Shared power converter for a wireless transmitter device

• US 10,734,840 B2
• Filed: 02/01/2017
• Issued: 08/04/2020
• Est. Priority Date: 08/26/2016
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Qiu, Weihong, Moussaoui, Zaki, Dayal, Rohan
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Ortiz, Elim
• Application Number:
  US15/422,345
• Publication Number:
  US 20180062442A1
• Time in Patent Office: 1,280 Days
• CPC Class Codes: H02J 50/12 of the resonant type

Abstract

A transmitter device is configured to transfer energy to multiple receiver devices. The transmitter device includes multiple transmitter coils, and a shared power converter is coupled to each transmitter coil. The shared power converter includes a leading half bridge and multiple trailing half bridges. Each transmitter coil is coupled between the leading half bridge and a respective one of the trailing half bridges. The shared power converter is dynamically configurable in that the leading half bridge may be coupled to multiple trailing half bridges when energy is to be transferred wirelessly to two or more receiver devices. The leading half bridge simultaneously operates with each trailing half bridge as an independent full-bridge phase shift inverter. A signal supplied to each transmitter coil is independently regulated by controlling a phase shift of a respective trailing half bridge with respect to the leading half bridge.

Claims

1. A shared power converter circuit for a wireless energy transfer system, the shared power converter circuit comprising:

a leading half bridge coupled between first and second input nodes of the shared power converter circuit and having a first intermediate node;

multiple transmitter coils, each coupled to the first intermediate node; and

multiple trailing half bridges coupled between the first and second input nodes, each trailing half bridge having a respective intermediate node coupled to a distinct one of the multiple transmitter coils;

wherein

the leading half bridge is configured to simultaneously operate with each trailing half bridge as an independent full-bridge phase shift inverter by;

applying a first voltage at the first intermediate node;

applying a second voltage at the respective intermediate node of a one of the multiple trailing half bridges; and

controlling a phase shift of the second voltage with respect to the first voltage;

wherein

a one of the multiple transmitter coils is between the first intermediate node and a second intermediate node.

2. The shared power converter circuit of claim 1, wherein the leading half bridge comprises:

a first switching element connected to the first intermediate node; and

a second switching element connected to the first intermediate node.

3. The shared power converter circuit of claim 2, wherein each trailing half bridge comprises:

a third switching element connected to the second intermediate node; and

a fourth switching element connected to the second intermediate node.

4. A wireless transmitter device, comprising:

a first transmitter coil;

a second transmitter coil;

a shared power converter coupled to the first and second transmitter coils, the shared power converter comprising;

a leading half bridge comprising;

a first switching element coupled between a power supply and a first intermediate node; and

a second switching element coupled between a ground and the first intermediate node;

a first trailing half bridge comprising;

a third switching element coupled between the power supply and a second intermediate node; and

a fourth switching element coupled between the ground and the second intermediate node, wherein the first transmitter coil is coupled between the first and second intermediate nodes;

a second trailing half bridge comprising;

a fifth switching element coupled between the power supply and a third intermediate node; and

a sixth switching element coupled between the ground and the third intermediate node, wherein the second transmitter coil is coupled between the first and third intermediate nodes; and

a processing device coupled to the shared power converter and configured to operate the shared power converter as a full bridge to transfer energy from the first transmitter coil by;

causing a first switch signal and a second switch signal to be respectively transmitted to the first switching element and the second switching element of the leading half bridge; and

causing a third switch signal and a fourth switch signal to be respectively transmitted to the third switching element and the fourth switching element of the first trailing half bridge;

wherein

the first and second switch signals produce a first voltage signal at the first intermediate node;

the third and fourth switch signals produce a second voltage signal at the second intermediate node; and

a phase of the second voltage signal is independent of a phase of the first voltage signal.

5. The wireless transmitter device of claim 4, wherein:

the full bridge comprises a first full bridge; and

the processing device is further configured to operate the shared power converter as a second full bridge to transfer energy from the second transmitter coil by;

causing a fifth switch signal and a sixth switch signal to be respectively transmitted to the fifth switching element and the sixth switching element of the second trailing half bridge, wherein;

the fifth and sixth switch signals produce a third voltage signal at the third intermediate node; and

a phase of the third voltage signal is independent of the phase of the first voltage signal.

6. The wireless transmitter device of claim 5, wherein the processing device is configured to create the first and the second full bridges simultaneously.

7. The wireless transmitter device of claim 4, further comprising a memory coupled to the processing device, the memory configured to store one or more switch signal characteristics for at least:

the first and second switch signals;

or

the third and fourth switch signals.

8. The wireless transmitter device of claim 7, further comprising a signal generator coupled to the processing device, wherein the processing device is further configured to cause the one or more switch signal characteristics to be transmitted to the signal generator, and based on the received one or more switch signal characteristics, the signal generator is configured to:

produce the first and second switch signals and respectively transmit the first and second switch signals to the first switching element and the second switching element of the leading half bridge;

or

produce the third and fourth switch signals and respectively transmit the third and fourth switch signals to the third switching element and the fourth switching element of the first trailing half bridge.

9. The wireless transmitter device of claim 4, further comprising:

first transmitter resonant circuitry coupled between the first trailing half bridge and the first transmitter coil; and

second transmitter resonant circuitry coupled between the second trailing half bridge and the second transmitter coil.

10. A method of operating a wireless transmitter device that is coupled to or includes a shared power converter comprising a leading half bridge and multiple trailing half bridges, wherein a respective transmitter coil is coupled between the leading half bridge and each of the multiple trailing half bridges, the method comprising:

detecting a receiver device on a transmitting surface of the wireless transmitter device; and

forming a full bridge in the shared power converter to transfer energy from the respective transmitter coil to the receiver device, wherein forming the full bridge comprises;

transmitting a first set of switch signals to the leading half bridge; and

transmitting a second set of second switch signals to a respective trailing half bridge that is coupled to the respective transmitter coil, wherein the second set of switch signals is phase-shifted independently with respect to the first set of switch signals.

11. The method of claim 10, further comprising:

determining one or more switch signal characteristics for the second set of switch signals prior to transmitting the first and second sets of switch signals, wherein the one or more switch signal characteristics comprises a phase difference of the second set of switch signals with respect to a phase of the first set of switch signals; and

transmitting the one or more switch signal characteristics to a signal generator that is coupled to the leading half bridge and to each of the multiple trailing half bridges, wherein the signal generator produces the first set of switch signals and produces the second set of switch signals based on the one or more switch signal characteristics.

12. The method of claim 11, further comprising determining a receiver device type for the receiver device prior to determining the one or more switch signal characteristics.

13. The method of claim 10, further comprising:

prior to detecting the receiver device on the transmitting surface, detecting an object on the transmitting surface;

determining if the object is the receiver device; and

forming the full bridge to transfer energy to the receiver device only when the object is the receiver device.

14. The method of claim 10, wherein the shared power converter is one of multiple shared power converters and the method comprises:

determining a location of the receiver device on the transmitting surface; and

identifying a respective one of the multiple shared power converters to receive the first and second sets of switch signals based on the determined location.

15. The method of claim 10, further comprising:

determining if the transfer of energy is to stop; and

stop transmitting the first and second sets of switch signals when the transfer of energy is to stop.

16. A method of operating a wireless transmitter device that includes or is coupled to a shared power converter, the shared power converter comprising a leading half bridge, first and second trailing half bridges, a first transmitter coil coupled between the leading half bridge and the first trailing half bridge, and a second transmitter coil coupled between the leading half bridge and the second trailing half bridge, the method comprising:

detecting a first receiver device on a transmitting surface of the wireless transmitter device;

forming a first full bridge in the shared power converter to transfer energy from the first transmitter coil to the first receiver device, wherein forming the first full bridge comprises;

transmitting a first set of switch signals to the leading half bridge; and

transmitting a second set of switch signals to the first trailing half bridge, wherein the second set of switch signals is phase-shifted independently with respect to the first set of switch signals;

detecting a second receiver device on the transmitting surface of the wireless transmitter device; and

forming a second full bridge in the shared power converter to transfer energy from the second transmitter coil to the second receiver device, wherein forming the second full bridge comprises;

transmitting a third set of switch signals to the second trailing half bridge, wherein the third set of switch signals is phase-shifted independently with respect to the first set of switch signals.

17. The method of claim 16, wherein the third set of switch signals is phase-shifted with respect to the first set of switch signals and with respect to the second set of switch signals.

18. The method of claim 16, wherein the first and second full bridges are formed simultaneously.

19. The method of claim 16, further comprising prior to transmitting the second set of switch signals:

determining one or more first switch signal characteristics for the second set of switch signals, wherein the one or more first switch signal characteristics comprises a phase difference of the second set of switch signals with respect to a phase of the first set of switch signals; and

generating the second set of switch signals based on the determined one or more first switch signal characteristics.

20. The method of claim 16, further comprising prior to transmitting the third set of switch signals:

determining one or more second switch signal characteristics for the third set of switch signals, wherein the one or more second switch signal characteristics comprises a phase difference of the third set of switch signals with respect to a phase of the first set of switch signals; and

generating the third set of switch signals based on the determined one or more second switch signal characteristics.

21. The method of claim 16, wherein transmitting the first set of switch signals to the leading half bridge comprises reading the first set of switch signals from a memory.

22. The method of claim 16, wherein transmitting the second set of switch signals to the first trailing half bridge comprises reading the second set of switch signals from a memory.

23. The method of claim 16, wherein transmitting the third set of switch signals to the second trailing half bridge comprises reading the third set of switch signals from a memory.

24. A power adapter, comprising:

a leading half bridge coupled between first and second input nodes, the leading half bridge comprising;

a first switching element coupled between the first input node and a first intermediate node; and

a second switching element coupled between the first intermediate node and the second input node;

a first trailing half bridge coupled between the first and the second input nodes, the first trailing half bridge comprising;

a third switching element coupled between the first input node and a second intermediate node; and

a fourth switching element coupled between the second intermediate node and the second input node, wherein a first load is coupled between the first intermediate node and the second intermediate node; and

a second trailing half bridge coupled between the first and the second input nodes, the second trailing half bridge comprising;

a fifth switching element coupled between the first input node and a third intermediate node; and

a sixth switching element coupled between the third intermediate node and the second input node, wherein a second load is coupled between the first intermediate node and the third intermediate node;

wherein the power adapter is configured to;

apply a first switching signal to the first switching element and a second switching signal to the second switching element;

apply a third switching signal to the third switching element and a fourth switching signal to the fourth switching element; and

apply a fifth switching signal to the fifth switching element and a sixth switching signal to the sixth switching element, the fifth and sixth switching signals having a phase independent of a phase of the first and second switching signals.

25. The power adapter of claim 24, wherein the first load and the second load each comprise a transmitter coil.