FAN CONTROL DURING LOW TEMPERATURE OPERATIONS TO REDUCE PLATFORM POWER

• US 20120185711A1
• Filed: 03/27/2012
• Published: 07/19/2012
• Est. Priority Date: 09/30/2008
• Status: Active Grant

• Current Assignee: Hee-Jun Parker, John Wallace
• Original Assignee: Hee-Jun Parker, John Wallace
• Inventors: Wallace, John, Parker, Hee-jun
• Granted Patent: US 8,868,947 B2
• Time in Patent Office: Days
• US Class Current: 713/320
• CPC Class Codes: G06F 1/203 for portable computers, e.g. for laptops
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 1/32 Means for saving power
• CPC Class Codes: G06F 1/3206 Monitoring of events, devices or parameters that trigger a change in power modality
• CPC Class Codes: G06F 1/3234 Power saving characterised by the action undertaken
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

In general, in one aspect, the disclosure describes running a cooling fan within a computer at low speed while the computer is in low temperature operations (e.g., idle). The operation of the cooling fan may reduce CPU temperature enough to decrease CPU leakage power, offsetting the power consumption of the fan, and possibly resulting in a net system power reduction. The benefit at the platform level increases further when considering the low efficiency of voltage regulation (VR) in this lower power regime, and potentially reductions in other components (e.g., graphics processor). The optimal fan speed is the speed at which the overall system power is reduced the most (e.g., CPU power savings is greater than fan power utilized). The optimal temperature may be determined dynamically during operation or may be determined in manufacturing and applied statically during operation.

Claims

1. A method comprising

determining a system is operating in a low temperature environment;

determining an optimal speed for a fan to operate at in order to reduce system power; and

running the fan at the optimal speed.

2. The method of claim 1, wherein the determining a system is operating in a low temperature environment includes determining the system is in idle mode.

3. The method of claim 1, wherein the determining an optimal speed for a fan includes determining CPU temperature and determining the optimal speed for the CPU temperature.

4. The method of claim 3, wherein the optimal speed over CPU temperature spectrum is predetermined.

5. The method of claim 4, further comprising defining the optimal speed over the CPU temperature spectrum in the CPU.

6. The method of claim 5, wherein the determining the optimal speed for the CPU temperature includes looking up the optimal fan speed for the CPU temperature.

7. The method of claim 1, wherein the determining an optimal speed for a fan includes measuring CPU power and fan power for varying fan speeds and determining the optimal speed as speed that provides lowest system power.

8. The method of claim 1, wherein the determining an optimal speed for a fan includes

measuring CPU power and fan power for an initial fan speed;

incrementing the fan speed and determining change in system power based on changes in CPU power and fan power;

incrementing the fan sped in the same direction if the change in system power was negative; and

incrementing the fan speed in an opposite direction if the change in system power was positive.

9. The method of claim 8, further comprising selecting the optimal speed.

10. The method of claim 9, further comprising validating the optimal speed selected at defined intervals.

11. The method of claim 9, further comprising validating the optimal speed selected based on system parameters.

12. An computer comprising

a fan;

a CPU;

a fan controller to control the operation of the fan, wherein the controller may operate the fan at low temperature conditions in order to reduce overall system power consumption.

13. The computer of claim 12, wherein optimal speed of the fan is determined during operation by determining power consumption of the fan and the CPU.

14. The computer of claim 12, wherein optimal speed of the fan is determined by determining system temperature and looking up an optimal speed for the temperature.