductive charger for transmitting power to an inductive receiver of an electronic device for charging the electronic device, the inductive charger comprising:

a metallic first enclosure having a non-metallic charging surface, the first enclosure further comprising:

an inductive charging coil comprising a spiral-shaped metallic Litz wire conductor that defines two charging coil terminals,

wherein the inductive charging coil has a first side that faces the charging surface and a second side that faces away from the charging surface opposite the first side, and

a soft magnetic shielding material positioned proximate the second side of the charging coil away from the charging surface;

a metallic second enclosure physically separated from the first enclosure, the second enclosure comprising:

a drive circuit and resonant capacitor electrically coupled to the inductive charging coil in the first enclosure to drive the inductive charging coil with an alternating current; and

a microcontroller electrically coupled to the drive circuit, wherein the microcontroller is configured to:

detect a received communication of information in a current or voltage modulation of the inductive charger coil by the inductive receiver; and

control the transmission of power during inductive power transfer; and

a cable means for electrically coupling the first enclosure and the second enclosure,

wherein the cable means comprises only two sets of twisted wires coupled to the two electrical terminals of the inductive charging coil to provide power and communication between the inductive charging coil in the first enclosure and the drive circuit and the microcontroller in the second enclosure, each set of twisted wires comprising multiple electrical wires to reduce electrical loss,

wherein the cable means further comprises a metallic electromagnetic shield coupled to an electrical ground that covers the two sets of twisted wires, and

wherein the cable means is at least ten centimeters in length.

13. The inductive charger of claim 12 , wherein the charging surface comprises a polymer and a thermally conductive additive to increase the polymer's thermal conductivity.

14. The inductive charger of claim 12 , further comprising a first shield having a thermally conductive carbon-based layer positioned between the first side of the inductive charging coil and the charging surface of the first enclosure such that the first shield covers the inductive charging coil and wherein the transmission of electromagnetic power through the first shield is allowed in the frequency range for inductive power transfer.

15. The inductive charger of claim 14 , wherein the thermally conductive layer comprises graphite.

16. The inductive charger of claim 12 , further comprising a second shield having an electrically conductive metal layer positioned between the first side of the inductive charging coil and the charging surface of the first enclosure such that the second shield covers the inductive charging coil, wherein the metal layer has a periodic pattern and wherein the transmission of electromagnetic power through the second shield is allowed in the frequency range for inductive power transfer.

17. The inductive charger of claim 16 , wherein the second shield further comprises a non-metallic thermally conductive layer.

18. The inductive charger of claim 17 , wherein the thermally conductive layer comprises graphite.

19. The inductive charger of claim 12 , wherein the cable means comprises a metal foil layer and a metal coated polymer covering the two sets of twisted wires.

20. The inductive charger of claim 19 , wherein the cable means has a length of greater than or equal to one meter.

21. The inductive charger of claim 20 , wherein the two sets of twisted wires are Litz wires selected for low loss transmission of current at the operating frequency.

22. The inductive charger of claim 12 , further comprising a far-field charger system and a far-field antenna for far-field power transfer frequency of over 1 GHz to provide power to an electronic device positioned at a distance from the charging surface of the inductive charger.

23. An inductive charger for transmitting power to an inductive receiver of an electronic device for charging the electronic device, the inductive charger comprising:

a metallic first enclosure having a non-metallic charging surface, the first enclosure comprising:

an inductive charging coil comprising a spiral-shaped metallic Litz wire conductor that defines two charging coil terminals,

wherein the inductive charging coil has a first side that faces the charging surface and a second side that faces away from the charging surface opposite the first side, and

a shield layer comprising a polymer layer and a heat conducting material in front of the inductive charging coil for heat distribution positioned proximate the second side of the charging coil away from the charging surface;