Methods for Detecting Mated Coils

• US 20170110911A1
• Filed: 12/29/2016
• Published: 04/20/2017
• Est. Priority Date: 06/03/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Herbst, Steven G., Bossetti, Chad A., Alves, Jeffrey M., Golko, Albert J., Terlizzi, Jeffrey, Graham, Christopher S.
• Granted Patent: US 10,594,159 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/10 using inductive coupling
• 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: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Methods and systems for improved efficiency when an inductive power transmitter associated with an inductive power transfer system experiences a low-load or no-load condition. More particularly, methods and systems for detecting when an inductive power receiver is absent or poorly connected to an inductive power transmitter. The inductive power transmitter includes, in one example, a current peak monitor coupled to an inductive power transmit coil. The current peak monitor waits for a current peak resulting from spatial displacement of a magnetic field source within the inductive power receiver, indicating to the inductive power transmitter that the inductive power receiver is moving, or has moved, toward the inductive power transmitter. Other examples include one or more Hall effect sensors within the inductive power transmitter to monitor for the magnetic field source of the inductive power receiver.

Claims

1-20. -20. (canceled)

21. A transmitter of a power transfer system the transmitter comprising:

a sensor configured to detect absence of a receiver;

a transmit coil;

a power supply coupled to the transmit coil and operable in;

a sustained power transmit mode associated with a first output of the sensor that corresponds to a detected alignment between the transmit coil and a receive coil associated with the receiver; and

an intermittent power transmit mode associated with a second output of the sensor that corresponds to absence of the receiver.

22. The transmitter of claim 21, wherein the power supply coupled to a processor configured to toggle between the sustained power transmit mode and the intermittent power transmit mode based on at least one of the first output and the second output.

23. The transmitter of claim 21, wherein the power supply operated in the intermittent power transmit mode in the absence of the first output.

24. The transmitter of claim 21, wherein the power supply switched form the intermittent power transmit mode to the sustained power transmit mode in response to the first output.

25. The transmitter of claim 21, wherein the sensor is configured to accept a signal from the receiver that corresponds to the first output.

26. The transmitter of claim 25, wherein the signal indicates that the receiver is ready to receive power.

27. The transmitter of claim 25, wherein the signal indicates that the receiver is not ready to receive power.

28. The transmitter of claim 21, wherein the signal includes information related to a state of the receiver device.

29. The transmitter of claim 21, wherein the transmitter is associated with an inductive power transmitting mat.

30. The transmitter of claim 21, wherein the sensor comprises a magnetic field sensor configured to detect the presence of a magnetic field associated with the receiver.

31. The transmitter of claim 21, wherein the sensor comprises an optical communication interface.

32. The transmitter of claim 21, wherein the sensor comprises a strain sensor mechanically coupled to an alignment magnet configured to attract to the receiver.

33. The transmitter of claim 21, wherein the sensor comprises an accelerometer configured to detect mechanical agitation of the transmitter.

34. The transmitter of claim 21, wherein the sensor comprises a capacitive sensor configured to detect capacitive changes associated with placing the receiver adjacent to the transmitter.

35. A power transfer system comprising:

an inductive power receiver comprising a receive coil;

an inductive power mat comprising;

a housing defining a surface configured to receive the inductive power receiver;

a transmit coil positioned below the surface;

a sensor positioned below the surface and configured to detect alignment of the inductive power receiver relative to the surface; and

a processor coupled to the transmit coil and the sensor; and

a power supply in communication with the processor and operable in a sustained power transmit mode, an intermittent power transmit mode, and an inactive mode;

wherein

the inactive mode is associated with a first output of the sensor that corresponds to absence of the receiver;

the intermittent power transmit mode is associated with a second output of the sensor that corresponds to possible presence of the receiver; and

the sustained power transmit mode is associated with a third output of the sensor that corresponds to a detected alignment between the transmit coil and the receive coil.

36. The power transfer system of claim 35, wherein the inductive power receiver is associated with one of:

a wearable device, a stylus, a medical device, a tablet computer, a laptop computer, a portable media player, or a cellular phone.

37. The power transfer system of claim 35, wherein the sensor comprises one of:

a magnetic field sensor;

an accelerometer;

a force-sensitive sensor;

an optical sensor;

an electric field sensor;

or

a strain sensor.

38. The power transfer system of claim 35, wherein the sensor comprises:

a first permanent magnet configure to attract a second permanent magnet within the inductive power receiver; and

a strain sensor coupled to the first permanent magnet and configured to detect attraction between the first permanent magnet and the second permanent magnet.

39. A method of activating transmit circuitry within a transmitter of an inductive power transfer system, the method comprising:

receiving a signal from a strain sensor coupled to a permanent magnet, the signal corresponding to a condition that the permanent magnet is attracted to an object;

determining whether the object is associated with a receiver device of the inductive power transfer system;

verifying that the receiver device is ready to receive power;

activating the transmit circuitry; and

activating a sustained power transmission mode of the transmit circuitry.

40. The method of claim 39, further comprising:

deactivating the transmit circuitry upon determining that the receiver device is not ready to receive power.