System and method for efficient wireless power transfer to devices located on and outside a charging base

• US 9,450,456 B2
• Filed: 06/07/2013
• Issued: 09/20/2016
• Est. Priority Date: 04/21/2008
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: Qualcomm, Inc.
• Inventors: Cook, Nigel P., Widmer, Hanspeter, Sieber, Lukas
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Bukhari, Aqeel
• Application Number:
  US13/913,036
• Publication Number:
  US 20130270923A1
• Time in Patent Office: 1,201 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence

Abstract

A wireless power transmission system and method for transmitting power from a charging base to receivers located both on and outside the charging base. The system utilizes wireless power transmission of a transmitter with a wound transmit coil.

Claims

1. An apparatus configured to transmit power via a magnetic field, the apparatus comprising:

an antenna circuit configured to inductively transmit power via the magnetic field at a magnetic field strength level sufficient to charge or power a receiver device;

a proximity detector configured to detect a proximity of a presence of a living being within a region of the magnetic field in which power is inductively transmitted at the magnetic field strength level; and

a controller configured to control the antenna circuit to adjust the magnetic field strength level in response to detecting the presence of the living being within the region of the magnetic field.

2. The apparatus of claim 1, further comprising an input mechanism configured to receive manual input from the living being, the input mechanism configured to activate the proximity detector in response to receiving the manual input.

3. The apparatus of claim 1, further comprising a driver circuit configured to drive the antenna circuit at a frequency substantially equal to a resonant frequency of the antenna circuit, and wherein the frequency is substantially equal to a resonant frequency of a receive antenna circuit of the receiver device.

4. The apparatus of claim 1, wherein the proximity detector comprises an infrared sensor.

5. The apparatus of claim 1, wherein the controller is configured to control the antenna circuit to reduce the magnetic field strength level to at least one of a lower magnetic field strength level or substantially zero.

6. The apparatus of claim 5, wherein the lower magnetic field strength level corresponds to a level configured to avoid biological harm to the living being.

7. The apparatus of claim 1, wherein the region corresponds to a near-field of the antenna circuit.

17. The apparatus of claim 1, wherein the controller is further configured to control the antenna circuit to decrease the magnetic field strength level to a lower magnetic field strength level sufficient to charge or power the receiver device in response to detecting the presence of the living being within the region of the magnetic field.

18. The apparatus of claim 17, wherein the controller is further configured to control the antenna circuit to increase the second magnetic field strength level in response to detecting an absence of the person in proximity of the region of the magnetic field.

19. The apparatus of claim 1, wherein the controller is further configured to cause the receive device to stop receiving the transmitted power.

8. A method of transmitting power via a magnetic field, the method comprising:

inductively transmitting, at an antenna circuit, power via the magnetic field at a magnetic field strength level sufficient to charge or power a receiver device;

detecting a proximity, via a proximity detector, of a presence of a living being within a region of the magnetic field in which power is inductively transmitted at the magnetic field strength level; and

controlling the antenna circuit to adjust the magnetic field strength level in response to detecting the presence of the living being within the region of the magnetic field.

9. The method of claim 8, further comprising receiving manual input from the living being via an input mechanism and activating the proximity detector in response to receiving the manual input.

10. The method of claim 8, wherein the proximity detector comprises an infrared sensor.

11. The method of claim 8, wherein adjusting controlling the magnetic field strength level comprises controlling the antenna circuit to reduce the magnetic field strength level to at least one of a lower magnetic field strength level or substantially zero.

12. The method of claim 11, wherein the lower magnetic field strength level corresponds to a level configured to avoid biological harm to the living being.

13. An apparatus configured to transmit power via a magnetic field, the apparatus comprising:

means for inductively transmitting power via the magnetic field at a magnetic field strength level sufficient to charge or power a receiver device;

means for detecting a proximity of a presence of a living being within a region of the magnetic field in which power is inductively transmitted at the magnetic field strength level; and

means for controlling the transmitting means to adjust the magnetic field strength level in response to detecting the presence of the living being within the region of the magnetic field.

14. The apparatus of claim 13, further comprising means for receiving manual input from the living being and means for activating the means for detecting in response to receiving the manual input.

15. The apparatus of claim 13, wherein the means for detecting the proximity of the living being comprises an infrared sensor.

16. The apparatus of claim 13, wherein the controlling means comprises means for controlling the transmitting means to reduce the magnetic field strength level to at least one of a lower magnetic field strength level or substantially zero.