A LED drive circuit with self-adaptive to temperature was designed. In this drive circuit, hysteresis thermal-shutdown circuit and self-adaptive circuit were integrated into one modular, that largely simplied the circuit. Hysteresis thermal-shutdown circuit would export an off signal to stop circuit operation when the system was at a high temperature, and self-adaptive circuit would produce a negative temperature coefficient to regulate the value of output current, which achieved the purpose of self-adaptive. Based on 0.5μm standard CMOS technology, the Spectre simulation results show that the variances of driving current is less than 0.57% when ambient temperature varies at 0-70℃. The maximum adjustable amplitude of driving current is 100 mA from 70℃ to 105℃. And when the temperature rises up to 108℃, the output circuit would turn off and wouldn’t restart until the temperature drops back to 65℃.%设计了一款对温度自适应的LED恒流驱动电路。在该电路中，将滞回关断电路与自适应电路集成到一个模块里，很大程度上简化了电路。滞回关断电路会在系统处于高温时输出关断信号，使电路停止工作；而自适应电路在系统处于调控温度时，会产生一个负温度系数的电压来调控输出电流的大小，达到自适应的目的。基于0.5μm CMOS工艺，Spectre仿真结果表明：当系统温度在0~70℃变化时，恒流输出变化小于0.57%；从70℃到105℃，调控输出电流可调幅度为100 mA；108℃时，电路关断输出，直到温度降回65℃后，重新开启。
展开▼
