WIRELESS POWER TRANSFERS WITH FREQUENCY RANGE SCANNING

• US 20170237290A1
• Filed: 02/17/2016
• Published: 08/17/2017
• Est. Priority Date: 02/17/2016
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: BAKKER, Anthonius, NATSUKI, Hiroji
• Granted Patent: US 10,601,256 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings

Abstract

A system, a circuit, and a method of wireless power transfer using a transmitter and a controller coupled to the transmitter. The controller is configured to perform operations including causing the transmitter to scan a frequency range that includes a maximum frequency and a minimum frequency. The operations further include determining one or more detections based at least on the scan of the frequency range. The detection may include a presence of one or more receivers, an absence of one or more receivers, and/or a presence of a foreign object. The operations include determining one or more further operations based on the one or more detections.

Claims

1. A wireless power transfer system, comprising:

a transmitter; and

a controller coupled to the transmitter, wherein the controller is configured to perform operations comprising;

causing the transmitter to scan a frequency range between a minimum frequency and a maximum frequency;

determining one or more detections based at least on the scan of the frequency range; and

determining one or more further operations based at least on the one or more detections.

2. The wireless power transfer system of claim 1, wherein the one or more detections comprises a detection of one or more receivers based at least on the frequency range scanned, and wherein determining the one or more further operations comprises determining an operation to charge the one or more receivers based on an electromagnetic field generated by the transmitter.

3. The wireless power transfer system of claim 1, wherein the one or more detections comprises a detection of an absence of one or more receivers based at least on the frequency range scanned, wherein determining the one or more further operations comprises determining an operation to terminate the scan of the frequency range.

4. The wireless power transfer system of claim 3, wherein the one or more further operations comprises causing the transmitter to periodically scan the frequency range for the one or more receivers based at least on a rest period.

5. The wireless power transfer system of claim 1, wherein causing the transmitter to scan the frequency range comprises causing the transmitter to periodically scan a frequency outside of the frequency range, wherein the periodic scan of the frequency outside of the frequency range causes one or more receivers to disconnect from an electromagnetic field generated by the transmitter.

6. The wireless power transfer system of claim 1, wherein causing the transmitter to scan the frequency range comprises causing the transmitter to periodically scan a frequency outside of the frequency range, wherein the controller is configured to perform further operations comprising:

measuring a power associated with the transmitter based on the periodic scan of the frequency outside of the frequency range, wherein determining the one or more further operations comprises determining a sleep mode based at least on the transmitter power measured.

7. The wireless power transfer system of claim 6, wherein the one or more detections comprises a detection of a foreign object based at least on the power measured, and wherein determining the sleep mode is based further on the foreign object detected.

8. A wireless power transfer circuit, comprising:

a transmitter comprising a transmitter coil; and

a controller coupled to the transmitter, wherein the controller is configured to perform operations comprising;

causing the transmitter coil to scan a frequency range that comprises a minimum frequency and a maximum frequency;

determining one or more detections based at least on the scan of the frequency range; and

transitioning to one or more modes based at least on the one or more detections.

9. The wireless power transfer circuit of claim 8, wherein causing the transmitter coil to scan the frequency range comprises causing the transmitter coil to periodically scan a frequency outside of the frequency range, and wherein the periodic scan causes one or more receivers to disconnect from an electromagnetic field generated by the transmitter coil.

10. The wireless power transfer circuit of claim 8, wherein the minimum frequency is approximately 80 kHz, wherein the maximum frequency is approximately 100 kHz, and wherein the frequency outside of the frequency range is approximately 70 kHz.

11. The wireless power transfer circuit of claim 8, wherein the controller is configured to perform further operations comprising:

measuring a power associated with the transmitter based at least on a periodic scan of a frequency outside of the frequency range;

determining a comparison of the power measured with a threshold power, and wherein transitioning to the one or more modes comprises transitioning to a sleep mode based at least on the comparison.

13. The wireless power transfer circuit of claim 8, wherein transitioning to the one or more modes comprises transitioning to a sleep mode, and wherein the controller is configured to perform further operations comprising:

measuring a power associated with the transmitter based at least on a periodic scan of the minimum frequency; and

detecting a foreign object based at least on a comparison of the power measured with a threshold power; and

continuing in the sleep mode based at least on detecting the foreign object.

14. The wireless power transfer circuit of claim 8, wherein transitioning to the one or more modes comprises transitioning to a sleep mode, and wherein the controller is configured to perform further operations comprising:

measuring a power associated with the transmitter based at least on a periodic scan of the minimum frequency; and

detecting an absence of one or more receivers based at least on a comparison of power measured with a threshold power; and

continuing in the sleep mode based at least on detecting the absence.

12. The wireless power transfer circuit of claim 12, wherein the power measured is further based on scanning the minimum frequency, and wherein the one or more detections comprises a detection of a foreign object based at least on the power measured being greater than or equal to the threshold power.

15. A method of detection for a wireless power transfer, comprising:

scanning, by a transmitter, a frequency range comprising a minimum frequency and a maximum frequency;

determining one or more detections associated with one or more receivers based at least on scanning the frequency range; and

transitioning to one or more modes based at least on the one or more detections.

16. The method of claim 15, wherein the one or more detections comprises a detection of the one or more receivers based at least on the frequency range scanned, and wherein transitioning to the one or more modes comprises transitioning to an active mode to charge the one or more receivers with an electromagnetic field generated based at least on the frequency range scanned.

17. The method of claim 15, wherein the one or more detections comprises a detection of an absence of the one or more receivers, wherein transitioning to the one or more modes comprises transitioning to a sleep mode to terminate the scan.

18. The method of claim 15, wherein scanning the frequency range comprises periodically scanning to a frequency outside of the frequency range, the method further comprising:

measuring a transmitter power based at least on periodically scanning to the frequency outside of the frequency range, wherein transitioning to the one or more modes comprises transitioning to a sleep mode based at least on the transmitter power measured.

19. The method of claim 18, wherein the one or more detections are determined based further on the transmitter power measured, wherein the one or more detections comprises a detection of a foreign object, and wherein transitioning to the one or more modes comprises transitioning to a sleep mode.

20. The method of claim 15, wherein transitioning to the one or more modes comprises transitioning to a sleep mode, the method further comprising:

measuring a power associated with the transmitter based at least on a periodic scan of the minimum frequency;

determining a comparison of the power measured with one or more threshold powers; and

continuing in the sleep mode based at least on the comparison.