Temperature-based clock frequency controller apparatus and method

• US 7,761,274 B1
• Filed: 11/07/2000
• Issued: 07/20/2010
• Est. Priority Date: 09/21/1993
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Pippin, Jack D.
• Primary Examiner(s): FREJD, RUSSELL WARREN
• Application Number:
  US09/707,486
• Time in Patent Office: 3,542 Days
• Field of Search: 307/409, 307/117, 307/417, 703/2, 703/13, 703/14, 716/1, 716/4, 702/132, 714/E11.018, 327/307, 327/512, 361/103
• US Class Current: 703/14
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence
• CPC Class Codes: G05F 3/265 using bipolar transistors only
• CPC Class Codes: G05F 3/267 using both bipolar and field-effect technology
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: G06F 1/324 by lowering clock frequency
• CPC Class Codes: G06F 11/3024 where the computing system component is a central processing unit [CPU]
• CPC Class Codes: G06F 11/3058 Monitoring arrangements for monitoring environmental properties or parameters of the computing system or of the computing system component, e.g. monitoring of power, currents, temperature, humidity, position, vibrations thermal management in cooling arrangements of a computing system G06F1/206
• CPC Class Codes: G06F 11/3093 Configuration details thereof, e.g. installation, enabling, spatial arrangement of the probes
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A temperature-based clock frequency controller is implemented in an integrated circuit such as a microprocessor. The temperature-based clock frequency controller includes a register to store a threshold temperature value, a thermal sensor, and clock adjustment logic to decrease a clock frequency in response to the thermal sensor indicating that the threshold temperature value has been exceeded. In a microprocessor implementation, the microprocessor contains a plurality of thermal sensors each placed in one of a plurality of different locations across the integrated circuit and an averaging mechanism to calculate an average temperature from the plurality of thermal sensors. Threshold adjustment logic increases the threshold temperature value to a new threshold temperature value in response to the thermal sensor indicating that the threshold temperature value has been exceeded. Threshold adjustment logic further lowers the new threshold temperature to detect decreases in temperature. In addition, the microprocessor contains halt logic that halts operation of the microprocessor when the temperature attains a critical temperature.

Claims

1. An integrated circuit comprising:

a register to store a threshold temperature value;

a thermal sensor; and

clock adjustment logic to decrease a clock frequency in response to the thermal sensor indicating that the threshold temperature value has been exceeded, the clock adjustment logic further to increase the clock frequency in response to passage of a predetermined amount of time following the decrease in clock frequency.

2. The integrated circuit of claim 1 further comprising:

a fail-safe sensor and halt logic to halt operation of the integrated circuit in response to the fail-safe sensor indicating that a fail-safe threshold temperature has been exceeded.

3. The integrated circuit of claim 2 wherein the halt logic comprises logic to inhibit operation of the integrated circuit by stopping a clock of the integrated circuit.

4. The integrated circuit of claim 2 wherein the fail-safe threshold temperature is a predetermined fixed critical temperature.

5. The integrated circuit of claim 1 further comprising:

an interrupt handler to display information regarding the sensed temperature to a user of the integrated circuit.

6. The integrated circuit of claim 1 wherein the clock adjustment logic executes instructions to vary the frequency of a clock signal of the integrated circuit in response to the thermal sensor.

7. The integrated circuit of claim 1 wherein the clock adjustment logic executes instructions to provide closed loop control of the integrated circuit clock frequency, thereby automatically reducing the temperature when overheating occurs.

8. The integrated circuit of claim 1 further comprising:

interrupt logic to activate an active cooling device in response to the thermal sensor.

9. An integrated circuit comprising:

a register to store a threshold temperature value;

a thermal sensor;

clock adjustment logic to decrease a clock frequency in response to the thermal sensor indicating that the threshold temperature value has been exceeded, the clock adjustment logic further to increase the clock frequency in response to one of passage of a predetermined amount of time following the decrease in clock frequency and the thermal sensor indicating that the sensed temperature is less than the threshold temperature value; and

threshold adjustment logic to increase the threshold temperature value to a new threshold temperature value in response to the thermal sensor indicating that the threshold temperature value has been exceeded.

10. The integrated circuit of claim 9 wherein the threshold adjustment logic comprises logic to increase the new threshold temperature value in response to the thermal sensor indicating that the new threshold temperature value has been exceeded.

11. The integrated circuit of claim 10 wherein the threshold adjustment logic comprises logic to lower the new threshold temperature value to detect decreases in temperature.

12. An integrated circuit comprising:

a register to store a threshold temperature value;

a thermal sensor; and

clock adjustment logic to decrease a clock frequency in response to the thermal sensor indicating that the threshold temperature value has been exceeded, the clock adjustment logic further to increase the clock frequency in response to one of passage of a predetermined amount of time following the decrease in clock frequency and the thermal sensor indicating that the sensed temperature is less than the threshold temperature value,

wherein the thermal sensor comprises a plurality of thermal sensors placed across the integrated circuit and an averaging mechanism to calculate an average temperature from the plurality of thermal sensors.

13. The integrated circuit of claim 12 further comprising:

interrupt logic to generate a first interrupt if the calculated average temperature exceeds a first threshold and a second interrupt if the calculated average temperature exceeds a second threshold.

14. A method comprising:

storing a threshold temperature value in a register of an integrated circuit;

sensing the temperature within the integrated circuit;

decreasing a clock frequency of the integrated circuit in response to the sensed temperature exceeding the threshold temperature value; and

increasing the clock frequency in response to passage of a predetermined amount of time following the decrease in clock frequency.

15. The method of claim 14 further comprising displaying information regarding the sensed temperature to a user of the integrated circuit.

16. The method of claim 14 further comprising executing instructions to vary the frequency of a clock signal of the integrated circuit in response to the sensed temperature.

17. The method of claim 14 further comprising executing instructions to provide closed loop control of the integrated circuit clock frequency, thereby automatically reducing the temperature when overheating occurs.

18. A method comprising:

storing a threshold temperature value in a register of an integrated circuit;

sensing the temperature within the integrated circuit;

decreasing a clock frequency of the integrated circuit in response to the sensed temperature exceeding the threshold temperature value;

increasing the clock frequency in response to one of passage of a predetermined amount of time following the decrease in clock frequency and sensing that the temperature within the integrated circuit is less than the threshold temperature value; and

increasing the threshold temperature value to a new threshold temperature value in response to the sensed temperature exceeding the threshold temperature value.

19. The method of claim 18 further comprising increasing the new threshold temperature value in response to the sensed temperature exceeding the threshold temperature value.

20. The method of claim 18 further comprising lowering the new threshold temperature value to detect decreases in temperature.

21. A microprocessor comprising:

a register to store a register value corresponding to a threshold temperature;

a programmable thermal sensor to receive the register value, wherein the programmable thermal sensor is to generate a first interrupt signal in response to an internal microprocessor temperature exceeding the threshold temperature corresponding to the register value;

clock circuitry to provide a clock signal for the microprocessor;

a processor unit coupled to the clock circuitry, wherein the processor unit executes instructions to reduce a frequency of the clock signal in response to the first interrupt signal; and

a fail-safe thermal sensor generating a fail-safe interrupt signal if the microprocessor temperature exceeds a fail-safe threshold temperature, wherein the processor unit is halted in response to the fail-safe interrupt signal,

wherein the clock circuitry further comprises a phase locked loop.

22. A microprocessor comprising:

a register to store a register value corresponding to a threshold temperature;

a programmable thermal sensor to receive the register value, wherein the programmable thermal sensor is to generate a first interrupt signal in response to an internal microprocessor temperature exceeding the threshold temperature corresponding to the register value;

clock circuitry to provide a clock signal for the microprocessor;

a processor unit coupled to the clock circuitry, wherein the processor unit executes instructions to reduce a frequency of the clock signal in response to the first interrupt signal; and

a fail-safe thermal sensor generating a fail-safe interrupt signal if the microprocessor temperature exceeds a fail-safe threshold temperature, wherein the processor unit is halted in response to the fail-safe interrupt signal,

wherein the thermal sensor comprises;

a current source;

a voltage reference coupled to the current source to provide a bandgap reference voltage, wherein the bandgap reference voltage is substantially constant over a range of temperatures;

programmable circuitry providing an output voltage varying with the microprocessor temperature in accordance with the register value; and

a comparator, wherein the comparator generates the first interrupt signal if a difference between the output voltage and the bandgap reference voltage indicates that the threshold temperature has been exceeded.

23. The microprocessor of claim 22 wherein the programmable circuitry further comprises:

a transistor coupled to the current source to provide the output voltage, a gain ratio of the output voltage to a junction voltage of the transistor controlled by a transistor bias, wherein the junction voltage varies in accordance with a junction temperature of the transistor, the junction temperature corresponding to the microprocessor temperature, a bias circuit providing the transistor bias to control the gain ratio, wherein the output voltage varies with the microprocessor temperature in accordance with the register value.

24. The microprocessor of claim 23 wherein the bias circuit further comprises binary weighted resistors.

25. A microprocessor comprising:

a register to store a register value corresponding to a threshold temperature;

a programmable thermal sensor to receive the register value, wherein the programmable thermal sensor is to generate a first interrupt signal in response to an internal microprocessor temperature exceeding the threshold temperature corresponding to the register value;

clock circuitry to provide a clock signal for the microprocessor; and

a processor unit coupled to the clock circuitry, wherein the processor unit executes instructions to reduce a frequency of the clock signal in response to the first interrupt signal, wherein

the clock circuitry includes a frequency divider to provide the clock signal, the frequency divider reducing a frequency of the clock signal in response to the first interrupt signal, and wherein

the processor unit executes instructions to provide closed loop control of the microprocessor clock frequency, thereby automatically reducing the temperature when overheating occurs.

26. A microprocessor comprising:

a register to store a register value corresponding to a threshold temperature;

a programmable thermal sensor to receive the register value, wherein the programmable thermal sensor is to generate a first interrupt signal in response to an internal microprocessor temperature exceeding the threshold temperature corresponding to the register value;

clock circuitry to provide a clock signal for the microprocessor; and

a processor unit coupled to the clock circuitry, wherein the processor unit executes instructions to reduce a frequency of the clock signal in response to the first interrupt signal, and

wherein the processor unit programs the register with another register value corresponding to another threshold temperature in response to the first interrupt signal.

27. A method of controlling a temperature of a microprocessor, comprising:

storing threshold temperature values in a register of the microprocessor;

generating a temperature signal within the microprocessor indicative of the temperature of the microprocessor;

comparing the temperature signal with a first threshold temperature level within the microprocessor;

generating an interrupt signal if the temperature signal indicates that the first threshold temperature level has been exceeded;

decreasing a microprocessor clock frequency in response to the interrupt signal; and

increasing the microprocessor clock frequency in response to passage of a predetermined amount of time following the decrease in microprocessor clock frequency.

28. The method of claim 27 further comprising:

generating a fail-safe interrupt signal if the microprocessor temperature exceeds a fail-safe threshold temperature; and

halting the microprocessor in response to the fail-safe interrupt signal.

29. The method of claim 27 further comprising providing closed loop control of the microprocessor clock frequency, thereby automatically reducing the temperature when overheating occurs.

30. The method of claim 27 further comprising programming the microprocessor with a second threshold temperature level.

31. A method of controlling a temperature of a microprocessor, comprising:

storing threshold temperature values in a register of the microprocessor;

generating a temperature signal within the microprocessor indicative of the temperature of the microprocessor;

comparing the temperature signal with a first threshold temperature level within the microprocessor;

generating an interrupt signal if the temperature signal indicates that the first threshold temperature level has been exceeded;

decreasing a microprocessor clock frequency in response to the interrupt signal; and

increasing the microprocessor clock frequency in response to one of passage of a predetermined amount of time following the decrease in microprocessor clock frequency, and the temperature signal indicating that the temperature of the microprocessor is less than the first threshold temperature level;

comparing the temperature signal with a second threshold temperature level, wherein the second threshold temperature level represents a fail-safe temperature; and

halting the microprocessor, if the temperature signal indicates that the second threshold temperature level has been exceeded.

32. A method of controlling a temperature of a microprocessor, comprising:

storing threshold temperature values in a register of the microprocessor;

generating a temperature signal within the microprocessor indicative of the temperature of the microprocessor;

comparing the temperature signal with a first threshold temperature level within the microprocessor;

generating an interrupt signal if the temperature signal indicates that the first threshold temperature level has been exceeded;

decreasing a microprocessor clock frequency in response to the interrupt signal; and

increasing the microprocessor clock frequency in response to one of passage of a predetermined amount of time following the decrease in microprocessor clock frequency, and the temperature signal indicating that the temperature of the microprocessor is less than the first threshold temperature level,

wherein generating a temperature signal comprises;

providing a bandgap reference voltage, that is substantially constant over a range of temperatures;

providing an output voltage varying with the microprocessor temperature in accordance with a stored register value; and

wherein generating an interrupt signal comprises generating the interrupt signal if a difference between the output voltage and the bandgap reference voltage indicates that the first threshold temperature level has been exceeded.