Dynamic power management in a portable media delivery system

• US 20070201703A1
• Filed: 02/27/2006
• Published: 08/30/2007
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Krueger, Scott, Dorogusker, Jesse, Michelet, Robert, Novotney, Donald, Hammerstrom, Jeffrey
• Granted Patent: US 7,848,527 B2
• Time in Patent Office: Days
• US Class Current: 381/58
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 1/30 Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations for resetting only G06F1/24
• CPC Class Codes: G06F 1/305 in the event of power-supply fluctuations
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices

Abstract

A consumer electronic product (e.g., a portable media player ported to a media delivery accessory) is powered by a limited capacity DC power source (such as a battery or mini-fuel cell). The consumer electronic product limits the maximum allowable sound pressure level (SPL) that can be produced by the speakers. In one embodiment, the maximum allowable SPL is based upon an amount of stored energy available in the limited capacity DC power source.

Claims

1. A method for managing power in a media delivery system operable in either a DC or an AC mode arranged to output audio by way of one or more speakers, comprising:

setting a maximum allowable sound pressure level (SPL) of an output audio signal that can be produced by the one or more speakers when the media delivery system is operating in the DC mode.

2. A method as recited in claim 1, further comprising:

monitoring a charge status of an internal power supply that provides power to the one or more speakers.

3. A method as recited in claim 2, comprising:

when the charge status is less than a threshold value, then,

shutting down the media delivery system, otherwise,

changing the maximum allowable SPL based upon the charge status of the internal power supply.

4. A method as recited in claim 3, wherein the changing the maximum allowable SPL comprises:

reducing the maximum allowable SPL by a preset factor.

5. A method as recited in claim 3, wherein the monitoring comprises;

sensing, in real time, a voltage across a capacitor electrically coupled to the internal power supply, wherein the sensed voltage is directly related to the charge status of the internal power supply.

6. A method as recited in claim 5, further comprising:

if the voltage is a downward going voltage,

determining if the downward going voltage crosses a threshold voltage level.

7. A method as recited in claim 6, further comprising;

when the downward going voltage crosses the threshold voltage level, then

determining if a subsequent upward going voltage re-crosses the threshold voltage within a predetermined length of time; and

generating a shutdown signal used to shut down the media delivery system if the subsequent upward going voltage does not re-cross the threshold voltage level in the predetermined length of time.

8. A method as recited claim 7, further comprising:

providing a clipping event signal if the subsequent upward going voltage does re-cross the threshold voltage level within the predetermined length of time, and

using the clipping event signal to reduce the maximum allowable SPL.

9. A method as recited claim 7, further comprising:

providing a proportional clipping event signal that is proportional to an amount of time that the upward going voltage remains below the threshold voltage that is less than the predetermined length of time; and

using the proportional clipping event signal to proportionally reduce the maximum allowable SPL 1.

10. A method as recited in claim 2, wherein the limited maximum allowable (SPL) in the DC mode is a DC maximum allowable SPL

11. A method as recited in claim 10, comprising;

setting the media delivery system to the AC mode by connecting to an external power supply that provides the power for the media delivery system; and

setting the maximum allowable SPL to an AC limited maximum SPL that is greater than the DC maximum allowable SPL in all cases.

12. A method as recited in claim 11, comprising:

setting the system to the DC mode when the media delivery system is disconnected from the external power supply; and

setting the DC maximum allowable SPL based upon a current charge status of the internal power supply.

13. A method as recited in claim 1, wherein when the speaker'"'"'s requested actual output SPL would be greater than the allowable maximum SPL, then

reducing the actual output SPL to a value that is no greater than the allowable maximum SPL.

14. A consumer electronic product operable in a DC mode and an AC mode, comprising:

a portable media player arranged to playback a selected one of a plurality of media files stored therein; and

a media delivery accessory unit electrically coupled to the portable media player having at least one speaker, wherein when the consumer electronic product is operating in the DC mode, a maximum allowable sound pressure level (SPL) of an output audio signal that can be produced by the at least one speaker is set to a DC maximum allowable SPL.

15. A consumer electronic product as recited in claim 14, further comprising:

a charge monitor coupled to an internal power supply that provides power to the one or more speakers arranged to monitor a charge status of internal power supply.

16. A consumer electronic product as recited in claim 15 wherein when the charge status is less than a threshold value, then the media delivery system is shutdown, otherwise, the maximum allowable SPL is changed based upon the charge status of the internal power supply.

17. A consumer electronic product as recited in claim 16 wherein when the maximum allowable SPL is changed, the maximum allowable SPL is changed by reducing the maximum allowable SPL by a preset factor.

18. A consumer electronic product as recited in claim 16, wherein the charge monitor comprises:

a capacitor electrically coupled to the internal power supply capable of developing a capacitor voltage; and

a capacitor voltage sensor arranged to sense, in real time, the capacitor voltage, wherein the sensed voltage is directly related to the charge status of the internal power supply.

19. A consumer electronic product as recited in claim 18, wherein if the sensed voltage is a downward going voltage that crosses a threshold voltage level and if a subsequent up going voltage does not re-cross the threshold voltage level in a pre-determined length of time, then the consumer electronic product generates a shutdown signal used to shut down the media delivery system.

20. A consumer electronic product as recited claim 19, wherein the monitor further comprises:

a clipping event signal generator for providing a clipping event signal if the subsequent upward going voltage does re-cross the threshold voltage level within the predetermined length of time that is used to reduce the maximum allowable SPL.

21. A consumer electronic product as recited claim 20, wherein the clipping event signal generator provides a proportional clipping event signal that is proportional to an amount of time when the upward going voltage remains below the threshold voltage for a period of time that is less than the predetermined length of time that is used to proportionally reduce the maximum allowable SPL 1.

22. A consumer electronic product as recited in claim 15, wherein the limited maximum allowable (SPL) in the DC mode is a DC maximum allowable SPL

23. A consumer electronic product as recited in claim 22 wherein in the AC mode, the maximum allowable SPL is set to an AC limited maximum SPL that is greater than the DC maximum allowable SPL in all cases.

24. A consumer electronic product as recited in claim 23 wherein when the media delivery system is in the DC mode, then the maximum allowable SPL is set to the DC maximum allowable SPL based upon a current charge status of the internal power supply.

25. A consumer electronic product as recited in claim 24, wherein when the speaker'"'"'s requested actual output SPL would be greater than the allowable maximum SPL, then the actual output SPL is reduced to a value that is no greater than the allowable maximum SPL.

26. A method of shutting down a consumer electronic product so as to avoid generation of audio artifacts, comprising:

determining if a shutdown is imminent,

muting an audio amplifier;

providing a user feedback indicating that a loss of power is imminent;

if all remaining electronic components are not powered down, then powering down all remaining electronic components in the consumer electronic product;

if all residual power is exhausted, then

discontinuing the user feedback.

27. A method as recited in claim 26, wherein the determining if a shutdown is imminent comprises:

receiving a shutdown signal indicating the imminent loss of power.

28. A method as recited in claim 27, further comprising;

receiving residual power from a stored charge in a capacitor coupled to an internal power supply used to monitor a charge status of the internal power supply prior to shutdown.

29. A method as recited in claim 28, wherein when the stored charge is depleted, then the residual power is exhausted.

30. Computer program product executable by a processor for shutting down a consumer electronic product so as to avoid generation of audio artifacts, comprising:

computer code for determining if a shutdown is imminent,

computer code for muting an audio amplifier;

computer code for providing a user feedback indicating that a loss of power is imminent;

computer code for powering down all remaining electronic components in the consumer electronic product if all remaining electronic components are not powered down;

computer code for discontinuing the user feedback if all residual power is exhausted; and

computer readable medium for storing the computer code.

31. Computer program product as recited in claim 30, wherein the computer code for determining if a shutdown is imminent comprises:

computer code for receiving a shutdown signal indicating the imminent loss of power.

32. Computer program product as recited in claim 31, further comprising;

computer code for receiving residual power from a stored charge in a capacitor coupled to an internal power supply used to monitor a charge status of the internal power supply prior to shutdown.

33. Computer program product as recited in claim 32, wherein when the stored charge is depleted, then the residual power is exhausted.

34. Computer program product executable by a processor for managing power in a media delivery system operable in either a DC or an AC mode arranged to output audio by way of one or more speakers, comprising:

computer code for setting a maximum allowable sound pressure level (SPL) of an output audio signal that can be produced by the one or more speakers when the media delivery system is operating in the DC mode; and

computer readable medium for storing the computer code.

35. Computer program product as recited in claim 34, further comprising:

computer code for monitoring a charge status of an internal power supply that provides power to the one or more speakers.

36. Computer program product as recited in claim 35, comprising:

computer code for shutting down the media delivery system, when the charge status is less than a threshold value; and

computer code for changing the maximum allowable SPL based upon the charge status of the internal power supply, otherwise.

37. Computer program product as recited in claim 36, wherein the computer code for changing the maximum allowable SPL comprises:

computer code for reducing the maximum allowable SPL by a preset factor.

38. Computer program product as recited in claim 37, wherein the computer code for monitoring comprises;

computer code for sensing, in real time, a voltage across a capacitor electrically coupled to the internal power supply, wherein the sensed voltage is directly related to the charge status of the internal power supply.

39. Computer program product as recited in claim 38, further comprising:

computer code for determining if the downward going voltage crosses a threshold voltage level if the voltage is a downward going voltage.

40. Computer program product as recited in claim 39, further comprising;

computer code for determining if a subsequent upward going voltage re-crosses the threshold voltage within a predetermined length of time when the downward going voltage crosses the threshold voltage level; and

computer code for generating a shutdown signal used to shut down the media delivery system if the subsequent upward going voltage does not re-cross the threshold voltage level in the predetermined length of time.

41. Computer program product as recited claim 40, further comprising:

computer code for providing a clipping event signal if the subsequent upward going voltage does re-cross the threshold voltage level within the predetermined length of time, and

computer code for using the clipping event signal to reduce the maximum allowable SPL.

42. Computer program product as recited claim 41, further comprising:

computer code for providing a proportional clipping event signal that is proportional to an amount of time that the upward going voltage remains below the threshold voltage that is less than the predetermined length of time; and

computer code for using the proportional clipping event signal to proportionally reduce the maximum allowable SPL 1.

43. Computer program product as recited in claim 34, wherein the limited maximum allowable (SPL) in the DC mode is a DC maximum allowable SPL

44. Computer program product as recited in claim 43, comprising;

computer code for setting the media delivery system to the AC mode by connecting to an external power supply that provides the power for the media delivery system; and

computer code for setting the maximum allowable SPL to an AC limited maximum SPL that is greater than the DC maximum allowable SPL in all cases.

45. Computer program product as recited in claim 44, comprising:

computer code for setting the system to the DC mode when the media delivery system is disconnected from the external power supply; and

computer code for setting the DC maximum allowable SPL based upon a current charge status of the internal power supply.

46. Computer program product as recited in claim 34, comprising:

computer code for reducing the actual output SPL to a value that is no greater than the allowable maximum SPL when the speaker'"'"'s requested actual output SPL would be greater than the allowable maximum SPL.