Detection circuit for auto detecting avalanche magnitude of voltage of avalanche photodiode and method

Abstract

The invention discloses a test circuit for automatically testing the avalanche voltage of avalanche photodiodes and a method. The test circuit comprises a boost power chip with a current detector and a boost controller for providing bias voltage and current for an avalanche photodiode; a microcontroller with three internal analogue converters for adjusting and sampling the bias voltage and current; four resistance capacitance networks for connecting the internal circuits between the microcontroller and the boost power chip. The three analogue converters of the microcontroller are respectivelyconnected with the feedback input of the boost controller, the bias voltage input of the current detector and the monitor output of the current detector via three resistance capacitance networks. Theinvention is based on automatic control theory, can automatically adjust safe bias voltage, can judge the avalanche breakdown region by comparing the sampled current value and a preset respected value, and can display the result on a man-machine interface of a microcomputer system, having wide dynamic range, accurate and adjustable output, fast and accurate measurement.

Description

technical field [0001] The present invention relates to an avalanche photodiode (Avalanche Photo Diode, hereinafter referred to as APD) widely used in optical fiber communication network, optical fiber sensing, laser ranging and other photoelectric conversion data processing systems. More specifically, the present invention provides a circuit and method for safely, accurately and quickly measuring the avalanche voltage value of an avalanche photodiode based on successive approximation algorithm and automatic control principle. Background technique [0002] Avalanche photodiode is a semiconductor light detector with small size, high sensitivity and fast speed. Since the gain of an avalanche photodiode has a great relationship with the reverse bias voltage and temperature, it is necessary to control the reverse bias voltage to keep the gain stable. It can be seen that in order to make the avalanche photodiode work in the best state, it is necessary to set an appropriate bias ...

AI Technical Summary

Problems solved by technology

Because the method is manual operation, the efficiency is low. Even for skilled workers, the process usually takes about one minute, and it is easy to burn the expensive avalanche photodiode in the case of improper operation, resulting in waste of materials.

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