Parasitic circuit for device protection

• US 9,094,057 B2
• Filed: 03/02/2011
• Issued: 07/28/2015
• Est. Priority Date: 08/25/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Low, Zhen Ning, Wheatley, Charles E. III, Estrada, Sergio P.
• Primary Examiner(s): Nguyen, Nam V
• Application Number:
  US13/039,142
• Publication Number:
  US 20120050015A1
• Time in Patent Office: 1,609 Days
• Field of Search: 340/10.1, 340/572.3, 340/572.5, 340/10.2, 340/10.5, 235/492, 307/91, 455/1, 455/12.1, 455/41.2
• US Class Current: 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 protecting circuitry, comprising:

a first circuit configured to receive a first transmitted signal from a first transmitter at an operational frequency; and

a second circuit configured to generate a magnetic field that opposes at least a portion of another magnetic field generated by a second transmitter at a frequency that is different from the operational frequency of the first circuit,

wherein the second circuit is further configured to exhibit a first impedance in response to the operational frequency and exhibit a second impedance in response to the frequency that is different from the operational frequency.

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

3. The device of claim 2, wherein the second circuit is configured to exhibit the second impedance by exhibiting a short circuit impedance.

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

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

6. The device of claim 1, wherein the first circuit and/or the second circuit are integrated within one of an NFC card or an RFID card.

7. The device of claim 1, wherein the second circuit is coupled to a surface of one of an NFC card or an RFID card.

8. The device of claim 1, wherein the operational frequency comprises a frequency that is substantially equal to 13.56 MHz, and wherein the frequency that is different from the operational frequency comprises one of a frequency that is substantially equal to 468.75 KHz or a frequency that is substantially equal to 6.78 MHz.

9. The device of claim 1, wherein the second circuit circumscribes the first circuit.

10. The device of claim 1, wherein the first circuit is further configured to receive one of a wireless power signal and a near-field communication signal.

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

12. The device of claim 1, wherein the generated magnetic field opposes at least one of a portion of a field generated by the first transmitter or a portion of another field proximate the first circuit.

13. A method for protecting circuitry, comprising:

receiving a first transmitted signal from a first transmitter at an operational frequency by a first circuit; and

generating a magnetic field by a second circuit that opposes at least a portion of another magnetic field generated by a second transmitter at a frequency that is different from the operational frequency of the first circuit,

wherein the second circuit is further configured to exhibit a first impedance in response to the operational frequency and exhibit a second impedance in response to the frequency that is different from the operational frequency.

14. The method of claim 13, wherein the first transmitted signal is at a frequency that is substantially equal to 13.56 MHz and wherein the generated magnetic field generated in response to receipt of a second transmitted signal from the second transmitter comprises one of a frequency that is substantially equal to 468.75 KHz or a frequency that is substantially equal to 6.78 MHz.

15. The method of claim 13, wherein the second circuit is configured to exhibit a short circuit impedance.

16. The method of claim 13, wherein the second circuit circumscribes the first circuit.

17. The method of claim 13, wherein the second circuit comprises a shunt-series circuit coupled to a coil.

18. The method of claim 13, wherein the second circuit is integrated within one of an NFC card or an RFID card.

19. The method of claim 13, wherein generating the magnetic field by the second circuit comprises generating a current that opposes the at least a portion of another magnetic field generated by the second transmitter.

20. The method of claim 13, wherein the generated magnetic field opposes at least one of a portion of a field generated by the first transmitter or a portion of another field proximate the first circuit.

21. The method of claim 13, wherein the second impedance is lower than the first impedance.

22. The method of claim 21, further comprising exhibiting a short circuit impedance in response to the frequency that is different from the operational frequency.

23. A device for protecting circuitry, comprising:

means for receiving a first transmitted signal from a first transmitter at an operational frequency; and

means for generating a magnetic field that opposes at least a portion of another magnetic field generated by a second transmitter at a frequency that is different from the operational frequency of the receiving means,

wherein the generating means is further configured to exhibit a first impedance in response to the operational frequency and exhibit a second impedance in response to the frequency that is different from the operational frequency.

24. The device of claim 23, wherein the generating means comprises means for generating a current that opposes the at least the portion of another magnetic field generated by the second transmitter.

25. The device of claim 23, wherein the receiving means comprises a receive coil and the generating means comprises a parasitic coil.