CN220795349U - Current detection circuit and current detection device - Google Patents
Current detection circuit and current detection device Download PDFInfo
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- CN220795349U CN220795349U CN202322221325.XU CN202322221325U CN220795349U CN 220795349 U CN220795349 U CN 220795349U CN 202322221325 U CN202322221325 U CN 202322221325U CN 220795349 U CN220795349 U CN 220795349U
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Abstract
The application provides a current detection circuit and current detection equipment, and current detection circuit includes: the first conversion circuit comprises an open-loop Hall current sensor, and the open-loop Hall current sensor is used for converting the measured current into a first voltage signal and outputting the first voltage signal through a signal pin; a reference voltage generating circuit for generating and outputting a second voltage signal having the same magnitude and polarity as the bias voltage; the differential proportion operation circuit is used for carrying out differential proportion operation on the first voltage signal and the second voltage signal and outputting a third voltage signal; the input end of the second conversion circuit is electrically connected with the output end of the differential proportion operation circuit, and the circuit is used for converting the third voltage signal into a corresponding current value to obtain the tested current. The current detection method and device solve the problem that current detection accuracy is low in the prior art.
Description
Technical Field
The present application relates to the field of current detection, and in particular, to a current detection circuit and a current detection device.
Background
How to accurately and conveniently measure the current is always the subject of continuous search for the pursuit of measurement technology. In the prior art, a current detection device adopting a magneto-resistance effect element is generally used for detecting current, and the current is easily interfered by external noise and electromagnetism during detection, so that the detection result is inaccurate.
Disclosure of Invention
The main object of the present application is to provide a current detection circuit and a current detection device, so as to solve the problem of lower accuracy of current detection in the prior art.
In order to achieve the above object, according to one aspect of the present application, there is provided a current detection circuit including: the first conversion circuit comprises an open-loop Hall current sensor, a part of a conductor carrying a measured current is positioned in a cavity of the open-loop Hall current sensor, the open-loop Hall current sensor is used for converting the measured current into a first voltage signal and then outputting the first voltage signal through a signal pin, and the first voltage signal comprises the sum of the bias voltage of the open-loop Hall current sensor and the voltage corresponding to the measured current; a reference voltage generating circuit for generating and outputting a second voltage signal, the second voltage signal being the same as the bias voltage; the differential proportion operation circuit comprises a first input end, a second input end and an output end, wherein the first input end of the differential proportion operation circuit is electrically connected with the signal pin, the second input end of the differential proportion operation circuit is electrically connected with the output end of the reference voltage generation circuit, and the differential proportion operation circuit is used for carrying out differential proportion operation on the first voltage signal and the second voltage signal and outputting a third voltage signal; the input end of the second conversion circuit is electrically connected with the output end of the differential proportion operation circuit, and the second conversion circuit is used for converting the third voltage signal into a corresponding current value to obtain the measured current.
Optionally, the reference voltage generating circuit includes: the first voltage dividing device comprises a first end and a second end, and the first end of the first voltage dividing device is used for being electrically connected with a first power supply; the second voltage division device comprises a first end and a second end, the first end of the second voltage division device is electrically connected with the second end of the first voltage division device, and the second end of the second voltage division device is grounded; the first operational amplifier comprises a non-inverting input end, an inverting input end and an output end, wherein the non-inverting input end of the first operational amplifier is electrically connected with the first end of the second voltage dividing device, the inverting input end of the first operational amplifier is electrically connected with the output end of the first operational amplifier, and the output end of the first operational amplifier is the output end of the reference voltage generating circuit.
Optionally, the reference voltage generating circuit further includes: the first end of the second voltage division device is electrically connected with the non-inverting input end of the first operational amplifier through the first load; the inverting input end of the first operational amplifier is electrically connected with the output end of the first operational amplifier through the second load; wherein the resistance of the first load is the same as that of the second load.
Optionally, the first voltage dividing device includes a first resistor, and the second voltage dividing device includes a second resistor.
Optionally, the differential proportional operation circuit includes: the first end of the third voltage dividing device is a first input end of the differential proportion operation circuit; the balance resistor comprises a first end and a second end, the first end of the balance resistor is electrically connected with the second end of the third voltage dividing device, and the second end of the balance resistor is grounded; the first end of the fourth voltage dividing device is a second input end of the differential proportion operation circuit; the second operational amplifier comprises a non-inverting input end, an inverting input end and an output end, wherein the non-inverting input end of the second operational amplifier is electrically connected with the first end of the balance resistor, the inverting input end of the second operational amplifier is electrically connected with the second end of the fourth voltage divider, and the output end of the second operational amplifier is the output end of the differential proportion operational circuit; the feedback resistor comprises a first end and a second end, wherein the first end of the feedback resistor is electrically connected with the inverting input end of the second operational amplifier, and the second end of the feedback resistor is electrically connected with the output end of the second operational amplifier.
Optionally, the resistance of the third voltage dividing device is the same as that of the fourth voltage dividing device, and the resistance of the balancing resistor is the same as that of the feedback resistor.
Optionally, the third voltage dividing device includes a third resistor, and the fourth voltage dividing device includes a fourth resistor.
Optionally, the second conversion circuit includes: the input end of the singlechip is electrically connected with the output end of the differential proportion operation circuit, and an analog-to-digital conversion module in the singlechip is used for carrying out analog-to-digital conversion on the third voltage signal to obtain converted voltage, and converting the converted voltage into a corresponding current value to obtain the tested current.
Optionally, the first conversion circuit further includes: the first end of the fifth resistor is used for being electrically connected with a second power supply, and the second end of the fifth resistor is electrically connected with a power supply pin of the open-loop Hall current sensor; and the first end of the capacitor is electrically connected with the power pin of the open-loop Hall current sensor, and the second end of the capacitor is electrically connected with the grounding pin of the open-loop Hall current sensor.
According to another aspect of the present application, there is provided a current detection apparatus including any one of the current detection circuits.
By means of the technical scheme, the open-loop Hall current sensor converts a detected current into a first voltage signal and outputs the first voltage signal to the first input end of the differential proportion operation circuit through the signal pin, the reference voltage generation circuit generates a second voltage signal and sends the second voltage signal to the second input end of the differential proportion operation circuit through the output end, the second voltage signal is identical to the bias voltage of the open-loop Hall current sensor, the first voltage signal and the second voltage signal are input into the differential proportion operation circuit, differential proportion operation is carried out through the differential proportion operation circuit, and finally the voltage signal after differential proportion operation is converted into a current signal through the second conversion circuit, so that detection of the detected current is achieved. Compared with the prior art, the single-ended tested signal is tested, the signal anti-interference capability is weak, the transmission distance is short, the open-loop Hall current sensor and the reference voltage generating circuit generate differential signals, and the differential signals are processed through the differential proportion operation circuit, so that the effect of relieving and even counteracting the influence of noise and electromagnetic interference on the first voltage signal is achieved, the anti-interference capability and the transmission distance of the tested signal are improved, and the finally obtained current value is accurate.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:
FIG. 1 shows a schematic diagram of a current detection circuit provided in accordance with an embodiment of the present application;
FIG. 2 shows a schematic diagram of a reference voltage generation circuit provided in accordance with an embodiment of the present application;
fig. 3 shows a schematic diagram of a differential proportional operation circuit provided according to an embodiment of the present application.
Wherein the above figures include the following reference numerals:
10. a first conversion circuit; 11. an open loop hall current sensor; 20. a reference voltage generation circuit; 30. a differential proportion operation circuit; 40. a second conversion circuit; 50. a first power supply; 60. a second power supply; 70. a third power supply; 80. a fourth power supply; 21. a first voltage dividing device; 22. a second voltage dividing device; 23. a first operational amplifier; 24. a first load; 25. a second load; 31. a third voltage dividing device; 32. balancing resistance; 33. a fourth voltage dividing device; 34. a second operational amplifier; 35. and (5) feeding back the resistor.
Detailed Description
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. Furthermore, in the description and in the claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element or "connected" to the other element through a third element.
As described in the background art, the current detection device in the prior art is easy to be interfered by external noise and electromagnetic waves when detecting current, so that the detection result is inaccurate.
In an exemplary embodiment of the present application, there is provided a current detection circuit, as shown in fig. 1, including:
the first conversion circuit 10 includes an open loop hall current sensor 11, a portion of a conductor carrying a measured current is located in a cavity of the open loop hall current sensor 11, the open loop hall current sensor 11 is configured to convert the measured current into a first voltage signal, and the first voltage signal is output through a signal pin, where the first voltage signal includes a sum of a bias voltage of the open loop hall current sensor 11 and a voltage corresponding to the measured current;
a reference voltage generating circuit 20 for generating and outputting a second voltage signal, wherein the second voltage signal is the same as the bias voltage, specifically, the second voltage signal has the same amplitude and the same polarity as the bias voltage;
a differential ratio operation circuit 30 including a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal of the differential ratio operation circuit 30 is electrically connected to the signal pin, the second input terminal of the differential ratio operation circuit 30 is electrically connected to the output terminal of the reference voltage generation circuit 20, and the differential ratio operation circuit 30 is configured to perform differential ratio operation on the first voltage signal and the second voltage signal, and output a third voltage signal;
the second conversion circuit 40, the input end of the second conversion circuit 40 is electrically connected to the output end of the differential ratio operation circuit 30, and the second conversion circuit 40 is configured to convert the third voltage signal into a corresponding current value, so as to obtain the measured current.
Through the above embodiment, in the current detection circuit of the present application, the open loop hall current sensor converts the detected current into the first voltage signal and outputs the first voltage signal to the first input end of the differential proportion operation circuit through the signal pin, the reference voltage generating circuit generates the second voltage signal and sends the second voltage signal to the second input end of the differential proportion operation circuit through the output end, the second voltage signal is the same as the bias voltage of the open loop hall current sensor, the first voltage signal and the second voltage signal are input into the differential proportion operation circuit, differential proportion operation is performed through the differential proportion operation circuit, and finally the voltage signal after differential proportion operation is converted into the current signal through the second conversion circuit, so as to realize the detection of the detected current. Compared with the prior art, the single-ended tested signal is tested, the signal anti-interference capability is weak, the transmission distance is short, the open-loop Hall current sensor and the reference voltage generating circuit generate differential signals, and the differential signals are processed through the differential proportion operation circuit, so that the effect of relieving and even counteracting the influence of noise and electromagnetic interference on the first voltage signal is achieved, the anti-interference capability and the transmission distance of the tested signal are improved, and the finally obtained current value is accurate.
Specifically, the bias voltage refers to a fixed bias voltage output by the open-loop hall current sensor when the input current is 0, the second voltage signal and the bias voltage have the same amplitude and the same polarity, and the second voltage signal and the bias voltage form a differential signal. Specifically, since the first voltage signal output by the open-loop hall current sensor has the bias voltage, the reference voltage generating circuit generates the second voltage signal having the same magnitude and polarity as those of the bias voltage, and inputs the first voltage signal and the second voltage signal to the differential ratio calculating circuit to perform differential operation, so that the bias voltage in the first voltage signal can be subtracted from the bias voltage to obtain a voltage value corresponding to the current to be measured, and the current to be measured can be accurately measured.
As shown in fig. 2, in one embodiment of the present application, the reference voltage generating circuit 20 includes: a first voltage divider 21, including a first end and a second end, where the first end of the first voltage divider 21 is electrically connected to the first power source 50; a second voltage divider 22 including a first end and a second end, the first end of the second voltage divider 22 being electrically connected to the second end of the first voltage divider 21, the second end of the second voltage divider 22 being grounded; the first operational amplifier 23 includes a non-inverting input terminal, an inverting input terminal, and an output terminal, the non-inverting input terminal of the first operational amplifier 23 is electrically connected to the first terminal of the second voltage divider 22, the inverting input terminal of the first operational amplifier 23 is electrically connected to the output terminal of the first operational amplifier 23, and the output terminal of the first operational amplifier 23 is the output terminal of the reference voltage generating circuit 20. The first voltage divider and the second voltage divider with proper resistance values are selected to enable the reference voltage generating circuit to generate a second voltage signal with the same amplitude and the same polarity as the bias voltage, and the first operational amplifier is arranged to enable the output end of the operational amplifier to be electrically connected with the inverting input end of the operational amplifier, so that the operational amplifier forms a voltage follower, the second voltage signal with the same phase input end is generated on the premise of not interfering with the preceding circuit (namely the voltage of the non-phase input end of the operational amplifier), meanwhile, the isolation buffer function is achieved, the interference of the following circuit (namely the voltage of the output end of the operational amplifier) to the preceding circuit is reduced, and the reference voltage generating circuit is enabled to be more stable.
Specifically, the first voltage divider may include a resistor, an inductor, and other components with a certain resistance value; the second voltage divider may include a resistor, an inductor, or other components having a certain resistance.
In other embodiments, as shown in fig. 2, the reference voltage generating circuit further includes: a first load 24, wherein a first end of the second voltage divider 22 is electrically connected to a non-inverting input terminal of the first operational amplifier 23 through the first load 24; a second load 25, wherein an inverting input terminal of the first operational amplifier 23 is electrically connected to an output terminal of the first operational amplifier 23 through the second load 25; wherein, the resistance of the first load 24 is the same as that of the second load 25. By setting the first load and the second load, proper resistance values are selected for voltage division, so that the voltage and the current of the non-inverting input end and the inverting input end of the operational amplifier are controlled, meanwhile, the isolation buffer effect between the front-stage circuit and the rear-stage circuit is achieved, the stability of the reference voltage generating circuit is further guaranteed, the resistance values of the first load and the second load are the same, the reference voltage generating circuit is matched and symmetrical, and the relation between the front-stage circuit and the rear-stage circuit is not affected.
Specifically, the first load may include a resistor, an inductor, and other components with a certain resistance value; the second load may include a resistor, an inductor, or other components having a certain resistance.
More specifically, in some embodiments, as shown in fig. 2, the first voltage divider 21 is a first resistor, and the second voltage divider 22 is a second resistor.
Specifically, in the reference voltage generating circuit, the first load, the second load, and the first operational amplifier form a voltage follower, and the second voltage signal V output from the reference voltage generating circuit OUT- The calculation formula of (2) is as follows:
wherein R is 1 R is the resistance of the second resistor 2 V is the resistance of the first resistor CC1 The power supply voltage value of the first power supply.
In still other alternatives of the present application, as shown in fig. 3, the differential proportional operation circuit 30 includes: a third voltage divider 31, wherein a first end of the third voltage divider 31 is a first input end of the differential ratio operation circuit 30; a balancing resistor 32 including a first end and a second end, wherein the first end of the balancing resistor 32 is electrically connected to the second end of the third voltage divider 31, and the second end of the balancing resistor 32 is grounded; a fourth voltage divider 33, wherein a first end of the fourth voltage divider 33 is a second input end of the differential ratio operation circuit 30; a second operational amplifier 34 including a non-inverting input terminal, an inverting input terminal, and an output terminal, the non-inverting input terminal of the second operational amplifier 34 being electrically connected to the first terminal of the balancing resistor 32, the inverting input terminal of the second operational amplifier 34 being electrically connected to the second terminal of the fourth voltage divider 33, the output terminal of the second operational amplifier 34 being the output terminal of the differential ratio operation circuit 30; and a feedback resistor 35 including a first end and a second end, wherein the first end of the feedback resistor 35 is electrically connected to the inverting input terminal of the second operational amplifier 34, and the second end of the feedback resistor 35 is electrically connected to the output terminal of the second operational amplifier 34. The voltage and the current of the non-inverting input end and the inverting input end of the second operational amplifier are controlled by setting the third voltage dividing device and the fourth voltage dividing device and selecting proper resistance for voltage division, so that the second operational amplifier can work under normal current and voltage, and the reliability and the stability of the differential proportional operation circuit are improved; by arranging the second operational amplifier, differential proportion operation is carried out on the first voltage signal and the second voltage signal which are input into the second operational amplifier, so that at least partial external noise can be counteracted; by setting the feedback resistor, the third voltage signal output by the output end of the second operational amplifier can be stabilized; by setting the balance resistor, the differential proportional operation circuit can be symmetrical, and the state reliability of the output end of the second operation amplifier can be improved.
Specifically, the third voltage divider may include a resistor, an inductor, and other components with a certain resistance value; the fourth voltage divider may include a resistor, an inductor, or other components having a certain resistance.
Specifically, the ratio value of the differential proportional amplifying circuit is the ratio of the feedback resistor to the fourth voltage divider; the ratio may be greater than 1, i.e., the resistance of the feedback resistor is greater than the resistance of the fourth voltage divider; the ratio may also be less than 1, i.e. the resistance of the feedback resistor is less than the resistance of the fourth voltage divider; the ratio may also be equal to 1, i.e. the resistance of the feedback resistor is equal to the resistance of the fourth voltage divider; the ratio is specifically determined by the difference between the first voltage signal and the second voltage signal and the maximum input voltage of the second conversion circuit, that is, the difference between the third voltage signal and the maximum input voltage of the second conversion circuit cannot be too large, and a person skilled in the art can flexibly select a suitable resistor to connect according to actual needs.
More specifically, in some embodiments, as shown in fig. 3, the resistance of the third voltage dividing device 31 and the fourth voltage dividing device 33 is the same, and the resistance of the balancing resistor 32 and the feedback resistor 35 is the same. Therefore, symmetry and stability of the differential proportional operation circuit can be further guaranteed.
More specifically, in some embodiments, as shown in fig. 3, the third voltage dividing device 31 is a third resistor, and the fourth voltage dividing device 33 is a fourth resistor.
Specifically, the third voltage signal V output from the differential ratio operation circuit OUT The calculation formula of (2) is as follows:
wherein R is 3 R is the resistance of the feedback resistor 4 V is the resistance of the fourth resistor OUT+ The voltage value of the first voltage signal.
In an actual application process, the signal output by the differential proportional operation circuit is generally an analog signal, and for convenience of detection, in other embodiments, the second conversion circuit includes: the input end of the singlechip is electrically connected with the output end of the differential proportion operation circuit, and an analog-to-digital conversion module in the singlechip is used for carrying out analog-to-digital conversion on the third voltage signal to obtain converted voltage, and converting the converted voltage into the corresponding current value to obtain the tested current. The singlechip converts the analog third voltage signal into a digital signal through an internal analog-to-digital conversion module, calculates and converts the digital signal into a corresponding current value to obtain the tested current, and further realizes a current detection function.
Of course, besides the above-mentioned single-chip microcomputer, the above-mentioned second conversion circuit may also be other devices with analog-to-digital conversion and signal processing functions, such as DSP (Digital Signal Processing, digital signal processor) and ARM (Advanced (Reduced Instruction Set Computer) Machines, advanced reduced instruction set computer) etc. Those skilled in the art can flexibly select a suitable device as the second conversion circuit according to actual needs.
Specifically, the corresponding relation between the voltage and the current is stored in the singlechip, and the current value corresponding to the converted voltage can be calculated and output according to the converted voltage obtained after analog-digital conversion through the corresponding relation. For example, the corresponding relation between the converted voltage and the current value may be i=v×x, where X is a proportionality coefficient between the converted voltage and the current value, and the single chip microcomputer includes an analog-to-digital converter and a multiplier. For another example, the single chip microcomputer includes an analog-to-digital converter and a register, the register stores a corresponding relation table of voltage and current, the analog-to-digital converter performs analog-to-digital conversion after receiving the voltage signal, then outputs the converted voltage to the register, and the register determines a current value corresponding to the converted voltage by searching the corresponding relation table and outputs the current value.
According to other embodiments of the present application, the second conversion circuit includes: the input end of the analog-to-digital converter is the input end of the second conversion circuit, and the analog-to-digital converter is used for carrying out analog-to-digital conversion on the third voltage signal to obtain a converted voltage; the input end of the combinational logic circuit is the output end of the analog-to-digital converter, and the combinational logic circuit is used for outputting the corresponding current value according to the input voltage after conversion.
In still other alternatives of the present application, the first conversion circuit further includes: a fifth resistor, wherein a first end of the fifth resistor is used for being electrically connected with a second power supply, and a second end of the fifth resistor is electrically connected with a power supply pin of the open-loop Hall current sensor; and the first end of the capacitor is electrically connected with the power pin of the open-loop Hall current sensor, and the second end of the capacitor is electrically connected with the grounding pin of the open-loop Hall current sensor.
Specifically, the first power supply is configured to supply power to the first conversion circuit, the second power supply is configured to supply power to the reference voltage generation circuit, and the first power supply and the second power supply may be the same or different.
In this embodiment, as shown in fig. 1, the first power supply 50 is the same as the second power supply 60.
Of course, as shown in fig. 1, the current detection circuit may further include: a third power supply 70 for supplying power to the differential ratio operation circuit 30; a fourth power supply 80 for supplying power to the second conversion circuit 40.
According to another aspect of the present application, there is also provided a current detection apparatus including any one of the above-described current detection circuits.
The current detection device comprises any one of the current detection circuits, wherein in the current detection circuit, the open-loop Hall current sensor converts the detected current into a first voltage signal and outputs the first voltage signal to the first input end of the differential proportion operation circuit through the signal pin, the reference voltage generation circuit generates a second voltage signal and sends the second voltage signal to the second input end of the differential proportion operation circuit through the output end, the second voltage signal is identical to the bias voltage of the open-loop Hall current sensor, the first voltage signal and the second voltage signal are input into the differential proportion operation circuit, differential proportion operation is carried out through the differential proportion operation circuit, and finally the voltage signal after the differential proportion operation is converted into the current signal through the second conversion circuit, so that the detected current is detected. Compared with the prior art, the single-ended tested signal is tested, the signal anti-interference capability is weak, the transmission distance is short, the open-loop Hall current sensor and the reference voltage generating circuit generate differential signals, and the differential signals are processed through the differential proportion operation circuit, so that the effect of relieving and even counteracting the influence of noise and electromagnetic interference on the first voltage signal is achieved, the anti-interference capability and the transmission distance of the tested signal are improved, and the finally obtained current value is accurate.
From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:
1) In the current detection circuit, the open-loop Hall current sensor converts the detected current into a first voltage signal and outputs the first voltage signal to the first input end of the differential proportion operation circuit through the signal pin, the reference voltage generation circuit generates a second voltage signal and sends the second voltage signal to the second input end of the differential proportion operation circuit through the output end, the second voltage signal is identical with the bias voltage of the open-loop Hall current sensor, the first voltage signal and the second voltage signal are input into the differential proportion operation circuit, differential proportion operation is carried out through the differential proportion operation circuit, and finally the voltage signal after differential proportion operation is converted into a current signal through the second conversion circuit, so that the detection of the detected current is realized. Compared with the prior art, the single-ended tested signal is tested, the signal anti-interference capability is weak, the transmission distance is short, the open-loop Hall current sensor and the reference voltage generating circuit generate differential signals, and the differential signals are processed through the differential proportion operation circuit, so that the effect of relieving and even counteracting the influence of noise and electromagnetic interference on the first voltage signal is achieved, the anti-interference capability and the transmission distance of the tested signal are improved, and the finally obtained current value is accurate.
2) The current detection device comprises any one of the current detection circuits, wherein in the current detection circuit, the open-loop Hall current sensor converts detected current into a first voltage signal and outputs the first voltage signal to the first input end of the differential proportion operation circuit through the signal pin, the reference voltage generation circuit generates a second voltage signal and sends the second voltage signal to the second input end of the differential proportion operation circuit through the output end, the second voltage signal is identical to bias voltage of the open-loop Hall current sensor, the first voltage signal and the second voltage signal are input into the differential proportion operation circuit, differential proportion operation is carried out through the differential proportion operation circuit, and finally the voltage signal after the differential proportion operation is converted into the current signal through the second conversion circuit, so that detection of the detected current is realized. Compared with the prior art, the single-ended tested signal is tested, the signal anti-interference capability is weak, the transmission distance is short, the open-loop Hall current sensor and the reference voltage generating circuit generate differential signals, and the differential signals are processed through the differential proportion operation circuit, so that the effect of relieving and even counteracting the influence of noise and electromagnetic interference on the first voltage signal is achieved, the anti-interference capability and the transmission distance of the tested signal are improved, and the finally obtained current value is accurate.
The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims (10)
1. A current detection circuit, comprising:
the first conversion circuit comprises an open-loop Hall current sensor, a part of a conductor carrying a measured current is positioned in a cavity of the open-loop Hall current sensor, the open-loop Hall current sensor is used for converting the measured current into a first voltage signal and then outputting the first voltage signal through a signal pin, and the first voltage signal comprises the sum of the bias voltage of the open-loop Hall current sensor and the voltage corresponding to the measured current;
a reference voltage generating circuit for generating and outputting a second voltage signal, the second voltage signal being the same as the bias voltage;
the differential proportion operation circuit comprises a first input end, a second input end and an output end, wherein the first input end of the differential proportion operation circuit is electrically connected with the signal pin, the second input end of the differential proportion operation circuit is electrically connected with the output end of the reference voltage generation circuit, and the differential proportion operation circuit is used for carrying out differential proportion operation on the first voltage signal and the second voltage signal and outputting a third voltage signal;
the input end of the second conversion circuit is electrically connected with the output end of the differential proportion operation circuit, and the second conversion circuit is used for converting the third voltage signal into a corresponding current value to obtain the measured current.
2. The current detection circuit according to claim 1, wherein the reference voltage generation circuit includes:
the first voltage dividing device comprises a first end and a second end, and the first end of the first voltage dividing device is used for being electrically connected with a first power supply;
the second voltage division device comprises a first end and a second end, the first end of the second voltage division device is electrically connected with the second end of the first voltage division device, and the second end of the second voltage division device is grounded;
the first operational amplifier comprises a non-inverting input end, an inverting input end and an output end, wherein the non-inverting input end of the first operational amplifier is electrically connected with the first end of the second voltage dividing device, the inverting input end of the first operational amplifier is electrically connected with the output end of the first operational amplifier, and the output end of the first operational amplifier is the output end of the reference voltage generating circuit.
3. The current detection circuit according to claim 2, wherein the reference voltage generation circuit further comprises:
the first end of the second voltage division device is electrically connected with the non-inverting input end of the first operational amplifier through the first load;
the inverting input end of the first operational amplifier is electrically connected with the output end of the first operational amplifier through the second load;
wherein the resistance of the first load is the same as that of the second load.
4. The current detection circuit of claim 2, wherein the first voltage divider device comprises a first resistor and the second voltage divider device comprises a second resistor.
5. The current detection circuit according to any one of claims 1 to 4, wherein the differential ratio operation circuit includes:
the first end of the third voltage dividing device is a first input end of the differential proportion operation circuit;
the balance resistor comprises a first end and a second end, the first end of the balance resistor is electrically connected with the second end of the third voltage dividing device, and the second end of the balance resistor is grounded;
the first end of the fourth voltage dividing device is a second input end of the differential proportion operation circuit;
the second operational amplifier comprises a non-inverting input end, an inverting input end and an output end, wherein the non-inverting input end of the second operational amplifier is electrically connected with the first end of the balance resistor, the inverting input end of the second operational amplifier is electrically connected with the second end of the fourth voltage divider, and the output end of the second operational amplifier is the output end of the differential proportion operational circuit;
the feedback resistor comprises a first end and a second end, wherein the first end of the feedback resistor is electrically connected with the inverting input end of the second operational amplifier, and the second end of the feedback resistor is electrically connected with the output end of the second operational amplifier.
6. The current detection circuit according to claim 5, wherein the third voltage dividing device and the fourth voltage dividing device have the same resistance, and the balance resistor and the feedback resistor have the same resistance.
7. The current detection circuit of claim 5, wherein the third voltage divider device comprises a third resistor and the fourth voltage divider device comprises a fourth resistor.
8. The current detection circuit according to any one of claims 1 to 4, wherein the second conversion circuit includes:
the input end of the singlechip is electrically connected with the output end of the differential proportion operation circuit, and an analog-to-digital conversion module in the singlechip is used for carrying out analog-to-digital conversion on the third voltage signal to obtain converted voltage, and converting the converted voltage into a corresponding current value to obtain the tested current.
9. The current detection circuit according to any one of claims 1 to 4, wherein the first conversion circuit further includes:
the first end of the fifth resistor is used for being electrically connected with a second power supply, and the second end of the fifth resistor is electrically connected with a power supply pin of the open-loop Hall current sensor;
and the first end of the capacitor is electrically connected with the power pin of the open-loop Hall current sensor, and the second end of the capacitor is electrically connected with the grounding pin of the open-loop Hall current sensor.
10. A current detection apparatus, characterized by comprising: the current detection circuit of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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