Method and device for the contactless energy transfer to an apparatus equipped with a loudspeaker

• US 10,439,439 B2
• Filed: 08/31/2017
• Issued: 10/08/2019
• Est. Priority Date: 02/13/2017
• Status: Active Grant

• Current Assignee: STMicroelectronics Grand Ouest SAS (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Grand Ouest SAS (STMicroelectronics NV)
• Inventors: Cimaz, Lionel
• Primary Examiner(s): Kim, Paul
• Assistant Examiner(s): Odunukwe, Ubachukwu A
• Application Number:
  US15/693,188
• Publication Number:
  US 20180233950A1
• Time in Patent Office: 768 Days
• Field of Search: 381 77, 381120, 381331, 381111
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/03 the amplifier being designed for audio applications
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 3/183 with semiconductor devices only
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A device includes a first module having an electromagnetic loudspeaker having an inductive element configured to drive a membrane of the electromagnetic loudspeaker. A second module is coupled between the inductive element and a load. The second module is configured to carry out a contactless transfer of energy from an emitter to the load via the inductive element.

Claims

1. A method for contactless energy transfer between an emitter and a device, the method comprising:

receiving an audio signal with a first module, the first module comprising an electromagnetic loudspeaker having an inductive element configured to drive a membrane of the electromagnetic loudspeaker, wherein changes in a position of the inductive element cause movements of the membrane; and

transferring energy from the emitter to a load via the inductive element.

2. The method of claim 1, further comprising reproducing audio via the electromagnetic loudspeaker using the first module at the same time as transferring energy from the emitter to the load via the inductive element.

3. The method of claim 1, wherein:

the audio signal comprises frequencies lower than 20 KHz; and

a signal for transferring energy from the emitter to the load comprises frequencies higher than 100 KHz.

4. The method of claim 3, wherein:

the audio signal consists of frequencies lower than 20 KHz; and

a signal for transferring energy from the emitter to the load consists of frequencies higher than 100 KHz.

5. The method of claim 1, wherein transferring energy from the emitter to the load comprises transferring energy according to the Qi standard.

6. The method of claim 1, further comprising applying a DC voltage to the inductive element.

7. The method claim 6, further comprising controlling transferring energy from the emitter to the load by adjusting the DC voltage applies to the inductive element.

8. A device comprising:

a first module comprising an electromagnetic loudspeaker having an inductive element configured to drive a membrane of the electromagnetic loudspeaker so that changes in a position of the inductive element cause movements of the membrane; and

a second module coupled between the inductive element and a load, the second module configured to carry out a contactless transfer of energy from an emitter to the load via the inductive element.

9. The device of claim 8, wherein the load comprises a rechargeable battery.

10. The device of claim 8, wherein:

the first module comprises an audio amplifier circuit configured to transmit first signals to the inductive element, and a first matching circuit coupled between the inductive element and the audio amplifier circuit;

the second module comprises a transfer circuit configured to receive second signals from the inductive element, and a second matching circuit coupled between the inductive element and the transfer circuit;

the first matching circuit is configured to allow a transmission of the first signals to the inductive element and for prohibiting a transfer of the second signals to the audio amplifier circuit; and

the second matching circuit is configured to allow a transmission of the second signals to the transfer circuit and for prohibiting a transfer of the first signals to the transfer circuit.

11. The device of claim 10, wherein:

the first matching circuit comprises a resonant circuit having a main resonance frequency and configured to exhibit a first impedance between the audio amplifier circuit and the inductive element when the second signals have a frequency higher than the main resonance frequency; and

prohibiting the transfer of the second signals to the audio amplifier circuit is based on the first impedance.

12. The device of claim 11, wherein the first impedance has a value greater or equal to 20 ohms.

13. The device of claim 12, wherein the first impedance has a value greater or equal to 200 ohms.

14. The device of claim 10, wherein:

the second matching circuit comprises a capacitive stage configured to exhibit a second impedance when the first signals are received;

and the second impedance is higher than an impedance of the inductive element.

15. The device of claim 14, wherein the second impedance is at least ten times higher than the impedance of the inductive element.

16. The device of claim 8, further comprising a driver circuit coupled to the inductive element and configured to drive, respectively and exclusively, the first and second modules.

17. The device of claim 8, furthermore comprising a control circuit configured to apply a DC voltage to the inductive element.

18. A device comprising:

an audio amplifier circuit configured to be coupled to a coil, the audio amplifier circuit configured to drive a membrane of a loudspeaker via the coil so that changes in a position of the coil cause movements of the membrane; and

a rectifier circuit configured to be coupled between the coil and a load, the rectifier circuit configured to receive energy from an emitter via contactless communication using the coil.

19. The device of claim 18, further comprising the coil and the load, wherein the load comprises a battery.

20. The device of claim 19, further comprising an external housing, wherein the coil is disposed in the immediate vicinity of the external housing.

21. The device of claim 19, wherein the coil comprises a shape analogous to a shape of a coil of the emitter.

22. The device of claim 18, further comprising:

a first matching circuit coupled to an output of the audio amplifier circuit; and

a capacitive stage coupled to an input of the rectifier circuit.

23. The device of claim 22, wherein the first matching circuit comprises:

a first inductor; and

an LC tank comprising a second inductor in series with a first capacitor, the first inductor coupled in parallel with the LC tank.

24. The device of claim 23, wherein:

the first inductor comprises an inductance of 22 uH;

the second inductor comprises an inductance of 1 uH;

the first capacitor comprises a capacitance of 63 nF; and

the capacitive stage comprises a second capacitor having a capacitance of 200 nF.

25. The device of claim 18, further comprising a wireless speaker or an MP3 player.