Intelligent power management for a variable speed fan
First Claim
1. A method for controlling the operation of a brushless DC fan for cooling heat generating components of a system when system temperature of said system exceeds a prescribed limit, the method comprising:
- sensing temperature of said system and generating a system temperature signal indicative of the system temperature;
generating an intelligent shutdown enable signal to shut down the fan when system temperature is less than said prescribed limit;
comparing the system temperature signal with the shutdown enable signal;
operating the fan at a speed generally proportional to said system temperature after comparing the system temperature signal with the shutdown enable signal if the system temperature as indicated by the system temperature signal is greater than the shutdown temperature value as indicated by the shutdown enable signal;
entering a shutdown mode by the fan after comparing the system temperature signal with the shutdown enable signal if the system temperature as indicated by the system temperature signal is less than the shutdown temperature value as indicated by the shutdown enable signal;
comparing the system temperature signal with the shutdown enable signal after entering the shutdown mode by the fan; and
initiating operation of the fan if the system temperature as indicated by the system temperature signal is greater than the shutdown enable signal value.
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Accused Products
Abstract
A method for controlling the operation of a brushless DC fan for cooling heat generating components of a system is provided. The method includes providing a system temperature signal indicative of a system temperature and providing an intelligent shutdown enable signal. The system temperature signal is compared with a shutdown temperature signal if the intelligent shutdown enable signal has a first value. The shutdown temperature signal is representative of a shutdown temperature value. The fan is operated at a generally temperature proportional speed after comparing the system temperature signal with the shutdown temperature signal if the system temperature as indicated by the system temperature signal is greater than the shutdown temperature value as indicated by the shutdown temperature signal. A shutdown mode is entered by the fan after comparing the system temperature signal with the shutdown temperature signal if the system temperature as indicated by the system temperature signal is less than the shutdown temperature value as indicated by the shutdown temperature signal. The system temperature signal is compared with the shutdown temperature signal after entering the shutdown mode by the fan. Operation of the fan is initiated if the system temperature as indicated by the system temperature signal is greater than the shutdown temperature value as indicated by the shutdown temperature signal and the fan is in the shutdown mode.
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Citations
30 Claims
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1. A method for controlling the operation of a brushless DC fan for cooling heat generating components of a system when system temperature of said system exceeds a prescribed limit, the method comprising:
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sensing temperature of said system and generating a system temperature signal indicative of the system temperature; generating an intelligent shutdown enable signal to shut down the fan when system temperature is less than said prescribed limit; comparing the system temperature signal with the shutdown enable signal; operating the fan at a speed generally proportional to said system temperature after comparing the system temperature signal with the shutdown enable signal if the system temperature as indicated by the system temperature signal is greater than the shutdown temperature value as indicated by the shutdown enable signal; entering a shutdown mode by the fan after comparing the system temperature signal with the shutdown enable signal if the system temperature as indicated by the system temperature signal is less than the shutdown temperature value as indicated by the shutdown enable signal; comparing the system temperature signal with the shutdown enable signal after entering the shutdown mode by the fan; and initiating operation of the fan if the system temperature as indicated by the system temperature signal is greater than the shutdown enable signal value. - View Dependent Claims (2, 3, 4)
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5. An apparatus for controlling the operation of a brushless DC fan for cooling heat generating components of a system, the apparatus comprising:
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the fan; a fan controller coupled to control the speed of the fan; a thermal manager coupled to provide an intelligent shutdown control signal to the fan controller;
whereinthe fan controller includes a temperature sensing circuit coupled to provide a temperature dependent electrical effect; a pulse width modulator coupled to receive the intelligent shutdown control signal, the pulse width modulator generating an output signal having a first value when the intelligent shutdown control signal has a second value; and the temperature dependent electrical effect, the pulse width modulator being operable to generate the output signal having pulses of a third value when the intelligent shutdown control signal has a fourth value, the pulses having a width dependent on the temperature dependent electrical effect; and a switch coupled to receive the pulses, the switch applying power to the fan during each of the pulses of the output signal. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for controlling the operation of a brushless DC fan for cooling heat generating components of a system, the apparatus comprising:
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means for providing a system temperature signal indicative of a system temperature; means for providing an intelligent shutdown enable signal; means for comparing the system temperature signal with a shutdown temperature signal if the intelligent shutdown enable signal has a first value, the shutdown temperature signal being representative of a shutdown temperature value; means for operating the fan at a generally temperature proportional speed after comparing the system temperature signal with the shutdown temperature signal if the system temperature signal has a first relation to the shutdown temperature signal; means for entering a shutdown mode by the fan after comparing the system temperature signal with the shutdown temperature signal if the system temperature signal has a second relation to the shutdown temperature signal; means for comparing the system temperature signal with the shutdown temperature signal after entering the shutdown mode by the fan; and means for initiating operation of the fan if the system temperature signal has the first relation to the shutdown temperature and the fan is in the shutdown mode. - View Dependent Claims (26, 27, 28, 29, 30)
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Specification