Adaptive passive ping

Patent metadata

Field	Value
Publication number	US-11336129-B2
Application number	US-202117368770-A
Country	US
Kind code	B2
Filing date	Jul 6, 2021
Priority date	May 28, 2019
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

Systems, methods and apparatus for wireless charging are disclosed. A charging device has a charging circuit that includes a charging coil located proximate to a surface of the charging device, a pulse generating circuit, and a controller. The pulse generating circuit may be configured to provide a pulsed signal to the charging circuit, where each pulse in the pulsed signal includes a plurality of cycles of a clock signal that has a frequency greater or less than a nominal resonant frequency of the charging circuit. The controller may be configured to detect a change in resonance of the charging circuit based on a difference in response of the charging circuit to first and second pulses transmitted in the pulsed signal. The controller may be further configured to determine that a chargeable device has been placed in proximity to the charging coil based on the difference in responses.

First claim

What is claimed is:

1. A method for detecting an object, comprising:
transmitting a pulsed signal using a resonant circuit in a wireless charging device, wherein each pulse in the pulsed signal comprises a plurality of cycles of a clock signal that has a frequency that is greater than a nominal resonant frequency of the resonant circuit;
for each pulse in the pulsed signal:
generating a measurement signal representative of quality factor (Q factor) of the resonant circuit during transmission of the each pulse; and
filtering the measurement signal to obtain a filtered measurement signal indicative of Q factor of the resonant circuit during transmission of the each pulse; and

determining that a chargeable device has been placed in proximity to a coil of the resonant circuit when a first Q factor of the resonant circuit is different from a second Q factor of the resonant circuit, wherein the first Q factor is measured during transmission of a first pulse and the second Q factor is measured during transmission of a previously-transmitted second pulse.

2. The method of claim 1 , wherein the first Q factor exceeds a threshold value when the chargeable device has been placed in proximity to the coil of the resonant circuit.

3. The method of claim 2 , wherein the second Q factor is less than the threshold value before the chargeable device has been placed in proximity to the coil of the resonant circuit.

4. The method of claim 1 , further comprising:
detecting a change in the measurement signal between transmission of the first pulse and transmission of the second pulse; and
determining that the chargeable device has been placed in proximity to the coil of the resonant circuit when the change in the measurement signal exceeds a threshold difference value.

5. The method of claim 1 , further comprising:
providing a low-pass filtered version of the measurement signal and a filtered version of the measurement signal to respective inputs of a comparator; and
determining that the chargeable device has been placed in proximity to the coil of the resonant circuit when the comparator indicates a difference between its inputs.

6. The method of claim 5 , wherein the low-pass filtered version of the measurement signal is obtained from a low-pass filter configured to block higher frequency components of the measurement signal.

7. The method of claim 5 , wherein the comparator comprises a hysteresis circuit.

8. The method of claim 1 , wherein the measurement signal is obtained by measuring current in the resonant circuit.

9. The method of claim 1 , wherein the measurement signal is obtained by measuring voltage in the resonant circuit.

10. The method of claim 1 , further comprising:
using the resonant circuit to transmit an active ping in accordance with standards-defined specifications for charging the chargeable device; and
identifying the chargeable device from information encoded in a modulated signal received from the chargeable device,
wherein the clock signal has a frequency that is greater than nominal resonant frequency defined by the standards-defined specifications.

11. A charging device, comprising:
a resonant circuit that includes a charging coil located proximate to a surface of the charging device;
a pulse generating circuit configured to provide a pulsed signal to the resonant circuit, wherein each pulse in the pulsed signal comprises a plurality of cycles of a clock signal that has a frequency that is greater than a nominal resonant frequency of the resonant circuit;
a measurement circuit configured to provide a measurement signal indicative of Q factor of the resonant circuit during transmission of each pulse in the pulsed signal;
a filter configured to provide a filtered measurement signal indicative of Q factor of the resonant circuit during transmission of the each pulse;
comparison logic configured to compare a first Q factor measured during transmission of a first pulse and a second Q factor is measured during transmission of a previously-transmitted second pulse; and
a controller configured to determine that a chargeable device has been placed in proximity to a coil of the resonant circuit when the first Q factor of the resonant circuit is different from the second Q factor of the resonant circuit.

12. The charging device of claim 11 , wherein the first Q factor exceeds a threshold value when the chargeable device has been placed in proximity to the coil of the resonant circuit.

13. The charging device of claim 12 , wherein the second Q factor is less than the threshold value before the chargeable device has been placed in proximity to the coil of the resonant circuit.

14. The charging device of claim 11 , wherein the controller is further configured to:
detect a change in the measurement signal between transmission of the first pulse and transmission of the second pulse; and
determine that the chargeable device has been placed in proximity to the coil of the resonant circuit when the change in the measurement signal exceeds a threshold difference value.

15. The charging device of claim 11 , wherein the comparison logic is further configured to:
determine that the chargeable device has been placed in proximity to the coil of the resonant circuit based on a comparison of provide a low-pass filtered version of the measurement signal with a filtered version of the measurement signal.

16. The charging device of claim 15 , further comprising:
a low-pass filter configured to provide the low-pass filtered version of the measurement signal by blocking higher frequency components of the measurement signal.

17. The charging device of claim 15 , wherein the comparison logic comprises a hysteresis circuit.

18. The charging device of claim 11 , wherein the measurement signal is obtained by measuring current in the resonant circuit.

19. The charging device of claim 11 , wherein the measurement signal is obtained by measuring voltage in the resonant circuit.

20. The charging device of claim 11 , wherein the controller is further configured to:
use the resonant circuit to transmit an active ping in accordance with standards-defined specifications for charging the chargeable device; and
identify the chargeable device from information encoded in a modulated signal received from the chargeable device,
wherein the clock signal has a frequency that is greater than nominal resonant frequency defined by the standards-defined specifications.

Assignees

• Aira Inc

Inventors

• Goodchild Eric Heindel
• Winters John

Classifications

• H02J7/42

  with electronic devices having internal batteries, e.g. mobile phones · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H02J50/40

  using two or more transmitting or receiving devices (H02J50/50 takes precedence) · CPC title

• H02J50/10

  using inductive coupling · CPC title

• H02J50/402

  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 title