Multi-mode resonant wireless power transmitter

• US 10,291,036 B2
• Filed: 01/08/2016
• Issued: 05/14/2019
• Est. Priority Date: 07/17/2015
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Muratov, Vladimir A.
• Primary Examiner(s): Gannon, Levi
• Application Number:
  US14/990,833
• Publication Number:
  US 20170018937A1
• Time in Patent Office: 1,222 Days
• Field of Search: 307104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 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 Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Abstract

A wireless power transmitter includes a multi-mode drive circuit having a controllable resonant frequency. The multi-mode drive circuit is controlled to have a first resonant frequency to drive wireless power transmission at a first transmit frequency. The multi-mode drive circuit is also controlled to have a second resonant frequency higher than the first resonant frequency to drive wireless power transmission at a second transmit frequency higher than the first transmit frequency.

Claims

1. A wireless power transmitter, comprising:

a multi-mode drive circuit having a controllable resonant frequency, the multi-mode drive circuit being controlled to have a first resonant frequency to drive wireless power transmission at a first transmit frequency, and being controlled to have a second resonant frequency different from the first resonant frequency to drive wireless power transmission at a second transmit frequency different from the first transmit frequency;

a first matching network coupled to an output of the multi-mode drive circuit, wherein the first matching network is configured to provide a first signal at the first transmit frequency to a first transmit coil; and

a second matching network coupled to the output of the multi-mode drive circuit, wherein the second matching network is configured to provide a second signal at the second transmit frequency to a second transmit coil,

wherein the wireless power transmitter is configured to detect a type of wireless power receiver that is present in the vicinity of the wireless power transmitter, and control the multi-mode drive circuit to have the first resonant frequency in response to detecting that the wireless power receiver is of a type that receives power wirelessly at the first transmit frequency, and

wherein the first matching network is connected to the second matching network.

2. The wireless power transmitter of claim 1, wherein the multi-mode drive circuit comprises an inverter.

3. The wireless power transmitter of claim 2, wherein the multi-mode drive circuit comprises a class E amplifier.

4. The wireless power transmitter of claim 1, wherein the multi-mode drive circuit has a variable capacitance that is controlled to change the controllable resonant frequency.

5. The wireless power transmitter of claim 4, wherein the multi-mode drive circuit comprises:

a capacitor; and

a switch controlled to connect or disconnect the capacitor to control whether the capacitor contributes to the variable capacitance.

6. The wireless power transmitter of claim 4, wherein the multi-mode drive circuit has a variable inductance that is controlled based on a mode of operation of the multi-mode drive circuit.

7. The wireless power transmitter of claim 6, wherein the multi-mode drive circuit comprises:

an inductor; and

a switch controlled to connect or disconnect the inductor to control whether the inductor contributes to the variable inductance.

8. The wireless power transmitter of claim 7, wherein the switch connects the inductor so that the inductor contributes to the variable inductance when the multi-mode drive circuit is controlled to drive wireless power transmission at the first transmit frequency.

9. The wireless power transmitter of claim 8, wherein the switch disconnects the inductor so that the inductor does not contribute to the variable inductance when the multi-mode drive circuit is controlled to drive wireless power transmission at the second transmit frequency.

10. The wireless power transmitter of claim 1, wherein the first transmit frequency is lower than 300 kHz and the second transmit frequency is higher than 1 MHz.

11. The wireless power transmitter of claim 10, wherein the second transmit frequency is between 6.765 MHz and 6.795 MHz.

12. The wireless power transmitter of claim 1, further comprising:

the first transmit coil to transmit wireless power at the first transmit frequency; and

the second transmit coil to transmit wireless power at the second transmit frequency.

13. The wireless power transmitter of claim 1, wherein a first terminal of the first matching network is connected to a first terminal of the second matching network, and wherein a second terminal of the first matching network is connected to a second terminal of the second matching network.

14. The wireless power transmitter of claim 1, wherein the multi-mode drive circuit is an inverter, the first matching network is connected to an output of the inverter and the second matching network is connected to the output of the inverter.

15. A wireless power transmission method for a wireless power transmitter comprising a multi-mode drive circuit having a controllable resonant frequency, the method comprising:

(A) detecting, by the wireless power transmitter, a type of wireless power receiver that is present in the vicinity of the wireless power transmitter,

(B) controlling the multi-mode drive circuit to have a first resonant frequency to drive wireless power transmission at a first transmit frequency in response to detecting that the wireless power receiver is of a type that receives power wirelessly at the first transmit frequency, wherein the wireless power transmission at the first transmit frequency is performed by providing a first signal from the multi-mode drive circuit to a first matching network that provides the first signal to a first transmit coil; and

(C) controlling the multi-mode drive circuit to have a second resonant frequency to drive wireless power transmission at a second transmit frequency different from the first transmit frequency, wherein the wireless power transmission at the second transmit frequency is performed by providing a first signal from the multi-mode drive circuit to a second matching network that provides the second signal to a second transmit coil, and wherein the first matching network is connected to the second matching network.

16. The wireless power transmission method of claim 15, further comprising changing a variable capacitance of the multi-mode drive circuit to change the controllable resonant frequency.

17. The wireless power transmission method of claim 16, wherein the variable capacitance is changed by a switch that is controlled to connect or disconnect a capacitor to control whether the capacitor contributes to the variable capacitance.

18. The wireless power transmission method of claim 17, further comprising changing a variable inductance of the multi-mode drive circuit by connecting an additional inductor when the capacitor is connected.

19. The wireless power transmission method of claim 15, further comprising changing a variable inductance of the multi-mode drive circuit.

20. The wireless power transmission method of claim 19, wherein the variable inductance is changed by a switch that is controlled to connect or disconnect an inductor to control whether the inductor contributes to the variable inductance.

21. The wireless power transmission method of claim 20, further comprising changing a variable capacitance of the multi-mode drive circuit by connecting a capacitor when the inductor is connected.

22. The wireless power transmission method of claim 15, wherein (C) is performed in response to detection of a wireless power receiver that can receive power wirelessly at the second transmit frequency.

23. The wireless power transmission method of claim 15, wherein a first terminal of the first matching network is connected to a first terminal of the second matching network, and wherein a second terminal of the first matching network is connected to a second terminal of the second matching network.

24. The wireless power transmission method of claim 15, wherein the multi-mode drive circuit is an inverter, the first matching network is connected to an output of the inverter and the second matching network is connected to the output of the inverter.