宽频带低漂移光电耦合隔离电路的研制

Development of a Broadband Lowdrift Optocoupler Isolation Circuit

提出一种实现低成本、宽频带、低漂移线性光电耦合隔离电路的方案。这种电路是由高速光电耦合器件组成的交流通道与普通光电耦合器件按脉冲调宽(PWM)原理制成的直流通道组合而成的。用计算机辅助分析软件PSPICE设计了均衡网络并对电路进行了分析。分析和实验结果表明,这种隔离电路的3dB带宽超过300kHZ,幅频响应曲线的波动低于5％,并保持了原直流通道的低漂移、高线性的特点。

A scheme to develope a low price, broadband, low drift and high linearity optocoupler isolation circuit has devoted. The circuit is based on composing of the AC channel composed of the high-speed optocouplers and the DC channel with conventional optocoupler realized by using the PWM technique. The computer CAD software PSPICE is used to design an equalizer and to analyse the isolation circuit. Both of analytic and experiemental results show that the 3 dB bandwidth of the isolation circuit is larger than 300 kHz, and the ripple of the amplitude response curve is less than 5%. The features, involving low drift and high linearity of the original DC channel are still maintained.