MULTI-MODE WIRELESS POWER TRANSMITTER

• US 20150357827A1
• Filed: 05/21/2015
• Published: 12/10/2015
• Est. Priority Date: 06/10/2014
• Status: Active Grant

• Current Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Original Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Inventors: Muratov, Vladimir A., Riehl, Patrick Stanley
• Granted Patent: US 10,135,305 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H04B 5/263 Multiple coils at either side
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

Some embodiments relate to a multi-mode wireless power transmitter. The transmitter includes an inverter configured to produce at its output a first signal having a first frequency or a second signal having a second frequency. The transmitter also includes a first transmit coil coupled to the output of the inverter and configured to wirelessly transmit power at the first frequency. The transmitter also includes a second transmit coil coupled to the output of the inverter and configured to wirelessly transmit power at the second frequency. The transmitter further includes at least one matching network coupled to the first transmit coil, the second transmit coil, and the output of the inverter. The at least one matching network is configured to provide power to the first transmit coil in response to the first signal and inhibit providing power to the second transmit coil in response to the first signal.

Claims

1. A wireless power transmitter, comprising:

an inverter configured to produce at its output a first signal having a first frequency or a second signal having a second frequency;

a first transmit coil coupled to the output of the inverter and configured to wirelessly transmit power at the first frequency;

a second transmit coil coupled to the output of the inverter and configured to wirelessly transmit power at the second frequency; and

at least one matching network coupled to the first transmit coil, the second transmit coil, and the output of the inverter, the at least one matching network being configured to provide power to the first transmit coil in response to the first signal and inhibit providing power to the second transmit coil in response to the first signal.

2. The wireless power transmitter of claim 1, wherein the second frequency is higher than the first frequency.

3. The wireless power transmitter of claim 2, wherein the first frequency is lower than 300 kHz and the second frequency is higher than 1 MHz.

4. The wireless power transmitter of claim 3, wherein the second frequency is between 6.765 MHz and 6.795 MHz.

5. The wireless power transmitter of claim 1, having a first impedance between the output of the inverter and the first transmit coil, and a second impedance between the output of the inverter and the second transmit coil, wherein the first impedance is at least five times lower than the second impedance at the first frequency.

6. The wireless power transmitter of claim 5, wherein the first impedance is at least twenty-five times lower than the second impedance at the first frequency.

7. The wireless power transmitter of claim 1, wherein the wireless power transmitter is configured to provide power to the second transmit coil in response to the second signal and inhibit providing power to the first transmit coil in response to the second signal.

8. The wireless power transmitter of claim 7, wherein the first transmit coil has an inductance that inhibits providing power to the first transmit coil in response to the second signal.

9. The wireless power transmitter of claim 1, wherein the at least one matching network comprises a capacitive element that inhibits providing power to the second transmit coil in response to the first signal.

10. The wireless power transmitter of claim 1, wherein the inverter has a full-bridge configuration or a half-bridge configuration.

11. The wireless power transmitter of claim 1, further comprising at least one switch configured to inhibit power from being delivered to the first transmit coil or the second transmit coil.

12. The wireless power transmitter of claim 1, further comprising a resistor configured to be switched into parallel with the second transmit coil.

13. The wireless power transmitter of claim 1, wherein the wireless power transmitter is configured to determine a frequency for wireless power transmission suitable for wireless power delivery to a receiver within wireless power transmission range of the wireless power transmitter, and to produce the first signal or the second signal at the determined frequency.

14. The wireless power transmitter of claim 1, wherein the at least one matching network comprises a first matching network coupled to the first transmit coil and a second matching network coupled to the second transmit coil.

15. The wireless power transmitter of claim 14, wherein the first matching network comprises a capacitive element in series with the first transmit coil.

16. The wireless power transmitter of claim 14, wherein the second matching network comprises a capacitive element in series with the second transmit coil.

17. The wireless power transmitter of claim 1, wherein the first transmit coil is disposed within a boundary of the second transmit coil or outside a boundary of the second transmit coil.

18. The wireless power transmitter of claim 1, further comprising a three terminal coil assembly that includes the first transmit coil and the second transmit coil.

19. The wireless power transmitter of claim 18, wherein the three terminal coil assembly has a common terminal between the first and second transmit coils, the common terminal being connected to a ground terminal of the wireless power transmitter.

20. A wireless power transmission method, comprising:

determining, by a wireless power transmitter, a first frequency for wireless power transmission suitable for wireless power delivery to a first receiver within wireless power transmission range of the wireless power transmitter;

the wireless power transmitter driving, by an inverter, a first transmit coil using a first signal having the first frequency;

determining, by the wireless power transmitter, a second frequency for wireless power transmission suitable for wireless power delivery to a second receiver within wireless power transmission range of the wireless power transmitter; and

the wireless power transmitter driving, by the inverter, a second transmit coil using a second signal having the second frequency.

21. A wireless power transmitter operable in plurality of modes of operation, the wireless power transmitter comprising:

an inverter configured to produce at its output a first wireless power transmission signal having a first frequency when the wireless power transmitter is in a first mode of operation, or a second wireless power transmission signal having a second frequency when the wireless power transmitter is in a second mode of operation, wherein the first wireless power transmission frequency is different from the second wireless power transmission frequency; and

a controller coupled to the inverter and configured to control the inverter in the first mode of operation or the second mode of operation.

22. A wireless power transmission method, comprising:

controlling an inverter in a first mode of operation to produce a first wireless power transmission signal having a first frequency; and

controlling the inverter in a second mode of operation to produce a second wireless power transmission signal having a second frequency.