CN215576337U - Multi-range variable-gain current source - Google Patents
Multi-range variable-gain current source Download PDFInfo
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- CN215576337U CN215576337U CN202122480138.4U CN202122480138U CN215576337U CN 215576337 U CN215576337 U CN 215576337U CN 202122480138 U CN202122480138 U CN 202122480138U CN 215576337 U CN215576337 U CN 215576337U
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Abstract
The utility model discloses a multi-range variable-gain current source, and belongs to the technical field of current source equipment. The existing current source power amplification circuit is unstable in work. The utility model relates to a multi-range variable gain current source which comprises a front-end circuit, an amplifying circuit, a push-pull circuit and a switching circuit. The variable resistor of the front-end circuit adjusts the gain of the operational amplifier by changing the resistance value. The amplifying circuit amplifies the voltage of the small signal of the front-end circuit and outputs the small signal to the push-pull circuit; and a power triode of the push-pull circuit amplifies the power of the voltage signal of the amplifying circuit so as to drive a rear-stage high-power load. The front-end circuit is provided with the variable resistor, and the gain of the operational amplifier is adjusted by changing the resistance value of the variable resistor, so that the current source can adapt to various gain requirements, the problem that the current power amplifier is easy to oscillate under different measuring ranges is effectively solved, and the front-end circuit is simple in scheme, practical, feasible and low in manufacturing cost.
Description
Technical Field
The utility model relates to a multi-range variable-gain current source, and belongs to the technical field of current source equipment.
Background
Chinese patent (CN208461788U) discloses a program-controlled automatic gain signal amplifier, which comprises a single-chip microcomputer control circuit, a DA gain control circuit, an automatic gain amplification circuit and an AD feedback control circuit; the single chip microcomputer control circuit outputs gain control words, the gain control words are converted into analog control voltage through the DA gain control circuit, the analog control voltage carries out amplification gain adjustment on the automatic gain amplification circuit and then outputs the analog control voltage to a load end, the voltage of the load end is sampled through the AD feedback control circuit and carries out analog-to-digital conversion, then the analog control voltage is fed back to the single chip microcomputer control circuit, and the single chip microcomputer control circuit dynamically adjusts the gain control words again, so that the signal amplitude output by the automatic gain amplification circuit is kept consistent within a certain range.
Although the above scheme can realize automatic adjustment of the gain, in the actual use process, the higher the gain is, the more easily the gain is caused to oscillate, and the above scheme does not disclose how to avoid the occurrence of circuit oscillation, which leads to unstable operation of the power amplifier circuit and further influences the reliability of the current source.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects of the prior art, the utility model aims to provide a multi-range variable gain current source which is provided with a variable resistor, wherein the gain of an operational amplifier is adjusted through the variable resistor, so that the current source can adapt to various gain requirements, and the problem that the current amplifier is easy to generate oscillation under different ranges is effectively solved.
In order to achieve the purpose, the technical scheme of the utility model is as follows:
a multi-range variable gain current source comprises a front-end circuit, an amplifying circuit, a push-pull circuit and a switching circuit;
the front-end circuit is used for receiving a voltage signal from a signal source and realizing circuit gain adjustment and is provided with an operational amplifier and a variable resistor;
the resistance value of the variable resistor can be changed to adapt to different measuring ranges;
the amplifying circuit is used for amplifying the voltage signal output by the front-end circuit to make the output voltage meet the requirement;
the push-pull circuit is used for amplifying the power of the voltage signal output by the amplifying circuit to enable the voltage signal to drive a load and is provided with a power triode;
the switching circuit is used for converting the voltage output by the push-pull circuit into current and is provided with a V/I converter and a current transformer;
the variable resistor of the front-end circuit adjusts the gain of the operational amplifier by changing the resistance value;
the amplifying circuit amplifies the voltage of the small signal of the front-end circuit and outputs the small signal to the push-pull circuit;
a power triode of the push-pull circuit amplifies the power of the voltage signal of the amplifying circuit so as to drive a rear-stage high-power load;
the V/I converter of the switching circuit converts the voltage into current, and the current signal of the current transformer is fed back to the front-end circuit.
Through continuous exploration and test, the utility model is provided with a front-end circuit, an amplifying circuit, a push-pull circuit and a switching circuit; meanwhile, the front-end circuit is provided with the variable resistor, and the gain of the operational amplifier is adjusted by changing the resistance value of the variable resistor, so that the current source can adapt to various gain requirements, the problem that the current power amplifier is easy to oscillate under different measuring ranges is effectively solved, and the current source is more reliable, simple in scheme, practical, feasible and low in manufacturing cost.
As a preferable technical measure:
the front-end circuit further comprises a feedback resistor and a capacitor bank.
As a preferable technical measure:
the operational amplifier is a double operational amplifier, the model number of the operational amplifier is NJM4560, and the operational amplifier has the advantages of low temperature drift, low zero point, high open-loop gain and the like.
As a preferable technical measure:
the variable resistor is a numerical control electronic potentiometer, and the model number of the variable resistor is X9221;
the digital control electronic potentiometer is provided with two groups of resistors with adjustable resistance values, the resistance values of the resistors are 0-10K, the adjustment steps are 50 omega, so that very wide gain adjustment is realized, and communication is realized through a serial bus II 2C.
As a preferable technical measure:
the numerical control electronic potentiometer is connected with a front-end circuit by adopting a T-shaped feedback resistor network connection method so as to realize the adjustment of gain within the range of 1-100 times.
As a preferable technical measure:
the switching circuit further comprises at least one relay and a sampling resistor;
the relay switches different gears to output through on-off control.
The sampling resistor samples the small current converted by the current transformer and feeds the small current back to the front-end circuit.
The V/I converter converts the voltage into current, and the current transformer sampling circuit loop converts the current into small current which is fed back to the front-end circuit after being sampled by the precision resistor.
100A, 50A, 20A, 10A, 5A, 2.5A, 1A, 0.5A, 0.25A, 0.1A, 20mA, 10mA and 5mA taps are respectively led out of the V/I converter and the current transformer so as to meet the current stability of 0.3mA-100A in a new regulation and ensure the accuracy of output current.
As a preferable technical measure:
the V/I converter and the current transformer are respectively provided with N contacts, and the contacts are electrically connected with the relay;
when a certain current value is output, the corresponding relay is closed, so that the relay works at a proper gear.
As a preferable technical measure:
also comprises a main control circuit which is connected with the main control circuit,
the main control circuit is used for collecting output voltage to judge the output state of the current source, and realizing gain setting and gear switching, can communicate with an upper computer, and is provided with a main control board.
The main control board comprises a communication module, a gear switching module, a signal acquisition module and a gain control module;
the communication module is used for communicating with the upper computer and executing commands issued by the upper computer;
the gear switching module is used for realizing gear switching of the circuit, and when a source raising command is received, a proper gear is switched according to a current value of a source raising;
the signal acquisition module is used for acquiring a voltage value output by the push-pull circuit, judging whether the output of the power amplifier exceeds the limit or not by measuring the voltage value, and protecting the power amplifier when the output of the power amplifier exceeds the maximum voltage;
and the gain control module is used for communicating with an electronic potentiometer X9221 through II2C after the current gear switching is finished, and writing a resistance value to change the gain of the operational amplifier.
As a preferable technical measure:
the main control board is a single chip microcomputer ARM, and the model number of the main control board is STM32F 103;
the main control board is provided with a plurality of acquisition channels ADC and a serial port communication module, and the resource requirements of the utility model can be met.
As a preferable technical measure:
the current source H-type current source is provided with a linear amplifier, the waveform reduction degree is high, the current source H-type current source is sensitive to the load type, and the output current is wide (0.3 mA-120A).
Compared with the prior art, the utility model has the following beneficial effects:
through continuous exploration and test, the utility model is provided with a front-end circuit, an amplifying circuit, a push-pull circuit and a switching circuit; meanwhile, the front-end circuit is provided with the variable resistor, and the gain of the operational amplifier is adjusted by changing the resistance value of the variable resistor, so that the current source can adapt to various gain requirements, the problem that the current power amplifier is easy to oscillate under different measuring ranges is effectively solved, and the circuit is simple in scheme, practical, feasible and low in manufacturing cost.
Drawings
FIG. 1 is a block diagram of the circuit of the present invention;
FIG. 2 is a schematic diagram of a front end circuit of the present invention;
FIG. 3 is a diagram of a switching circuit according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.
On the contrary, the utility model is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the utility model as defined by the appended claims. Furthermore, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details.
A multi-range variable gain current source comprises a front-end circuit, an amplifying circuit, a push-pull circuit and a switching circuit;
the front-end circuit is used for receiving a voltage signal from a signal source and realizing circuit gain adjustment and is provided with an operational amplifier and a variable resistor;
the resistance value of the variable resistor can be changed to adapt to different measuring ranges;
the amplifying circuit is used for amplifying the voltage signal output by the front-end circuit to make the output voltage meet the requirement;
the push-pull circuit is used for amplifying the power of the voltage signal output by the amplifying circuit to enable the voltage signal to drive a load and is provided with a power triode;
the switching circuit is used for converting the voltage output by the push-pull circuit into current and is provided with a V/I converter and a current transformer;
the variable resistor of the front-end circuit adjusts the gain of the operational amplifier by changing the resistance value;
the amplifying circuit amplifies the voltage of the small signal of the front-end circuit and outputs the small signal to the push-pull circuit;
a power triode of the push-pull circuit amplifies the power of the voltage signal of the amplifying circuit so as to drive a rear-stage high-power load;
the V/I converter of the switching circuit converts the voltage into current, and the current signal of the current transformer is fed back to the front-end circuit.
Through continuous exploration and test, the utility model is provided with a front-end circuit, an amplifying circuit, a push-pull circuit and a switching circuit; meanwhile, the front-end circuit is provided with the variable resistor, and the gain of the operational amplifier is adjusted by changing the resistance value of the variable resistor, so that the current source can adapt to various gain requirements, the problem that the current power amplifier is easy to oscillate under different measuring ranges is effectively solved, and the circuit is simple in scheme, practical, feasible and low in manufacturing cost.
As shown in fig. 1, a preferred embodiment of the present invention:
a multi-range variable gain current source is composed of a front-end circuit, an amplifying circuit, a push-pull circuit, a switching circuit and a main control circuit.
The pre-circuit is connected with the amplifying circuit, the feedback signal and the standard signal Ui are input to the operational amplifier 4560, and the feedback gain of the operational amplifier adopts a program control gain adjustable mode.
The amplifying circuit amplifies the voltage of the small signal of the front-end circuit and outputs the small signal to the push-pull circuit part. The push-pull circuit is composed of a high-power triode and is used for amplifying the power of a voltage signal of the amplifying circuit and driving a rear-stage high-power load.
The switching circuit consists of a V/I converter, a current transformer and a relay switching circuit, wherein the V/I converter converts voltage into current, the current transformer samples a circuit loop and converts the current into small current, and the small current is sampled by a precision resistor and then fed back to the front-end circuit. 100A, 50A, 20A, 10A, 5A, 2.5A, 1A, 0.5A, 0.25A, 0.1A, 20mA, 10mA and 5mA taps are respectively led out of the V/I converter and the current transformer so as to meet the current stability of 0.3mA-100A in a new regulation and ensure the accuracy of output current.
The main control circuit is provided with a main control board and is used for being responsible for functions of gain setting, gear switching, communication with an upper computer, output signal acquisition protection and the like.
The main control board adopts ARM singlechip STM32F103, and the chip is abundant in internal resource, and a plurality of ADC acquisition channels, a plurality of serial ports communication module can satisfy the resource demand of this project.
In the utility model, the front-end circuit is provided with the variable resistor, under the general condition, the higher the gain of the operational amplifier is, the better the performance is, but in the practical use process, the higher the gain is, the more easily the oscillation is caused, the variable resistor is added in the utility model, and the T-shaped feedback resistance network connection method is adopted, so that the gain can be adjusted within the range of 1-100 times. When a certain current value is output, the main control board is switched to a proper current gear, the resistance value of the electronic potentiometer X9221 is written in through II2C communication, each current gear corresponds to one group of gain, and the power amplifier can work stably in each measuring range.
The utility model ensures the reliability of the current source by adjusting the gain of the operational amplifier, monitors the output signal of the current source in real time during the operation process, judges whether the current source is in an oscillation state, and reduces the gain by adjusting the variable resistor, thereby eliminating the oscillation and improving the stability of the current source.
The H-type current source is high in waveform reduction degree, sensitive to load types and wide in output current (0.3mA-120A), so that the H-type current source is particularly suitable for calibrating the electric energy meter, but the H-type current source is easy to vibrate in the actual use process to influence the stability of the current source.
Therefore, the existing H-type current source technology and the scheme of the utility model can be combined, so that the H-type current source can select proper gain under different gears, the problems that a current power amplifier is easy to oscillate under different ranges and the like are solved, the utility model is particularly suitable for detecting a new version of electric energy meter, the fault probability of the H-type current source is greatly reduced, and the meter detection efficiency is indirectly improved.
As shown in fig. 2 and fig. 3, a specific embodiment of the circuit module of the present invention:
the front-end circuit mainly comprises an operational amplifier, a variable resistor, a feedback resistor and a capacitor, and is shown in figure 2.
The operational amplifier adopts a double operational amplifier NJM4560 and has the advantages of low temperature drift, low zero point, high open-loop gain and the like.
The variable resistor adopts an X9221 numerical control electronic potentiometer, two groups of variable resistors are arranged inside the variable resistor, II2C communication is adopted, the resistance adjusting range can reach 0-10K, the adjusting step can reach 50 omega, and very wide gain adjustment can be realized.
The numerical control electronic potentiometer X9221 is communicated with the main control board through II2C, and when the gear is switched, the main control board controls the potentiometer to change the resistance value so as to change the gain of the operational amplifier.
An amplifying circuit: and voltage amplification is carried out on the voltage signal output by the front-end circuit, so that the output voltage meets the requirement.
A push-pull circuit: and the voltage signal output by the amplifying circuit is subjected to power amplification, so that the load can be driven by the voltage signal.
The switching circuit mainly comprises a V/I converter, a current transformer and a relay switching circuit, and is shown in figure 3.
The V/I converter converts the voltage output by the push-pull circuit into current, and the current transformer converts the current into a feedback signal to the front-end circuit. The relay switching circuit selects different gears to output.
The V/I converter and the current transformer output current, the V/I converter and the current transformer are respectively provided with N taps which are connected through a relay, and when a certain current value is output, the main control board can attract the relay at a certain gear to enable the main control board to work at a proper gear.
The main control circuit is a control core part of the current source and comprises a communication module, a gear switching module, a signal acquisition module, a gain control module and other four modules, and is mainly responsible for switching different current gears and selecting proper gain, and output voltage is acquired in the operation process to judge the output state of the current source.
The main control board is an ARM chip STM32F103 and is provided with abundant peripheral modules, a multipath communication serial port, an ADC measuring interface and the like, and the dominant frequency can reach 72M.
And the communication module is used for communicating with the upper computer and executing a command issued by the upper computer.
The gear switching module is used for realizing gear switching of the circuit, and when a source raising command is received, a proper gear is switched according to a current value of a source raising.
The signal acquisition module is used for acquiring a voltage value output by the push-pull circuit, judging whether the output of the power amplifier exceeds the limit or not by measuring the voltage value, and protecting the power amplifier when the output of the power amplifier exceeds the maximum voltage.
And the gain control module is used for communicating with an electronic potentiometer X9221 through II2C after the current gear switching is finished, and writing a resistance value to change the gain of the operational amplifier.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the utility model without departing from the spirit and scope of the utility model, which is to be covered by the claims.
Claims (10)
1. A multi-range variable gain current source is characterized in that,
the circuit comprises a front-end circuit, an amplifying circuit, a push-pull circuit and a switching circuit;
the front-end circuit is used for receiving a voltage signal from a signal source and realizing circuit gain adjustment and is provided with an operational amplifier and a variable resistor;
the resistance value of the variable resistor can be changed to adapt to different measuring ranges;
the amplifying circuit is used for amplifying the voltage signal output by the front-end circuit to make the output voltage meet the requirement;
the push-pull circuit is used for amplifying the power of the voltage signal output by the amplifying circuit to enable the voltage signal to drive a load and is provided with a power triode;
the switching circuit is used for converting the voltage output by the push-pull circuit into current and is provided with a V/I converter and a current transformer;
the variable resistor of the front-end circuit adjusts the gain of the operational amplifier by changing the resistance value;
the amplifying circuit amplifies the voltage of the signal of the front-end circuit and outputs the signal to the push-pull circuit;
a power triode of the push-pull circuit amplifies the power of the voltage signal of the amplifying circuit so as to drive a rear-stage high-power load;
the V/I converter of the switching circuit converts the voltage into current, and the current signal of the current transformer is fed back to the front-end circuit.
2. A multi-range variable gain current source according to claim 1,
the front-end circuit further comprises a feedback resistor and a capacitor bank.
3. A multi-range variable gain current source according to claim 1,
the operational amplifier is a double operational amplifier with the model number of NJM 4560.
4. A multi-range variable gain current source according to claim 1,
the variable resistor is a numerical control electronic potentiometer, and the model number of the variable resistor is X9221;
the digital control electronic potentiometer is provided with two groups of resistors with adjustable resistance values, the resistance values of the resistors are 0-10K, the adjustment steps are 50 omega, gain adjustment is achieved, and communication is achieved through a serial bus II 2C.
5. A multi-range variable gain current source according to claim 4,
the numerical control electronic potentiometer is connected with a front-end circuit by adopting a T-shaped feedback resistor network connection method so as to realize the adjustment of gain within the range of 1-100 times.
6. A multi-range variable gain current source according to claim 1,
the switching circuit further comprises at least one relay and a sampling resistor;
the relay switches different gears to output through on-off control;
the sampling resistor samples the small current converted by the current transformer and feeds the small current back to the front-end circuit.
7. A multi-range variable gain current source according to claim 6,
the V/I converter and the current transformer are respectively provided with N contacts, and the contacts are electrically connected with the relay;
when a certain current value is output, the corresponding relay is closed, so that the relay works at a proper gear.
8. A multi-range variable gain current source according to any of claims 1 to 7,
also comprises a main control circuit which is connected with the main control circuit,
the main control circuit is provided with a main control board,
the main control board comprises a communication module, a gear switching module, a signal acquisition module and a gain control module;
the communication module is used for communicating with the upper computer and executing commands issued by the upper computer;
the gear switching module is used for realizing gear switching of the circuit, and when a source raising command is received, a proper gear is switched according to a current value of a source raising;
the signal acquisition module is used for acquiring a voltage value output by the push-pull circuit, judging whether the output of the power amplifier exceeds the limit or not by measuring the voltage value, and protecting the power amplifier when the output of the power amplifier exceeds the maximum voltage;
and the gain control module is used for communicating with an electronic potentiometer X9221 through II2C after the current gear switching is finished, and writing a resistance value to change the gain of the operational amplifier.
9. A multi-range variable gain current source according to claim 8,
the main control board is a single chip microcomputer ARM, and the model number of the main control board is STM32F 103;
the main control board is provided with a plurality of acquisition channels ADC and a serial port communication module.
10. A multi-range variable gain current source according to claim 1,
the current source is an H-type current source provided with a linear amplifier.
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| CN202122480138.4U CN215576337U (en) | 2021-10-14 | 2021-10-14 | Multi-range variable-gain current source |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115728530A (en) * | 2022-11-14 | 2023-03-03 | 浙江涵普电力科技有限公司 | Wide-load adaptive AC testing voltage source device |
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2021
- 2021-10-14 CN CN202122480138.4U patent/CN215576337U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115728530A (en) * | 2022-11-14 | 2023-03-03 | 浙江涵普电力科技有限公司 | Wide-load adaptive AC testing voltage source device |
| CN115728530B (en) * | 2022-11-14 | 2024-06-04 | 浙江涵普电力科技有限公司 | Wide load adaptability alternating current test voltage source device |
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