Dual control of fan speed-input corresponding to power supply temperature or software command from the processor corresponding to processor temperature

• US 6,654,894 B2
• Filed: 10/19/2001
• Issued: 11/25/2003
• Est. Priority Date: 11/20/1998
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Squibb, George F., Kaminski, George A.
• Primary Examiner(s): Lee, Thomas
• Assistant Examiner(s): WANG, ALBERT C
• Application Number:
  US10/039,983
• Publication Number:
  US 20020059533A1
• Time in Patent Office: 767 Days
• Field of Search: 713/300, 702/132, 361/695
• US Class Current: 713/300
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: H05K 7/20209 Thermal management, e.g. fan control
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method and system for controlling the power supply fan in a computer system. The speed of a power supply fan can be made directly proportional to the temperature of the power supply. The fan speed can also be controlled by a processor with software commands according to the temperature of the processor. The speed of the fan will be dictated by the higher of the two commands driving it. Therefore, the power supply fan can never be commanded by the processor to run at a lower speed than that required by its own thermal environment. A Fan Speed Control Circuit enables the computer system to command the power supply fan to run at a higher speed. The processor temperature can be monitored with a temperature transducer and analog signal conditioning circuitry.

Claims

1. An electronic system, comprising:

a processor;

a power supply electrically coupled to the processor;

a fan; and

a control circuit to control the fan, the control circuit being electrically coupled to a plurality of command inputs, wherein a first command input corresponds to the power supply temperature and a second command input is a software command corresponding to the processor temperature provided by the processor, wherein the control circuit automatically selects the command input which indicates the highest fan speed to drive the fan.

2. The system as recited in claim 1, wherein the first command input is provided by a thermistor.

3. The system as recited in claim 1, wherein the fan speed is increased when one of the plurality of command inputs represents a desired fan speed that is greater than current fan speed.

4. The system as recited in claim 1, wherein the fan speed is decreased only when both the first and the second command inputs represent a desired fan speed that is less than current fan speed.

5. The system as recited in claim 1, wherein the control circuit is disposed within the power supply.

6. The system as recited in claim 1, wherein the control circuit is operable to discontinue operation of the power supply if the fan fails.

7. A method for controlling speed of a fan in an electronic system, comprising the acts of:

providing a first control signal to drive the fan at a first speed corresponding to temperature at a first location within the electronic system;

providing a second control signal from a processor to drive the fan at a second speed, the second control signal comprising a software command corresponding to the processor temperature;

identifying a desired fan speed based on the first and second control signals which represents the highest fan speed to drive the fan; and

controlling fan speed to establish the desired fan speed.

8. The method as recited in claim 7, wherein providing a first control signal comprises providing a thermistor to monitoring the temperature of a power supply.

9. The method as recited in claim 7, wherein controlling comprises selecting the command input that represents the highest fan speed to drive the fan and establishing fan speed based on the selected command input.

10. The method as recited in claim 7, wherein providing a second control signal comprises physically coupling a thermistor to the surface of the processor.

12. The system as recited in claim 7, comprising a temperature sensor physically coupled to the processor to provide the processor with a processor temperature signal.

11. A computer system, comprising:

a processor;

a power supply electrically coupled to the processor;

a fan; and

a control circuit operable to receive a plurality of command inputs, a first command input corresponding to the power supply temperature and a second command input being a software command corresponding to the processor temperature provided by the processor, wherein the control circuit controls fan operation to establish fan speed in response to the plurality of command inputs.

13. The system as recited in claim 11, comprising a temperature sensor physically coupled to the processor to provide the processor with a processor temperature signal.

14. The system as recited in claim 11, wherein the fan speed decreases with a decrease in the greatest of the desired fan speeds.

15. The system as recited in claim 11, wherein the control circuit is operable to discontinue operation of the power supply if the fan falls.

16. The system as recited in claim 11, wherein the control circuit controls fan operation by selecting the command input that represents the greatest fan speed to drive the fan and establishing fan speed based on the selected command input.

17. The system as recited in claim 11, wherein the processor is a central processing unit of a computer system.

18. The system as recited in claim 17, wherein the computer system is a portable computer system.