Wireless charging recognizing receiver movement over charging pad with NFC antenna array

• US 9,270,343 B2
• Filed: 12/20/2012
• Issued: 02/23/2016
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: van Lammeren, Johannes Petrus Maria, Sedzin, Aliaksei Vladimirovich, Brink, Klaas
• Primary Examiner(s): Whitmore, Stacy
• Application Number:
  US13/721,504
• Publication Number:
  US 20140176055A1
• Time in Patent Office: 1,160 Days
• Field of Search: 320107-108
• US Class Current: 1/1
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/263 Multiple coils at either side
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An apparatus (pad) and method for wirelessly charging a receiver are disclosed. The pad includes one or more NFC antennas which can receive an NFC signal from the receiver. The pad also contains one or more charging coils. Measurement of the signal strength at each charging NFC antenna helps determine which charging coil(s) should be utilized to effect the most efficient charging of the receiver.

Claims

1. A method for charging a receiver capable of creating an NFC field comprising:

providing a pad having a plurality of charging coils arranged in an array and a plurality of NFC antennas arranged in an array;

placing said receiver upon said pad;

causing said receiver to create an NFC field;

measuring said NFC field strength at two or more NFC antennas in said pad;

comparing said NFC field strengths at said two or more NFC antennas to determine at least one NFC antenna with greater field strength;

selecting one or more charging coils associated with said at least one NFC antenna according to a predetermined rule; and

activating said one or more charging coils to charge said receiver by maintaining a charge to the receiver by assessing movement of the receiver on the pad and re-selecting one or more charging coils.

2. The method of claim 1 in which each of said charging coils has an associated concentric NFC antenna.

3. The method of claim 1 in which the steps of measuring said NFC field strength and comparing said NFC field strength is performed multiple times during the charging process, and further including the step of assessing said NFC field strengths at said two or more NFC antennas to determine at least one NFC antenna with greater field strength and determining therefrom whether the receiver has moved.

4. The method of claim 3 further including selecting at least one different charging coil and activating said at least one different charging coil during the charging process in response to the step of determining therefrom whether the receiver has moved.

5. The method of claim 1 in which the number of charging coils is equal to the number of NFC antennas.

6. The method of claim 1 in which the number of charging coils is equal to the number of NFC antennas and said predetermined rule associates one charging coil with an unique NFC antenna and prescribes the activation of said associated one charging coil if said unique NFC antenna has receives greatest field strength.

7. The method of claim 1 in which each or a part of each charging coil is also an NFC antenna.

8. A charging pad comprising:

a plurality of charging coils, each said coil having first, second, and third taps;

said first and second taps being located to permit the reception of an NFC signal;

a pad electrically coupled to the taps of each of the plurality of charging coils for charging a receiver on the pad;

said first and third taps connecting to the ends of said coil for providing charging energy; and

a controller circuit coupled to the plurality of charging coils and configured for receiving measurements of field strength and selecting one or more, but less than all, of said charging coils through which the receiver on the pad is to be charged; and

the controller circuit being further configured for maintaining a procedure to charge the receiver by assessing sequential locations of the receiver on the pad.

9. The device of claim 8 further including a controller for receiving said measurement of field strength and selecting one or more, but less than all, of said charging coils to perform charging.

10. The device of claim 8 wherein the controller circuit is further configured for receiving said NFC signal and determining at which coil(s) said NFC signal is strongest and for causing said coil(s) to commence providing charging energy and for determining whether the receiver has moved on the pad.

11. The device of claim 8 wherein the controller circuit is further configured for receiving said NFC signal and determining at which coil(s) said NFC signal is strongest and for causing said coil(s) to commence providing charging energy, for determining whether the receiver has moved on the pad, and for maintaining a charge procedure by responding to the determination of whether the receiver has moved on the pad with a re-selection of another set of one or more, but less than all, of said charging coils through which the receiver on the pad is to be charged.