WIRELESS CHARGER COMMUNICATION AUTOMATIC GAIN CONTROL

• US 20150093989A1
• Filed: 10/02/2014
• Published: 04/02/2015
• Est. Priority Date: 10/02/2013
• Status: Active Grant

• Current Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Original Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Inventors: Plumb, William, Satyamoorthy, Anand, Riehl, Patrick Stanley
• Granted Patent: US 9,705,566 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• 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 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 2001/0416 having gain or transmission power control
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A variable gain circuit used in an in-band communication system is provided that includes a current sense pickup that is coupled to the output of a DC power source that senses current from the DC power source and provides a first output signal. A variable controlled amplifier structure, that is coupled to the DC power source, receives the first output signal and provides a specified amount of gain to the first output signal so as to produce a second output signal. A digital signal is produced using the second output having a selected frequency bandwidth.

Claims

1. A variable gain circuit used in an in-band communication system comprising:

a current sense pickup that is coupled to the output of a DC power source that senses current from the DC power source and provides a first output signal; and

a variable controlled amplifier structure, that is coupled to the DC power source, receives the first output signal and provides a specified amount of gain to the first output signal so as to produce a second output signal, wherein a digital signal is produced using the second output having a selected frequency bandwidth.

2. The variable gain circuit of claim 1, wherein the variable controlled amplifier structure is coupled to a resonator structure.

3. The variable gain circuit of claim 1, wherein the variable controlled amplifier structure provides its output to an analog to digital converter (ADC).

4. The variable gain circuit of claim 1, wherein the amplifier structure comprises variable gain.

5. The variable gain circuit of claim 1, wherein the variable controlled amplifier structure receives input from an external source to control its variable gain.

6. The variable gain circuit of claim 5, wherein the external source receives as input the output of an ADC to control the variable gain of the amplifier structure.

7. The variable gain circuit of claim 1, wherein the variable controlled amplifier structure comprises high pass filters at its input.

8. The variable gain circuit of claim 1, wherein the variable controlled amplifier structure and current sense pickup are positioned on a transmitter side of the in-band communication system.

9. A wireless power system comprising:

a transmitter side that transmits a transmitted signal for reception;

a receiver side that receives the transmitted signal from the transmitter side;

a current sense pickup that is coupled to the output of a DC power source that senses current from the DC power source and provides a first output signal; and

a variable controlled amplifier structure, that is coupled to the DC power source, receives the first output signal and provides a specified amount of gain to the first output signal so as to produce a second output signal, wherein a digital signal is produced using the second output having a selected frequency bandwidth.

10. The wireless power system of claim 9, wherein the variable controlled amplifier structure is coupled to a resonator structure.

11. The wireless power system of claim 9, wherein the variable controlled amplifier structure provides its output to an analog to digital converter (ADC).

12. The wireless power system of claim 9, wherein the variable controlled amplifier structure comprises variable gain.

13. The wireless power system of claim 9, wherein the variable controlled amplifier structure receives input from an external source to control its variable gain.

14. The wireless power system of claim 13, wherein the external source receives as input the output of an ADC to control the variable gain of the amplifier structure.

15. The wireless power system of claim 9, wherein the variable controlled amplifier structure comprises high pass filters at its input.

16. The wireless power system of claim 9, wherein the variable controlled amplifier structure and current sense pickup are positioned on a transmitter side of the in-band communication system.

17. A wireless power transmitter comprises a detection circuit for in-band communications, the detection circuit comprising one or more sense amplifiers, wherein the gain of the detection circuit is variable.

18. The wireless power transmitter of claim 17, wherein the signal is detected by means of a sense resistor in series with the power supply input to the power amplifier.

19. The wireless power transmitter of claim 18, wherein the voltage across the sense resistor is dc-coupled to one or more sense amplifiers.

20. The wireless power transmitter of claim 18, wherein the voltage across the sense resistor is ac-coupled to one or more sense amplifiers.

21. The wireless power transmitter of claim 17, wherein the sense amplifier has a plurality of gain settings.

22. The wireless power transmitter of claim 17, wherein the outputs of the one or more sense amplifiers are processed by a low-pass filter.

23. The wireless power transmitter of claim 17, wherein the outputs of the one or more sense amplifiers are processed by a band-pass filter.

24. The wireless power transmitter of claim 17, wherein the outputs of the one or more sense amplifiers are digitized by an analog digital converter (ADC).

25. The wireless power transmitter of claim 17, wherein the output of the ADC provides an input to a digital AGC controller that controls the gain of the one or more sense amplifiers.

26. The wireless power transmitter of claim 25, wherein the digital AGC controller controls the gain to the maximum value at which clipping of the signal does not occur.

27. The wireless power transmitter of claim 25, wherein the digital AGC controller controls the gain dynamically for each time slot depending on the expected signal level from each Load device.

28. The wireless power transmitter of claim 17, wherein the detection circuit comprises a plurality of sense amplifiers, each with a different fixed gain.

29. The wireless power transmitter of claim 28, wherein one of the sense amplifier outputs can be selected to be digitized by the ADC and decoded.

30. The wireless power transmitter of claim 28, wherein all of the sense amplifier outputs can be selected to be digitized by the ADC in an interleaved fashion.

31. The wireless power transmitter of claim 30, wherein a signal stream selection element selects which data stream to decode.

32. The wireless power transmitter of claim 31, wherein the signal stream selection element chooses the data stream that provides the maximum signal without clipping.

33. The wireless power transmitter of claim 31, wherein the signal stream selection element selects the data stream dynamically for each time slot depending on the expected signal level from each target device.

45. The method of claim 33, wherein the detection circuit comprises a plurality of sense amplifiers, each with a different fixed gain.

46. The method of claim 45, wherein one of the sense amplifier outputs can be selected to be digitized by the ADC and decoded.

47. The method of claim 45, wherein all of the sense amplifier outputs can be selected to be digitized by the ADC in an interleaved fashion.

48. The method of claim 47, wherein a signal stream selection element selects which data stream to decode.

49. The method of claim 48, wherein the signal stream selection element chooses the data stream that provides the maximum signal without clipping.

50. The method of claim 48, wherein the signal stream selection element selects the data stream dynamically for each time slot depending on the expected signal level from each target device.

34. A method for decoding an in-band communications signal in a wireless power transmitter comprising:

providing a detection circuit for in-band communications; and

providing one or more sense amplifiers, wherein the gain of the detection circuit is variable.

35. The method of claim 34, wherein the signal is detected by means of a sense resistor in series with the power supply input to the power amplifier.

36. The method of claim 35, wherein the voltage across the sense resistor is dc-coupled to one or more sense amplifiers.

37. The method of claim 35, wherein the voltage across the sense resistor is ac-coupled to one or more sense amplifiers.

38. The method of claim 34, wherein the sense amplifier has a plurality of gain settings.

39. The method of claim 34, wherein the outputs of the one or more sense amplifiers are processed by a low-pass filter.

40. The method of claim 34, wherein the outputs of the one or more sense amplifiers are processed by a band-pass filter.

41. The method of claim 35, wherein the outputs of the one or more sense amplifiers are digitized by an analog digital converter (ADC).

42. The method of claim 35, wherein the output of the ADC provides an input to a digital AGC controller that controls the gain of the one or more sense amplifiers.

43. The method of claim 42, wherein the digital AGC controller controls the gain to the maximum value at which clipping of the signal does not occur.

44. The method of claim 42, wherein the digital AGC controller controls the gain dynamically for each time slot depending on the expected signal level from each Load device.

51. A wireless power system comprising:

a transmitter side that transmits a transmitted signal for reception;

a receiver side that receives the transmitted signal from the transmitter side;

a current sense pickup structure that receives a signal stream having a plurality of DC signals and senses the current for each input signal producing a second signal stream; and

a plurality of variable amplifier structures that receive the second signal stream, each variable amplifier structure provides a specified amount of gain to their respective second signal in the second signal stream so as to produce a third output signal stream; and

a multiplexer that selects a third signal from the third output signal stream, via a signal stream selection module, to produce a digital signal.