一个双极性的宽带高精度光耦隔离放大器

A Bipolar Optocoupler Isolation Amplifier with High Precision And Wide Bandwidth

为适应电阻抗断层成像系统的技术要求,实现了一个改进的基于单个模拟光电耦合器件的双极性光电隔离放大器。测量结果表明,该隔离放大器不仅具有高于800KHz的-3dB全功率带宽,小于50uVRMS的等效输出噪声,在±4V范围内优于0.01%的线性度等特点,且结构简单,并消除了常规方法中因所选用的光电耦合器性能参数的不完全一致而导致的信号失真。

To fit the technological requirements in electrical impedance tomography system, an improved bipolar optocoupler isolation amplifier based on single analog optocoupler was realized. The experimental results illustrates that the full power -3dB bandwidth of this circuit is greater than 800 KHz, the equivalent output noise is lower than 50 UVRMs, and the linearity at±4 V inputs is lower than 0.01%. In addition to these features, the circuit also have the advantages of simple structure and no distortion caused by mismatch between analog optocouplers.