差动型双通道光电系统的检测电路设计

Design of Detection Circuit for Differential Dual channel Optoelectronic System

摘要:

常用的差动型双通道光电系统对两路光电信号的处理在电路上要求有很好的一致性，否则会影响其精度和灵敏度，据此设计了一种能满足这种光电系统要求的检测电路。它由双对数放大器ADL5310完成光电流到电压信号的变换，输出两路独立的与光电流呈对数关系的电压信号；再由仪表放大器AD620对这两路电压信号进行求差，最终完成检测。经实验测试表明，所设计的电路是正确、可行的。该检测电路可接收3nA～3mA的大动态范围的光电流输入，带宽为120dB，在缓变光信息检测方面具有一定的普适性。

Abstract:

The fine consistency of two photoelectric signal processing circuits in differential dual channel optoelectronic system has a great influence on the precision and sensitivity of the system, based on which, a kind of detection circuit was designed to meet the requirements of photoelectric system. For this circuit, double logarithmic amplifier ADL5310 was applied to convert the photocurrent to voltage signals and produce two independent voltage outputs which have a logarithmic relation with optical current; then instrumentation amplifier AD620 was used to implement differential operation on the two voltage outputs. The experimental results show that this detection circuit is correct and feasible. It can detect the current ranging from 3nA to 3mA, dynamic range of 120dB，therefore it may have wide applications in other slow variable optical signal detection.