CN204314347U - A kind of electronic load - Google Patents
A kind of electronic load Download PDFInfo
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- CN204314347U CN204314347U CN201420738103.3U CN201420738103U CN204314347U CN 204314347 U CN204314347 U CN 204314347U CN 201420738103 U CN201420738103 U CN 201420738103U CN 204314347 U CN204314347 U CN 204314347U
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Abstract
The utility model relates to a kind of electronic load, comprises single-chip microcomputer, also comprises reference voltage generating circuit, power constant current source generation and control circuit, ripple voltage amplification and precise rectification circuit and A/D change-over circuit.The output terminal of reference voltage generating circuit is connected with the reference voltage input of single-chip microcomputer.Power constant current source produce and control circuit output terminal respectively with the input end of single-chip microcomputer, ripple voltage amplifies and the input end of precise rectification circuit is connected.Ripple amplifies and the output terminal of precise rectification circuit is connected with the input end of A/D change-over circuit, and the output terminal of A/D change-over circuit is connected with the input end of single-chip microcomputer.From above technical scheme, the utility model can solve conventional resistive load and cause the problems such as electronic product test result is inaccurate because thermonoise and own temperature rise sharply, and ensures the accuracy of electronic product test result.
Description
Technical field
The utility model relates to electronic product technical field of measurement and test, is specifically related to a kind of electronic load.
Background technology
Load plays an important role in various electronic product test process as a conventional electronic equipment, and the quality of its performance directly affects precision and the accuracy of test result.In order to obtain desirable test result, resistance is accurate, the load of function admirable is necessary.Such as: when carrying out parameter detecting to equipment such as some high-precision regulated power supplies, power device, batteries, the bad meeting of performance of load makes the parameter value out of true recorded, and causes measurement result inaccurate.
At present, slide rheostat and resistance box etc. is usually adopted to be used as load for testing in electronic product technical field of measurement and test.But, because the ohmic load (slide rheostat and resistance box) of routine can cause change in resistance because of its temperature variation.Therefore, when very large by the electric current of conventional ohmic load, the rising suddenly of its thermonoise produced and own temperature usually can affect test result.
Utility model content
The purpose of this utility model is to provide a kind of electronic load, and this electronic load can solve conventional resistive load and cause the problems such as electronic product test result is inaccurate because thermonoise and own temperature rise sharply, and ensures the accuracy of electronic product test result.
For achieving the above object, the utility model have employed following technical scheme:
A kind of electronic load, comprises single-chip microcomputer, also comprises reference voltage generating circuit, power constant current source generation and control circuit, ripple voltage amplification and precise rectification circuit and A/D change-over circuit;
The output terminal of described reference voltage generating circuit is connected with the reference voltage input of single-chip microcomputer;
Described power constant current source produce and control circuit output terminal respectively with the input end of single-chip microcomputer, ripple voltage amplifies and the input end of precise rectification circuit is connected;
Described ripple amplifies and the output terminal of precise rectification circuit is connected with the input end of A/D change-over circuit, and the described output terminal of A/D change-over circuit is connected with the input end of single-chip microcomputer.
Further, described reference voltage generating circuit adopts TL431 voltage source.
Further, described power constant current source produces and control circuit comprises digital to analog converter U2, operational amplifier IC5B, operational amplifier IC5A, transistor N2, transistor N3, resistance R5, resistance R10, resistance R11, resistance R12, resistance R13, resistance R14, resistance R15, resistance R16, resistance R17, resistance R18 and resistance R19;
Described digital to analog converter U2, its the first current output terminal connects the inverting input of operational amplifier IC5B, its the second current output terminal connects the in-phase input end of operational amplifier IC5B, its data latches write gate input end, chip selection signal input end and the equal ground connection of data transfer control signal input end, its feedback signal input terminal connects the output terminal transporting amplifier IC5B;
Described operational amplifier IC5B, its output terminal connects the in-phase end input end of operational amplifier IC5A through resistance R19; Described operational amplifier IC5A, its inverting input is through resistance R18 ground connection, and its output terminal connects the base stage of transistor N3 through resistance R15;
Described transistor N2, its collector connects power supply, and its emitter connects the base stage of transistor N3; Described transistor N3, its emitter is through resistance R17 and resistance R18 ground connection;
Described resistance R5 and R12 is connected in parallel on resistance R17 and R18 two ends after connecting, resistance R13 and R11 is connected in parallel on resistance R17 and R18 two ends after connecting, resistance R14 and R10 is connected in parallel on resistance R17 and R18 two ends after connecting, described resistance R16, the in-phase input end of one termination operational amplifier IC5A, its other end is connected with the junction of resistance R12 and R5, the junction of resistance R13 and R11, the junction of resistance R14 and R10 respectively.
Further, described ripple voltage amplifies and precise rectification circuit comprises ripple voltage amplifying circuit and precise rectification circuit; Described ripple voltage amplifying circuit, the output terminal of its input termination power constant current source generation and control circuit, it exports the input end of termination precise rectification circuit; Described precise rectification circuit, its output terminal connects the input end of single-chip microcomputer;
Described ripple voltage amplifying circuit comprises electric capacity C1, electric capacity C2, electric capacity C11, operational amplifier IC1, operational amplifier IC2, resistance R1, resistance R2, resistance R3, resistance R4, resistance R6, resistance R9; Described electric capacity C1, the output terminal of the generation of one termination power constant current source and control circuit, the in-phase input end of its another termination operational amplifier IC1; Described operational amplifier IC1, its in-phase input end is through resistance R9 ground connection, and its inverting input is through resistance R4 ground connection, and its output terminal connects the in-phase input end of operational amplifier IC2 through electric capacity C2, and its output terminal is also through resistance R3, resistance R4 ground connection; Described operational amplifier IC2, its inverting input is through resistance R2 ground connection, and its output terminal is through resistance R1 and resistance R2 ground connection, and its output terminal also connects the input end of precise rectification circuit through electric capacity C11;
Described precise rectification circuit comprises operational amplifier IC3, operational amplifier IC4, diode D1, diode D2, electric capacity C4, electric capacity C5, resistance R0, resistance R7, resistance R8, resistance R20, resistance R21 and resistance R22; Described operational amplifier IC3, its in-phase input end ground connection, its inverting input connects the output terminal of ripple voltage amplifying circuit through resistance R0, and its output terminal is connected with the negative electrode of diode D1, the anode of diode D2 respectively; Described diode D1, its anode connects the output terminal of ripple voltage amplifying circuit through resistance R8, and its anode also connects the inverting input of operational amplifier IC4 through resistance R7; Described diode D2, its negative electrode connects the output terminal of ripple voltage amplifying circuit through resistance R22, and its negative electrode also connects the in-phase input end of operational amplifier IC4; Described operational amplifier IC4, its inverting input connects its output terminal through resistance R20, and its output terminal is through resistance R21 and electric capacity C4 parallel with one another and electric capacity C5 ground connection.
Further, described A/D change-over circuit adopts ICL7135 converter.
Described single-chip microcomputer adopts AT89C5X series monolithic.
Described digital to analog converter U2 adopts DAC0832 digital to analog converter; Described operational amplifier IC5A and operational amplifier IC5B adopts LM358 operational amplifier.
From above technical scheme, the utility model can overcome thermonoise and own temperature and to rise sharply the impact brought to himself parametric stability in electronic product test process, accurately can test out the load characteristic parameter of measured object, improve the designing quality of product.The utility model have energy-conservation, volume is little, efficiency high.
Accompanying drawing explanation
Fig. 1 is schematic diagram of the present utility model;
Fig. 2 is the circuit theory diagrams of power constant current source generation and control circuit;
Fig. 3 is the circuit theory diagrams of ripple voltage amplifying circuit;
Fig. 4 is the circuit theory diagrams of precise rectification circuit;
Fig. 5 is the circuit theory diagrams of A/D change-over circuit.
Wherein:
1, single-chip microcomputer, 2, reference voltage generating circuit, 3, power constant current source produces and control circuit, 4, ripple voltage amplifies and precise rectification circuit, 5, A/D change-over circuit.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described further:
A kind of electronic load as shown in Figure 1, comprises single-chip microcomputer 1, also comprises reference voltage generating circuit 2, power constant current source generation and control circuit 3, ripple voltage amplification and precise rectification circuit 4 and A/D change-over circuit 5.The output terminal of described reference voltage generating circuit 2 is connected with the reference voltage input of single-chip microcomputer 1.Described power constant current source produce and control circuit 3 output terminal respectively with the input end of single-chip microcomputer 1, ripple voltage amplifies and the input end of precise rectification circuit 4 is connected.Described ripple amplifies and the output terminal of precise rectification circuit 4 is connected with the input end of A/D change-over circuit 5, and the output terminal of described A/D change-over circuit 5 is connected with the input end of single-chip microcomputer 1.Described single-chip microcomputer 1 adopts AT89C5X series monolithic.
Further, described reference voltage generating circuit 2 adopts TL431 voltage source.The left side in Fig. 5 is reference voltage generating circuit.The voltage reference of a 1.0V is provided with TL431, the reference voltage of 2.5V is exported when the adjustment end of TL431 and the direct short circuit of output terminal, this reference voltage is used as the calibration voltage of A/D conversion on the one hand, exports the voltage reference of 1.0V for ICL7135 on the other hand through R and RW.
Further, as shown in Figure 2, described power constant current source produces and control circuit 3 comprises digital to analog converter U2, operational amplifier IC5B, operational amplifier IC5A, transistor N2, transistor N3, resistance R5, resistance R10, resistance R11, resistance R12, resistance R13, resistance R14, resistance R15, resistance R16, resistance R17, resistance R18 and resistance R19.Described digital to analog converter U2 adopts DAC0832 digital to analog converter; Described operational amplifier IC5A and operational amplifier IC5B adopts LM358 operational amplifier.
Described digital to analog converter U2, its the first current output terminal connects the inverting input of operational amplifier IC5B, its the second current output terminal connects the in-phase input end of operational amplifier IC5B, its data latches write gate input end, chip selection signal input end and the equal ground connection of data transfer control signal input end, its feedback signal input terminal connects the output terminal transporting amplifier IC5B.
Described operational amplifier IC5B, its output terminal connects the in-phase end input end of operational amplifier IC5A through resistance R19.Described operational amplifier IC5A, its inverting input is through resistance R18 ground connection, and its output terminal connects the base stage of transistor N3 through resistance R15.
Described transistor N2, its collector connects power supply, and its emitter connects the base stage of transistor N3.Described transistor N3, its emitter is through resistance R17 and resistance R18 ground connection.
Described resistance R5 and R12 is connected in parallel on resistance R17 and R18 two ends after connecting, resistance R13 and R11 is connected in parallel on resistance R17 and R18 two ends after connecting, resistance R14 and R10 is connected in parallel on resistance R17 and R18 two ends after connecting, described resistance R16, the in-phase input end of one termination operational amplifier IC5A, its other end is connected with the junction of resistance R12 and R5, the junction of resistance R13 and R11, the junction of resistance R14 and R10 respectively.
Power constant current source produces and the principle of work of control circuit is: the working current being controlled power constant current source by D/A converting circuit.In the circuit shown in Fig. 2, operational amplifier forms voltage follower circuit, and power MOS pipe plays the effect of power amplification.The analog voltage U+ that D/A converter part exports is added to the in-phase input end of operational amplifier, and source voltage Us and the U+ of metal-oxide-semiconductor is identical, and the pass that resistance produces electric current I r, Ir and a Us is Ir=Us/R=U+/R.As long as the value of the control U+ Ir size that just can control in other words, namely controls the size of electronic load working current.Therefore, as long as the value controlling D/A converter part input data just can adjust the size of electronic load working current.Load current control voltage U+ is produced by digital to analog converter DAC0832 and operational amplifier LM358, and physical circuit as shown in Figure 2.The electric current that DAC0832 exports becomes through amplifier IC5B that voltage exports U+, IC5A, N 2, N 3 and peripheral circuit thereof form V/I change-over circuit, its output current Io and voltage U+pass be:
Output current Io and control voltage U+ meets linear relationship as can be seen here.
Further, described ripple voltage amplifies and precise rectification circuit 4 comprises ripple voltage amplifying circuit and precise rectification circuit.Described ripple voltage amplifying circuit, the output terminal of its input termination power constant current source generation and control circuit, it exports the input end of termination precise rectification circuit.Described precise rectification circuit, its output terminal connects the input end of single-chip microcomputer.
As shown in Figure 3, described ripple voltage amplifying circuit comprises electric capacity C1, electric capacity C2, electric capacity C11, operational amplifier IC1, operational amplifier IC2, resistance R1, resistance R2, resistance R3, resistance R4, resistance R6, resistance R9.Described electric capacity C1, the output terminal of the generation of one termination power constant current source and control circuit, the in-phase input end of its another termination operational amplifier IC1.Described operational amplifier IC1, its in-phase input end is through resistance R9 ground connection, and its inverting input is through resistance R4 ground connection, and its output terminal connects the in-phase input end of operational amplifier IC2 through electric capacity C2, and its output terminal is also through resistance R3, resistance R4 ground connection.Described operational amplifier IC2, its inverting input is through resistance R2 ground connection, and its output terminal is through resistance R1 and resistance R2 ground connection, and its output terminal also connects the input end of precise rectification circuit through electric capacity C11.
As shown in Figure 4, described precise rectification circuit comprises operational amplifier IC3, operational amplifier IC4, diode D1, diode D2, electric capacity C4, electric capacity C5, resistance R0, resistance R7, resistance R8, resistance R20, resistance R21 and resistance R22.Described operational amplifier IC3, its in-phase input end ground connection, its inverting input connects the output terminal of ripple voltage amplifying circuit through resistance R0, and its output terminal is connected with the negative electrode of diode D1, the anode of diode D2 respectively.Described diode D1, its anode connects the output terminal of ripple voltage amplifying circuit through resistance R8, and its anode also connects the inverting input of operational amplifier IC4 through resistance R7.Described diode D2, its negative electrode connects the output terminal of ripple voltage amplifying circuit through resistance R22, and its negative electrode also connects the in-phase input end of operational amplifier IC4.Described operational amplifier IC4, its inverting input connects its output terminal through resistance R20, and its output terminal is through resistance R21 and electric capacity C4 parallel with one another and electric capacity C5 ground connection.
Ripple voltage amplifies and the principle of work of precise rectification circuit is: ripple voltage is the effective value of circuit output end of pressure-stabilizing AC compounent, is also a kind of AC signal.Ripple voltage is as one of direct supply very important parameter index, and its value is the smaller the better.The electronic load of the utility model design has measuring ability to ripple voltage, does not need additional checkout equipment.Ripple voltage generally is millivolt level, so its difficulty detected is also very large.The utility model have employed AC signal and amplifies again after precise rectification circuit makes very little ripple voltage be converted into larger DC voltage, and carry out analog to digital conversion by A/D converter ICL7135, its circuit as shown in Figure 3 and Figure 4.Ripple voltage is coupled to the in-phase end of high speed operation amplifier NE5534 through electric capacity C1, be coupled to through electric capacity C3 the precise rectification circuit be made up of IC3, IC4 after the homophase operational amplification circuit amplification that two-stage is made up of operational amplifier, when ripple voltage signal is at positive half cycle, the external output low level of 6 pin of IC3, make diode D1 conducting, D2 ends.With should ripple voltage signal when negative half period, IC3 6 pin export high level, make diode D2 conducting, D1 end.Precision rectifying is carried out to alternating voltage, then obtains DC voltage by integrating circuit.
Further, as shown in Figure 5, described A/D change-over circuit 5 adopts ICL7135 converter.Analog to digital conversion circuit, on detection power constant current source, voltage and current value realize the function of conventional load.
Above-described embodiment is only be described preferred implementation of the present utility model; not scope of the present utility model is limited; under the prerequisite not departing from the utility model design spirit; the various distortion that those of ordinary skill in the art make the technical solution of the utility model and improvement, all should fall in protection domain that the utility model claims determine.
Claims (7)
1. an electronic load, comprises single-chip microcomputer (1), it is characterized in that: also comprise reference voltage generating circuit (2), power constant current source generation and control circuit (3), ripple voltage amplification and precise rectification circuit (4) and A/D change-over circuit (5);
The output terminal of described reference voltage generating circuit (2) is connected with the reference voltage input of single-chip microcomputer (1);
Described power constant current source produce and control circuit (3) output terminal respectively with the input end of single-chip microcomputer (1), ripple voltage amplifies and the input end of precise rectification circuit (4) is connected;
Described ripple amplifies and the output terminal of precise rectification circuit (4) is connected with the input end of A/D change-over circuit (5), and the output terminal of described A/D change-over circuit (5) is connected with the input end of single-chip microcomputer.
2. a kind of electronic load according to claim 1, is characterized in that: described reference voltage generating circuit (2) adopts TL431 voltage source.
3. a kind of electronic load according to claim 1, is characterized in that: described power constant current source produces and control circuit (3) comprises digital to analog converter U2, operational amplifier IC5B, operational amplifier IC5A, transistor N2, transistor N3, resistance R5, resistance R10, resistance R11, resistance R12, resistance R13, resistance R14, resistance R15, resistance R16, resistance R17, resistance R18 and resistance R19;
Described digital to analog converter U2, its the first current output terminal connects the inverting input of operational amplifier IC5B, its the second current output terminal connects the in-phase input end of operational amplifier IC5B, its data latches write gate input end, chip selection signal input end and the equal ground connection of data transfer control signal input end, its feedback signal input terminal connects the output terminal transporting amplifier IC5B;
Described operational amplifier IC5B, its output terminal connects the in-phase end input end of operational amplifier IC5A through resistance R19; Described operational amplifier IC5A, its inverting input is through resistance R18 ground connection, and its output terminal connects the base stage of transistor N3 through resistance R15;
Described transistor N2, its collector connects power supply, and its emitter connects the base stage of transistor N3; Described transistor N3, its emitter is through resistance R17 and resistance R18 ground connection;
Described resistance R5 and R12 is connected in parallel on resistance R17 and R18 two ends after connecting, resistance R13 and R11 is connected in parallel on resistance R17 and R18 two ends after connecting, resistance R14 and R10 is connected in parallel on resistance R17 and R18 two ends after connecting, described resistance R16, the in-phase input end of one termination operational amplifier IC5A, its other end is connected with the junction of resistance R12 and R5, the junction of resistance R13 and R11, the junction of resistance R14 and R10 respectively.
4. a kind of electronic load according to claim 1, is characterized in that: described ripple voltage amplifies and precise rectification circuit (4) comprises ripple voltage amplifying circuit and precise rectification circuit; Described ripple voltage amplifying circuit, the output terminal of its input termination power constant current source generation and control circuit, it exports the input end of termination precise rectification circuit; Described precise rectification circuit, its output terminal connects the input end of single-chip microcomputer;
Described ripple voltage amplifying circuit comprises electric capacity C1, electric capacity C2, electric capacity C11, operational amplifier IC1, operational amplifier IC2, resistance R1, resistance R2, resistance R3, resistance R4, resistance R6, resistance R9; Described electric capacity C1, the output terminal of the generation of one termination power constant current source and control circuit, the in-phase input end of its another termination operational amplifier IC1; Described operational amplifier IC1, its in-phase input end is through resistance R9 ground connection, and its inverting input is through resistance R4 ground connection, and its output terminal connects the in-phase input end of operational amplifier IC2 through electric capacity C2, and its output terminal is also through resistance R3, resistance R4 ground connection; Described operational amplifier IC2, its inverting input is through resistance R2 ground connection, and its output terminal is through resistance R1 and resistance R2 ground connection, and its output terminal also connects the input end of precise rectification circuit through electric capacity C11;
Described precise rectification circuit comprises operational amplifier IC3, operational amplifier IC4, diode D1, diode D2, electric capacity C4, electric capacity C5, resistance R0, resistance R7, resistance R8, resistance R20, resistance R21 and resistance R22; Described operational amplifier IC3, its in-phase input end ground connection, its inverting input connects the output terminal of ripple voltage amplifying circuit through resistance R0, and its output terminal is connected with the negative electrode of diode D1, the anode of diode D2 respectively; Described diode D1, its anode connects the output terminal of ripple voltage amplifying circuit through resistance R8, and its anode also connects the inverting input of operational amplifier IC4 through resistance R7; Described diode D2, its negative electrode connects the output terminal of ripple voltage amplifying circuit through resistance R22, and its negative electrode also connects the in-phase input end of operational amplifier IC4; Described operational amplifier IC4, its inverting input connects its output terminal through resistance R20, and its output terminal is through resistance R21 and electric capacity C4 parallel with one another and electric capacity C5 ground connection.
5. a kind of electronic load according to claim 1, is characterized in that: described A/D change-over circuit (5) adopts ICL7135 converter.
6. a kind of electronic load according to claim 1, is characterized in that: described single-chip microcomputer (1) adopts AT89C5X series monolithic.
7. a kind of electronic load according to claim 3, is characterized in that: described digital to analog converter U2 adopts DAC0832 digital to analog converter; Described operational amplifier IC5A and operational amplifier IC5B adopts LM358 operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420738103.3U CN204314347U (en) | 2014-12-01 | 2014-12-01 | A kind of electronic load |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420738103.3U CN204314347U (en) | 2014-12-01 | 2014-12-01 | A kind of electronic load |
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| Publication Number | Publication Date |
|---|---|
| CN204314347U true CN204314347U (en) | 2015-05-06 |
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| CN201420738103.3U Active CN204314347U (en) | 2014-12-01 | 2014-12-01 | A kind of electronic load |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108459645A (en) * | 2017-02-22 | 2018-08-28 | 苏州普源精电科技有限公司 | Constant current control loop and electronic load |
-
2014
- 2014-12-01 CN CN201420738103.3U patent/CN204314347U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108459645A (en) * | 2017-02-22 | 2018-08-28 | 苏州普源精电科技有限公司 | Constant current control loop and electronic load |
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