Systems and methods for detecting and identifying a wireless power device

• US 9,252,846 B2
• Filed: 05/04/2012
• Issued: 02/02/2016
• Est. Priority Date: 09/09/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lee, Kevin Douglas, Low, Zhen Ning
• Primary Examiner(s): Tran, Thienvu
• Assistant Examiner(s): Stables, David M
• Application Number:
  US13/464,834
• Publication Number:
  US 20130062959A1
• Time in Patent Office: 1,369 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/73 for taking measurements, e.g. using sensing coils
• CPC Class Codes: H04B 5/77 for interrogation
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

Embodiments are directed to detecting and identifying a type of a wireless power device in a wireless power transfer field. According to one aspect, systems and methods are disclosed which describe limiting power transfer to non-compliant devices and detection of undesired power absorbers, such as metal objects, in a wireless power system. A method may include detecting one or more non-compliant devices and/or undesired wireless power absorbers positioned within a charging region of a wireless power transmitter. The method may further include limiting an amount of power transmitted by a transmitter in response to the detection, or reducing the amount of power received by the non-compliant device.

Claims

1. An apparatus for detecting an object within a power delivery region of a wireless power transmitter configured to transfer power to a device having a wireless power receiver, the apparatus comprising:

a driver configured to generate a driving signal to drive a circuit to output a wireless power field;

a sensor configured to sense an amount of power drawn by the driver to generate a sensing signal;

a communication unit configured to receive, from the wireless power receiver, a signal indicative of a change in power received by the wireless power receiver, the signal including information regarding a direction of change in current, a direction of change in voltage, and a magnitude of the change in power received by the wireless power receiver; and

a controller configured to monitor a change in a power drawn by the driver based on the sensing signal and identify the type of object based at least in part on a comparison of the direction of change in current, the direction of change in voltage, and the magnitude of the change in power received by the wireless power receiver and the monitored change in power drawn, the controller further configured to compare the change in power drawn to a first threshold and the received signal to a second threshold.

2. The apparatus of claim 1, wherein the sensor is configured to sense an initial level of power drawn by the driver, and the controller is configured to determine a baseline value of power drawn by the driver based on the sensed initial level.

3. The apparatus of claim 2, wherein the controller is configured to determine the change in power drawn based on a comparison of the sensing signal and baseline value.

4. The apparatus of claim 1, further comprising adjusting the output power of the wireless power field when at least one of the first and second thresholds is exceeded.

5. The apparatus of claim 1, wherein the signal indicative of a change in power received by the wireless power receiver is determined based on comparison of a measured amount of power received by the wireless power receiver relative to a baseline amount of power received by the wireless power receiver, and wherein the baseline amount of power received is predetermined by the wireless power receiver.

6. The apparatus of claim 1, wherein the controller is configured to determine a direction of change in current, a direction of change in voltage, and a magnitude of the change in power drawn by the driver, and wherein the controller is configured. to identify the type of object based at least in part on the direction of change in current, the direction of change in voltage, and the magnitude of the change in power drawn by the driver.

7. The apparatus of claim 1, wherein the object is one of a near-field communication (NFC) device, a radio frequency identification (RFID) device, an unauthorized wireless power receiver, an authorized wireless power receiver, and a metal object.

8. The apparatus of claim. 1, wherein the controller is configured to monitor a change in current drawn by the driver.

9. The apparatus of claim 1, wherein the information regarding the direction of change in voltage comprises a magnitude and direction of a change in voltage received at an input of a voltage regulator of the wireless power receiver.

10. A method of identifying a type of an object within a power transfer region of a wireless power transmitter configured to transfer power to a device including a wireless power receiver, the method comprising:

monitoring a change in a power drawn by the wireless power transmitter;

receiving, from the wireless power receiver, a signal indicative of a change in power received by the wireless power receiver, the signal including information regarding a direction of change in current, a direction of change in voltage, and a magnitude of the change in power received by the wireless power receiver; and

identifying the type of the object based at least in part on a comparison of the direction of change in current, the direction of change in voltage, and the magnitude of the change in power received by the wireless power receiver and the monitored change in power drawn, wherein the identifying the object comprises comparing the change in power drawn to a first threshold and the received signal to a second threshold.

11. The method of claim 10, further comprising receiving a signal indicative of an amount of power received by one or more wireless power receivers.

12. The method of claim 11, further comprising determining an efficiency level of power transferred to the one or more receivers;

comparing the determined efficiency level with a threshold efficiency level; and

determining if a new receiver identification message has been received if the efficiency level is greater than the threshold efficiency level.

13. The method of claim 12, further comprising determining that a metal object is present if a new receiver identification message has not been received.

14. The method of claim 11, further comprising comparing the amount of power received by a wireless power receiver with a threshold receive power level, and determining that a near-field communication device is present if the received power is less than the threshold level.

15. The method of claim 11, further comprising determining an efficiency level of power transferred to the one or more receivers;

comparing the determined efficiency level with a threshold efficiency level; and

determining that a metal object is present if the efficiency level is less than the threshold efficiency level.

16. The method of claim 10, wherein the signal indicative of a change in power received by the wireless power receiver is determined based on comparison of a measured amount of power received by the wireless power receiver relative to a baseline amount of power received by the wireless power receiver, wherein the baseline amount of power received is predetermined by the wireless power receiver.

17. The method of claim 16, further comprising receiving a signal indicative of the baseline amount of power received by the receiver, and wherein the second threshold value is determined based on the baseline value.

18. The method of claim 10, further comprising adjusting the output power of a wireless power field when at least one of the first and second thresholds is exceeded.

19. The method of claim 10, further comprising sensing an initial level of power drawn by the driver, and determining the first threshold value based on the initial level of power drawn by the driver.

20. The method of claim 10, wherein the object is one of a near-field communication (NFC) device, a radio frequency identification (RFID) device, an unauthorized wireless power receiver, an authorized wireless power receiver, and a metal object.

21. The method of claim 10, wherein monitoring the change in power comprises monitoring a change in current drawn by a driver of the wireless power transmitter.

22. The method of claim 10, wherein the information regarding the direction of change in voltage comprises a magnitude and direction of a change in voltage at an input of a regulator.

23. An apparatus for identifying a type of an object within a power transfer region of a wireless power transmitter configured to transfer power to a device including a wireless power receiver, the apparatus comprising:

means for monitoring a change in a power drawn by the wireless power transmitter;

means for receiving, from the wireless power receiver, a signal indicative of a change in power received by the wireless power receiver, the signal including information regarding a direction of change in current, a direction of change in voltage, and a magnitude of the change in power received by the wireless power receiver;

means for comparing the change in power drawn to a first threshold and the received signal to a second threshold; and

means for identifying the type of the object based at least in part on a comparison of the direction of change in current, the direction of change in voltage, and the magnitude of the change in power received by the wireless power receiver and the monitored change in power drawn.

24. The apparatus of claim 23, wherein the means for monitoring comprises a current sensor coupled to a driver of the wireless power transmitter, the means for receiving comprises a communication or detection unit, and the means for identifying comprises a controller.