DETECTING RESONANT FREQUENCIES

• US 20170093170A1
• Filed: 09/25/2015
• Published: 03/30/2017
• Est. Priority Date: 09/25/2015
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Saunamaki, Esa Ilmari
• Granted Patent: US 10,361,565 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

Techniques for wirelessly transferring energy are described. An example device includes a transmitter coil to generate a magnetic field to wirelessly charge a battery. The device also includes a noise signal generator to generate a noise signal and send the noise signal to the transmitter coil. A frequency detection circuit is used to detect a resonance due to the noise signal and calculate a frequency of the resonance.

Claims

1. A device for wirelessly transferring energy, comprising:

a transmitter coil to generate a magnetic field to wirelessly charge a battery;

a noise signal generator to generate a noise signal and send the noise signal to the transmitter coil; and

a frequency detection circuit to detect a resonance due to the noise signal and calculate a frequency of the resonance.

2. The device of claim 1, wherein the resonance is the resonance of the transmitter coil and the frequency is a resonant frequency of the transmitter coil.

3. The device of claim 2, further comprising a matching circuit to detune the transmitter coil before sending the noise signal to the transmitter coil.

4. The device of claim 2, wherein the resonant frequency of the coil is used to calculate an adjustment of a matching circuit to impedance match the transmitter coil to a power amplifier.

5. The device of claim 1, further comprising a controller to determine whether the frequency is a resonant frequency of a component in the vicinity of the transmitter coil.

6. The device of claim 5, wherein the controller is configured to disable wireless charging if the frequency is a resonant frequency of a component in the vicinity of the transmitter coil.

7. The device of claim 5, wherein the controller is configured to enable a low power charging mode if the frequency is a resonant frequency of a component in the vicinity of the transmitter coil.

8. The device of claim 5, wherein the controller is configured to display a message to a user if the frequency is a resonant frequency of a component in the vicinity of the transmitter coil.

9. The device of claim 1, wherein the noise signal is configured to pulse between an on period and an off period and to identify interference sources during the off period.

10. The device of claim 9, further comprising an adjustable filter to filter out any identified noise sources.

11. A method of operating a wireless power transmitter, comprising:

generating a noise signal and sending the noise signal to a transmitter coil;

detecting a resonance caused by the noise signal and calculating a frequency of the resonance; and

sending a charging signal to the transmitter to power an electrical device based on the frequency of the resonance.

12. The method of claim 11, wherein the resonance is the resonance of the transmitter coil and the frequency is a resonant frequency of the transmitter coil.

13. The method of claim 12, comprising, if the resonant frequency is within a specified range, generating a charging signal and sending the charging signal to the transmitter coil.

14. The method of claim 12, comprising, if the resonant frequency is outside of a specified range, calculating an adjustment of a matching circuit to impedance match the transmitter coil to a power amplifier.

15. The method of claim 11, comprising determining whether the frequency is a resonant frequency of a component in the vicinity of the transmitter coil.

16. The method of claim 15, comprising, if the frequency is a resonant frequency of a component in the vicinity of the transmitter coil, disabling wireless charging.

17. The method of claim 15, comprising, if the frequency is a resonant frequency of a component in the vicinity of the transmitter coil, enabling a low power charging mode.

18. The method of claim 15, comprising, if the frequency is a resonant frequency of a component in the vicinity of the transmitter coil, displaying a message to a user.

19. The method of claim 11, comprising pulsing the noise signal between an on period and an off period and identifying interference sources during the off period.

20. The method of claim 19, comprising adjusting a filter to filter out any identified noise sources.

21. A system for tuning in a wireless power transmitter, comprising:

a transmitter coil configured to generate a magnetic field to wirelessly charge a battery;

a matching circuit to impedance match the transmitter coil to a power amplifier;

a noise signal generator to generate a noise signal and send the noise signal to the transmitter coil;

a frequency detection circuit to detect a resonant frequency of the transmitter coil based on an electrical response to the noise signal; and

a controller to adjust the matching circuit based on the resonant frequency.

22. The system of claim 21, wherein the controller is configured to detect additional resonant frequencies to identify additional resonant components in the vicinity of the transmitter coil.

23. The system of claim 22, wherein the controller is configured to enable a low power charging mode if at least one of the additional resonant frequencies indicates a Near Field Communication (NFC) device is in the vicinity of the transmitter coil.

24. The system of claim 21, wherein the noise signal generator is configured to pulse the noise signal between an on period and an off period and interference sources are identified during the off period.

25. The system of claim 24, comprising an adjustable filter to filter out any identified noise sources.