Method and apparatus for managing a power load change in a system

• US 7,437,586 B2
• Filed: 11/14/2005
• Issued: 10/14/2008
• Est. Priority Date: 01/18/2002
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Cornelius, William P.
• Primary Examiner(s): Du; Thuan N
• Application Number:
  US11/274,691
• Publication Number:
  US 20060123256A1
• Time in Patent Office: 1,065 Days
• Field of Search: 713/340, 713/300, 327/540
• US Class Current: 713/340
• 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 1/324 by lowering clock frequency
• CPC Class Codes: G06F 1/3296 by lowering the supply or operating voltage
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An apparatus and method for maintaining a state during a power load change. The apparatus of one embodiment includes a voltage controller coupled to receive a signal from a detector of current change. The detector of current change in this embodiment is coupled to detect change in the current level at a microprocessor and signal a voltage controller of such change, which in turn causes a change in the voltage supplied to the microprocessor. An embodiment of the method comprises using a current detector in detecting current change in a microprocessor, determining according to the current change the power level that is needed to be maintained and increasing the voltage level for a predetermined amount of time to compensate for (any) voltage droop. In an alternative embodiment, a change in power is determined before the change occurs and as such determines the power level needed at the microprocessor.

Claims

1. An apparatus in a data processing system, said apparatus comprising:

a voltage controller having an output to prevent power droop caused by a change in computational state, and being coupled to receive a control signal; and

a detector to detect power change, the detector being coupled to said voltage controller to provide said control signal to indicate a change in power level in said data processing system wherein the voltage controller is configured to deliver an increased voltage for a predetermined amount of time, wherein the predetermined amount of time is determined based on a period of anticipated voltage droop from a change to an increased computational state.

2. An apparatus according to claim 1 wherein said voltage controller is configured to boost voltage by a boost value during the predetermined amount of time and wherein said apparatus compensates for a potential voltage droop and wherein the voltage controller adjusts the output, in response, to the change to the increased computational state, from a first voltage to a second voltage plus the boost value for the predetermined amount of time which is an initial portion of time of operating in the increased computational state and after the initial portion of time, while in the increased computational state, the voltage controller sets the output at the second voltage, and wherein the second voltage exceeds the first voltage.

3. An apparatus according to claim 2 wherein said voltage controller is coupled with a power distribution bus and wherein said detector detects a change in one of current or voltage.

4. An apparatus according to claim 2 wherein the boost value is based on the anticipated voltage droop.

5. An apparatus according to claim 1 wherein said voltage controller provides an adjustable reference voltage based upon the control signal from said detector.

6. An apparatus according to claim 1 wherein said detector is coupled to a microprocessor and said detector detects a change in current drawn by said microprocessor.

7. An apparatus according to claim 1 wherein said detector comprises at least one of a hardware or a software detector.

8. A method for providing a supply of power in a data processing system, said method comprising:

detecting a change in current, drawn by said data processing system;

determining according to the change in current a power level; and

increasing a voltage level for a predetermined amount of time to prevent voltage droop,

wherein the predetermined amount of time is determined based on a period of

anticipated voltage droop from a change to an increased computational state.

9. A method as in claim 8 wherein said change in current is detected at a microprocessor to determine whether an increase in demand for power is occurring or is about to occur.

10. A method as in claim 9 wherein said method is used to compensate for a voltage droop in said data processing system.

11. A method as in claim 10 wherein said detecting comprises determining a change in compute load as an indicator of the change in current level.

12. A method as in claim 10 wherein a voltage controller is coupled to receive a current level signal and said voltage controller adjusts said voltage level based on said current level signal.

13. A method as in claim 12 wherein an adjustable reference voltage is provided by the voltage controller and the voltage controller provides the voltage level via a power distribution bus to said microprocessor.

14. A method as in claim 12 wherein said voltage controller, in order to neutralize any voltage droop that can occur at the beginning of the increased computational state, increases the voltage level at the microprocessor by a boost voltage level for the predetermined amount of time up to a predetermined voltage level.

15. A method as in claim 14 wherein said voltage controller after the predetermined amount of time has elapsed decreases the voltage back to within normal parameters during a period of time after the beginning of the increased computational state.

16. A method for providing a supply of power in a data processing system, said method comprising:

programming a microprocessor in said data processing system with instructions to anticipate changes in compute load levels;

determining according to said compute load level the power level needed at the microprocessor;

increasing an output voltage level from a first voltage to a second voltage plus a boost value, in response to an increased compute load level, for an initial portion of time of the increased compute load level to prevent power droop in response to said determining.

17. A method as in claim 16 wherein said programming instructions are used to anticipate changes in compute load, which are coupled with current level changes, and, in turn, determine xvhether an increase in demand for power is occurring or is about to occur.

18. A method as in claim 16 wherein said programming instructions cause a signal to be sent to a voltage controller to indicate the changes in current level at the microprocessor.

19. A method as in claim 18 wherein said voltage controller is coupled to receive said signal and said voltage controller determines the voltage level needed to be supplied a power distribution bus to said microprocessor and wherein the output voltage level is increased to prevent power droop before a change to the increased compute load level.

20. A method as in claim 19 wherein said voltage controller, in order to neutralize any voltage droop that may occur, increases the voltage level for the initial portion of time up to the second voltage plus the boost value.

21. A method as in claim 20 wherein said voltage controller after the initial portion of time has elapsed decreases the output voltage level back to within normal parameters during a remainder of the increased compute load level.

22. An apparatus in a data processing system, said apparatus comprising:

a voltage controller having an output to provide power to at least one component in the

data processing system and being coupled to receive a control signal;

a detector to detect power change, the detector being coupled to the voltage controller to

provide the control signal to indicate a change to an increased computational state, wherein the voltage controller is configured to adjust the output, in response to the change to the increased computational state, from a first voltage to a second voltage plus a boost value for an initial portion of time operating in the increased computational state and after the initial portion of time, while in the increased computational state, the voltage controller sets the output to the second voltage and wherein the second voltage exceeds the first voltage.

23. The apparatus as in claim 22 wherein the boost value is based on an anticipated voltage droop during the initial portion of time.

24. The apparatus as in claim 22 wherein the voltage controller adjusts the output to the second voltage plus the boost value before the beginning of the increased computational state.

25. The apparatus as in claim 22 wherein the detector comprises at least one of a hardware and a software detector.

26. A method for providing a supply of power in a data processing system, the method comprising:

detecting a change in computational load of the data processing system;

determining a power level according to the change in computational load;

increasing a power level, in response to an increased computational load, from a first

power level to a second power level plus a boost value for an initial portion of

time operating in the increased computational load and after the initial portion of

time while in the increased computational load setting the power level to the

second power level which exceeds the first power level.