Wireless charging system with inductance imaging

• US 10,326,316 B2
• Filed: 11/06/2017
• Issued: 06/18/2019
• Est. Priority Date: 02/10/2017
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Yang, Heng, Qiu, Weihong, Moussaoui, Zaki
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Tran, Thai H
• Application Number:
  US15/804,596
• Publication Number:
  US 20180233954A1
• Time in Patent Office: 589 Days
• Field of Search: 307104, 320108
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/263 Multiple coils at either side

Abstract

A wireless power transmission system has a wireless power receiving device that is located on a charging surface. The wireless power transmitting device has an array of wireless power transmitting coils that overlap the charging surface. The wireless power transmitting device uses inductance measurement circuitry that is coupled to the coil array to measure coil inductances for the wireless power transmitting coils. The wireless power receiving device may contain a communications integrated circuit, display circuitry, or other sensitive components. The location and orientation of the wireless receiving device on the charging surface can be determined by analyzing the coil inductances. This information and information on the location of the sensitive component within the wireless power receiving device can be used to select a wireless power transmitting coil to transmit wireless power signals to the wireless power receiving device without exposing the sensitive component to excessive wireless power signals.

Claims

1. A wireless power transmitting device having a charging surface configured to receive a wireless power receiving device, wherein the wireless power receiving device has a sensitive component that is sensitive to exposure to wireless power signals and that has a wireless power receiving coil configured to receive wireless power signals from the wireless power transmitting device while the sensitive component is at a location on the charging surface, the wireless power transmitting device comprising:

an array of wireless power transmitting coils;

inverter circuitry coupled to the array of wireless power transmitting coils, wherein the inverter circuitry is configured to supply drive signals to the array of wireless power transmitting coils to produce the wireless power signals;

inductance measurement circuitry coupled to the array of wireless power transmitting coils; and

control circuitry configured to;

gather coil inductance measurements from the array of wireless power transmitting coils with the inductance measurement circuitry;

determine the location of the sensitive component on the charging surface by analyzing the coil inductance measurements to identify an area in the wireless power receiving device that is sensitive to wireless power signal exposure; and

select at least a given wireless power transmitting coil from among the array of wireless power transmitting coils to transmit the wireless power signals to the wireless power receiving coil based on the location of the sensitive component and based on coil inductance measurements.

2. The wireless power transmitting device defined in claim 1 wherein the control circuitry is configured to analyze the coil inductance measurements to determine a location and orientation of the wireless power receiving device on the charging surface.

3. The wireless power transmitting device defined in claim 2 wherein the control circuitry is configured to determine the location of the sensitive component on the charging surface using the location and orientation of the wireless power receiving device on the charging surface and using information on a location of the sensitive component within the wireless power receiving device.

4. The wireless power transmitting device defined in claim 3 further comprising storage, wherein the control circuitry is configured to determine the location of the sensitive component within the wireless power receiving device by retrieving information on the location of the sensitive component within the wireless power receiving device from the storage.

5. The wireless power transmitting device defined in claim 4 wherein the control circuitry is configured to retrieve the information on the location of the sensitive component within the wireless power receiving device based on information identifying the wireless power receiving device.

6. The wireless power transmitting device defined in claim 5 wherein the control circuitry is configured to produce the information identifying the wireless power receiving device by analyzing the coil inductance measurements.

7. The wireless power transmitting device defined in claim 5 wherein the control circuitry is configured to obtain the information identifying the wireless power receiving device from the wireless power receiving device over a wireless communications link.

8. The wireless power transmitting device defined in claim 1 wherein the inductance measurement circuitry comprises impulse response measurement circuitry.

9. The wireless power transmitting device defined in claim 8 wherein the control circuitry is configured to detect that the wireless power receiving device is present on the charging surface using the impulse response measurement circuitry.

10. The wireless power transmitting device defined in claim 9 wherein the control circuitry is configured to:

establish a wireless communications link with the wireless power receiving device in response to detecting that the wireless power receiving device is present on the charging surface; and

obtain information identifying where the sensitive component is located within the wireless power receiving device from the wireless power receiving device over the communications link.

11. A wireless power transmitting device having a charging surface configured to receive a wireless power receiving device, wherein the wireless power receiving device has a sensitive component that includes circuitry that is sensitive to radio-frequency interference when exposed to wireless power signals and that has a wireless power receiving coil configured to receive wireless power signals from the wireless power transmitting device while the sensitive component is at a location on the charging surface, the wireless power transmitting device comprising:

an array of wireless power transmitting coils;

inverter circuitry coupled to the array of wireless power transmitting coils, wherein the inverter circuitry is configured to supply drive signals to the array of wireless power transmitting coils to produce the wireless power signals that are received by the wireless power receiving device;

inductance measurement circuitry coupled to the array of wireless power transmitting coils; and

control circuitry configured to;

measure coil inductances for the wireless power transmitting coils using the inductance measurement circuitry; and

analyze the coil inductances to select a wireless power transmitting coil to transmit the wireless power signals to the wireless power receiving coil, wherein when the wireless power receiving coil overlaps a first of the wireless power transmitting coils by a first amount and overlaps a second of the wireless power transmitting coils by a second amount that is less than the first amount and when the first wireless power transmitting coil is coupled to the sensitive component more than the second wireless power transmitting coil, the second coil is the selected coil.

12. The wireless power transmitting device defined in claim 11 wherein the control circuitry is configured to select the wireless power transmitting coil to transmit the wireless power signals based at least partly on the location of the sensitive component on the charging surface.

13. The wireless power transmitting device defined in claim 12 wherein the control circuitry is configured to determine the location of the sensitive component on the charging surface by analyzing the coil inductances.

14. The wireless power transmitting device defined in claim 12 wherein the control circuitry is configured to determine the location of the sensitive component on the charging surface based at least partly on information received wirelessly from the wireless power receiving device over a wireless communications link.

15. The wireless power transmitting device defined in claim 11 wherein the control circuitry is configured to analyze the coil inductances to determine a location and orientation for the wireless power receiving device on the charging surface and is configured to use the location and orientation of the wireless power receiving device to select the wireless power transmitting coil.

16. The wireless power transmitting device defined in claim 15 wherein the control circuitry is configured to determine the location of the sensitive component on the charging surface using the location and orientation of the wireless power receiving device on the charging surface and using information on a location of the sensitive component within the wireless power receiving device.

17. A wireless power transmitting device configured to supply wireless power signals to a wireless power receiving device that contains a sensitive component that is sensitive to interference from the wireless power signals, comprising:

an array of wireless power transmitting coils overlapping a charging surface;

inverter circuitry coupled to the array of wireless power transmitting coils, wherein the inverter circuitry is configured to supply drive signals to the array of wireless power transmitting coils to produce the wireless power signals;

impulse response measurement circuitry coupled to the array of wireless power transmitting coils; and

control circuitry configured to;

measure coil inductances for the wireless power transmitting coils using the impulse response measurement circuitry;

determine a location and orientation of the wireless power receiving device on the charging surface from the measured coil inductances; and

identify a given one of the wireless power transmitting coils to use to transmit the wireless power signals without interfering with the sensitive component based on the location and orientation of the wireless power receiving device.

18. The wireless power transmitting device defined in claim 17 wherein the control circuitry is configured to:

determine a location at which the sensitive component overlaps the charging surface by analyzing the measured coil inductances; and

identify the given one of the wireless power transmitting coils to transmit the wireless power signals based at least partly on the location at which the sensitive component overlaps the charging surface.

19. The wireless power transmitting device defined in claim 17 wherein the control circuitry is configured to:

determine a location at which the sensitive component overlaps the charging surface based on the location and orientation of the wireless power receiving device; and

identify the given one of the wireless power transmitting coils to use in transmitting the wireless power signals based at least partly on the location at which the sensitive component overlaps the charging surface.