CN204086333U - A kind of electronic load - Google Patents
A kind of electronic load Download PDFInfo
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- CN204086333U CN204086333U CN201420535433.2U CN201420535433U CN204086333U CN 204086333 U CN204086333 U CN 204086333U CN 201420535433 U CN201420535433 U CN 201420535433U CN 204086333 U CN204086333 U CN 204086333U
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Abstract
The utility model relates to a kind of electronic load, belongs to electronic applications.A kind of electronic load, comprise the data interface circuit for receiving outside digital signal, D/A converting circuit, for selecting electronic load to be the working mode control circuit of constant current mode or constant-resistance pattern, comparator circuit, the first sample circuit, the second sample circuit, impedance adjustment circuit and power supply.The utility model uses the conduction amount of field effect transistor in digital control, digital-to-analog conversion and resistance sampling feedback accurate power control impedance adjustment circuit, the electronic load that accurate adjustment load current exports to obtain constant current or constant-resistance.
Description
Technical field
The utility model belongs to electronic applications, particularly a kind of electronic load.
Background technology
In recent years, the high speed development that China's economy is advanced by leaps and bounds, the process of the modernization of industry and electronics and information industry increase with the speed continuous high speed of more than 20%, have driven the quick rising of transducer market.The application of sensor in the special electronic equipment such as medical treatment, environmental protection, meteorology also increases fast, and sensor used accounts for about 15% of the market share.And electronic load for aiding sensors use and test is very important, in order to solve the demand of the different electronic load of relevant enterprise, particularly important to the research and development of dissimilar electronic load.
Conditional electronic load, in sensor application field, needs reliability and the load capacity of accurately detection power supply and plays the protective effects such as overvoltage, overcurrent, overpower.But the conditional electronic load used in the design production of sensor just reaches constant-resistance and constant current with fixed resistance value resistance, can not change the output of electronic load flexibly, can not meet in sensor test board the flexible that electronic load exports.
Summary of the invention
The purpose of this utility model is for the problems referred to above, provides a kind of fast response time, cost low and can the electronic load of flexible load.
The purpose of this utility model is achieved in that
A kind of electronic load, is characterized in that, comprise data interface circuit, D/A converting circuit, working mode control circuit, comparator circuit, the first sample circuit, the second sample circuit, impedance adjustment circuit and power supply;
Described data interface circuit, for receiving outside digital signal, and by this digital signal through latching and difference input service mode control circuit and D/A converting circuit after Phototube Coupling;
Described D/A converting circuit, for converting the digital signal received to corresponding analog voltage signal, and using one of them comparison signal input comparator circuit of this analog voltage signal as comparator circuit;
Described working mode control circuit, for selecting the mode of operation of electronic load to be constant current or constant-resistance according to the digital signal received, it comprises two output terminals, wherein the output signal of the first output terminal is as another comparison signal input comparator circuit of comparator circuit, and the output signal of the second output terminal is as the reference voltage signal input D/A converting circuit of D/A converting circuit;
Described comparator circuit, output signal for the output signal of logarithmic mode change-over circuit and first of working mode control circuit amplification of making comparisons, its output signal connects the control end of impedance adjustment circuit, regulates the size of current of this impedance adjustment circuit;
Described first sample circuit and the second sample circuit, feed back to working mode control circuit after being respectively used to sample to impedance adjustment circuit output voltage and input voltage;
Described impedance adjustment circuit, by the size of current regulating the conduction amount of the field effect transistor in this impedance adjustment circuit to change this impedance adjustment circuit, realizes constant-resistance or constant current with this;
Described power supply, for directly providing operating voltage for data interface circuit, the output voltage of described power supply after DC/DC power supply changeover device is as the operating voltage of D/A converting circuit, working mode control circuit, comparator circuit and impedance adjustment circuit.
Wherein, described working mode control circuit comprises latch, the first analog switch, the second analog switch, the first voltage follower circuit, the second voltage follower circuit and voltage selecting circuit;
The gating end of the first output signal access first analog switch of described latch, the input end grounding of described first analog switch, the output signal of the output terminal of described first analog switch connects the negative input end of the first voltage follower circuit as the model-following control signal of the first voltage follower circuit, the feedback voltage of positive input termination first sample circuit of described first voltage follower circuit, the output signal input comparator circuit of described first voltage follower circuit;
The gating end of the second output signal access second analog switch of described latch, the input end grounding of described second analog switch, the output signal of the output terminal of described second analog switch connects the second voltage follower circuit negative input end as the model-following control signal of the second voltage follower circuit, the output signal of the positive input termination voltage selecting circuit of described second voltage follower circuit, the output signal of described second voltage follower circuit is the reference voltage signal of D/A converting circuit.
Wherein, described voltage selecting circuit selects the feedback voltage of fixed voltage or the second sample circuit according to the control signal received, and comprises phase inverter, the 3rd analog switch, the 4th analog switch and voltage generator;
Described control signal connects the gating end of phase inverter and the 3rd analog switch respectively, the feedback voltage of input termination second sample circuit of described 3rd analog switch, the output of described phase inverter connects the gating end of the 4th analog switch, the output terminal of the input termination voltage generator of described 4th analog switch, the positive input terminal of output terminal parallel connection access second voltage follower circuit of described third and fourth analog switch.
Wherein, the output voltage of described power supply after DC/DC power supply changeover device is as the operating voltage of D/A converting circuit, working mode control circuit, comparator circuit and impedance adjustment circuit.
The beneficial effects of the utility model are, use the conduction amount of field effect transistor in digital control, digital-to-analog conversion and resistance sampling feedback accurate power control impedance adjustment circuit, the electronic load that accurate adjustment load current exports to obtain constant current or constant-resistance.
Accompanying drawing explanation
Fig. 1 is theory diagram of the present utility model.
Embodiment
Below in conjunction with specific embodiments and the drawings, set forth the utility model further.
As shown in Figure 1, a kind of electronic load 200, comprises data interface circuit 210, D/A converting circuit 220, working mode control circuit 230, comparator circuit 240, first sample circuit 250, second sample circuit 260, impedance adjustment circuit 270 and power supply.
Data interface circuit 210, for receiving outside digital signal 100, and by this digital signal 100 through latching and difference input service mode control circuit 230 and D/A converting circuit 220 after Phototube Coupling.
Described data interface circuit 210 specifically comprises octal latch and eight photoisolators that a model is 74573, described digital signal 100 is eight, inputted by eight data input pins of latch, finally exported by the output terminal of eight photoisolators, output signal and digital signal 100 one_to_one corresponding totally eight, wherein, front four signals are as first to fourth data input signal of latch in the data-signal of D/A converting circuit 220 and working mode control circuit 230, 5th and the 6th signal are as the address signal of D/A converting circuit, 5th and the 6th signal make the enable signal of the output after NAND Logic computing as latch in working mode control circuit 230, 7th signal after two inverter delay as the clock signal of latch in the write signal of D/A converting circuit and working mode control circuit 230, use photoisolator, the level of the control circuit of electronic load front end and the input voltage of electronic load is isolated, avoids it to influence each other.
D/A converting circuit 220, for converting the digital signal received 100 to corresponding analog voltage signal, and using one of them comparison signal input comparator circuit 240 of this analog voltage signal as comparator circuit 240.
Working mode control circuit 230, for selecting the mode of operation of electronic load 200 to be constant current or constant-resistance according to the digital signal 100 received, it comprises two output terminals, wherein the output signal of the first output terminal as the output signal of another comparison signal input comparator circuit 240, second output terminal of comparator circuit 240 as the reference voltage signal input D/A converting circuit 220 of D/A converting circuit 220.
Working mode control circuit 230 specifically comprises latch 231, first analog switch 232, second analog switch 233, first voltage follower circuit 234, second voltage follower circuit 235 and voltage selecting circuit 236.
Described latch 231 specifically select model be 74377 octal latch, the gating end of the first output signal access first analog switch 232 of this latch 231, the input end grounding of the first analog switch 232, the output signal of the output terminal of the first analog switch 232 connects the negative input end of the first voltage follower circuit 234 as the model-following control signal of the first voltage follower circuit 234, the feedback voltage of positive input termination first sample circuit 250 of the first voltage follower circuit 234, the output signal input comparator circuit 240 of the first voltage follower circuit 234; Wherein, the first voltage follower circuit 234 is made up of amplifier, for being realize it to follow function, first output signal of latch 231 is always 0, make the first analog switch 232 be always off-state with this, and then make the negative input end of amplifier without input signal, coating-forming voltage follower.
The gating end of the second output signal access second analog switch 233 of described latch 231, the input end grounding of the second analog switch, the output signal of the output terminal of the second analog switch 233 connects the second voltage follower circuit 235 negative input end as the model-following control signal of the second voltage follower circuit 235, the output signal of the positive input termination voltage selecting circuit 236 of the second voltage follower circuit 235, the output signal of the second voltage follower circuit 235 is the reference voltage signal of D/A converting circuit 220; Wherein, the second voltage follower circuit 235 is identical with the first voltage follower circuit 234.
Described voltage selecting circuit 236 selects according to the control signal received the feedback voltage exporting fixed voltage or the second sample circuit 260, specifically comprises phase inverter 2361, the 3rd analog switch 2362, the 4th analog switch 2363 and voltage generator 2364; Wherein control signal is the 8th output signal of data interface circuit 210.
Described control signal connects the gating end of phase inverter 2361 and the 3rd analog switch 2362 respectively, the feedback voltage of input termination second sample circuit 260 of the 3rd analog switch 2362, the output of phase inverter 2361 connects the gating end of the 4th analog switch 2363, the output terminal of the input termination voltage generator 2364 of the 4th analog switch 2363, the positive input terminal of output terminal parallel connection access second voltage follower circuit 235 of the 3rd analog switch 2362 and the 4th analog switch 2363; Wherein, the gating signal of the 3rd analog switch 2362 and the 4th analog switch 2363 is contrary all the time, realizes voltage selection function with this; When the 8th output signal of data interface circuit 210 is 0, the output of voltage selecting circuit 236 is fixed voltage; When the 8th output signal of data interface circuit 210 is 1, the output of voltage selecting circuit 236 is the feedback voltage of the second sample circuit 260, i.e. the input voltage of impedance adjustment circuit.
Comparator circuit 240, amplification of making comparisons is outputed signal for the output signal of logarithmic mode change-over circuit 220 and first of working mode control circuit 230, the control end of its output signal joint impedance adjustment circuit 270, controls the size of current of this impedance adjustment circuit 270, realizes constant-resistance or constant current with this;
First sample circuit 250 and the second sample circuit 260, is respectively used to sample to impedance adjustment circuit 270 output current and input current, and feeds back to working mode control circuit 230 after converting voltage signal to;
Impedance adjustment circuit 270, according to the conduction amount of the field effect transistor in the control signal adjustment impedance adjustment circuit 270 that its control end receives, to realize constant current or the constant-resistance of impedance adjustment circuit 270, the input voltage 300 of the input termination electronic load of described impedance adjustment circuit 270;
Power supply is used for directly providing operating voltage for data interface circuit 210, and the output voltage of power supply after DC/DC power supply changeover device is as the operating voltage of D/A converting circuit 220, working mode control circuit 230, comparator circuit 240 and impedance adjustment circuit 270.
Principle of the present utility model is: the output voltage of impedance adjustment circuit 270 and fixed voltage or variable voltage are made comparisons, wherein fixed voltage is directly proportional to the output voltage of voltage generator 2364, and variable voltage is directly proportional to the input voltage of impedance adjustment circuit 270; By the control signal of difference amplifying signal as impedance adjustment circuit 270 comparing output, namely as the control signal regulating field effect transistor conduction amount in impedance adjustment circuit 270, by controlling the size of field effect transistor conduction amount, realize constant current mode or the constant-resistance pattern of this electronic load.
1) constant current mode: in such a mode, requires the constant current hold in impedance adjustment circuit 270, namely requires that the output of comparator circuit 240 remains unchanged; Now the negative input end input signal of comparator circuit 240 is the feedback voltage of the first sample circuit 250, the i.e. voltage of output current after resistance conversion of impedance adjustment circuit 270, the positive input terminal of comparator circuit 240 is fixed voltage, the difference of aforementioned feedback voltage and fixed voltage is fixed value, therefore the output signal of comparator circuit 240 keeps constant, namely the control signal of impedance adjustment circuit 270 keeps constant, make the constant current hold in impedance adjustment circuit 270, realize constant current electronic load with this.
2) constant-resistance pattern: in such a mode, requires that the electric current in impedance adjustment circuit 270 is directly proportional all the time to its input voltage; Now the input signal of the negative input end of comparator circuit 240 is with aforementioned constant current mode, the input signal of positive input terminal is directly proportional to the feedback voltage of the second sample circuit 260, and the feedback voltage of described second sample circuit 260 is the input voltage of impedance adjustment circuit 270; When the input voltage of impedance adjustment circuit 270 changes, the output signal of comparator circuit 240 can change thereupon, namely the control signal of impedance adjustment circuit 270 changes thereupon, the conduction amount of the field effect transistor in impedance adjustment circuit 270 is changed with this, the output current of impedance adjustment circuit 270 is directly proportional all the time to its input voltage, realizes constant-resistance electronic load with this.
The utility model uses the conduction amount of field effect transistor in digital control, digital-to-analog conversion and resistance sampling feedback accurate power control impedance adjustment circuit, the electronic load that accurate adjustment load current exports to obtain constant current or constant-resistance.
Claims (3)
1. an electronic load, it is characterized in that, comprise data interface circuit (210), D/A converting circuit (220), working mode control circuit (230), comparator circuit (240), the first sample circuit (250), the second sample circuit (260), impedance adjustment circuit (270) and power supply;
Described data interface circuit (210), for receiving outside digital signal (100), and by this digital signal (100) through latching and difference input service mode control circuit (230) and D/A converting circuit (220) after Phototube Coupling;
Described D/A converting circuit (220), for converting the digital signal received (100) to corresponding analog voltage signal, and using this analog voltage signal one of them comparison signal input comparator circuit (240) as comparator circuit (240);
Described working mode control circuit (230), for selecting the mode of operation of electronic load to be constant current or constant-resistance according to the digital signal (100) received, it comprises two output terminals, wherein the output signal of the first output terminal is as another comparison signal input comparator circuit (240) of comparator circuit (240), and the output signal of the second output terminal is as reference voltage signal input D/A converting circuit (220) of D/A converting circuit (220);
Described comparator circuit (240), amplification of making comparisons is outputed signal for the output signal of logarithmic mode change-over circuit (220) and first of working mode control circuit (230), its output signal connects the control end of impedance adjustment circuit (270), regulates the size of current of this impedance adjustment circuit (270);
Described first sample circuit (250) and the second sample circuit (260), feed back to working mode control circuit (230) after being respectively used to sample to impedance adjustment circuit (270) output voltage and input voltage;
Described impedance adjustment circuit (270), by the size of current regulating the conduction amount of the field effect transistor in this impedance adjustment circuit (270) to change this impedance adjustment circuit (270), realizes constant-resistance or constant current with this;
Described power supply, for directly providing operating voltage for data interface circuit (210), the output voltage of described power supply after DC/DC power supply changeover device is as the operating voltage of D/A converting circuit (220), working mode control circuit (230), comparator circuit (240) and impedance adjustment circuit (270).
2. electronic load according to claim 1, it is characterized in that, described working mode control circuit (230) comprises latch (231), the first analog switch (232), the second analog switch (233), the first voltage follower circuit (234), the second voltage follower circuit (235) and voltage selecting circuit (236);
The gating end of the first output signal access first analog switch (232) of described latch (231), the input end grounding of described first analog switch (232), the output signal of the output terminal of described first analog switch (232) connects the negative input end of the first voltage follower circuit (234) as the model-following control signal of the first voltage follower circuit (234), the feedback voltage of positive input termination first sample circuit (250) of described first voltage follower circuit (234), output signal input comparator circuit (240) of described first voltage follower circuit (234),
The gating end of the second output signal access second analog switch (233) of described latch (231), the input end grounding of described second analog switch (233), the output signal of the output terminal of described second analog switch (233) connects the second voltage follower circuit (235) negative input end as the model-following control signal of the second voltage follower circuit (235), the output signal of the positive input termination voltage selecting circuit (236) of described second voltage follower circuit (235), the output signal of described second voltage follower circuit (235) is the reference voltage signal of D/A converting circuit (220).
3. electronic load according to claim 2, it is characterized in that, described voltage selecting circuit (236) selects the feedback voltage of fixed voltage or the second sample circuit (260) according to the control signal received, and comprises phase inverter (2361), the 3rd analog switch (2362), the 4th analog switch (2363) and voltage generator (2364);
Described control signal connects the gating end of phase inverter (2361) and the 3rd analog switch (2362) respectively, the feedback voltage of input termination second sample circuit (260) of described 3rd analog switch (2362), the output of described phase inverter (2361) connects the gating end of the 4th analog switch (2363), the output terminal of the input termination voltage generator (2364) of described 4th analog switch (2363), described third and fourth analog switch (2362, 2363) positive input terminal of output terminal parallel connection access the second voltage follower circuit (235).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420535433.2U CN204086333U (en) | 2014-09-17 | 2014-09-17 | A kind of electronic load |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420535433.2U CN204086333U (en) | 2014-09-17 | 2014-09-17 | A kind of electronic load |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204086333U true CN204086333U (en) | 2015-01-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420535433.2U Expired - Fee Related CN204086333U (en) | 2014-09-17 | 2014-09-17 | A kind of electronic load |
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| CN (1) | CN204086333U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106872736A (en) * | 2016-12-29 | 2017-06-20 | 新华三技术有限公司 | A kind of electronic load |
| CN108267622A (en) * | 2018-01-22 | 2018-07-10 | 常州同惠电子股份有限公司 | A kind of electronic load device with electric voltage reverse-connection defencive function |
-
2014
- 2014-09-17 CN CN201420535433.2U patent/CN204086333U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106872736A (en) * | 2016-12-29 | 2017-06-20 | 新华三技术有限公司 | A kind of electronic load |
| CN108267622A (en) * | 2018-01-22 | 2018-07-10 | 常州同惠电子股份有限公司 | A kind of electronic load device with electric voltage reverse-connection defencive function |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150107 Termination date: 20200917 |