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US 7,096,134 B2Granted
Method and apparatus for measuring the rotational speed of a fan
AssigneeStandard Microsystems Corporation
InventorWayne A. Miller, Jr.
Life of this patent
Estimating the term…
Abstract
A system may include a PWM (Pulse Width Modulator) configured to generate a PWM signal, a signal modifier configured to generate a modified PWM signal that includes a sampling activation signal having a different frequency than the PWM signal, fan drive circuitry configured to provide power to a fan in response to the modified PWM signal; and a sampling unit configured to sample a fan tachometer signal in response to an indication that the fan is currently powered.
Claims31
A system comprising:
- a PWM (Pulse Width Modulator) configured to generate a PWM signal;
- a signal modifier coupled to the PWM and configured to generate a modified PWM signal, wherein the modified PWM signal includes a sampling activation signal having a different frequency than the PWM signal;
- fan drive circuitry configured to receive the modified PWM signal and to provide power to a fan in response to the modified PWM signal;
- and
- a sampling unit configured to sample a fan tachometer signal in response to an indication that the fan is currently powered.
2 more elements
A method comprising:
- generating a PWM signal;
- modifying the PWM signal to create a modified PWM signal, wherein the modified PWM signal includes a sampling activation signal having a different frequency than the PWM signal;
- powering a fan according to the modified PWM signal;
- and
- sampling a fan tachometer signal in response to an indication that the fan is currently powered.
2 more elements
A system comprising:
- means for generating a power signal;
- means for modifying the power signal to create a modified power signal, wherein the modified power signal includes a signal having a different frequency than the power signal;
- means for conveying the modified power signal to a fan;
- and
- means for sampling a fan tachometer signal in response to the signal having the different frequency.
2 more elements
Dependencies are inferred from the claim text.