Maxim MAX31785六路智能风扇控制方案
Maxim 公司的MAX31785是比环六路智能风扇控制器，支持3线和4线风扇，基于RPM或PWM的控制，可选择快慢PWM频率，支持多达11个温度传感器，PMBus兼容，I2C/SMBus兼容，主要用在网络交换/路由器，基站，服务器，智能电网网络系统和工业控制。本文介绍了MAX31785主要特性，方框图，多个器件连接框图以及典型工作电路图。
The MAX31785 is a closed-loop multichannel fan controller. Automatic closed-loop fan control saves system power by operating the fans at the lowest possible speeds. Added benefits of slower fan speeds include lower audible noise, longer fan life, and reduced system maintenance. Based on a user-programmable lookup table (LUT), the device automatically adjusts the speeds of the six independent fans based on one or more of the 11 available temperature sensors. Alternately, an external host can manually command the fan speeds and the device automatically adjusts the fan speeds. The device contains a fan-health-diagnostic function to help users predict impending fan failures. The device can also monitor up to six remote voltages.
MAX31785主要特性：
Six Independent Channels of Fan Control
Supports 3-Wire and 4-Wire Fans
Automatic Closed-Loop Fan Speed Control
RPM- or PWM-Based Control
Optional Manual Mode Control
Fast and Slow PWM Frequency Options ..
