CN112067889A - Current measurement circuit and equipment applying same - Google Patents
Current measurement circuit and equipment applying same Download PDFInfo
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- CN112067889A CN112067889A CN202011056605.4A CN202011056605A CN112067889A CN 112067889 A CN112067889 A CN 112067889A CN 202011056605 A CN202011056605 A CN 202011056605A CN 112067889 A CN112067889 A CN 112067889A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/257—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques using analogue/digital converters of the type with comparison of different reference values with the value of voltage or current, e.g. using step-by-step method
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Abstract
The application provides a current detection circuit and applied this circuit's equipment, current detection circuit includes detection module, analog-to-digital converter and processing module, detection module is used for converting the sampling current of input into sampling voltage signal, analog-to-digital converter is used for comparing the sampling voltage signal of input and reference fixed voltage, outputs digital signal, processing module is used for with digital signal and standard value calculation comparison to obtain measuring result.
Description
Technical Field
The application relates to the technical field of information electronics, in particular to a current measuring circuit and equipment using the same.
Background
The current detection technology has extremely wide application, and the current flowing in and out needs to be detected in many systems. Such as current protection/monitoring devices, 4-20mA current loop systems, programmable current sources, linear/switch mode power supplies, and chargers or fuel gauges that require knowledge of the ratio of the incoming and outgoing currents.
The existing current detection technology generally adopts a transition transfer method, wherein the transition transfer method is to measure a resistor according to a voltammetry principle so as to obtain a current value, specifically, a shunt is connected into a circuit, the voltage at two ends of the shunt is measured, and then the measured voltage is divided by the resistance value of the shunt according to an ohm law so as to obtain the current value in the circuit.
In the current detection scheme of the transition transfer method, a discrete or semi-discrete element circuit is generally adopted, and since the electric power consumed by the current on the resistor of the current divider is converted into heating energy, the resistance value of the circuit is changed, the phase of the voltage at two ends relative to the phase of the current is out of phase, and additional phase shift is generated.
Disclosure of Invention
The application provides a current measurement circuit and use device of this circuit, through sampling simultaneously to being surveyed signal and reference fixed voltage, processing module handles two signals simultaneously, therefore has eliminated test current error and drift and to the influence of measuring result, has improved the measuring degree of accuracy.
In one aspect, the present application provides a current detection circuit, which includes a detection module, an analog-to-digital converter and a processing module, wherein the detection module is configured to convert an input sampling current into a sampling voltage signal, the analog-to-digital converter is configured to compare the input sampling voltage signal with a reference fixed voltage and output a digital signal, and the processing module is configured to compare the digital signal with a standard value and obtain a measurement result.
The measured signal and the reference fixed voltage (standard signal) are sampled simultaneously, and the processing module processes the two signals simultaneously, so that the influence of the error and the drift of the test current on the measurement result is eliminated, and the measurement accuracy is improved.
In one possible embodiment of the current detection circuit, the measurement result is a current value obtained according to detection by the current detection circuit.
In a possible implementation manner of the current detection circuit, the analog-to-digital converter specifically includes an integrated operational amplifier, two input ends of the integrated operational amplifier are respectively a first input end and a second input end, the sampling voltage signal obtained by the detection module is input through the first input end, and the reference fixed voltage is input through the second input end. The integrated operational amplifier outputs a digital signal by comparing the input sampling voltage signal with the reference fixed voltage, thereby converting the sampling voltage signal into a digital signal.
The integrated operational amplifier samples the sampling voltage signal and the reference fixed voltage signal at the same time and carries out operational amplifier comparison processing. That is, an analog voltage signal is compared with a reference fixed voltage, and at a value around the same amplitude, the output voltage will make a transition, and correspondingly output a high level or a low level, thereby converting the analog signal of the sampling voltage signal into a digital signal.
In a possible implementation manner of the current detection circuit, the analog-to-digital converter may further specifically include a plurality of integrated operational amplifiers, and the plurality of integrated operational amplifiers are arranged in series. In particular, the analog-to-digital converter may include a first integrated operational amplifier and a second integrated operational amplifier.
The sampling voltage signal obtained by the detection module is input into one input end of the first integrated operational amplifier, and a signal output by the output end of the first integrated operational amplifier is input into the other input end of the first integrated operational amplifier. The signal output by the output end of the first integrated operational amplifier is input into one input end of the second integrated operational amplifier, and the reference fixed voltage is input into the other input end of the second integrated operational amplifier.
The first integrated operational amplifier and the second integrated operational amplifier are adopted to realize the two operational amplifier circuits, so that the double ADC samples the tested signal and the reference fixed voltage (standard signal) at the same time, and the processing module processes the two signals at the same time, thereby further eliminating the influence of the test current error and the drift on the measurement result and improving the accuracy of measurement.
In one possible embodiment of the current detection circuit, the sampling current may be a dc excitation current.
In a possible implementation manner of the current detection circuit, the processing module may be a single chip microcomputer. The processing module can also be a signal processing system of a single chip microcomputer.
In one possible embodiment of the current detection circuit, the analog-to-digital converter and the processing module may be integrated together.
In a possible implementation manner of the current detection circuit, the current detection circuit may further include a current divider, and the current divider is configured to sample a current to be measured and output a sampled current obtained by sampling to the detection module.
In a second aspect, the present application also provides an electronic device including a circuit to be detected, the current detection circuit in the first aspect, and a control circuit, the current detection circuit being configured to detect a current in the circuit to be detected, and the control circuit being configured to control the circuit to be detected according to a measurement result of the current detection circuit.
In one possible implementation of the electronic device, the electronic device may be a power supply device.
In one possible embodiment of the electronic device, the detected circuit may be a motor.
Drawings
FIG. 1 is a schematic diagram of the components of an embodiment of the current sense circuit of the present application;
FIG. 2 is a circuit diagram of an embodiment of a current sensing circuit of the present application; and
fig. 3 is a schematic component diagram of an embodiment of an electronic device of the present application.
Detailed Description
The present application will now be described in detail with reference to the drawings attached hereto.
Some terms in the present application are first explained to facilitate understanding by those skilled in the art.
ADC: is called Analog-to-digital converter, and the translation into Chinese is: analog-to-digital converters, also referred to as analog-to-digital converters, are a class of devices used to convert continuous signals in analog form to discrete signals in digital form. An analog to digital converter may provide the signal for measurement. The device opposite to the analog-to-digital converter is called a digital-to-analog converter. A typical analog-to-digital converter can convert an analog signal to a digital signal representing a proportional voltage value.
A single chip microcomputer: the singlechip is an integrated circuit chip, which is a small and perfect microcomputer system formed by integrating functions (possibly including a display drive circuit, a pulse width modulation circuit, an analog multiplexer, an A/D converter and other circuits) of a Central Processing Unit (CPU), a Random Access Memory (RAM), a read-only memory (ROM), various input/output (I/O) ports, an interrupt system, a timer/counter and the like with data processing capacity on a silicon chip by adopting a super-large scale integrated circuit technology, and the singlechip is widely applied to the field of industrial control.
Exciting current: in english, Exciting Current is the Current flowing through the rotor of the synchronous motor (with this Current, the rotor is equivalent to an electromagnet, and has N and S poles). Conventionally, this dc voltage is supplied from a dc motor, and is currently supplied by rectifying it with a thyristor in most cases.
In the embodiment of the application, the measurement of the resistance ratio in the conventional transition transfer method is changed into the measurement of the potential ratio, and the resistance measurement of the voltammetry principle is changed into the ratio measurement method.
Current detecting circuit
As shown in fig. 1 and fig. 2, an embodiment of the present application provides a current detection circuit, which includes a detection module, an analog-to-digital converter and a processing module, wherein the detection module is configured to convert an input sampling current into a sampling voltage signal, the analog-to-digital converter is configured to compare the input sampling voltage signal with a reference fixed voltage and output a digital signal, and the processing module is configured to calculate and compare the digital signal with a standard value and obtain a measurement result.
In the embodiment of the current detection circuit, the measured signal and the reference fixed voltage (standard signal) are sampled simultaneously, and the processing module processes the two signals simultaneously, so that the influence of the test current error and the drift on the measurement result is eliminated, and the measurement accuracy is improved.
In an embodiment of the current detection circuit of the present application, the measurement result is a current value obtained according to detection by the current detection circuit.
In an embodiment of the current detection circuit of the present application, if the sampled current input to the detection module is a weak current, the detection module converts the weak sampled current into a weak voltage signal.
In fig. 2, the circuitry within the dashed box is the circuitry of one embodiment of the detection module.
As shown in fig. 2, in an embodiment of the current detection circuit of the present application, the analog-to-digital converter specifically includes an integrated operational amplifier, two input ends of the integrated operational amplifier are respectively a first input end and a second input end, the sampling voltage signal obtained by the detection module is input through the first input end, and the reference fixed voltage is input through the second input end. The integrated operational amplifier outputs a digital signal by comparing the input sampling voltage signal with the reference fixed voltage, thereby converting the sampling voltage signal into a digital signal.
The integrated operational amplifier samples the sampling voltage signal and the reference fixed voltage signal at the same time and carries out operational amplifier comparison processing. That is, an analog voltage signal is compared with a reference fixed voltage, and at a value around the same amplitude, the output voltage will make a transition, and correspondingly output a high level or a low level, thereby converting the analog signal of the sampling voltage signal into a digital signal.
In an embodiment of the current detection circuit of the present application, the analog-to-digital converter may further specifically include a plurality of integrated operational amplifiers, which are arranged in series. In particular, the analog-to-digital converter may include a first integrated operational amplifier and a second integrated operational amplifier.
The sampling voltage signal obtained by the detection module is input into one input end of the first integrated operational amplifier, and a signal output by the output end of the first integrated operational amplifier is input into the other input end of the first integrated operational amplifier. The signal output by the output end of the first integrated operational amplifier is input into one input end of the second integrated operational amplifier, and the reference fixed voltage is input into the other input end of the second integrated operational amplifier.
The amplifier on the left in fig. 2 is a specific implementation of the first integrated operational amplifier and the amplifier on the right in fig. 2 is a specific implementation of the second integrated operational amplifier.
In the embodiment of the current detection circuit, the first integrated operational amplifier and the second integrated operational amplifier are adopted, so that the double ADC samples the detected signal and the reference fixed voltage (standard signal) at the same time, the processing module processes the two signals at the same time, the influence of the test current error and the drift on the measurement result can be further eliminated, and the measurement accuracy is improved.
In the embodiment of the current detection circuit of the present application, the integrated operational amplifier in the analog-to-digital converter may adopt a high-precision operational amplifier circuit.
In the embodiment of the current detection circuit of the application, the analog-to-digital converter adopts the high-precision operational amplifier circuit to convert the analog signal of the sampling voltage signal into the digital signal, and because the ADC has high conversion accuracy, the measurement accuracy can be further improved, the voltage loss can be effectively reduced, the current range and the precision measurement can be increased, the power consumption can be reduced, the intelligent acquisition can be realized, the cost can be reduced, and the resource utilization efficiency can be improved.
Embodiments of the current detection circuit of the present application may be used to detect a direct current excitation current. That is, the sampling current may be a direct current excitation current.
In an embodiment of the current detection circuit of the present application, the processing module may be a single chip microcomputer. The processing module can also be a signal processing system of a single chip microcomputer.
In an embodiment of the current detection circuit of the present application, the analog-to-digital converter and the processing module may be integrally disposed together, for example: the analog-to-digital converter is arranged in the single chip microcomputer.
The singlechip is provided with an ADC (analog to digital converter), so that continuous signals in an analog form can be converted into digital signals, and the ADC is a bridge for measuring direct-current exciting current. With the development of ADC and single chip microcomputer and the low price thereof, the single chip microcomputer signal processing system based on ADC sampling is widely applied to a resistance measuring device and a resistance measuring instrument.
As shown in fig. 1, in an embodiment of the current detection circuit of the present application, a current divider may be further included, and the current divider is configured to sample a current to be measured and output a sampled current obtained by sampling to the detection module. The current divider is used for measuring direct current, the function of the current divider is equivalent to a resistor with small resistance value, and the current divider is manufactured according to the principle that voltage is generated at two ends of the resistor when the direct current passes through the resistor.
In the embodiment of the current detection circuit, a high-precision current divider with excellent low self-heating power coefficient and low additional phase shift can be adopted, so that the heat loss during the operation of a system can be greatly reduced, and the influence of the self-heating power coefficient of the current divider and the influence of the long-term stability of the resistance value of the current divider can be compensated.
As shown in FIG. 1 and FIG. 2, the current divider is connected to the 1MT +/1 MT-node of the circuit.
(II) electronic device
As shown in fig. 3, an embodiment of the present application further provides an electronic device, which includes a detected circuit 101, the current detection circuit 102 in the above embodiment, and a control circuit 103, where the current detection circuit 102 is configured to detect a current in the detected circuit 101, and the control circuit 103 is configured to control the detected circuit 101 according to a measurement result of the current detection circuit 102.
In an embodiment of the electronic device of the present application, the electronic device may be a power supply device.
In an embodiment of the electronic device of the present application, the detected circuit 101 may be a motor.
Although the subject matter of the present application has been described in language specific to structural features/functional/methodological acts, the specific structural features/functional/methodological acts are merely examples of the claimed subject matter and are not intended to limit the scope of the present application, as any person skilled in the art can readily devise many variations or alterations within the scope of the present disclosure.
Claims (10)
1. The circuit is characterized by comprising a detection module, an analog-to-digital converter and a processing module, wherein the detection module is used for converting an input sampling current into a sampling voltage signal, the analog-to-digital converter is used for comparing the input sampling voltage signal with a reference fixed voltage and outputting a digital signal, and the processing module is used for calculating and comparing the digital signal with a standard value and obtaining a measurement result.
2. The current detection circuit according to claim 1, wherein the analog-to-digital converter specifically includes an integrated operational amplifier, two input terminals of the integrated operational amplifier are a first input terminal and a second input terminal, respectively, the sampling voltage signal obtained by the detection module is input through the first input terminal, and the reference fixed voltage is input through the second input terminal. The integrated operational amplifier outputs a digital signal by comparing the input sampling voltage signal with the reference fixed voltage, thereby converting the sampling voltage signal into a digital signal.
3. The current sensing circuit of claim 1, wherein the analog-to-digital converter comprises a plurality of integrated operational amplifiers arranged in series.
4. The current sensing circuit of claim 1, wherein the analog-to-digital converter comprises a first integrated operational amplifier and a second integrated operational amplifier, the sampled voltage signal obtained by the sensing module is input to one input terminal of the first integrated operational amplifier, and a signal output from an output terminal of the first integrated operational amplifier is input to the other input terminal of the first integrated operational amplifier. The signal output by the output end of the first integrated operational amplifier is input into one input end of the second integrated operational amplifier, and the reference fixed voltage is input into the other input end of the second integrated operational amplifier.
5. The current detection circuit according to claim 1, further comprising a current divider for sampling a current to be measured and outputting a sampled current obtained by the sampling to the detection module.
6. The current sensing circuit of claim 1, wherein in one possible implementation of the current sensing circuit, the sampled current is a direct current excitation current.
7. The current detection circuit of claim 1, wherein the processing module is a single-chip microcomputer, or the processing module is a signal processing system of the single-chip microcomputer.
8. The current sense circuit of claim 1 wherein the analog-to-digital converter and the processing module are integrally disposed together.
9. An electronic apparatus, characterized in that the apparatus comprises a circuit to be detected for detecting a current in the circuit to be detected, a control circuit for controlling the circuit to be detected based on a measurement result of the current detection circuit, and the current detection circuit as claimed in any one of claims 1 to 5.
10. The electronic device of claim 9, wherein the detected circuit is a motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011056605.4A CN112067889A (en) | 2020-09-29 | 2020-09-29 | Current measurement circuit and equipment applying same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011056605.4A CN112067889A (en) | 2020-09-29 | 2020-09-29 | Current measurement circuit and equipment applying same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112067889A true CN112067889A (en) | 2020-12-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011056605.4A Pending CN112067889A (en) | 2020-09-29 | 2020-09-29 | Current measurement circuit and equipment applying same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112067889A (en) |
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2020
- 2020-09-29 CN CN202011056605.4A patent/CN112067889A/en active Pending
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