文档介绍：AVR441: Intelligent BLDC Fan Controller with
Temperature Sensor and Serial Interface
Features
• Application Example for Controlling Brushless DC Motors
- Ideal for Use as an Integrated Fan Controller 8-bit
• Automatically Adjusts Fan Speed According to Chip Temperature Microcontrollers
• Automatically Detects Fan Failures
• Two-Wire Interface for Remote Control and Monitoring
Application Note
1 Introduction
As package dimensions go down and power consumption figures goes up thermal
management es an increasingly important factor in modern day electronics
design. Perhaps the simplest form of thermal management is forced convection,
. increasing the dissipation of heat by moving the air inside and around the heat
source. This is most conveniently done using fans, which are powered by
Brushless DC (BLDC) motors. BLDC motors mutated electronically,
eliminating problems such as mechanical wear of brushes, but also reducing EMI
(Electro-ic Interference). The most straightforward fan designs simply spin
the fan rotor at full speed, but as the number of fans tends to increase so does the
noise. The noise level es an annoyance, which creates a demand to adjust
the speed of the fan according to environmental conditions.
When cooling is not ponents may overheat and suffer temporary or
permanent failures. A modern fan must therefore be able to react to changes in
temperature, mechanical wear and even physical obstacles (jamming the fan). As
fans are used puterized environments thermal control can be made more
efficient if fans are connected to a master, such as the CPU in a typical PC.
This application note describes how to integrate a low-cost, feature-rich AVR
microcontroller into mutator electronics of a BLDC fan. The ATtiny25 used
in this application note is a low-cost, low-power, 8-bit microcontroller based on the
AVR enhanced RISC architecture. It contains 2 KB Flash program memory, 128
bytes of EEP