CN101308191A

CN101308191A - Diode electrical characteristics test system

Info

Publication number: CN101308191A
Application number: CN 200810062659
Authority: CN
Inventors: 周道明; 郑国军
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-07-03
Filing date: 2008-07-03
Publication date: 2008-11-19
Anticipated expiration: 2028-07-03
Also published as: CN101308191B

Abstract

The invention relates to a diode electrical property test system, which comprises: a constant current driving module for producing stable current for the tested diode; a D/A switching circuit for controlling the analog quantity of the given constant current driving module; a capacitor for providing a power supply of transient heavy current for the constant current driving module; a capacitor charging management module for managing the charging of the capacitor and detecting the state of the capacitor; an A/D conversion adaptation circuit for sampling the voltage of both ends of the tested diode and converting the voltage into the digital quantity which is transmitted to a microprocessor; the microprocessor; an I/O module; a keyboard circuit; a communication module; a display module; and a power supply circuit. The diode electrical property test system of the invention has advantages of low energy consumption, large output amplitude, free setup of testing parameters, high testing accuracy and fast testing speed.

Description

A kind of diode electrical characteristics test system

(1) technical field

The present invention relates to a kind of diode electrical characteristics test system.

(2) background technology

Diode electrical characteristics test system is used for the analysis, control of diode product quality and with the evaluation of product index: parameter is with transient thermal resistance Δ VF, oppositely transient thermal resistance Δ VFR, disruptive voltage VBR1-VBR4, forward voltage drop VFm and VF, leakage current Ir, dynamic resistance Rdz.Mainly there is following shortcoming in existing diode electrical characteristics test system:

1. degree of accuracy is difficult to characterize product orientation: the heating current 100A as transient thermal resistance Δ VF is an example, general user's reading system difference is all about 6-10mV, the degree of accuracy index is at ± 2mV, in other words absolute difference in the 4mV production line uses because internal components temperature rise and error is bigger, even the error of appearance ± 3-4mV, it is poor almost to take system, adds that repetition rate is not high, be difficult to stepping, biased suspicion still arranged as good discriminating with difference.Reason is that resolution is low, with 12 A/D, has only 4096 altogether, can not differentiate 0.1mV for the range of 5V.

2. added losses are too big: another reason that influences degree of accuracy is that the additional energy consumption of generation steady current is too big, existing the constant current that the analog-driven mode obtains the 200A of permissible error is set with it, continue 24 joules of 100mS outputs, the additional power consumption minimum of institute must be more than 3.3KW, the temperature rise of equipment is very high, device must have big temperature rise out of control to cause the variation of measured value, is inevitable.Power attenuation more than 93% is on driver module, and efficient but need change less than 7%.This has just produced another drawback, promptly is the failure rate height, the time and keep in repair, change power component, the stability of product is difficult to satisfy needs of production.

3. running institute energy requirement is big and prolong setup time, causes test period to prolong: existing product test period is generally in 3-5 second.To product investigation and analysis judgement, transient thermal resistance is the key index that guarantees product quality, is the sign of numerous parameters according to the expert.Therefore all having carried out ten thousand of " every pipe must be surveyed " daily outputs in the industry is not big factory, and this series products output of current China is very big, and test job is heavy unusually.The cry that the user constantly sends quick test and tests automatically still can not satisfy the demands on the existing market.

(3) summary of the invention

Technical matters to be solved by this invention is to provide that a kind of energy loss is low, output spoke degree is big, test parameter, test accuracy height, the fast diode electrical characteristics test system of test speed can freely be set.

Described diode electrical characteristics test system comprises:

One constant-current driven module is used for measured diode is produced stable electric current;

One D/A change-over circuit is connected with constant-current driven module, is used for the control analog quantity of given constant-current driven module;

One capacitor is connected with constant-current driven module, is used to constant-current driven module that the power supply of instantaneous large-current is provided;

One electric capacity charge management module is connected with capacitor, is used to manage the charging of capacitor and the state that detects capacitor;

One A/D conversion adaptation circuit, the voltage at the measured diode two ends that are used to sample changes into digital quantity and passes to microprocessor;

One microprocessor is connected with above-mentioned constant-current driven module, D/A change-over circuit, electric capacity charge management module, A/D conversion adaptation circuit, is used to provide various control signals, and the data of A/D conversion adaptation circuit sampling are carried out analyzing and processing;

One I/O module is connected with microprocessor, is used for the control to outside input and output;

One keyboard circuit is connected with microprocessor, is used to import operations;

One communication module is connected with microprocessor, is used for communicating with the external world;

One display module is connected with microprocessor, is used to show the result of microprocessor processes;

One power circuit is used to above-mentioned each module that required direct current is provided.

Further, described communication module is the RS422 communication module.

Further, described display module is a LCD.

Beneficial effect of the present invention is:

(1) adopt the numeric type constant current drive mode, the pressure drop of module itself is dwindled, and the required power consumption on the module has also promptly been saved 99% electric energy loss less than 1.0% of existing product pattern, and economic and social benefit is arranged;

(2) output amplitude is big, can export 200mS during 640A of the present invention, and the VI*t maximal value is 180.0 (joule) even bigger;

(3) the degree of accuracy height of Ce Lianging: relatively existing pattern, this programme all has big breakthrough at highest resolution and pinpoint accuracy: bring up to 0.01V in the 0-100V scope from the resolution of 0.1V; Pinpoint accuracy from ± 2.5% bring up to ± 1%; Bring up to 0.1mV at 0-2.5V range delta VF or Δ VFR value from the resolution of 1.0mV; Pinpoint accuracy from ± bring up to more than the 2.0mV ± 0.3mV;

(4) test speed is fast: its test speed is brought up to 0.5 second/time item from 5 seconds/time items of existing product.Simultaneous adaptation and industrial computer (as PLC), host computer (PC) connect the machine operation, have long, the reliable and stable characteristics of communication distance, have realized High-Speed Automatic test.

(4) description of drawings

Fig. 1 is the structured flowchart of the described diode electrical characteristics test system of embodiment.

Fig. 2 is the circuit diagram of the described constant-current driven module of embodiment.

Fig. 3 is the circuit diagram of the described electric capacity charge management module of embodiment.

Fig. 4 is the circuit diagram of the described I/O module of embodiment.

Fig. 5 is the circuit diagram of the described communication module of embodiment.

Fig. 6 is the circuit diagram of the described power circuit of embodiment.

(5) embodiment

The invention will be further described below in conjunction with embodiment, but protection scope of the present invention is not limited to this.

With reference to Fig. 1, a kind of diode electrical characteristics test system comprises:

One constant-current driven module 50 is used for measured diode is produced stable electric current;

One D/A change-over circuit 40 is connected with constant-current driven module, is used for the control analog quantity of given constant-current driven module;

One capacitor 20 is connected with constant-current driven module, is used to constant-current driven module that the power supply of instantaneous large-current is provided;

One electric capacity charge management module 30 is connected with capacitor, is used to manage the charging of capacitor and the state that detects capacitor;

One A/D conversion adaptation circuit 60, the voltage at the measured diode two ends that are used to sample changes into digital quantity and passes to microprocessor;

One microprocessor 70 is connected 60 with above-mentioned constant-current driven module 50, D/A change-over circuit 40, electric capacity charge management module 30, A/D conversion adaptation circuit, is used to provide various control signals, and the data of A/D conversion adaptation circuit sampling are carried out analyzing and processing;

One I/O module 80 is connected with microprocessor 70, is used for the control to outside input and output;

One keyboard circuit 110 is connected with microprocessor 70, is used to import operations;

One communication module 100 is connected with microprocessor 70, is used for communicating with the external world;

One display module 90 is connected with microprocessor 70, is used to show the result of microprocessor processes;

One power circuit 10 is used to above-mentioned each module that required direct current is provided.

Described communication module 100 is the RS422 communication module.

Described display module 90 is a LCD.

System work process is as follows:

After microprocessor 70 control capacitance charge management module 30 charge to given voltage to capacitor 20, export corresponding analog quantity according to setting value control D/A change-over circuit again, after starting test by keyboard circuit 110 or outside input by I/O module 80, microprocessor 70 control constant-current driven modules 50 produce the electric current of setting and pass through measured diode; 60 pairs of diode both end voltage of microprocessor 70 control A/D conversion adaptation circuit are sampled simultaneously, and the data of last 70 pairs of A/D conversion adaptation circuit of microprocessor, 60 samplings carry out demonstrating every test data by LCD 90 after the analyzing and processing.

As shown in Figure 2, constant-current driven module 50 is a constant-current source circuit.By the steady current of the analog quantity control output of D/A change-over circuit 40 input, by the output time of microprocessor 70 Control current, and the current value that reads back, thereby obtain the steady current of high precision and high stability by the output that control algolithm is adjusted D/A change-over circuit 40.

As shown in Figure 3, electric capacity charge management module 30 main bodys are a power MOSFET switch tube V1.To capacitor 20 chargings, microprocessor 70 is the voltage and the charging current of monitoring capacitor in real time, with the break-make of control V1 by V1 for VCC.

As shown in Figure 4, I/O module 80 is made up of load module 82 and output module 81.Load module 82 and output module 81 usefulness optocouplers are hedged off from the outer world and do not match and prevent that external interference from entering inside to handle level.821 ports of load module 82 are external input port.811 ports of output module 81 are output port, triode T4, and T5 strengthens the driving force of port.

As shown in Figure 5, RS422 communication module 100 is a RS422 communication chip, is connected with microprocessor 70, is responsible for communicating by letter with extraneous, and wherein port one 001, port one 002, and port one 003, port one 004 connects external communication device.

As shown in Figure 6, power circuit 10 is made up of many groups transformer, and the 220V civil power is organized transformer through each, and wherein one the tunnel forms one group ± 12V power supply with two linear voltage stabilization pieces, and other one the tunnel then is made of the power supply of one group of 12V and one group of 5V respectively two linear voltage stabilization pieces.

Claims

1, a kind of diode electrical characteristics test system is characterized in that comprising:

2, diode electrical characteristics test system according to claim 1 is characterized in that: described communication module is the RS422 communication module.

3, diode electrical characteristics test system according to claim 1 is characterized in that: described display module is a LCD.