A kind of Full-automatic diode volt-ampere characteristic test device

Description
A kind of Full-automatic diode volt-ampere characteristic test device
Technical field
The invention belongs to electrotechnical, electronic measuring apparatus field, it is related to a kind of Full-automatic diode volt-ampere characteristic test device.
Background technology
It is often necessary to understand rapidly forward and reverse C-V characteristic of some diodes, correctly to connect in engineering practice Enter circuit and play corresponding function.Basic measurement thinking is, in the case of being powered using normal signal source, to access circuit The pressure drop at diode two ends and carry out accordingly progressively measuring and being depicted as curve by flowing through the electric current of diode, thus can To recognize its C-V characteristic.Although in addition, some the Testing Instrument for Volt-ampere Characteristic devices seen at present can complete diode volt-ampere spy The basic test of property, but there is also some problems, such as: for the positive and negative characteristic of measuring diode simultaneously, in an experiment cannot be fast Speed carries out changing road and connects, many complex circuit cannot do not increase hardware cost and time-consuming in the case of realize many Individual measurement.Additionally, traditional circuit connecting can cause various errors, the result of test is inevitable also unreliable.Although adopting The scheme cost changing the multiple measurement in road with commonly taking out stitches is relatively low, but when controller is multiple for complex changeable circuit increase During additional function, its motility is not it is impossible to reach simply workable effect, and increases the complicated journey of hardware on the contrary Degree.Generally, the facilitation degree of these measuring methods is not high, poor accuracy.
From the trend of test instrunment development, total trend is automatization, intelligent.A kind of device is therefore provided, can With the data acquisition higher using quality and numerical procedure, routing function is realized with more easily method, become in the time of consideration Select on the premise of this requirement to be suitable for the hardware unit of this design.It can be considered to select with based on single-chip microcomputer as core Module is designing this Testing Instrument for Volt-ampere Characteristic.More clear and definite accurately stepped voltage can not only be provided directly to circuit, also simultaneously Can the voltage at Real-time Collection diode and resistance two ends its result is shown and stores, make the people can be rapidly and accurately Understand the C-V characteristic of element, be just particularly important.
Content of the invention
It is an object of the invention to proposing a kind of Full-automatic diode volt-ampere characteristic test device, it is avoided that manual operation institute Cause error impact, and make simple to operate, convenient.In addition, the invention enables experiment can be carried out in controlled scope, data Collection, host computer show and more intuitively change, integrated after with the popularization of electronic device and the progressively cheaper of price, the present invention More met development trend from now on.
In order to realize the purpose of the present invention, technical solution is to provide a kind of Full-automatic diode volt-ampere characteristic test dress Put, comprising:
Stepping power supply: for powering to test circuit, using avr development board, including atmega16 single-chip microcomputer, usb device Pdiusbd12 and dac conversion chip tlv5617, wherein pdiusbd12 realize a usb interface using modular method, permit Permitted select in numerous available microcontrollers most suitable as system controller it is allowed to using existing architecture and make Firmware investment is minimized, and tlv5617 is main dac conversion chip, is converted to corresponding digital quantity using it Corresponding stepping supply voltage, atmega16 by controller control tlv5617 corresponding digital quantity is carried out being converted to right The stepping supply voltage answered, to realize power supply stepping；
Control switching circuit module: to carry out the switching of circuit using the relay of two 6v, so as not to disconnect Circuit can directly carry out the test of forward and reverse C-V characteristic of diode, and this two relays use the unidirectional current of 6v voltage-controlled System, one diode of reversal connection on the normally closed circuit of relay, normally opened track circuit accesses the resistance of a 100k ω wherein；Separately The normally closed resistance being terminated with 500 ω of one relay, normally opened track circuit is directly accessed circuit；
Data acquisition module: using based on the avr single-chip data acquisition system under matlab environment, using atmega16 As microcontroller, signals collecting result is sent directly into work space the gui using matlab of matlab by usb interface Interface display, is easy to analysis and the process of signal；
Host computer: for manipulating whole device and receiving and show test result in real time；
DC current regulator power supply: power for whole system.
Described stepping power supply is to realize Digital DC Voltage-stabilized Power Source function, voltage step on the basis of d/a modular converter Enter for 0.1v, stepping time is 1s, the scope of output voltage is 0.0-4.0v；
Described usb device pdiusbd12, mainly completes the data transfer work(between host computer data collecting device Can, its maximal rate can reach 12mb/s, be carried out the transmission of control data by host computer, send analog digital conversion, digital-to-analogue when upper When conversion, i/o input and output or the order disposably completing digital-to-analogue conversion and analog digital conversion, what equipment carried out correlation should It is operated with program, and result is sent to preservation in the relief area of pdiusbd12, when host computer sends the life reading data After order request, pdiusbd12 is transferred to the data in buffer area in matlab application software in the form of frames, in order to data Process.
Having the beneficial effect that with respect to prior art
1) stepping Power Management Design: using avr development board, based on atmega16 as core, pdiusbd12, tlv5617 etc. Method based on important chip carries out design and the realization of stepping power supply.
2) the forward and reverse switching of diode: design circuit makes diode carry out forward and reverse switching rapidly using relay, this Sample can achieve that Testing Instrument for Volt-ampere Characteristic is integrated.Relay and combining of stepping power supply make original measurement circuit more intelligent, Gradually disengage the loaded down with trivial details of Non-follow control.
3) voltage of diode does not need to convert, and the electric current of diode needs with the voltage at resistance two ends divided by resistance Obtain.
4) collection of data: using the avr single-chip data acquisition system based on matlab.Using avr series Atmega16, as microcontroller, can improve system running speed.Its internal 10 precision a/d with 8 passage independences simultaneously Interface, works in noise reduction sound pattern, enhances capacity of resisting disturbance and reduces cost.
5) display of signal and storage: the work space that signals collecting result is sent directly into matlab by usb interface is simultaneously Gui interface display using matlab.When pdiusbd12 receives the read data request that host computer sends, just data is sent out Deliver to pc generator terminal.
Brief description
Fig. 1 is using the volt-ampere of characteristic diode curve of traditional voltammetry manual test；
The volt-ampere of characteristic diode curve that Fig. 2 is tested with Full-automatic diode volt-ampere characteristic test device；
Fig. 3 tradition voltammetry manual test result and the ratio of Full-automatic diode volt-ampere characteristic test device test result Relatively；
Fig. 4 is capture card circuit diagram of the present invention；
Fig. 5 is circuit diagram of the present invention.
Specific embodiment
Below in conjunction with the accompanying drawings the present invention is described in further details:
As shown in Figure 4,5: a kind of Full-automatic diode volt-ampere characteristic test device, comprising:
Stepping power supply: for powering to test circuit, using avr development board, including atmega16 single-chip microcomputer, usb device Pdiusbd12 and dac conversion chip tlv5617, wherein pdiusbd12 realize a usb interface using modular method, permit Permitted select in numerous available microcontrollers most suitable as system controller it is allowed to using existing architecture and make Firmware investment is minimized, and tlv5617 is main dac conversion chip, is converted to corresponding digital quantity using it Corresponding stepping supply voltage, atmega16 by controller control tlv5617 corresponding digital quantity is carried out being converted to right The stepping supply voltage answered, to realize power supply stepping；
Control switching circuit module: to carry out the switching of circuit using the relay of two 6v, so as not to disconnect Circuit can directly carry out the test of forward and reverse C-V characteristic of diode, and this two relays use the unidirectional current of 6v voltage-controlled System, one diode of reversal connection on the normally closed circuit of relay, normally opened track circuit accesses the resistance of a 100k ω wherein；Separately The normally closed resistance being terminated with 500 ω of one relay, normally opened track circuit is directly accessed circuit；
Data acquisition module: using based on the avr single-chip data acquisition system under matlab environment, using atmega16 As microcontroller, signals collecting result is sent directly into work space the gui using matlab of matlab by usb interface Interface display, is easy to analysis and the process of signal；
Host computer: for manipulating whole device and receiving and show test result in real time；
DC current regulator power supply: power for whole system.
Described stepping power supply is to realize Digital DC Voltage-stabilized Power Source function, voltage step on the basis of d/a modular converter Enter for 0.1v, stepping time is 1s, the scope of output voltage is 0.0-4.0v；
Described usb device pdiusbd12, mainly completes the data transfer work(between host computer data collecting device Can, its maximal rate can reach 12mb/s, be carried out the transmission of control data by host computer, send analog digital conversion, digital-to-analogue when upper When conversion, i/o input and output or the order disposably completing digital-to-analogue conversion and analog digital conversion, what equipment carried out correlation should It is operated with program, and result is sent to preservation in the relief area of pdiusbd12, when host computer sends the life reading data After order request, pdiusbd12 is transferred to the data in buffer area in matlab application software in the form of frames, in order to data Process.
The mechanism of the present invention and technical characterstic:
Powered using the stepping power supply that controlled pressure value is incremented by, and circuit to be realized switch in time, data acquisition and knot Fruit display is it is therefore desirable to design a test system that intelligence is convenient, cost performance is high, simple to operate.This system is based on atmea16 For the control module of core, additionally need the design carrying out power supply by modular converter, to reach using dynamic power supplies to circuit The effect of power supply, also needs to carry out when necessary fast circuit switching, the diode in afterwards different electrical power being powered and resistance Voltage is acquired and carries out analog digital conversion, after showing, fits to VA characteristic curve after data is processed.This survey Die trial block mainly the mould such as shows by stepping power supply output module, relay switching circuit module, data acquisition module, collection result Block is constituted.This scheme is with single-chip microcomputer as core, and major control core is exactly the design to stepped voltage, by the step for just Can completely be distinguished with traditional experiment, pass through other modules afterwards and control data to process operation by every, it is to avoid In experiment before, the error impact caused by manual operation, greatly reduces some lengthy and jumbled operations.Furthermore with relatively Efficiently conceptual design makes experiment can carry out in controlled scope, and data acquisition, host computer show more intuitively to be changed.
Using avr development board, based on atmega16 as core, pdiusbd12, tlc27l4c, mcp1541, tlv5617 Carry out design and the realization of stepping power supply etc. the method based on important chip.Atmega16 among these is based on enhanced 8 cmos microcontrollers of the low-power consumption of avr risc structure, due to its advanced instruction set and single clock cycle instruction execution Time, the data throughput of atmega16 is up to 1mips/mhz, such that it is able to mitigation systems between power consumption and processing speed Contradiction.Therefore select this chip as the core of power module design.Pdiusbd12 is the usb device that a performance optimizes, should Device realizes a usb interface it is allowed to select most suitable work in numerous available microcontrollers using modular method For system controller it is allowed to using existing architecture and make firmware investment be minimized.The dac that tlv5617 is main turns Change chip, corresponding digital quantity can be carried out being converted to corresponding stepping supply voltage using it.
When carrying out C-V characteristic test, in order to no longer manual teardown wire is to reach the effect that diode reverse accesses circuit Really, directly design circuit makes diode reversely be switched rapidly using relay, so can realize C-V characteristic test Instrument is integrated, can lay a good foundation for later large-scale use.So, the use of relay and stepping power supply will Jointly will be more intelligent for original measurement circuit, gradually disengage the tedious steps of Non-follow control.
Because the reverse current very little of diode is it is impossible to accurate measure.The present invention is in diode reverse characteristic test circuit The resistance of one 100k ω of middle addition, the voltage at small reverse current resistance two ends is shown.Processing data when Wait, the voltage of diode does not need to convert, the electric current of diode needs to be obtained divided by resistance with the voltage at resistance two ends.
Data acquisition is using based on the avr single-chip data acquisition system under matlab environment.Monolithic using avr series Atmega16 in machine, as microcontroller, can improve system running speed.Its internal 10 essence with 8 passage independences simultaneously Degree a/d interface, works in noise reduction sound pattern, enhances capacity of resisting disturbance and reduce cost.Signals collecting result passes through usb Interface is sent directly into work space the gui interface display using matlab of matlab, is easy to analysis and the process of signal.
Carrying out its workflow during data acquisition is: measured signal carries out after 1:1 amplification through amplifier, defeated from analogue signal Enter passage input, deliver to the adc module of atmega16, adc module is embedded in inside avr single-chip microcomputer, programming realization can be passed through Adc changes；After EOC, result is sent in the data buffer area of pdiusbd12；On pdiusbd12 receives During the read data request that position machine sends, just transmit data to pc generator terminal；And dac part ought receive machine and send When dac convert requests order and change data, atmega16 will start, and control da chip tlv5617, proceed by dac and turn Change.Wherein in system, adc circuit contains 4 tunnel inputs, and dac circuit contains 2 tunnel outputs, and the front two-way input gain of adc can be by anti- Resistor value is adjusting.
Usb interface circuit mainly completes the data-transformation facility between host computer data collecting device.Its maximum Speed can reach 12mb/s, and the transmission power to make decision of data to be controlled by host computer completely.This secondary design uses philip public The usb chip pdiusbd12 of department.Send analog digital conversion, digital-to-analogue conversion, i/o input and output or disposably complete number when upper During the order of mould conversion and analog digital conversion, the application program that equipment carries out correlation is operated, and result is sent to Preserve in the relief area of pdiusbd12.After host computer sends the command request reading data, pdiusbd12 will be caching Data in area is transferred in matlab application software in the form of frames, in order to data processing.
Host computer matlab graphical interfaces and Interface design: graphic user interface is by window, cursor, button, menu, word One user interface of composition is described etc..User is selected, is activated these figures pair by certain method (as mouse or keyboard) As making computer produce certain action or change, such as realizing calculating, draw etc..Virtual oscilloscope utilizes the figure of matlab The data of user interface display collection.So, both can make background acquisition using the fireballing feature of vc, matlab can be utilized again Power, this has great significance for the researcher making data analysiss.This virtual oscilloscope interface achieves The functions such as historgraphic data recording, lead-lag triggering, measurement range selection.
The matlab and required data recording is aobvious on virtual oscilloscope can be connected rapidly based on this block collection plate Show true measurement, so directly increased the function of test result plot and display in the design.The powerful work(of matlab Can be it is known that but its hardware of directly supporting be little and extremely expensive, almost not the having of usb interface.(the exploitation of this block collection plate Plate) aim at matlab optimization design, can directly support that simulink carries out Hardware-in-the-loop.
Employ the data acquisition board based on atmega16 and connect the display that host computer carries out experimental result, specific display Result and side circuit analysis substantially conform to, and data is true and reliable.
Test process
1) first, using the positive C-V characteristic of traditional voltammetry manual test diode, circuit selects electric current off-balancesheet Connection, the voltage and current data of manually recorded diode.
2) with the reverse V-A characteristic using traditional voltammetry manual test diode, circuit selects ammeter inner connection Method, the voltage and current data of manually recorded diode.
3) with the C-V characteristic of Full-automatic diode volt-ampere characteristic test device test diode proposed by the present invention, utilize The forward and reverse switching of diode realized by relay, provides, using stepping power supply, the voltage that stepped voltage is 0.1v, is adopted using data Collection modules acquiring data, automatic data display is simultaneously saved in host computer.
4) data input obtaining conventional test methodologies, in software, draws the VA characteristic curve of diode.
5) by the data copy of Full-automatic diode volt-ampere characteristic test device acquisition in software, the voltage of diode is not Need to convert, the electric current of diode needs to be obtained divided by resistance with the voltage at resistance two ends, then draws two using software The VA characteristic curve of pole pipe.
Test result
According to above-mentioned test condition, initially with the C-V characteristic of traditional voltammetry measuring diode.Using origin Software data processing, obtains the VA characteristic curve of diode, as shown in Figure 1.About 0.7 volt of forward conduction voltage；When reversely, directly Reach 15 volts to voltage, diode is constantly in cut-off state.
C-V characteristic followed by Full-automatic diode volt-ampere characteristic test device test diode of the present invention.Profit Use origin software data processing, obtain the VA characteristic curve of diode, as shown in Figure 2.
For comparing the difference of two kinds of test results, using origin software, by traditional voltammetry manual test result and entirely Automatically volt-ampere of characteristic diode test device test result is placed on same width in figure, as shown in Figure 3.It can be seen that, the two coincide.
As shown in figure 4, the operation principle of the present invention is: (diode forward characteristic test: host computer issues order to stepping Power supply, stepping power supply starts the voltage scanning of 0-4v, sweep speed 0.1v/s, and now relay 1 and relay 2 all do not power up Pressure, now, voltage is added to the resistance of 500 ω and diode two ends to be measured, and diode is in forward bias condition, the electricity between ab Pressure is the voltage at the resistance two ends of 500 ω, and the voltage between bc is the voltage at diode two ends, and this two voltage signals are by data It is sent to single-chip microcomputer after acquisition module collection.
Diode reverse characteristic test: powered to relay 1 and relay 2 using DC current regulator power supply, two are continued Electrical equipment action, circuit automatically switches to reverse characteristic test circuit.Issue order using host computer to stepping power module, stepping Power module starts the voltage scanning of 0-4v, sweep speed 0.1v/s, and now, voltage is added to the resistance of 100k ω and two poles to be measured Pipe two ends, diode is in reverse-bias state, and the voltage between ab is the voltage at diode two ends, and the voltage between bc is The voltage at 100k ω resistance two ends, this two voltage signals are sent to single-chip microcomputer after data collecting module collected.
It is completed, data is processed, the voltage at resistance two ends is worth to electric current divided by resistance, by the electricity of diode Pressure and current data import origin software, obtain the VA characteristic curve of diode to be measured.