CN203149082U

CN203149082U - Photoelectric avalanche diode (APD) automatic parameter tester

Info

Publication number: CN203149082U
Application number: CN 201320150496
Authority: CN
Inventors: 曾庆立; 陈善荣; 杨永东
Original assignee: Jishou University
Current assignee: Jishou University
Priority date: 2013-03-29
Filing date: 2013-03-29
Publication date: 2013-08-21
Anticipated expiration: 2023-03-29

Abstract

The utility model relates to a photoelectric avalanche diode (APD) automatic parameter tester, which belongs to the test measuring instrument technical field. Parameter discreteness of an APD diode is obvious, the debug difficulty for equipment employing the APD diode is increased, the utility model provides the tester used for rapidly and accurately measuring main parameter of the APD and drawing a volt-ampere characteristic curve of the APD diode, and comprises a power supply circuit, a control circuit, a measure circuit and a display circuit; the tester uses a single lithium battery for supplying power, positive 5V and negative 5V direct voltage are generated for supplying power for a processing circuit of simulation small signal; 6V to 7V is generated by 2mV stepping to realize voltage scanning for providing offset voltage to the APD diode, the bias circuit has a function for rapidly responding over-current protection, a 10 bit one-chip microcomputer of AD is used for measuring current of the APD diode under different bias, the volt-ampere characteristic curve of the APD diode can be drawn, and the calculated APD parameter can be displayed on a TFT-LCD screen, and the photoelectric avalanche diode (APD) automatic parameter tester is portable.

Description

Photoelectricity avalanche diode (APD) Automatic parameter tester

Technical field

The utility model relates to a kind of photoelectricity avalanche diode (APD) testing apparatus, belongs to the surveying instrument technical field.

Background technology

Photoelectricity avalanche diode (APD) is a kind of electrooptical device that photoelectric field extensively adopts, and it has high opto-electronic conversion sensitivity and very short reaction time.But the parameter discrete of photoelectricity avalanche diode (APD) clearly, and batch its parameter difference of product is also bigger together, increased the debugging difficulty that adopts the equipment of APD pipe.How quick and precisely to measure the major parameter of APD and the volt-ampere characteristic of drafting APD pipe important theory and practice significance are arranged.

The important parameter of measuring photoelectricity electricity avalanche diode is faced with Several Key Problems with the opto-electronic conversion curve: 1, different photoelectricity avalanche diodes enter avalanche process required voltage wider range, most of communication with APD pipe bias voltage from about the 30V to 80V, and it is very responsive to voltage noise, and how producing the bias voltage that satisfies condition is first problem that faces in the test.2, in a single day photoelectricity electricity avalanche diode enters avalanche condition its electric current under no current-limiting circuit situation and increases sharply and damage, and its time must guarantee in the measurement that only in the microsecond level APD does not damage, and protects voltage to be absolutely necessary fast.3, the major parameter that how to draw the photoelectricity avalanche diode from test process needs the raw data that analysis-by-synthesis is measured.4, demonstrate measurement parameter and curve with form intuitively.5, traditional equipment can't adapt to the requirement of field test with mains-supplied.More than four problems hindered the exploitation of photoelectricity avalanche diode automatically testing parameters instrument, at present domestic do not have patent achievement open, external APD parameter tester uses civil power can't adapt to the field test requirement.According to above analysis, preferably resolve this several problems by studying our the portable APD automatically testing parameters instrument of design.

The utility model content

The purpose of this utility model is a kind of measuring equipment of design, realizes the volt-ampere characteristic that the APD pipe was measured and drawn to APD pipe major parameter, solves that to use parameter in the APD process to regulate improper work undesired and cause the practical problems of device damage.The scheme that we propose preferably resolves above-mentioned main several problems, has has successfully researched and developed APD automatically testing parameters instrument instrument and has used single lithium battery power supply, possesses the field test ability.

To achieve the above object, the utility model adopts following technical scheme: photoelectricity avalanche diode (APD) Automatic parameter tester comprises power circuit, control circuit, metering circuit and display circuit; Described power circuit is by single 3V to 5V powered battery, is converted into positive 5V and negative 5V DC voltage to the power supply of simulation small-signal treatment circuit by the low noise switching power circuit; By under the 1.2V reference voltage, produced accurate control voltage by 12 D/A, the control bias generating circuit, precision with 2mV boosts to 6V to 75V with described single 3V to 5V cell voltage, for APD provides suitable bias voltage, realize that overcurrent protection function that voltage scanning, this bias circuit have a quick response makes the APD pipe avoid damaging when unusual; Described metering circuit use integrated 10 AD chip microcontroller the electric current of APD pipe under different bias voltages measured; Described display circuit will be drawn the volt-ampere characteristic of APD pipe according to measured value, and the APD parameter that calculates is presented on the TFT-LCD screen.Described display circuit uses the TFT-LCD of bus interface, realizes that abundant curve and parameter show.

Described power circuit, bias generating circuit and high-speed and low-noise amplifying circuit are an independently analog signal processing circuit plate, input end connects the lithium battery of a 3.6V, output terminal have output-5V ,+5V ,+12V～+ the 80V adjustable dc voltage adjusts input lead with five output leads measuring output and ground and voltage.Control circuit board and display circuit are an independently circuit board, comprise the MCU circuit with the interface of power supply circuit board, 12 D/A converter circuit that are used for adjusting the APD bias voltage, key circuit, integrated 10 A/D on it; Display circuit supports that by one the 320*240 LCD of MPU bus interface is that core constitutes, and it is realized with the mode that is connected with 16 buses of MCU, has accelerated drafting APD volt-ampere characteristic and speed of displaying.

Description of drawings

Fig. 1 is general structure block diagram of the present utility model;

Fig. 2 is power circuit of the present utility model and low noise feeble signal amplifying circuit;

Fig. 3 is the utility model APD bias-voltage generating circuit;

Fig. 4 is control survey of the present utility model and display circuit schematic diagram.

Embodiment

Below in conjunction with accompanying drawing embodiment of the present utility model is described in further detail:

Among Fig. 1, (1) power circuit is realized by the also stable output+5V of single lithium battery input 3.6V boost in voltage, the stable-5V power supply of voltage reversal output, and+5V one tunnel supplies the control display part for another road of dual power supply amplifier through LDO output 3.3V.For prolonging battery service time, require quiescent current little, the conversion efficiency height.(2) the small-signal amplifier section is responsible for amplifying the faint light electric current that APD produces, and photocurrent requires amplifying circuit to have very low electric noise density at microampere order, and very high response speed is arranged simultaneously.(3) the required APD bias voltage that adds should be able to accurately be regulated because different APD pipes changes in 20 to 80V scopes, simultaneously perfect defencive function should be arranged.(4) control survey and display circuit are that the TFT LCD of 320*240 constitutes by the microprocessor of integrated 10 A/D and 12 D/A and resolution.

Among Fig. 2, constitute booster circuit by U101, R100 arranges output current current limliting thresholding, and R101, R102 arrange output voltage, and the design is output as 5V.U101 is that core constitutes the voltage reversal circuit, and output voltage is-5V.U102 is that core constitutes the feeble signal amplifying circuit, uses low noise to stride the resistance amplifier at a high speed and realizes.The microampere order photocurrent is converted to the volt step voltage supplies with metering circuit.

Among Fig. 3, U103 is that core constitutes the APD bias circuit.The control voltage of 6 pin of output voltage and U103 is linear when the control voltage of 6 pin is lower than 1.2V, realized the accurate control of output voltage, R112 and R113 arrange the maximal value of output voltage, and this programme is made as 75V, and output voltage can be adjustable in 6V to 75V linearity.10 pin of U103 are with the mirror-image monitoring electric current of 1:1 output APD.9 pin resistance R 106 arrange the transient protective electric current of APD pipe.Guarantee that in the microsecond level APD pipe is not damaged actuation time.

Among Fig. 4, U200 is for measuring the voltage-stabilizing device of control and display part, stable output 3.3V.U201 is the single-chip microcomputer of integrated 10 A/D, parallel port P00～P07 of U201 and P20～P27 connect 16 bit data ends of TFT display module, triode Q200 connects the backlight control end of TFT_LCD, realizes that software control backlight is to reach energy-conservation and to prolong battery service time.U201 is 12 D/A converters, and the bias voltage of the Control of Voltage APD pipe of its output changes.U202 arranges the reference voltage of A/D conversion, uses the accurate reference voltage integrated circuit of 1.25V.During test, single-chip microcomputer is low to high control voltage by D/A converter output, is measured the electric current of APD simultaneously indirectly by built-in 10 D/A.Note parameters such as the avalanche voltage of APD pipe and leakage current, drawn out the volt-ampere characteristic of APD pipe by electric current corresponding under each voltage for designer's design reference.

The avalanche diode of the utility model patent (APD) Automatic parameter tester has the function of measuring APD pipe parameter and drawing corresponding volt-ampere characteristic, strong to the adaptability of environment by the power dependence of unmatchful mains-supplied of monocell, it is intuitively convenient to be shown by TFT_LCD, has solved the difficulty of APD pipe parameter testing.

Claims

1. photoelectricity avalanche diode (APD) Automatic parameter tester is characterized in that: comprise power circuit, control circuit, metering circuit and display circuit; Described power circuit is by single 3V to 5V powered battery, is converted into positive 5V and negative 5V DC voltage to the power supply of simulation small-signal treatment circuit by the low noise switching power circuit; By under the 1.2V reference voltage, produced accurate control voltage by 12 D/A, the control bias generating circuit, precision with 2mV boosts to 6V to 75V with described single 3V to 5V cell voltage, for APD provides suitable bias voltage, realize that overcurrent protection function that voltage scanning, this bias circuit have a quick response makes the APD pipe avoid damaging when unusual; Described metering circuit use integrated 10 AD chip microcontroller the electric current of APD pipe under different bias voltages measured; Described display circuit will be drawn the volt-ampere characteristic of APD pipe according to measured value, and the APD parameter that calculates is presented on the TFT-LCD screen.

2. photoelectricity avalanche diode according to claim 1 (APD) Automatic parameter tester is characterized in that, described display circuit uses the TFT-LCD of bus interface, realizes that abundant curve and parameter show.