Advanced programmable closed loop fan control method

• US 7,098,617 B1
• Filed: 02/16/2005
• Issued: 08/29/2006
• Est. Priority Date: 02/16/2005
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Johnson, Jeffrey David, Oljaca, Miroslav
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US11/059,250
• Publication Number:
  US 20060181232A1
• Time in Patent Office: 559 Days
• Field of Search: 318260-268, 318/254, 318/471, 318/599, 318/600, 318/811, 388/806, 388/804, 361/697, 361/687, 710/100, 710/200, 700/108, 700/300, 706/52, 417/14
• US Class Current: 318/268
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: H02P 29/60 Controlling or determining the temperature of the motor or of the drive H02P29/02 takes precedence
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A fan control system and method that maintains the operating temperature of computer and electronic devices or components at about a predetermined control level to minimize power consumption and audible noise. The fan control system is a programmable closed loop system including a temperature sensor, first and second fan controllers, and a fan/motor assembly including a power converter, a motor, and a fan. The first fan controller provides programmable acceleration/deceleration of the fan during an initial fan spin up, and the second fan controller runs the fan only as fast as necessary to keep the sensed temperature level of a computer device as close as possible to the predetermined control level, thereby minimizing the power consumption of the system and the audible noise of the fan.

Claims

1. A fan control system, comprising:

at least one temperature sensor operative to sense at least one first temperature associated with at least one first location;

at least one fan fuzzy logic controller having at least one input; and

at least one fan controller;

wherein the input is operative to receive a feedback control signal representing a calculated difference between the first sensed temperature and a predetermined control temperature, and

wherein the fan fuzzy logic controller is selectively selecting the at least one fan controller operative to generate at least one first fan control output signal for minimizing the difference between the first sensed temperature and the predetermined control temperature.

2. The system of claim 1 wherein the at least one first location is associated with at least one integrated circuit device, and the at least one temperature sensor comprises at least one thermal diode temperature sensor operative to provide a representation of a local die temperature of the integrated circuit device.

3. The system of claim 2 wherein the predetermined control temperature is less than a maximum case temperature of the integrated circuit device.

4. The system of claim 1 further including a DC motor and fan, and wherein the at least one fan controller comprises at least one pulse width modulation (PWM) controller operative to control a speed of the DC motor and fan.

5. The system of claim 4 wherein the PWM controller is operative to receive the feedback control signal as input, and to provide PWM pulses having variable duty cycles based on the feedback control signal.

7. The system of claim 1 wherein the first fan control output signal is operative to run a cooling fan at less than maximum speed.

6. A fan control circuit, comprising:

at least one temperature sensor operative to sense at least one first temperature associated with at least one first location;

at least one fan fuzzy logic controller having at least one input,

at least one fan controller; and

wherein the input is operative to receive a feedback control signal representing a calculated difference between the first sensed temperature and a predetermined control temperature, and

wherein the fan fuzzy logic controller is operative selectively connected to the at least one fan controller to generate at least one first fan control output signal for minimizing the difference between the first sensed temperature and the predetermined control temperature,

wherein the at least one fan controller is selected from the group consisting of a proportional integral derivative (PID) controller, a fuzzy controller, and a combination of a fuzzy controller and a non-fuzzy controller.

8. A method of controlling a cooling fan, comprising the steps of:

sensing at least one first temperature associated with at least one first location by at least one temperature sensor;

receiving a feedback control signal representing a calculated difference between the first sensed temperature and a predetermined control temperature by at least one fuzzy logic fan controller;

controlling the fan with at least one fan controller; and

selectively generating at least one first fan control output signal for minimizing the difference between the first sensed temperature and the predetermined control temperature by the fan fuzzy logic controller.

9. The method of claim 8 wherein the cooling fan is a DC fan, wherein the fan controller comprises a pulse width modulation (PWM) controller, and the receiving step includes receiving the feedback control signal as input by the PWM controller, and providing PWM pulses having variable duty cycles based on the feedback control signal by the PWM controller.

11. The method of claim 8 further including the step of using the at least one first fan control output signal to run the cooling fan at less than maximum speed.

10. A method of controlling a cooling fan, comprising the steps of:

sensing at least one first temperature associated with at least one first location by at least one temperature sensor;

receiving a feedback control signal representing a calculated difference between the first sensed temperature and a predetermined control temperature by at least one fan fuzzy logic controller;

selectively generating at least one first fan control output signal for minimizing the difference between the first sensed temperature and the predetermined control temperature by the fan fuzzy logic controller; and

wherein the fan controller is selected from the group consisting of a proportional integral derivative (PID) controller, a fuzzy controller, and a combination of a fuzzy controller and a non-fuzzy controller.

12. A method of controlling a cooling fan, the method being used to control a temperature at a first location, comprising the steps of:

sensing a temperature associated with the first location;

in the event the sensed temperature is less than a predetermined control temperature, at least one fan fuzzy logic controller selectively connecting at least one fan controller for providing at least one first fan control signal to run the cooling fan at one or more speeds sufficient for allowing the sensed temperature to increase gradually to substantially the predetermined control temperature; and

in the event the sensed temperature is greater than the predetermined control temperature, the at least one fuzzy logic controller selectively connecting the at least one fan control for providing at least one second fan control signal to run the cooling fan at one or more speeds sufficient for gradually decreasing the sensed temperature to substantially the predetermined control temperature.

13. The method of claim 12 wherein the first location is associated with an integrated circuit device, and the sensed temperature is a representation of a local die temperature of the integrated circuit device.

14. The method of claim 13 wherein the predetermined control temperature is less than a maximum case temperature of the integrated circuit device.

15. The method of claim 12 further including the step of, in the event the sensed temperature is less than a predetermined minimum temperature, deactivating the cooling fan.

16. A method of performing a soft start of a cooling fan, the cooling fan being operative to run at multiple speeds, comprising the steps of:

providing a first fan control signal to the cooling fan for running the fan at a speed corresponding to a minimum fan speed;

selectively providing at least one second fan control signal to the cooling fan for gradually increasing the fan speed from the minimum fan speed to a maximum fan speed over a first predetermined time period;

maintaining the fan speed at substantially the maximum fan speed over a second predetermined time period; and

selectively providing at least one third fan control signal to the cooling fan for gradually decreasing the fan speed from the maximum fan speed to an intermediate fan speed over a third predetermined time period, the intermediate fan speed being between the minimum fan speed and the maximum fan speed.

17. The method of claim 16 wherein at least one of the first and third predetermined time periods is programmable for varying an acceleration and a deceleration, respectively, of the cooling fan.

18. The method of claim 16 wherein the intermediate fan speed is programmable.