基于光耦的小电流线性隔离传输特性研究

Study on Characteristics of Small Current Linear Isolation Transmission Based on Optocoupler

小电流模拟信号的隔离传输最简单常用的方法是采用线性光耦进行传输,但是线性光耦应用复杂,采用改变非线性高速光耦的使用方式来实现小电流模拟信号的线性隔离传输。通过对高速光耦进行理论分析,并结合以Fairchild 6N136高速光耦为研究对象的实验验证发现,高速光耦的发光二极管-光电二极管之间小电流传输时线性度好、温度特性好,而且高速光耦的CTR稳定性较好。因此高速光耦的此种使用方式在非高精度,且要求隔离的小电流模拟信号传输领域具有一定的适用性。

The most simple and common method of small current linear isolation transmission is to use linear optocoupler,but its application is complex.We achieved small current linear isolation transmission by the way of changing the way of using high-speed optocoupler.According to the theoretical analysis of high speed optocoupler and the experimental study on the Fairchild 6N136 high-speed optocoupler,We find that high-speed optocoupler has good linearity, good temperature characteristic when transmit small current between led and photodiode.lts CTR has good stability.Therefore,the application of the high-speed optocoupler is suitable for the situation when high accuracy is not required,but small current linear isolation transmission is needed.