用于光强检测的前置放大及量程自动转换电路  

Design of preamplifier and range automatic switching circuit using in light intensity detection

作　　者：许四云 邓焯泳[1] 许瀚朗[1] 冯金垣[1] 

机构地区：[1]华南理工大学理学院,广东广州510640

出　　处：《电子设计工程》2015年第4期99-101,104,共4页Electronic Design Engineering

摘　　要：设计出了一种用于光强检测的前置放大及量程自动转换电路。许多光强信号放大电路仅追求高增益,忽略了对测量范围的考虑。本文采用同轴尾纤型光电探测器把光强信号转换成光电流信号,精密截波稳定型运算放大器ICL7652把光电流信号转化为电压信号,量程转换电路74HC4052受单片机控制可在4个量程之间自动转换,通过调节暗电流补偿电路减小光电二极管暗电流所产生的影响。仿真测试结果表明,电路参数选择合理、电路模块性能稳定,并且很好地降低了噪声的影响,设计的电路具有低噪声、高增益、高共模抑制比、失调小等优点,探测光强动态范围可达76 d B。A kind of preamplifier and circuit of range automatic switch which could be applied to the system of light intensity detection has been devised. In many amplifying circuit of light intensity signal,the high gain is taken into account, while ignoring the consideration of measurement range. In this paper,using the photoelectric detector of coaxial pigtailed type（ICL7652） to light intensity signal is converted into current signal,adopting the operational amplifier of precision chopper stabilized to current signal into voltage signal,range switching circuit（74HC4052） is controlled by chip microprocessor can automatically convert between four range, the influence of dark current could be reduce to adjusting the dark current compensation circuit.The simulation test results show that the circuit parameter is reasonable selected,the function of the circuit performed stably,and the influence of the noise is efficiently reduced.The designation is of the advantages such as low noise,high gain,high common-mode rejection ratio,small disturbance,etc,the dynamic range of light intensity of wide can reach 76 d B.

关 键 词：光强检测 前置放大 量程转换 ICL7652 74HC4052 

分 类 号：TN721[电子电信—电路与系统]