Temperature-Based Fan Control Using the MAXQ2000 Microcontroller

Introduction

With its numerous features, the MAXQ2000 can create a multitude of useful applications, such as controlling a fan's speed by pulse width modulation (PWM). Among the many features of the MAXQ2000 are its timer with PWM and Serial Peripheral Interface (SPI™) and 1-Wire® capabilities. This application note describes how the MAXQ2000 can be used to drive a fan and change its speed, in real time, by PWM. This process requires the use of another Maxim product, the MAX1407 multichannel data-acquisition system (DAS). Using SPI, the MAXQ2000 can communicate with the MAX1407 (containing a 16-bit analog-to-digital converter [ADC] and digital-to-analog converter [DAC]). As an alternative to using a thermistor, the MAXQ2000's 1-Wire bus master can be used in conjunction with a temperature iButton (DS1920). The source code used in this application note is available for download.
Temperature-Based Fan Control Using the MAXQ2000
Microcontroller
Sep 16, 2005

Abstract: This application note describes how to use a MAXQ2000 microcontroller to control DC fan speed and monitor
temperature from a thermistor oriButton.


Introduction
With its numerous features, the MAXQ2000 can create a multitude of useful applications, such as controlling a fan's speed by pulse
width modulation (PWM). Among the many features of the MAXQ2000 are its timer with PWM andSerial Peripheral
Interface(SPI) and 1-Wire capabilities. This application note describes how the MAXQ2000 can be used to drive a fan and
change its speed, in real time, by PWM. This process requires the use of another Maxim product, the MAX1407 multichannel data-
acquisition system (DAS). Using SPI, the MAXQ2000 can communica