CN202177843U - LCD intelligent current source - Google Patents
LCD intelligent current source Download PDFInfo
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- CN202177843U CN202177843U CN2011203243543U CN201120324354U CN202177843U CN 202177843 U CN202177843 U CN 202177843U CN 2011203243543 U CN2011203243543 U CN 2011203243543U CN 201120324354 U CN201120324354 U CN 201120324354U CN 202177843 U CN202177843 U CN 202177843U
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Abstract
The utility model provides an LCD intelligent current source which comprises six parts including a power module, an input module, a V/I conversion module, an A/D conversion module, a microcontroller module, and a display module. The power module is connected with the V/I conversion module and the A/D conversion module for providing normal working voltage for the modules; the input module is connected with the V/I conversion module; the V/I conversion module is connected with the A/D conversion module; the A/D conversion module is connected with the microcontroller module; and the microcontroller module is connected with the display module. The circuit devices required by the current source are simple, easy to operate, and easy to realize; only a slide varistor, a definite value resistor, and a triode are needed to realize constant-current output, and other devices are not needed; and the display mode adopts digital display, so that the reading is convenient and the precision is high. The current source has a broad application prospect.
Description
Technical field
The utility model belongs to the design of intelligent instrument field, is specially a kind of liquid crystal display intelligence current source.
Background technology
In electronic circuit is measured, need use various signal sources, be added to system under test (SUT) to voltage or current signal, use the performance parameter that measuring method is confirmed its each item.DC current source is exactly wherein a kind of.Though traditional current source can be accomplished the output of high precision, wide-range current, owing to adopt Analogic Electronic Circuits, make complex structure, the adjustment difficulty is indicated also not directly perceived.The development of Along with computer technology, characteristics such as intelligence instrument is strong with its function, dirigibility is good have obtained using widely.
The utility model content
The utility model technical matters to be solved provides intelligent electric current source simple in structure, easy to operate and the demonstration electric current.
The technical scheme that the utility model adopted is:
A kind of liquid crystal display intelligence current source, hardware circuit comprises power module, load module, V/I modular converter, A/D modular converter, micro controller module and display module six parts; Power module links to each other with V/I modular converter, A/D modular converter respectively; Normal working voltage is provided for these modules; Load module links to each other with the V/I modular converter; The V/I modular converter links to each other with the A/D modular converter, and the A/D modular converter links to each other with micro controller module, and micro controller module links to each other with display module.
Said load module is made up of a triode and a slide rheostat and a fixed value resistance, and the part of slide rheostat, fixed value resistance are connected with triode.Load module also provides one+12V D.C. regulated power supply, to input circuit normal working voltage is provided.
Said power module is by an AC220V/AC5V transformer, one group of full-bridge diode, voltage stabilizer and filtering device; The device annexation is: transformer links to each other with the full-bridge diode; Diode links to each other with filtering device, and filtering device links to each other with voltage stabilizer, and filtering device is made up of electric capacity.
Said V/I change-over circuit is made up of high precision operating amplifier OP27 and Darlington circuit.High precision operating amplifier links to each other with Darlington circuit, and voltage transitions is become electric current, obtains constant current output, and Darlington circuit is by three transistor Q1, Q2, and Q3 forms.
Said A/D modular converter adopts ADC0832, and ADC0832 is to be digital signal with the input end analog signal conversion, is handled by single-chip microcomputer.It has the 8 bit serial I/O mouths and the double channel A/D conversion of multicircuit switch; Input voltage is between 0～5V during the power supply of 5V power supply; Frequency of operation is 250KH
Z, be 32 μ s switching time.
Said micro controller module is the AT89C51 single-chip microcomputer.
Said display module is the LCD1602 LCDs.LCD1602 shows two row totally 32 characters, and WV is+5V that working current is 2.0mA.
The required circuit devcie of the utility model is simple, and easy operating is realized easily.Only need a slide rheostat, a fixed value resistance and a triode just can realize constant current output, do not need other device, finally the form with numeral shows, convenient reading, and degree of accuracy is high, is with a wide range of applications.
Description of drawings
The structured flowchart in the intelligent electric current of accompanying drawing 1 the utility model source
Accompanying drawing 2 the utility model importation circuit diagrams
Accompanying drawing 3 the utility model V/I change-over circuit figure
Accompanying drawing 4 the utility model system architectures are always schemed
Accompanying drawing 5 the utility model main program flow charts
Embodiment
By Fig. 1, the utility model hardware is formed and is comprised power module 1, load module 2, V/I modular converter 3, A/D modular converter 4, micro controller module 5, display module 6.Power module 1 links to each other with V/I modular converter 3, A/D modular converter 4 respectively, normal working voltage is provided for these modules.Load module 2 links to each other with V/I modular converter 3, is specially: what load module 2 was exported is continuous current, and pairing output voltage is the input end of V/I modular converter 3; V/I modular converter 3 links to each other with A/D modular converter 4, is specially: V/I modular converter 3 resulting output currents and voltage have certain relation, can obtain current value through magnitude of voltage, and magnitude of voltage is as the input of A/D modular converter 4; A/D modular converter 4 links to each other with micro controller module 5, and micro controller module 5 links to each other with display module 6.
Power module is made up of a transformer, one group of full-bridge diode, voltage stabilizer and filtering device resistance and electric capacity.Transformer voltage ratio is 220/15, is the alternating current that the 220V alternating current is reduced to 5V; The 5V alternating current is through one group of full-bridge diode, and the full-bridge diode is made up of four diodes, with AC rectification is+the 5V direct current.The full-bridge diode links to each other with filter capacitor, and filter capacitor links to each other regulated output voltage with three terminal regulator 7805.
The V/I modular converter is by accurate amplifier OP27 and transistor Q1; Q2, the Darlington circuit that Q3 forms constitutes, and the OP27 high precision operating amplifier has extremely low input offset voltage; Extremely low offset voltage temperature is floated, characteristics such as low-down input noise voltage amplitude and long-term stability.OP27 discharges the voltage signal of load module as the input of Darlington circuit; Darlington circuit is made up of three TIP122 transistors, and the TIP122 transistor has higher collector to-boase voltage and collector emitter voltage, and base-emitter voltage is 5V, and collector current is 5A.It is to utilize the negative-feedback circuit of the smooth output characteristics of transistor and the degree of depth to obtain stable constant current output, makes system's carrying load ability strong, and its output area reaches 0～3A.
In the output loop of V/I change-over circuit, introduce a feedback resistance Rf, output current I obtains a feedback voltage V f through feedback resistance, and Vf=V11-V12 is added to two input ends of amplifier through R7, R8.If the voltage of the in-phase end of operational amplifier and end of oppisite phase is V3, V2, Vi is imported by input circuit.Because the input current of ideal operational amplificr approximates zero, and V3=V2, then have
V12(1-R8/(R3+R8))+ViR8/(R3+R8)＝V11R4(R4+R8)
Since V12=V11-Vf, then
V11R3/(R3+R8)+(ViR8-VR3)/(R3+R8)＝V11R4(R4+R7)
If make R3=R4=10K, R7=R8=1K then has
Vf＝ViR8/R3＝Vi/10
Omit the electric current of backfeed loop, I=Vf/Rf=Vi/ (10Rf) is then arranged.
This shows that the demarcation of output current is linear transformation by the output voltage V f and the Rf decision of input circuit.Rf is made by big line footpath constantan wire, its temperature coefficient very little (5 * 10-6/ ℃), and big line footpath can make its temperature effect reduce to minimum.
That the A/D modular converter adopts is ADC0832.Middling speed of ADC0832, high-precision 8 A/D converters, its voltage request is+5V.Realize being A/D conversion needs 32 μ S one time 8.It becomes digital signal to import single-chip microcomputer into the output analog signal conversion of V/I modular converter, by Single-chip Controlling, and output current value.Because its volume is little, compatible strong, cost performance Gao Ershen is welcome by single-chip microcomputer fan and enterprise, and it has had very high popularity rate at present.
That display module adopts is LCDs LCD1602.Every row shows 16 characters, divides two row to show totally 32 characters, WV is+4.5～+ 5.5V, the utility model provides+5V voltage, and corresponding working current is 2.0mA.Control the 4th pin RS data/command selection end (H/L) through mcu programming, the 5th pin R/W read/write selecting side (H/L), the 6th pin E connects enable signal, thereby realizes display effect.
What micro controller module adopted is the AT89C51 single-chip microcomputer, and AT89C51 has 4K byte flash memory able to programme, 8 internal RAM, 32 programmable I/O mouths, two 16 bit timing device/counters and 5 interrupt sources.It is the core of total system, electric current is calculated, shows the judgement execution of output by it.P0 (32～39) mouth meets LCDs LCD1602, shows transmission as output data, and P21, P22, P23 are the control ports of liquid crystal display; P25, P26, P27 meet ADC0832, as the I/O data transmission; P14, P15 meet the data-carrier store 24C02 that capacity is 2K, can realize the storage of power down data.
Intelligence current source current procedure for displaying is following:
Give WV of load module, input circuit is exported the electric current of an approximately constant through triode.Realized the basic function of current source.The output voltage of load module is as the input of V/I conversion.Through Darlington circuit, obtain the linear relationship of an input voltage and output current.The input of the output signal of V/I change-over circuit as the A/D conversion, the A/D conversion converts analog quantity to digital quantity and imports single-chip microcomputer into then, and single-chip microcomputer is handled data and shown.
The maximum characteristics of native system adopt triode to come the design current source exactly, and institute's device of selecting for use is few, easy to be realized.And, carry out liquid crystal output through Single-chip Controlling, and realized intellectuality, substituted traditional total indicator reading.The software main program flow process is seen Fig. 5.
Program at first is to each chip initiation, gives that each module powers on, the parameter assignment.Need to detect serial ports after the initialization, detect single-chip microcomputer and whether send signal, in time make corresponding action.Sent signal if detect single-chip microcomputer, just carried out Y, otherwise carried out N, returned and continue to detect.After these are accomplished, will change, convert digital signal to the analog input of A/D conversion.Digital signal shows electric current at last through Single-chip Controlling on liquid crystal.
In main program flow chart, mainly accomplished three functions: 1, the initialization of system comprises the initialization of each peripheral interface chip; 2, serial ports detects and adopts interrupt mode to detect the control signal whether the serial ports address has microcomputer to send, and realizes the output of system controlled by computer electric current; 3, realize A/D conversion and D/A conversion.
Claims (7)
1. a liquid crystal display intelligence current source is characterized by this current source and comprises power module, load module, V/I modular converter, A/D modular converter, micro controller module and display module six parts; Power module links to each other with V/I modular converter, A/D modular converter respectively; Normal working voltage is provided for these modules; Load module links to each other with the V/I modular converter; The V/I modular converter links to each other with the A/D modular converter, and the A/D modular converter links to each other with micro controller module, and micro controller module links to each other with display module.
2. a kind of liquid crystal display intelligence current source as claimed in claim 1 is characterized by said load module and is made up of a triode and a slide rheostat and a fixed value resistance, and the part of slide rheostat, fixed value resistance are connected with triode.Load module also provides one+12V D.C. regulated power supply, to input circuit WV is provided.
3. a kind of liquid crystal display intelligence current source as claimed in claim 1; It is characterized by said power module by an AC220V/AC5V transformer, one group of full-bridge diode, voltage stabilizer and filtering device; The device annexation is: transformer links to each other with the full-bridge diode; Diode links to each other with filtering device, and filtering device links to each other with voltage stabilizer, and filtering device is made up of electric capacity.
4. a kind of liquid crystal display intelligence current source as claimed in claim 1 is characterized by said V/I change-over circuit and is made up of high precision operating amplifier OP27 and Darlington circuit.High precision operating amplifier links to each other with Darlington circuit, and voltage transitions is become electric current, obtains constant current output, and Darlington circuit is by three transistor Q1, Q2, and Q3 forms.
5. a kind of liquid crystal display intelligence current source as claimed in claim 1 is characterized by said A/D modular converter and adopts ADC0832, and ADC0832 is to be digital signal with the input end analog signal conversion, is handled by single-chip microcomputer.It has the 8 bit serial I/O mouths and the double channel A/D conversion of multicircuit switch; Input voltage is between 0～5V during the power supply of 5V power supply; Frequency of operation is 250KH
Z, be 32 μ s switching time.
6. a kind of liquid crystal display intelligence current source as claimed in claim 1, it is characterized by said micro controller module is the AT89C51 single-chip microcomputer.
7. a kind of liquid crystal display intelligence current source as claimed in claim 1; It is characterized by said display module is the LCD1602 LCDs; Every row shows 16 characters, divides two row to show totally 32 characters, WV is+4.5～+ 5.5V; The utility model provides+5V voltage, and corresponding working current is 2.0mA.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203243543U CN202177843U (en) | 2011-08-31 | 2011-08-31 | LCD intelligent current source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203243543U CN202177843U (en) | 2011-08-31 | 2011-08-31 | LCD intelligent current source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202177843U true CN202177843U (en) | 2012-03-28 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011203243543U Expired - Fee Related CN202177843U (en) | 2011-08-31 | 2011-08-31 | LCD intelligent current source |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202177843U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102622029A (en) * | 2012-04-27 | 2012-08-01 | 航天科技控股集团股份有限公司 | Single-power-supply non-isolated adjustable constant-current source |
| WO2024020924A1 (en) | 2022-07-28 | 2024-02-01 | The Procter & Gamble Company | Absorbent article with fastening component for disposal |
-
2011
- 2011-08-31 CN CN2011203243543U patent/CN202177843U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102622029A (en) * | 2012-04-27 | 2012-08-01 | 航天科技控股集团股份有限公司 | Single-power-supply non-isolated adjustable constant-current source |
| WO2024020924A1 (en) | 2022-07-28 | 2024-02-01 | The Procter & Gamble Company | Absorbent article with fastening component for disposal |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120328 Termination date: 20130831 |