Controlling a Power Converter

• US 20080048499A1
• Filed: 06/29/2007
• Published: 02/28/2008
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Litovsky, Roman, Greenberger, Hal
• Granted Patent: US 7,880,330 B2
• Time in Patent Office: Days
• US Class Current: 307/45
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02M 1/0019 the disturbance parameters being load current fluctuations
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

A load is powered by a power source and a capacitive element in series such that the voltage provided to the load is the sum of the voltages of the power source and the capacitive element. A power converter imposing a limit on a flow of current through at least a portion of the power converter is coupled to the power source and the capacitive element, and selectively causes the capacitive element to either be charged or to discharge depending on the amount of current drawn by the load. As the capacitor discharges, the power source is permitted to supply a relatively higher amount of current to the load.

Claims

1. An apparatus comprising:

a load;

a power source;

a capacitive element coupled in series with the power source to enable the power source and the capacitive element to provide the load with a supply voltage that is a sum of the voltages of the power source and the capacitive element; and

a power converter coupled to the capacitive element and the power source, wherein the power converter imposes a limit on current flowing through the power converter, thereby causing the power converter to charge the capacitive element while the load draws a relatively smaller amount of current and causing the power converter to enable the capacitive element to discharge to enable the load to draw a relatively higher amount of current through both the power converter and the capacitive element as the capacitive element discharges.

2. The apparatus of claim 1, wherein load is an amplifier capable of driving at least one acoustic driver.

3. The apparatus of claim 2, wherein the at least one acoustic driver is a speaker.

4. The apparatus of claim 3, wherein the speaker is disposed on a casing of a portable electronic device.

5. The apparatus of claim 2, further comprising a compressor to receive and alter an input signal provided to the load.

6. The apparatus of claim 5, further comprising a sensor to monitor the supply voltage and to enable the compressor to reduce the amplitude of at least one peak of the input signal to the load in response to a reduction in the supply voltage.

7. The apparatus of claim 5, further comprising a sensor to monitor an output signal from the load to the at least one acoustic driver and to enable the compressor to reduce the amplitude of at least one peak of he input signal to the load in response to an occurrence of clipping in the output signal.

8. The apparatus of claim 2, wherein the load incorporates a gain control to reduce a gain employed by the load in amplifying an input signal received by the load in driving the at least one acoustic driver.

9. The apparatus of claim 1, wherein the load is an electromechanical actuator.

10. The apparatus of claim 9, wherein the electromechanical actuator is a linear motor.

11. The apparatus of claim 1, wherein the power source is a battery.

12. The apparatus of claim 1, wherein the power source is provided via a cable from an electronic device.

13. The apparatus of claim 12, wherein the cable carries digital serial communications.

14. The apparatus of claim 1, wherein the capacitive element comprises at least one supercapacitor.

15. The apparatus of claim 1, wherein the power converter is a buck converter.

16. The apparatus of claim 1, wherein the power converter is structured to enable the capacitor to discharge to return stored energy to the power source in response to the apparatus being turned off.

17. The apparatus of claim 1, wherein:

an anode of the power source is coupled to the load and to an input terminal of the power converter;

a cathode of the power source is coupled to an anode of the capacitive element and an output terminal of the power converter; and

a cathode of the capacitive element is coupled to the load and to a common terminal of the power converter.

18. An electronic device comprising:

an amplifier to amplify an audio signal and drive an acoustic driver;

a power source;

a capacitive element coupled in series with the power source to enable the power source and the capacitive element to provide the amplifier with a supply voltage that is a sum of the voltages of the power source and the capacitive element; and

a power converter coupled to the capacitive element and the power source, wherein the power converter imposes a limit on current flowing through the power converter, thereby causing the power converter to charge the capacitive element while the amplifier draws a relatively smaller amount of current and causing the power converter to enable the capacitive element to discharge to enable the amplifier to draw a relatively higher amount of current through both the power converter and the capacitive element as the capacitive element discharges.

19. The electronic device of claim 18, further comprising a casing, and wherein the acoustic driver is a speaker disposed on the casing.

20. The electronic device of claim 19, wherein the electronic device is a cellular telephone.

21. The electronic device of claim 18, further comprising a compressor to alter the audio signal before the audio signal is provided as an input to the amplifier.

22. The electronic device of claim 21, further comprising a sensor to monitor the supply voltage and to enable the compressor to reduce the amplitude of at least one peak of the audio signal in response to a reduction in the supply voltage.

23. The electronic device of claim 21, further comprising a sensor to monitor an output signal from the amplifier and to enable the compressor to reduce the amplitude of at least one peak of the audio signal in response to an occurrence of clipping in the output signal.

24. The electronic device of claim 18, wherein the amplifier incorporates a gain control to reduce a gain employed by the amplifier in amplifying an audio signal.

25. The electronic device of claim 18, wherein the power source is a battery.

26. The electronic device of claim 18, wherein the power source si provided via a cable conveying digital serial communications from another electronic device.

27. The electronic device of claim 18, wherein the capacitive element comprises at least one supercapacitor.

28. The electronic device of claim 18, wherein the power converter is a back converter.

29. The electronic device of claim 18, wherein the power converter is structured to enable the capacitor to discharge to return stored energy to the power source in response to the apparatus being turned off.

30. A method comprising:

coupling a power source and a capacitive element in series to provide a load with power having a voltage that is the sum of the voltages of the power source and the capacitive element;

causing the capacitive element to be charged as the load draws a relatively smaller amount of current; and

enabling the power source to provide a relatively higher amount of current through the capacitive element by causing the capacitive element to discharge as the load draws a relatively higher current.

31. The method of claim 30, further comprising:

coupling a power converter to the power source and the capacitive element; and

imposing a limit on a flow of current through at least one portion of the power converter, whereby the limit selectively causes the capacitive element to be charged and causes the capacitive element to discharge.

32. The method of claim 31, further comprising imposing the limit on the flow of current through the at least one portion of the power converter as a limit on an amount of current permitted to be provided by the power source to the load subsequent to the discharge of the capacitive element.

33. The method of claim 30, wherein the load is an amplifier, and further comprising operating a compressor to reduce an amplitude of at least one peak of a signal provided to the load that causes the load to require the increase in the amount of current drawn by the load.

34. The method of claim 33, further comprising triggering the compressor to reduce the amplitude of at least one peak of the signal provided to the load in response to a preselected amount of time elapsing since a start in the increase in the amount of current drawn by the load.

35. The method of claim 34, wherein the preselected amount of time is chosen to correspond to an amount of time required to substantially discharge the capacitive element.

36. The method of claim 33, further comprising triggering the compressor to reduce the amplitude of at least one peak of the signal provided to the load in response to detecting a reduction in the voltage provided to the load.

37. The method of claim 30, wherein the load is an amplifier, and the load further comprises a gain control to reduce a gain by which the load amplifies a signal provided to the load that causes the load to require the increase in the amount of current drawn by the load.

38. The method of claim 37, further comprising triggering the gain control to reduce the gain in response to a preselected amount of time elapsing since a start in the increase in the amount of current drawn by the load.

39. The method of claim 38, wherein the preselected amount of time is chosen to correspond to an amount of time required to substantially discharge the capacitive element.

40. The method of claim 37, further comprising triggering the gain control to reduce the gain in response to detecting a reduction in the voltage provided to the load.

41. The method of claim 30, wherein the load is an electromechanical actuator, the method further comprising cutting off power to the load at a time when the capacitive element is substantially discharged in response to the increase in the amount of current drawn by the load continuing to the time when the capacitive element is substantially discharged.

42. The method of claim 41, further comprising:

enabling the capacitive element to recharge; and

reapplying power to the load after a period of time has elapsed.

43. The method of claim 42, wherein the length of the period of time is chosen to correspond to an amount of time required to substantially recharge the capacitive element.

44. The method of claim 30, further comprising returning power stored in the capacitive element to the power source.