Design of Photodiode Circuit Based on Signal Acquisition

摘要

Most of optical signals is collected using optical instruments. Although photodiodes have the same unilateral conductivity as ordinary diodes, it can act as a photoelectric sensor in circuit and play a significant role in signal acquisition. In this study, the photosensitivity of photodiode was studied, a circuit was designed selecting photodiode as photoelectric sensor, and the signal acquisition was realized by testing the feasibility of the designed circuit. The equivalent model of the designed circuit was established by Pspice software, and the circuit performance under different illumination and bias voltage was simulated and analyzed. It is concluded that the photodiode circuit designed in this paper could effectively reflect the intensity of optical signals. When the optical signal was fixed, the increase of the reverse bias voltage in a certain range increased the photocurrent in the circuit; as a result, the signal was enhanced. The reverse bias voltage should not exceed 90 V; otherwise the dark current in the circuit would interfere with the detection of optical signals. The designed circuit can collect the pulse optical signal effectively and adjust the response characteristics of the circuit through the reverse bias voltage; the higher the bias voltage in a certain range, the better the response characteristics.