一种高精度阈值可调过温保护电路的设计

摘要

设计了一种高精度阈值可调过温保护电路.该电路利用与温度无关的电压和一个具有负温度系数的电压相比较,实现温度的检测.通过基准分压得到高、低阈值电压可调的迟滞比较器,具有较高的精度.基于0.18 μmBCD工艺模型,利用Hspice软件对电路进行仿真.仿真结果表明,在典型应用下,当温度高于150.5℃时,过温保护电路输出高电平,关断电路;当温度低于130.5℃时,电路重新开启,具有20℃迟滞量.在3～5.5 V电源电压范围内,过温电压阈值和迟滞温度最大偏移量小于0.02℃.%A high precision threshold adjustable over-temperature protection circuit was presented.Temperature detection was achieved by comparing a independent voltage of temperature with a negative temperature coefficient voltage.By bandgap reference voltage division,a high accuracy hysteresis comparator with adjustable upper and lower threshold voltage was obtained.Based on 0.18 μm BCD process model,the circuit was simulated by using Hspice software.Simulation results show that,the output of over-temperature protection circuit is high level when temperature is higher than 150.5℃,then the circuit is shut down;it is restarted again when temperature is lower than 130.5 ℃,and the range of hysteresis temperature is 20 ℃.In the source voltage range of 3-5.5 V,the maximum temperature drift of over-temperature voltage threshold and hysteresis temperature is less than 0.02 ℃.