Design method for preventing negative voltage output of PSD signal processing circuit

Abstract

The invention discloses a design method for preventing negative voltage output of a PSD signal processing circuit. The combination of an I / V conversion circuit and an operational amplification circuitis used as pre-processing of a PSD signal, and the weak current signal outputted by a PSD device is converted into the preset voltage signal. The design method is characterized in that one path of output current of the PSD is defined as I1, the sampling resistor of the I / V conversion circuit is R1, the offset voltage of the operational amplifier of the I / V conversion circuit is deltau1, the amplification factor of the operational amplification circuit is K and the offset voltage of the operational amplification circuit is deltau2 so that the output voltage U1 of the corresponding signal processing circuit is: U1=(-I1*R1+deltau1)*K+ deltau2. The parameters K, deltau1 and deltau2 are selected so that U1=(-I1*R1+deltau1)*K+ deltau2>0, i.e. negative voltage output of the PSD signal processingcircuit can be avoided. The objective that negative voltage output of the PSD signal processing circuit can be avoided from the design source can be achieved.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to a design method for avoiding output negative pressure of a PSD signal processing circuit. Background technique [0002] As a mature photoelectric sensitive device, PSD (Position Sensitive Device) has been widely used in various fields such as test and measurement. The pre-processing of the PSD signal generally uses a combination of an I / V conversion circuit and an operational amplifier circuit to convert the weak current signal output by the PSD device into a predetermined voltage signal for further acquisition and processing. Due to the inherent offset voltage of the operational amplifier chip used in the I / V conversion circuit and the operational amplifier circuit, the PSD signal processing circuit may output a negative voltage, which is easy to cause damage to the subsequent acquisition equipment, or requires the acquisition equipment to have negative voltage Input capability...

AI Technical Summary

Problems solved by technology

Due to the inherent offset voltage of the operational amplifier chip used in the I / V conversion circuit and the operational amplifier circuit, the PSD signal processing circuit may output a negative voltage, which is easy to cause damage to the subsequent acquisition equipment, or requires the acquisition equipment to have negative voltage input capability

At present, the negative pressure output of the PSD signal processing circuit can be eliminated by increasing the processing circuit or enhancing the ambient light intensity. The method of increasing the processing circuit not only increases the research and development cost, but also increases the complexity of the circuit and reduces the reliability; enhance the ambient light strong method, it will increase the application limit of the circuit

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