Industrial automation equipment or the use of "Micro Cooling Fan", the original request as long as the normal full speed to meet the cooling requirements of the device. However, with the continuous development of technology, the miniaturization of the device more compact, quality and reliability of the fans are getting higher and higher. For fan power consumption, size requirements are increasingly small, amount of wind pressure and other technical indicators also demanding. At present, most manufacturers of DC fan "Micro Cooling Fan" existing limit reverse protection, self-recovery function, soft start, over-current protection, AC fan with multiple protective properties of these already have their own outside temperature protection , also needs to monitor the use of the fan. So, in the future in the field of automation with the use of fan speed alarm output or output functions, will be necessary. And at the same time meet the cooling device, but also a certain amount of energy savings, which requires the use of smart with PWM speed control function "Micro Cooling Fan" to control the speed. Ie: at 0 to 100% duty cycle, with stepless way to control the fan speed, and thus achieve the dual effect of heat and energy.