WIRELESS CHARGER WITH UNIFORM H-FIELD GENERATOR AND EMI REDUCTION

• US 20160087477A1
• Filed: 09/18/2014
• Published: 03/24/2016
• Est. Priority Date: 09/18/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jeong, Seong Heon, Kim, Jeong Il
• Granted Patent: US 10,243,411 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas

Abstract

The present disclosure pertains to wireless chargers. In one embodiment, a 2×2 array of conductive coils produces magnetic fields. Adjacent coils receive current having different directions to cancel magnetic fields around a periphery of the array. A wireless charging platform may include at least four such coils. Regions between and above the coils may include magnetic fields approximately parallel to the surface of the platform so that electronic devices may be charged while standing up during operation by a user with reduced exposure to magnetic radiation. An electronic device may also be placed flat on each coil for charging.

Claims

1. A wireless charger comprising:

at least four conductive coils arranged in a two-by-two array, each conductive coil in the two-by-two array arranged to have a first adjacent conductive coil and a second adjacent conductive coil, and when a particular conductive coil comprises a first current in a first direction around the particular conductive coil, a second current in the first adjacent conductive coil is in an opposite direction than the first direction around the first adjacent conductive coil and a third current in the second adjacent conductive coil is in the opposite direction than the first direction around the second adjacent conductive coil.

2. The wireless charger of claim 1 wherein the at least four conductive coils are arranged on a wireless charging platform.

3. The wireless charger of claim 2 wherein regions between and above adjacent conductive coils comprise magnetic fields approximately parallel to a plane of the charging platform for simultaneous operation and charging of an electronic device when said electronic device is placed at a first angle to a plane of the wireless charging platform in one of the regions.

4. The wireless charger of claim 1 wherein the first current, the second current, and the third current are AC currents and the first current is 180 degrees out of phase with the second current and the third current.

5. The wireless charger of claim 1 wherein the first current and the second current flow in the same direction along a portion of the particular conductive coil that is adjacent to the first adjacent conductive coil and the first current and the third current flow in the same direction along a portion of the particular conductive coil that is adjacent to the second adjacent conductive coil.

6. The wireless charger of claim 1 wherein the at least four conductive coils each comprise a plurality of loops.

7. The wireless charger of claim 6 wherein at least a portion of the plurality of loops are in the same plane.

8. The wireless charger of claim 6 wherein the plurality of loops are in two or more parallel planes.

9. The wireless charger of claim 1 wherein the at least four conductive coils are formed using a single conductor.

10. The wireless charger of claim 9, the at least four conductive coils comprising:

a first outer loop and a first inner loop, a first portion of the first outer loop comprising a first terminal, the first inner loop comprising a first crosspoint;

a second outer loop and a second inner loop non-adjacent to the first outer loop and the first inner loop, the second outer loop coupled to the first crosspoint of the first inner loop, the second inner loop comprising a second crosspoint;

a third outer loop and a third inner loop, the third outer loop coupled to the second crosspoint of the second inner loop, the third inner loop comprising a third crosspoint; and

a fourth outer loop and a fourth inner loop, the fourth outer loop coupled to the third crosspoint, the fourth inner loop comprising a fourth crosspoint,

wherein a second portion of the first outer loop is coupled to the fourth crosspoint and the second portion of the first outer loop comprises a second terminal, and

wherein current flows between the first terminal and the second terminal.

11. The wireless charger of claim 1 wherein the at least four conductive coils are formed on the same substrate.

12. The wireless charger of claim 1 wherein the at least four conductive coils are a number of coils equal to a power of four.

13. The wireless charger of claim 1 wherein the at least four conductive coils comprise a single winding.

14. The wireless charger of claim 1 wherein the at least four conductive coils comprise a plurality of windings.

15. The wireless charger of claim 1 wherein the at least four conductive coils comprise a symmetric geometric shape.

16. The wireless charger of claim 15 wherein the geometric shape is at least one of square, circular, hexagonal, or octagonal, or any combination thereof.

17. The wireless charger of claim 1 wherein the at least four conductive coils are arranged in the same plane.

18. A method comprising:

receiving a first current in a first conductive coil to produce a first magnetic field;

receiving a second current in a second conductive coil to produce a second magnetic field;

receiving a third current in a third conductive coil to produce a third magnetic field; and

receiving a fourth current in a fourth conductive coil to produce a fourth magnetic field;

wherein the first conductive coil, the second conductive coil, the third conductive coil, and the fourth conductive coil are arranged in a two-by-two array, and wherein the first conductive coil is arranged adjacent to the second conductive coil and the third conductive coil, and wherein the fourth conductive coil is arranged adjacent to the second conductive coil and the third conductive coil, and

wherein the first current and the fourth current are in a different direction than the second current and the third current.

19. The method of claim 18 wherein the first, second, third, and fourth conductive coils are arranged on a wireless charging platform, and wherein regions between and above adjacent conductive coils comprise magnetic fields approximately parallel to a plane of the charging platform for simultaneous operation and charging of an electronic device when said electronic device is placed at a first angle to the plane of the wireless charging platform in one of the regions.

20. A wireless charger comprising:

first means for producing a first magnetic field based on a first current;

second means for producing a second magnetic field based on a second current;

third means for producing a third magnetic field based on a third current; and

fourth means for producing a fourth magnetic field based on a fourth current;

wherein the first means, the second means, the third means, and the fourth means are arranged in a two-by-two array, and wherein the first means is arranged adjacent to the second means and the third means, and wherein the fourth means is arranged adjacent to the second means and the third means, and

wherein the first current and the fourth current are in a different direction than the second current and the third current.