Standard Microsystems Corporation

Wayne A Miller, Jr

Richard Wahler

Eileen Marando

Steven Burstein

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.

Method and apparatus for measuring the rotational speed of a fan

A system and method for increasing resolution of pulse width modulated (PWM) signal duty cycle calculations in a fan speed control system operating to control rotational speed of at least one fan. The method may comprise obtaining a temperature reading from a first temperature sensor in the fan speed control system during a first time period. The temperature reading has resolution of a first number of bits. A portion of the first number of bits is selected for calculating a PWM signal duty cycle with the resolution of the first number of bits in the temperature reading using only the portion of the first number of bits and zone parameters associated with the first temperature sensor. The PWM signal duty cycle may then be converted into a PWM signal that may be provided to the at least one fan.

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Port Jefferson Station, NY, United States of America

Wayne A Miller, Jr