A Design of Signal Processing Circuit Based on the Duo-Lateral PSD

The PSD (Position Sensing Detector) is an optoelectronic sensor which converts an incident light spot into continuous position data. Compared to the other photoelectric detectors, the PSD performs better in many occasions, and the linearity of a duo-lateral PSD is the highest among two-dimensional PSD. By analyzing the measurement principle of the PSD, we design a reverse bias circuit and a preamplifier circuit of the duo-lateral PSD. Considering the characteristics of the PSD device and the problems which exist in the design of the preamplifier circuit, some parts of the circuit have been improved. Experimental results show that the improved circuit has high measurement precision and accuracy.