Method and apparatus for thermal management in a computer system

• US 5,590,061 A
• Filed: 05/12/1994
• Issued: 12/31/1996
• Est. Priority Date: 05/12/1994
• Status: Expired due to Term

• Current Assignee: Apple Computer Incorporated (Apple Inc.)
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Hansen, Daniel J. Jr., Hollowell, J. Rhoads II, Beninghaus, James R.
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): PIPALA, EDWARD J
• Application Number:
  US08/241,962
• Time in Patent Office: 964 Days
• Field of Search: 364/483, 364/492, 364/550, 364/557, 364/571.03, 395/750, 395/575, 395/182.12, 395/182.2, 395/182.21, 395/182.22
• US Class Current: 702/130
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method and apparatus for providing thermal management to a computer system where the internal temperature is measured and, based on the temperature, heat generated in the computer system is reduced by turning off a portion of the system. When the portion of the system is off, no power is consumed by that portion. Accordingly, no heat is generated as well. In this manner, the heat generated in the computer system is reduced.

Claims

1. A method for regulating the internal temperature of a computer system, said method comprising the steps of:

monitoring the internal temperature of the computer system;

placing at least one integrated circuit within the computer system into a first powered state for a first period of time and then a second powered state for a second period of time repeatedly when the internal temperature is at least at a threshold temperature, wherein the step of placing comprises the step of selecting durations of the first period of time and the second period of time based on an amount the internal temperature exceeds the threshold temperature.

2. The method defined in claim 1 wherein the first powered state comprises a state in which said at least one integrated circuit is not powered and the second powered state comprises a fully powered state.

3. The method defined in claim 1 wherein the step of placing comprises placing said at least one integrated circuit into the first powered state and the second powered state periodically in accordance with a periodic interrupt, wherein the first period of time comprises a first number of occurrences of the periodic interrupt and the second period of time comprises a second number of occurrences of the periodic interrupt.

4. The method defined in claim 3 wherein the step of selecting durations of the first period of time and the second period of time is performed so that the ratio of the first period of time to the second period of time is increased as the amount the internal temperature exceeds the threshold temperature increases and is decreased as the amount the internal temperature exceeds the threshold temperature decreases.

5. A method for regulating the internal temperature of a computer system, said method comprising the steps of:

sensing the internal temperature of the computer system;

cyclically placing an integrated circuit within the computer system into and out of a powered state when the internal temperature is at least at a threshold temperature, wherein each cycle comprises a first time period in which the integrated circuit is in the powered state and a second time period in which the integrated circuit is out of the powered state,

wherein the step of cyclically placing the integrated circuit includes adjusting durations of the first time period and the second time period according to an amount that the internal temperature exceeds the threshold temperature, such that a ratio of when the integrated circuit is in the powered state to when the integrated circuit is out of the powered state is adjusted, and wherein said step of cyclically placing the integrated circuit into and out of the powered state continues until the internal temperature falls below the threshold temperature, such that heat generated within the computer system is reduced.

6. The method defined in claim 5 wherein the integrated circuit comprises a processor in the computer system.

7. The method defined in claim 5 wherein said step of adjusting includes the steps of:

increasing the ratio of the second time period to the first time period as the amount that the internal temperature exceeds the threshold temperature increases, and

decreasing the ratio of the second time period to the first time period as the amount that the internal temperature exceeds the threshold temperature decreases.

8. The method defined in claim 5 further comprising the step of periodically sensing the internal temperature while cyclically placing the integrated circuit into and out of the powered state.

9. The method defined in claim 5 further comprising the steps of coupling the integrated circuit to a power source and decoupling the integrated circuit from the power source to place the integrated circuit into and out of the powered state respectively.

10. The method defined in claim 5 further comprising the steps of asserting and de-asserting a pin on the integrated circuit to cause the integrated circuit to enter the powered state respectively.

11. A method for thermal management of a computer system having an internal temperature, said method comprising the steps of:

periodically sensing the internal temperature of the computer system at a first time interval while the internal temperature remains below a threshold temperature; and

cyclically placing an integrated circuit within the computer system into and out of a powered state when the internal temperature is at least at the threshold temperature, wherein each cycle comprises a first time period in which the integrated circuit is in the powered state and a second time period in which the integrated circuit is out of the powered state,

wherein the step of cyclically placing the integrated circuit includes adjusting durations of the first time period and the second time period according to an amount that the internal temperature exceeds the threshold temperature, such that a ratio of when the integrated circuit is in the powered state to when the integrated circuit is out of the powered state is changed, and periodically sensing the internal temperature at a second time interval shorter than the first time interval when the internal temperature is at least at the threshold temperature, wherein the integrated circuit is continually placed into and out of the powered state until the internal temperature falls below the threshold temperature, such that heat generated within the computer system is reduced.

12. The method defined in claim 11 further comprising the step of generating a periodic signal, wherein both the step of periodically sensing the internal temperature at the first interval and the step of periodically sensing the internal temperature at the second interval are performed synchronously with the periodic signal.

13. The method defined in claim 11 further comprising the step of generating a periodic signal, wherein the duration of the first time equals a first number of occurrences of the periodic signal and the duration of the second time period equals a second number of occurrences of the periodic signal.

14. The method defined in claim 13 wherein the step of adjusting durations of the first time period and second time period by comprising the step ..of incrementing or decrementing the second number of occurrences, such that the ratio Of the first number of occurrences to the second number of occurrences is increased or decreased as the second number of occurrences is decreased or increased respectively.

15. The method defined in claims 12 or 13 wherein the periodic signal comprises a periodic interrupt signal.

16. The method defined in claim 11 wherein the integrated circuit comprises a processor in the computer system.

17. The method defined in claim 11 wherein said step of adjusting includes the steps of:

increasing the ratio of the second time period to the first time period as the amount that the internal temperature exceeds the threshold temperature increases, and

decreasing the ratio of the second time period to the first time period as the amount that the internal temperature exceeds the threshold temperature decreases.

18. The method defined in claim 11 wherein the ratio of the first time period to the second time period is adjusted for each degree the internal temperature exceeds the threshold temperature.

19. A method for thermal management of a computer system having an internal temperature, said method comprising the steps of:

generating a periodic interrupt signal;

periodically sensing the internal temperature of the computer system every I number of occurrences of the periodic interrupt signal, wherein I is an integer; and

cyclically placing an integrated circuit within the computer system out of a powered state for m number of occurrences of the periodic interrupt signal and into the powered state for n number of occurrences of the periodic interrupt signal when the internal temperature is at least at the threshold temperature, and

wherein the step of cyclically placing the integrated circuit includes varying a ratio of time when the integrated circuit is out of the powered state to when the integrated circuit is in the powered state according to a number of degrees the internal temperature exceeds the threshold temperature, such that the ratio increases and decreases as the amount the internal temperature exceeds the threshold temperature increases and decreases respectively, wherein said step of cyclically placing the integrated circuit continues until the internal temperature falls below the threshold temperature, such that the heat generated within the computer system is reduced.

20. The method defined in claim 19 wherein the step of cyclically placing the integrated circuit into and out of the powered state further comprises the step of periodically sensing the internal temperature at less than I number of occurrences of the periodic interrupt signal when the internal temperature is at least at the threshold temperature.

21. In a computer system having a processor, an addressable memory for storing data and programs for operation on the processor, a plurality for peripheral data and a power supply for supplying power to the processor, the addressable memory and the plurality of peripheral devices, an apparatus for providing thermal management for the computer system comprising:

a temperature sensor that measures the internal temperature of the computer system;

control logic coupled to and responsive to the internal temperature sensor measuring the internal temperature as at least a threshold temperature, wherein the control logic repeatedly places the processor out of a powered state for a first period of time and into the powered state for a second period of time in cycles to reduce heat generated in the computer system until the internal temperature falls below the threshold temperature, wherein the control logic adjusts the first period of time or the second period of time according to an amount that the internal temperature exceeds the threshold temperature, such that a ratio of when the processor is out of the powered state to when the processor is in the powered state is changed.

22. The apparatus defined in claim 21 further comprising a switch coupled to the power supply and the processor and responsive to the control logic for selectively coupling the power supply to the processor to place the processor in the power state.

23. The apparatus defined in claim 21 further comprising a timer coupled to the control logic, wherein the timer periodically generates a periodic interrupt signal at a predetermined interval, and wherein the first period of time and the second period of time have durations of m number of occurrences and n number of occurrences of the periodic interrupt signal respectively, where n and m are integers.

24. The apparatus defined in claim 21 wherein the control logic periodically reads the internal temperature at a first predetermined interval while the internal temperature is below the threshold temperature and at a second predetermined interval shorter than the first predetermined interval when the internal temperature is at least at the threshold temperature.

25. The apparatus defined in claim 24 wherein the temperature sensor senses the temperature at every occurrence of a periodic interrupt signal when the internal temperature is at least the threshold temperature.

26. A method of managing a computer system comprising the steps of:

periodically executing a first task to determine if the internal temperature of the computer system exceeds a threshold temperature, wherein the first task is executed every n number of occurrences of a periodic interval;

installing a second task to place an integrated circuit in the computer system into and out of a reduced power consumption state to reduce the internal temperature when the internal temperature exceeds the threshold temperature;

executing the second task to place the integrated circuit into the reduced power consumption state for a first period of time and out of the reduced power consumption state for a second period of time to cause power to be cycled to the integrated circuit until the internal temperature falls below the threshold temperature.