Parasitic circuit for device protection

• US 10,270,494 B2
• Filed: 07/27/2015
• Issued: 04/23/2019
• Est. Priority Date: 08/25/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Low, Zhen Ning, Wheatley, III, Charles E., Estrada, Sergio P.
• Primary Examiner(s): Cole, Brandon S
• Application Number:
  US14/810,218
• Publication Number:
  US 20150334884A1
• Time in Patent Office: 1,366 Days
• Field of Search: 307104, 1 1
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: G06K 7/10158 methods and means used by the interrogation device for reliably powering the wireless record carriers using an electromagnetic interrogation field
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/75 for isolation purposes
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H05K 9/0071 Active shielding

Abstract

Exemplary embodiments are directed to a device include a parasitic coil for protection of the device. A device may include a first circuit configured to receive a first transmitted signal at an operational frequency. The device may also include a second circuit a second circuit configured to generate a field that opposes at least one of an undesirable portion of a wireless power field of the first transmitted signal and a portion of another wireless power field proximate the first circuit, the another wireless power field generated by a second transmitted signal at a non-operational frequency of the first circuit.

Claims

1. A device for providing protection from wireless power, comprising:

a first circuit configured to wirelessly receive power via a first magnetic field at an operational frequency from a transmitter and configured to power or charge a load based on the power received via the first magnetic field; and

a second circuit configured to generate an opposing magnetic field that opposes at least a portion of the first magnetic field at the operational frequency and that reduces the power received by the first circuit via the magnetic field, wherein the second circuit is configured to exhibit a first impedance in response to the operational frequency and exhibit a second impedance in response to a different frequency from the operational frequency, and wherein the first circuit is able to power or charge a load at the operational frequency.

2. The device of claim 1, wherein the first impedance is lower than the second impedance.

3. The device of claim 1, wherein the opposing magnetic field creates a null in at least a portion of the first magnetic field.

4. The device of claim 1, further comprising a display screen, wherein the opposing magnetic field creates a null in the first magnetic field at the display screen.

5. The device of claim 4, wherein at least a portion of the display screen is void of the first magnetic field and the opposing magnetic field.

6. The device of claim 1, wherein the first impedance corresponds to a short-circuit impedance at the operational frequency.

7. The device of claim 1, wherein the first circuit comprises a receive coil, and wherein the second circuit comprises a parasitic coil.

8. The device of claim 1, wherein the second circuit comprises a shunt-series circuit coupled to a coil.

9. The device of claim 1, wherein the second circuit is coupled to a surface of one of a near-field communication (NFC) card or a radio-frequency identification (RFID) card.

10. The device of claim 1, wherein the different frequency is substantially the same frequency as a frequency at which an NFC card operates.

11. The device of claim 1, wherein the second circuit is configured to act as a notch filter.

12. A method for providing protection from wireless power, comprising:

receiving power by a first circuit via a first magnetic field at an operational frequency from a transmitter at a power level sufficient to power or charge a load based on the power received via the first magnetic field; and

generating an opposing magnetic field by a second circuit that opposes at least a portion of the first magnetic field at the operational frequency and that reduces the power received by the first circuit via the magnetic field, wherein the second circuit is configured to exhibit a first impedance in response to the operational frequency and exhibit a second impedance in response to a different frequency from the operational frequency.

13. The device of claim 12, wherein the first impedance is lower than the second impedance.

14. The method of claim 12, wherein the opposing magnetic field creates a null in at least a portion of the first magnetic field.

15. The method of claim 12, wherein the opposing magnetic field creates a null in the first magnetic field at a display screen of a device.

16. The method of claim 15, wherein at least a portion of the display screen is void of the first magnetic field and the opposing magnetic field.

17. The method of claim 12, wherein the first circuit comprises a receive coil, and wherein the second circuit comprises a parasitic coil.

18. The device of claim 12, wherein the second circuit is coupled to a surface of one of a near-field communication (NFC) card or a radio-frequency identification (RFID) card.

19. The method of claim 12, wherein the different frequency is substantially the same frequency as a frequency at which an NFC card operates.

20. A device for providing protection from wireless power, comprising:

means for receiving power via a first magnetic field at an operational frequency from a transmitter and for powering or charging a load based on the power received via the first magnetic field; and

means for generating an opposing magnetic field that opposes at least a portion of the first magnetic field at the operational frequency and for reducing the power received by the first circuit via the magnetic field, wherein the means for generating is configured to exhibit a first impedance in response to the operational frequency and exhibit a second impedance in response to a different frequency from the operational frequency.