REDUCING TONAL EXCITATIONS IN A COMPUTER SYSTEM
First Claim
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1. A method for operating a computing system having at least one electro-mechanical component controlled by a processor, the method comprising:
- prior to operating the computing system at a first operating state, characterizing a noise produced by operating the electro-mechanical component at a first operating point with a first control signal;
modifying the first control signal to a second control signal wherein the second control signal operates the electro-mechanical component in a manner to produce prominent acoustic tones less than a predetermined threshold; and
,operating the electro-mechanical component with the second control signal.
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Abstract
The described embodiments relate generally to control of rotational components in a computer system. In one embodiment, the rotational component includes a cooling fan, the cooling fan being controlled in accordance with data tailored to reduce the acoustic noise produced by the cooling fan. In one embodiment, the cooling fan is operated with non-uniform pulse width modulated signals. The non-uniform pulse width modulated signals can be a function of desired rotation speed and can include fundamental and harmonic components.
30 Citations
22 Claims
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1. A method for operating a computing system having at least one electro-mechanical component controlled by a processor, the method comprising:
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prior to operating the computing system at a first operating state, characterizing a noise produced by operating the electro-mechanical component at a first operating point with a first control signal; modifying the first control signal to a second control signal wherein the second control signal operates the electro-mechanical component in a manner to produce prominent acoustic tones less than a predetermined threshold; and
,operating the electro-mechanical component with the second control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fan controller for controlling a cooling fan for a computing system, the controller comprising:
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a temperature sensor configured to determine a temperature of the computing system; a look up table configured to include at least one a non-uniform pulse width modulated (PWM) waveform parameter; an address generator coupled to the look up table inputs and configured to provide addresses to the look up table; a digital to analog converter (DAC) coupled to the look up table outputs and configured to provide non-uniform PWM fan control signals in response to the look up table outputs; a programmable voltage reference coupled to the DAC configured to provide a reference voltage for the DAC outputs; and a controller configured to determine the non-uniform PWM fan control signal in response to the determined temperature by; programming the address generator in accordance with the determined temperature, and setting a programmable voltage reference in accordance with the determined temperature. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A computer system including a non-uniform pulse width modulated (PWM) fan controller comprising:
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a temperature sensor configured to determine the temperature of the computer system; a cooling fan configured to move cooling air into and out of the computer system; and a fan controller configured to control the cooling fan in response to the determined temperature with non-uniform PWM fan signals that operate the cooling fan in a manner that produces prominent tones less than a predetermined threshold acoustic threshold. - View Dependent Claims (15, 16, 17, 18)
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19. Non-transient computer readable medium for storing computer code executable by a processor in a computer system for controlling a cooling fan in a computing system, the computer readable medium comprising:
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computer code for determining a temperature of the computing system; computer code for selecting parameters for a non-uniform pulse width modulated (PWM) waveform in response to the determined temperature; computer code for generating a non-uniform PWM waveform in accordance with the selected parameters; and computer code for operating the cooling fan with the non-uniform PWM waveform, wherein the operating produces prominent acoustic tones less than a predetermined threshold. - View Dependent Claims (20, 21, 22)
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Specification