Headset power management

• US 20070121959A1
• Filed: 01/17/2006
• Published: 05/31/2007
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Philipp, Harald
• Granted Patent: US 8,045,727 B2
• Time in Patent Office: Days
• US Class Current: 381/74
• CPC Class Codes: H04R 1/10 Earpieces; Attachments therefor ; Earphones; Monophonic headphones H04R1/28 takes precedence; stereophonic headphones H04R5/033
• CPC Class Codes: H04R 1/1008 Earpieces of the supra-aural or circum-aural type
• CPC Class Codes: H04R 1/1041 Mechanical or electronic switches, or control elements switches in general H01H
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 2460/03 Aspects of the reduction of energy consumption in hearing devices
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10

Abstract

The invention relates to an energy saving headset 100. The headset 100 comprises a power management unit 150 that is operable to reduce the power consumption of the headset 100 when a user 110 is not present. The power management unit 150 uses capacitive sensing to detect the presence of the user 110. Capacitive sensing is advantageous since it provides a flexible and reliable sensor that can accurately detect the presence or absence of a user 110 either by detecting user proximity or user contact. Moreover, in various embodiments, the sensitivity of a capacitive sensor may be adjusted to account for user movement or changes in environmental conditions, such as, for example, the presence of water, or sweat, on the headset 100 to further improve sensing reliability. The invention further relates to headsets using user presence signals based on capacitive sensing to control other functions of the headset or to control external devices to which the headset is connected, either wirelessly or by wires.

Claims

1. An apparatus comprising:

a headset including a sensing element;

a capacitance measurement circuit operable to measure the capacitance of the sensing element; and

a control circuit operable to determine whether a user is wearing the headset based on a measurement of the capacitance of the sensing element, and to control a function of the apparatus according to whether the headset is being worn.

2. The apparatus of claim 1, wherein the capacitance measurement circuit includes a sample capacitor and is further operable to transfer charge from the sensing element to the sample capacitor to generate an electric potential at the sample capacitor for measuring.

3. The apparatus of claim 2, comprising at least one switch operable to transfer a burst of charge packets sequentially from the sensing element to the sample capacitor prior to a measurement of the electric potential being made.

4. The apparatus of claim 1, wherein the control circuit is operable to determine whether a user is wearing the headset by comparing a measured capacitance of the sensing element to at least one predetermined threshold value.

5. The apparatus of claim 1, wherein the sensing element comprises an electrode that is electrically isolated from the user when the headset is being worn.

6. The apparatus of claim 1, wherein the capacitance measurement circuit is internal to the headset.

7. The apparatus of claim 6, wherein the control circuit is internal to the headset.

8. The apparatus of claim 7, wherein the function to be controlled is provided by a circuit element which is internal to the headset.

9. The apparatus of claim 1, wherein the function to be controlled is provided by a circuit element which is external to the headset.

10. The apparatus of claim 9, wherein the control circuit is external to the headset.

11. The apparatus of claim 10, wherein the capacitance measurement circuit is external to the headset.

12. The apparatus of claim 1, wherein the function to be controlled is a power saving function.

13. The apparatus of claim 1, further comprising an audio amplifier for supplying audio signals to speakers in the headset, and wherein the function to be controlled is the activation of the audio amplifier.

14. The apparatus of claim 1, further comprising a wireless communications transceiver, and wherein the function to be controlled is the activation of the wireless communications transceiver.

15. The apparatus of claim 1, further comprising an audio generator for outputting an audio signal, and wherein the function to be controlled is the outputting of an audio signal by the audio generator.

16. The apparatus of claim 1, further comprising input buttons for supplying operating signals to the control circuit to allow a user to govern the operation of the apparatus, and the function to be controlled is the inhibition of signals from the input buttons.

17. A method of operating an apparatus comprising a headset, the method comprising:

measuring the capacitance of a sensing element in the headset;

determining from the measured capacitance whether a user is wearing the headset; and

controlling a function of the apparatus in response to determining whether the headset is being worn.

18. The method of claim 17, wherein measuring the capacitance of the sensing element includes:

transferring charge from the sensing element to a sample capacitor;

measuring the electric potential at the sample capacitor; and

determining the capacitance of the sensing element from the measured electric potential of the sample capacitor.

19. The method of claim 18, wherein transferring charge from the sensing element to a sample capacitor comprises transferring a burst of charge packets in sequence from the sensing element to a sample capacitor.

20. The method of claim 17, wherein determining whether a user is wearing the headset or not comprises comparing the measured capacitance of the sensing element to at least one predetermined threshold value in order to determine whether the capacitance of the sensing element has been changed due to the proximity of a user.

21. The method of claim 20, comprising adjusting one or more of the threshold values in response to changes in operating conditions.

22. The method of claim 17, wherein the controlling a function of the apparatus comprises controlling whether or not the apparatus is in a power saving mode.

23. The method of claim 17, wherein the controlling a function of the apparatus comprises controlling whether or not wireless communications transceiver is activated.

24. The method of claim 17, wherein the controlling a function of the apparatus comprises controlling whether or not an audio signal generator is activated.

25. The method of claim 17, wherein the controlling a function of the apparatus comprises controlling whether or not user inputs for governing the operation of the apparatus are inhibited.

26. A headset comprising:

at least one circuit element;

a capacitive sensor operable to provide a capacitance measurement signal; and

a sensing circuit operable to generate a user presence signal responsive to the capacitance measurement signal indicating whether the headset is being worn and operable to control the at least one circuit element dependent on said user presence signal.

27. The headset of claim 26, wherein the sensing circuit includes a sample capacitor and is further operable to transfer charge from the capacitive sensor to the sample capacitor to generate an electric potential at the sample capacitor for measuring.

28. The headset of claim 27, comprising at least one switch operable to transfer a burst of charge packets sequentially from the capacitive sensor to the sample capacitor prior to any measurement of the electric potential being made.

29. The headset of claim 26, wherein the sensing circuit comprises a consensus filter for generating the user presence signal.

30. The headset of claim 26, wherein the sensing circuit is further operable automatically to perform a self-calibration operation.

31. The headset of claim 26, wherein the capacitive sensor comprises an electrode that is electrically isolated from the user when the headset is being worn.

32. The headset of claim 26, wherein at least one of the circuit elements comprises a wireless communications transceiver.

33. The headset of claim 26, further comprising a power management unit, of which the sensing circuit is a part, and wherein the power management unit is operable to reduce power consumption of the at least one circuit element dependent on said user presence signal, thereby to reduce power consumption of the headset.

34. A method of operating a headset in order to reduce power consumption, the method comprising:

measuring the capacitance of a capacitive sensor;

determining from the measured capacitance whether a user is present or not; and

powering down one or more circuit elements in the headset in response to determining that no user is present in order to reduce the power consumption of the headset.

35. The method of claim 34, wherein measuring the capacitance of the capacitive sensor includes:

transferring charge from the capacitive sensor to a sample capacitor;

measuring the electric potential at the sample capacitor; and

determining the capacitance of the capacitive sensor from the measured electric potential of the sample capacitor.

36. The method of claim 35, wherein transferring charge from the capacitive sensor to a sample capacitor comprises transferring a burst of charge packets in sequence from the capacitive sensor to a sample capacitor.

37. The method of claim 34, wherein determining whether a user is present or not comprises comparing the measured capacitance of the capacitive sensor to one or more predetermined threshold values in order to determine whether the capacitance of the capacitive sensor has been changed by the proximity of the user.

38. The method of claim 37, comprising adjusting one or more of the threshold values in response to changes in operating conditions.

39. A method of operating a headset, the method comprising:

measuring the capacitance of a capacitive sensor;

determining from the measured capacitance whether a user is present or not; and

controlling a function of the headset, or outputting an external output signal that can be received by another device to which the headset is connected, in response to determining whether the user is present or not.

40. The method of claim 39, wherein measuring the capacitance of the capacitive sensor includes:

transferring charge from the capacitive sensor to a sample capacitor;

measuring the electric potential at the sample capacitor; and

determining the capacitance of the capacitive sensor from the measured electric potential of the sample capacitor.

41. The method of claim 40, wherein transferring charge from the capacitive sensor to a sample capacitor comprises transferring a burst of charge packets in sequence from the capacitive sensor to a sample capacitor.

42. The method of claim 39, wherein determining whether a user is present or not comprises comparing the measured capacitance of the capacitive sensor to one or more predetermined threshold values in order to determine whether the capacitance of the capacitive sensor has been changed by the proximity of the user.

43. The method of claim 42, comprising adjusting one or more of the threshold values in response to changes in operating conditions.

44. The method of claim 39, wherein said device to which the headset is connected is connected thereto wirelessly.

45. The method of claim 39, wherein said device to which the headset is connected is wired thereto.