一种基于TL431输入过压保护电路的应用

An application of input over-voltage protection circuit based on TL431

设计一种基于TL431过压保护电路应用在直流风机领域,利用TL431的内部高精度基准电压和误差放大器提供稳定参考电压,控制TL431的阴极电压值,即电路中MOS管栅源电压值,从而实现输入过压时保护风机安全性,且针对风机为感性负载电流不能突变的特性,电路采用续流二极管实现MOS管断开时的风机能量吸收电路.该电路具有简单可靠、重量轻、响应速度快、效率高、电磁兼容性良好等特点.同时,通过实例分析和实验,验证了该保护电路的可行性.

An over-voltage protection circuit based on TL431 is proposed to be applied in the field of direct current fan.The internal high precision reference voltage and error amplifier of TL431 are used to provide stable reference voltage and control the cathode voltage of TL431,in order to protect the safety of the fan when the input voltage is over-voltage.And because the inductive load current of the fan can′t change suddenly,the energy absorption circuit of the fan when the MOS transistor is broken is realized by using the fly-back diode.The circuit is simple,reliable,light weight,fast response,high efficiency,good electromagnetic compatibility and so on.At the same time,the feasibility of the circuit is verified by example analysis and experiment.