一种高精度阈值可调节的过温保护电路设计

Design of an Over-Temperature Protection Circuit with High Precision and Adjustable Threshold

针对传统过温保护电路结构复杂、功耗大等问题,提出一种具有高精度的阈值可调节的过温保护电路。设计基于华虹0.35μm BCD工艺模型,通过将基准电压分压与随温度增大而增大的电压进行比较来实现功能,并在电路中引入迟滞,以消除比较器在跳变温度点附近的振荡现象。经Cadence Spectre软件仿真验证,当温度大于165℃时,输出由低变高,控制信号迫使整个芯片关断;当温度低于147℃时,输出由高转低,电路恢复正常工作状态,且有20℃的迟滞量。在3-5.5V电源电压范围内,该电路能很好的抑制电源电压变化造成的阈值点漂移,以较高精度确保电路性能稳定。

Aiming at the problems of complex structure and high power consumption of traditional over-temperature protection circuit,a high-precision over-temperature protection circuit with adjustable threshold is proposed.Based on the 0.35μm BCD process model of Hua Hong,the function is realized by comparing the voltage of reference voltage with the voltage that increases with the increase of temperature,and hysteresis is introduced in the circuit to eliminate the oscillation of comparator near the jump temperature point.The Cadence Spectre software simulation shows that when the temperature is higher than 165℃,the output changes from low to high,and the control signal forces the whole chip to turn off.When the temperature is lower than 147℃,the output changes from high to low,and the circuit returns to the normal working state with a hysteresis of 20℃.In the range of 3~5.5 V power supply voltage,the circuit can suppress the threshold drift caused by the change of power supply voltage,and ensure the stability of circuit performance with high accuracy.