利用三极管对高速大动态光电转换系统降噪分析

Analysis of Noise Reduction in High-Speed Large Dynamic Photoelectric Conversion System by Triode

在高速大动态光电转换系统中,高速开关在切换通道时产生的脉冲噪声使高速运放芯片的瞬态响应出现边沿脉冲,对高速光电转换电路的测量产生不可忽视的干扰。该文理论分析了光电二极管的等效电路中潜在的分流通路,通过实验分析了三极管射极和集电极间电阻特性与基极电压的关系,理论阐述采用在切换通道并联三极管利用其泄流原理对高速开关产生的脉冲噪声进行抑制的方案,并对比分析加三极管泄流和不加三极泄流的实验仿真结果,验证了并联三极管泄流的方案具有明显的降噪效果。

In high-speed and large dynamic photo-translating systems, the impulse noises generated by switching channel makes the edge pulses appear at the transient response of high-speed operational amplifiers in high-speed circuits. This paper analyzes the potential shunt circuits in the equivalent circuit of photodiode, experimentally studies the relationships between resistance characteristic and bias voltage of andion emitter and collector, and elaborates a project that controls the impulse noises produced by high-speed switch via aerial drainage theory of parallel connection of audion in switching channels. Finally, the simulation results of aerial drainage with and without an audion are compared. It is shows that the project of aerial drainage with parallel connection of audion can achieve a significant effect in reducing noises.