High-voltage biasing circuit of avalanche photodiode applied to weak fluorescence measurement

Abstract

The invention discloses a high-voltage biasing circuit of an avalanche photodiode (APD) applied to weak fluorescence measurement. The high-voltage biasing circuit is composed of a control signal unit, a control signal conditioning unit, a non-temperature drift amplification unit, an output buffer unit and a feedback unit. Signal conditioning is carried out on a control signal by the control signal conditioning unit; the processed signal is amplified by the control signal conditioning unit to obtain a needed bias voltage value; and the output buffer unit and the feedback unit are used for controlling stability of the output. According to the invention, on the basis of the method of mutual coupling of temperature drift coefficients between components, a problem of drifting of the voltage of the previous high-voltage biasing circuit due to the temperature drift can be solved. And the high-voltage biasing circuit has the advantages that high-voltage output with high temperature stability is realized and the output is not reduced with signal increasing and the like. And thus the high-voltage biasing demand during APD working is satisfied.

Description

technical field [0001] The invention belongs to the field of biomedical detection, and in particular relates to a high-voltage bias circuit of an avalanche diode APD used in weak fluorescence measurement. Background technique [0002] In the field of biomedicine, fluorescence technology is often used for qualitative and quantitative measurement of substances, research on immune proteins on the cell surface, and determination of DNA content. Because the fluorescence intensity is very weak, and APD (avalanche diode) can achieve avalanche multiplication, and has high quantum efficiency and low price, it is often used to test the fluorescence intensity. The normal operation of APD requires a high-voltage bias of tens to hundreds of volts, and its multiplication factor changes with the increase of the voltage. Therefore, in order to ensure the accuracy of the measurement results, a stable bias voltage needs to be provided to ensure that the APD can perform fluorescence accurately...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the problem that the bias voltage output of the traditional APD high-voltage bias circuit will decrease with the increase of the optical signal and the bias voltage will change with the drift of the temperature, so that the APD can be more accurately Perform bioluminescent tests

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