一种高精度过温保护电路的设计

Design of a High Precision Thermal-Shutdown Circuit

基于UMC 0.25μm BCD工艺,设计了一款高精度过温保护电路。通过基准电路中三极管的基极-发射极电压的负温度特性实现温度检测,调节电阻的比值产生迟滞温度量,避免了电路热振荡现象。经过HSPICE仿真验证,电路在温度130℃时,过温保护信号发生翻转,关断芯片,待温度降低到99℃时再次开启,具有31℃迟滞量。在电源电压变化时,过温保护电路的过温阈值和迟滞温度漂移量最大仅为0.24℃偏差。

Based on UMC 0.25 μm BCD technology,a high precision thermal-shutdown circuit is proposed. The temperature detection is achieved by using the negative temperature characteristic of transistor’s base-emitter voltage of bandgap reference. The hysteresis temperature is produced by adjusting the ratio of resistance to avoid the phenomenon of thermal oscillation. By simulation and verification with HSPICE,the thermal-shutdown output reverses to shut down the chip when the temperature reaches 130℃,and return to normal working when the temperature drops to 99℃. The amount of hysteresis temperature is 31℃. The thermal shutdown threshold and hysteresis temperature have a maximum drift error of only 0.24℃when supply voltage changes.