CN109752586B - PCB-based current detection device - Google Patents
PCB-based current detection device Download PDFInfo
- Publication number
- CN109752586B CN109752586B CN201910189990.0A CN201910189990A CN109752586B CN 109752586 B CN109752586 B CN 109752586B CN 201910189990 A CN201910189990 A CN 201910189990A CN 109752586 B CN109752586 B CN 109752586B
- Authority
- CN
- China
- Prior art keywords
- magnetic
- magnetic resistor
- resistor
- pcb
- lead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 62
- 230000035945 sensitivity Effects 0.000 claims abstract description 42
- 239000002184 metal Substances 0.000 claims description 7
- 230000006698 induction Effects 0.000 description 19
- 239000004020 conductor Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 3
- 230000005684 electric field Effects 0.000 description 3
- 230000017525 heat dissipation Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- FPWNLURCHDRMHC-UHFFFAOYSA-N 4-chlorobiphenyl Chemical compound C1=CC(Cl)=CC=C1C1=CC=CC=C1 FPWNLURCHDRMHC-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
The invention discloses a current detection device based on a PCB, wherein one device comprises: a PCB body; the lead is printed on the first surface of the PCB body and used for supplying current to be measured; the first magnetic resistor and the second magnetic resistor are arranged on the second surface of the PCB body, and the second surface is opposite to the first surface; the projection of the first magnetic resistor and the second magnetic resistor on the plane of the lead is different from the distance between the lead; the magnetic sensitivity directions of the first magnetic resistor and the second magnetic resistor are parallel to the PCB body, and the magnetic sensitivity directions of the first magnetic resistor and the second magnetic resistor are the same; the first magnetic resistor and the second magnetic resistor are connected in series, and two ends after being connected in series are connected with a power supply; and the input end of the signal processing module is connected between the first magnetic resistor and the second magnetic resistor and is used for acquiring and outputting a current value to be detected according to an electric signal between the first magnetic resistor and the second magnetic resistor. The current detection device based on the PCB provided by the invention has stronger capability of resisting the interference of an external magnetic field.
Description
Technical Field
The invention relates to the technical field of current sensors, in particular to a current detection device based on a PCB.
Background
The current detection product is widely applied to the fields of new energy, intelligent transportation, industrial control, intelligent household appliances, intelligent power grids and the like. The current detection product is usually a packaged chip, at least two pins of the chip are respectively used for leading in or leading out current to be detected, and the two pins are also connected through a wire inside the current detection chip; a magnetic sensor actually used for sensing a magnetic field to realize a function of detecting a current is also packaged in a chip, and the magnetic sensor is proximate to a wire connecting the two pins. The current detection chip has the following defects: (1) the withstand voltage of the chip is low; (2) The cross section area of the lead wire for connecting the two pins is smaller, so that the internal resistance of the lead wire is larger, the power consumption is larger, and the heat dissipation effect is poorer due to the chip type package, so that the chip is easy to generate heat.
To solve the above-mentioned drawbacks, the prior art provides a current detection device based on a PCB, as shown in fig. 1A and 1B, the current detection product includes a magnetic sensor 1, a wire 2 for passing a current to be detected, and a PCB board 3, wherein the magnetic sensor 1 and the wire 2 are respectively disposed on two opposite surfaces of the PCB board 3, and an "x" in the wire 2 indicates a direction of the current flowing in the wire (i.e., from one side of a paper or a screen to the other side of the paper or the screen). Because the PCB 3 is arranged between the magnetic sensor 1 and the lead 2 as a space, the magnetic field strength to be perceived by the magnetic sensor 1 can be reduced under the condition that the current to be detected is unchanged, so that the withstand voltage of a current detection product is improved, and the withstand voltage of the detection device can be further improved by adjusting the thickness and the size of the PCB. The conductor 2 can be printed on the board body when being manufactured into the PCB, and the conductor 2 is conveniently printed into various shapes, so that the width of the section of the conductor can be increased, the internal resistance of the conductor is reduced, the power consumption of the conductor is reduced, and the radiating effect of the printed conductor is better due to the fact that the radiating surface of the conductor is larger, so that the current detection device based on the PCB is less prone to heating.
However, the current detection device based on the PCB has weak capability of resisting the interference of external magnetic field, and for this reason, the existing product is usually provided with a shielding case outside the detection device to prevent the interference of external magnetic field. The common material (such as a metal material) may be capable of shielding the interference of the external electric field but not the interference of the external magnetic field, so that the shielding cover can only be made of a magnetic material. However, the magnetic shield causes hysteresis, and thus reduces the detection accuracy.
Disclosure of Invention
In view of this, the embodiment of the invention provides a current detection device based on a PCB, so as to solve the problem that the capability of the existing method for resisting the interference of external magnetic field is weak.
According to a first aspect, an embodiment of the present invention provides a PCB-based current detection apparatus, including: a PCB body; the lead is printed on the first surface of the PCB body and used for supplying current to be measured; the first magnetic resistor and the second magnetic resistor are arranged on the second surface of the PCB body, and the second surface is opposite to the first surface; the projection of the first magnetic resistor and the second magnetic resistor on the plane of the lead is different from the distance between the lead; the magnetic sensitivity directions of the first magnetic resistor and the second magnetic resistor are parallel to the PCB body, and the magnetic sensitivity directions of the first magnetic resistor and the second magnetic resistor are the same; the first magnetic resistor and the second magnetic resistor are connected in series, and two ends after being connected in series are connected with a power supply; and the input end of the signal processing module is connected between the first magnetic resistor and the second magnetic resistor, and is used for acquiring and outputting a current value to be detected according to the electric signal between the first magnetic resistor and the second magnetic resistor.
Optionally, the signal processing module is an operational amplifier, a first input end of the operational amplifier is connected between the first magnetic resistor and the second magnetic resistor, and a second input end of the operational amplifier is connected with a reference voltage.
Optionally, the reference voltage has a value that is half of the supply voltage.
According to a second aspect, an embodiment of the present invention provides a PCB-based current detection apparatus, comprising: a PCB body; the lead is printed on the first surface of the PCB body and used for supplying current to be measured; the first magnetic resistor, the second magnetic resistor, the third magnetic resistor and the fourth magnetic resistor are arranged on the second surface of the PCB body, and the second surface is opposite to the first surface; the first magnetic resistor and the second magnetic resistor are connected in series, two ends of the first magnetic resistor and the second magnetic resistor after being connected in series are connected with a power supply, the third magnetic resistor and the fourth magnetic resistor are connected in series, two ends of the first magnetic resistor and the third magnetic resistor after being connected in series are connected with the power supply, and the first magnetic resistor and the third magnetic resistor are connected with the same potential of the power supply; the distance between the projection of the first magnetic resistor on the plane of the lead and the lead is larger than the distance between the projection of the second magnetic resistor on the plane of the lead and the lead, and the distance between the projection of the fourth magnetic resistor on the plane of the lead and the lead is larger than the distance between the projection of the third magnetic resistor on the plane of the lead and the lead; the magnetic sensitivity directions of the first magnetic resistor, the second magnetic resistor, the third magnetic resistor and the fourth magnetic resistor are all parallel to the PCB body; the magnetic sensitivity directions of two magnetic resistors on the same serial branch are the same, the magnetic sensitivity directions of the magnetic resistors on different serial branches are different, or the magnetic sensitivity directions of four magnetic resistors are the same; the first input end of the signal processing module is connected between the first magnetic resistor and the second magnetic resistor, and the second input end of the signal processing module is connected between the third magnetic resistor and the fourth magnetic resistor; the signal processing module is used for acquiring a current value to be measured according to the electric signal between the first magnetic resistor and the second magnetic resistor and the electric signal between the third magnetic resistor and the fourth magnetic resistor.
Optionally, the distance between the projection of the first magnetic resistor and the fourth magnetic resistor on the plane of the lead and the lead is substantially equal, and the distance between the projection of the second magnetic resistor and the third magnetic resistor on the plane of the lead and the lead is substantially equal.
Optionally, the signal processing module is an operational amplifier.
Optionally, the projections of the respective magnetoresistors on the surface where the wire is located are all located on the same side of the wire.
Optionally, at least three detection units are included, the detection units including respective magneto-resistors and the wires.
Optionally, at least three of the wires are respectively used for passing three-phase current.
Optionally, the device further comprises a metal cover arranged on the second surface of the PCB board, and each magneto resistor and/or the signal processing module is/are located in the metal cover.
The current detection device based on the PCB provided by the embodiment of the invention has stronger capability of resisting the interference of an external magnetic field.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1A shows a side view of a prior art PCB-based current sensing device;
FIG. 1B shows a general structural schematic of a conventional PCB-based current sensing device;
FIG. 2A illustrates a side view of a PCB-based current sensing device according to an embodiment of the invention;
Fig. 2B is a schematic diagram showing the general structure of a PCB-based current detection apparatus according to an embodiment of the present invention;
FIG. 2C illustrates a top view of a PCB-based current detection device according to an embodiment of the invention;
FIG. 3 shows the electrical connection of the two magnetoresistors of FIGS. 2A, 2B, and 2C;
FIG. 4 is a schematic diagram showing electrical connections suitable for use in one of the operational amplifiers of FIG. 3;
FIG. 5A illustrates a side view of another PCB-based current sensing device according to an embodiment of the invention;
Fig. 5B illustrates an overall structural schematic of another PCB-based current detection apparatus according to an embodiment of the present invention;
FIG. 5C illustrates a top view of another PCB-based current detection device according to an embodiment of the invention;
FIG. 6 shows the electrical connection of the two magnetoresistors of FIGS. 5A, 5B, and 5C;
FIG. 7 is a schematic diagram showing electrical connections for an operational amplifier of FIG. 6;
Fig. 8A to 8H are schematic views showing the shape of a wire and the positional relationship with a magnetoresistive in a PCB-based current detecting apparatus according to an example of the present invention;
Fig. 9A to 9C show schematic diagrams of a PCB-based current detection apparatus including three detection units and respectively for passing three-phase currents.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.
The inventors have found that in existing PCB-based current detection devices, the magnetic sensor 1 often employs a hall sensor. Although the Hall sensor can convert the change amount of the magnetic field into an electric signal to be output, when the external magnetic field is disturbed, the Hall sensor also converts the external magnetic field into the electric signal to be output, so that the current detection device based on the PCB has weak capability of resisting the external magnetic field, and a magnetic shielding cover is required to be arranged. Based on this finding, the inventors have proposed a PCB-based current detection apparatus according to the present application, and the scheme of the present application will be described in detail below.
In the present application, the direction of magnetic sensitivity is a direction vector, and includes both "a direction in which a positive output value of the magnetic sensor increases (also referred to as a positive magnetic sensitivity direction) when a magnetic field in the direction increases" and "a direction in which a positive output value of the magnetic sensor decreases (also referred to as a negative magnetic sensitivity direction) when a magnetic field in the direction increases".
The application also provides that: when only the magnetic sensitive direction is mentioned, the magnetic sensitive direction comprises a positive magnetic sensitive direction and a negative magnetic sensitive direction, and the positive direction and the negative direction are not distinguished; when the magnetic sensitivity directions are the same or opposite, the positive magnetic sensitivity direction and the negative magnetic sensitivity direction are distinguished, that is, "the same magnetic sensitivity direction" means that the magnetic sensitivity directions are both positive magnetic sensitivity directions or both negative magnetic sensitivity directions, and "the magnetic sensitivity directions are opposite" means that one is positive magnetic sensitivity direction and the other is negative magnetic sensitivity direction.
Example 1
The embodiment of the invention provides a current detection device based on a PCB, wherein fig. 2A shows a side view thereof, fig. 2B shows a general structural schematic diagram thereof, fig. 2C shows a top view thereof, wherein 'x' in a wire 20 in fig. 2A indicates a direction of a current flowing in the wire (i.e. from one side of a paper or a screen to the other side of the paper or the screen where a reader is located), and arrows in the wire 20 in fig. 2B and 2C correspond to 'x' in fig. 2A and are also used for indicating the direction of the current flowing in the wire. The device comprises a first magneto resistor 11, a second magneto resistor 12, wires 20, a PCB body 30 and a signal processing module (not shown in fig. 2A, 2B and 2C).
The lead 20 is printed on the first surface of the PCB body 30 for passing a current to be measured. The first magnetic resistor 11 and the second magnetic resistor 12 are both arranged on the second surface of the PCB body 30, wherein the second surface of the PCB body is opposite to the first surface thereof. The projection of the first magnetic resistor 11 and the second magnetic resistor 12 on the plane of the wire 20 is different from the distance between the wires 20 (the projections of the first magnetic resistor 11 and the second magnetic resistor 12 on the surface of the wire 20 may be located on the same side of the wire 20, or may be located on two sides of the wire 20, respectively). The magnetic sensitivity directions of the first magnetic resistor 11 and the second magnetic resistor 12 are parallel to the PCB body, and the magnetic sensitivity directions of the first magnetic resistor and the second magnetic resistor are the same.
As shown in fig. 3, the first magnetic resistor 11 and the second magnetic resistor 12 are connected in series, and both ends after the series connection are connected to a power supply. The input end of the signal processing module is connected between the first magnetic resistor 11 and the second magnetic resistor 12, and is used for obtaining and outputting a current value to be detected according to an electric signal between the first magnetic resistor 11 and the second magnetic resistor 12.
Let R 1＝R0+k·B1 be the first magnetic resistance 11, wherein R 0 be the resistance value of the first magnetic resistance 11 when the magnetic induction is zero, B 1 be the magnetic induction where the first magnetic resistance 11 is located, and k be the rate of change of the first magnetic resistance 11; the resistance value of the second magnetic resistor 12 is R 2＝R0+k·B2, where R 0 is the resistance value of the second magnetic resistor 12 when the magnetic induction intensity is zero (the resistance values of the first magnetic resistor 11 and the second magnetic resistor 12 are equal when the magnetic induction intensity is zero), B 2 is the magnetic induction intensity where the second magnetic resistor 12 is located, and k is the change rate of the second magnetic resistor 12. Then the voltage between the first and second magneto-resistors 11 and 12 is
Wherein V cc is the supply voltage.
When no current is passed through the wires, the voltage between the first magnetic resistor 11 and the second magnetic resistor 12 should be V 0＝Vcc/2. Therefore, after power is applied, the difference between the output voltage of the first magnetic resistor 11 and the output voltage of the second magnetic resistor 12 and V 0 is:
it should be noted that, in the last step of the derivation of the above formula (1), since the value of R 0 is often far greater than the values of B 1 and B 2 in practical situations, 2R 0+k·(B1+B2) may be approximately 2R 0, so as to obtain the final result of the above formula (1).
As can be seen from the final result of the above formula (1), the current value to be measured can be obtained according to the difference between the voltage value output between the first magnetic resistor 11 and the second magnetic resistor 12 and the reference value, and the output result of the current to be measured depends on the difference of the magnetic induction intensities at the positions of the first magnetic resistor 11 and the second magnetic resistor 12 (the distance between the projection of the first magnetic resistor 11 and the second magnetic resistor 12 on the plane of the conductive line and the conductive line is different, so the above B 2-B1 is not necessarily 0). Therefore, even if there is interference of external magnetic field, the difference of magnetic induction intensity at the position where the two magnetic resistors with smaller distance are located is very small due to the smaller width of the wire 20, or the magnetic induction intensity of the external interference magnetic field at the position where the first magnetic resistor 11 and the second magnetic resistor 12 are located is almost equal due to the fact that the external magnetic field is usually uniform magnetic field (i.e. common mode interference), the difference of magnetic induction intensity at the position where the first magnetic resistor 11 and the second magnetic resistor 12 are located is not changed, so that the current detection device based on the PCB provided by the embodiment of the invention has stronger capability of resisting the interference of the external magnetic field.
However, in some cases, the external magnetic field is not a uniform magnetic field (i.e. differential mode interference), or the width of the wire 20 is set to be larger to increase the heat dissipation area, so that, to further improve the capability of the current detection device to resist differential mode interference, the projections of the first magnetic resistor 11 and the second magnetic resistor 12 on the surface where the wire 20 is located may be set to be located on the same side of the wire 20. The distance between the first magnetic resistor 11 and the second magnetic resistor 12 can be reduced, and even if the external magnetic field is not a uniform magnetic field, the difference value of the magnetic induction intensities of the two positions where the magnetic resistors with extremely small distances are located is very small, so that the influence on the detection result is small, and the capability of resisting differential mode interference of the current detection device is improved.
It should be noted that the reference value may be selected to be half of the power supply voltage value, or may be another fixed value. The signal processing module for obtaining the current value to be measured according to the difference between the voltage value output between the first magnetic resistor 11 and the second magnetic resistor 12 and the reference value may be an operational amplifier and its peripheral circuit, as shown in fig. 3 and 4, a first input terminal of the operational amplifier is connected between the first magnetic resistor 11 and the second magnetic resistor 12, a second input terminal is connected with the reference voltage, V o is the voltage between the first magnetic resistor 11 and the second magnetic resistor 12, V ref is the reference voltage, and may be set to half the power supply voltage value, i.e., V cc/2; or may be a module including a processor chip, or may be other electronic circuits, the application is not limited.
Alternatively, the wire 20 may be in a regular rectangular shape or a bar shape, for example, as shown in fig. 2C, where the connection line between the positions of the first magnetic resistor 11 and the second magnetic resistor 12 may be perpendicular to the current flowing in the wire 20, and/or the magnetically sensitive directions of the first magnetic resistor 11 and the second magnetic resistor 12 are perpendicular to the current flowing in the wire 20, so that the difference between the magnetic inductances sensed by the first magnetic resistor 11 and the second magnetic resistor 12 is larger (i.e. "the difference between the sensed magnetic inductances is not" the component of the difference between the magnetic inductances at the positions "), thereby improving the sensitivity of the detection device. As an alternative embodiment, the wire 20 may be irregularly shaped, as shown in fig. 8A to 8H (two squares in each figure represent the first and second magnetoresistors, respectively, and the area indicated by the dotted line represents the wire 20). In fig. 8A to 8H, four magnetic resistors described in the second embodiment may be provided at positions where two magnetic resistors are provided.
Example two
An embodiment of the present invention provides another PCB-based current detection device, fig. 5A shows a side view thereof, fig. 5B shows a general structural schematic view thereof, and fig. 5C shows a top view thereof. As can be seen from comparing fig. 2A to 2C, the device according to the embodiment of the present invention is different from the first embodiment in that the device includes four magnetic resistors, namely, a first magnetic resistor 11, a second magnetic resistor 12, a third magnetic resistor 13 and a fourth magnetic resistor 14, instead of two magnetic resistors. The specific arrangement of these four magnetic resistors in this embodiment will be described in detail below.
As shown in fig. 5A, the lead 20 for passing the current to be measured is printed on the first surface of the PCB board 30, and the first magnetic resistor 11, the second magnetic resistor 12, the third magnetic resistor 13, and the fourth magnetic resistor 14 are disposed on the second surface of the PCB board 30, where the second surface is opposite to the first surface. The projections of the four magnetic resistors on the surface of the conductive wire 20 may be all located on the same side of the conductive wire 20 (as shown in fig. 5B and 5C), or may be distributed on two sides of the conductive wire 20.
As shown in fig. 6, the first magnetic resistor 11 and the second magnetic resistor 12 are connected in series, both ends after the series connection are connected with a power supply, the third magnetic resistor 13 and the fourth magnetic resistor 14 are connected in series, both ends after the series connection are connected with the power supply, and the first magnetic resistor 11 and the third magnetic resistor 13 are connected with the same potential of the power supply. The distance between the projection of the first magnetic resistor 11 on the plane of the wire 20 and the wire 20 is "greater than" the distance between the projection of the second magnetic resistor 12 on the plane of the wire 20 and the wire 20 ", and the distance between the projection of the fourth magnetic resistor 14 on the plane of the wire 20 and the wire 20 is" greater than "the distance between the projection of the third magnetic resistor 13 on the plane of the wire 20 and the wire 20", so that the magnetic induction intensity at the position of the first magnetic resistor 11 is smaller than the magnetic induction intensity at the position of the second magnetic resistor 12, and the magnetic induction intensity at the position of the fourth magnetic resistor 14 is smaller than the magnetic induction intensity at the position of the third magnetic resistor 13. The magnetic sensitivity directions of the first magnetic resistor 11, the second magnetic resistor 12, the third magnetic resistor 13 and the fourth magnetic resistor 14 are all parallel to the PCB body 30, and the magnetic sensitivity directions of the two magnetic resistors on the same serial branch are the same, and the magnetic sensitivity directions of the magnetic resistors on different serial branches are different (namely, the magnetic sensitivity directions of the first magnetic resistor 11 and the second magnetic resistor 12 are the same, the magnetic sensitivity directions of the third magnetic resistor 13 and the fourth magnetic resistor 14 are the same, but the magnetic sensitivity directions of the first magnetic resistor 11 and the third magnetic resistor 13 are different).
The first input end of the signal processing module is connected between the first magnetic resistor 11 and the second magnetic resistor 12 (i.e. the V-position in fig. 6), and the second input end is connected between the third magnetic resistor 13 and the fourth magnetic resistor 14 (i.e. the V+ position in fig. 6); the signal processing module is used for obtaining a current value to be measured according to the electric signal between the first magnetic resistor 11 and the second magnetic resistor 12 and the electric signal between the third magnetic resistor 13 and the fourth magnetic resistor 14.
As shown in fig. 6, the first branch where the first magnetic resistor 11 and the second magnetic resistor 12 are located may be regarded as the circuit shown in fig. 3 alone, and the second branch where the third magnetic resistor 13 and the fourth magnetic resistor 14 are located may be regarded as the circuit shown in fig. 3 alone. Since the magnetic sensitivity directions of the two magnetic resistors on the same serial branch are the same, the magnetic sensitivity directions of the magnetic resistors on different serial branches are different, and the magnetic field directions of the positions where the four magnetic resistors are located are the same, when no current is conducted in the wire, the values of V- (namely, the voltage between the first magnetic resistor 11 and the second magnetic resistor 12) and V+ (namely, the voltage between the third magnetic resistor 13 and the fourth magnetic resistor 14) in fig. 6 are the same, and the difference between the two is 0; when current is passed through the wires, V-and v+ in fig. 6 change in opposite directions (i.e., one increases and the other decreases), respectively, by a factor of two. Therefore, compared with the first embodiment, the current detection device provided by the embodiment can improve the detection sensitivity while having stronger capability of resisting the interference of the external magnetic field.
Similarly to the first embodiment, when the external magnetic field is not a uniform magnetic field (i.e. differential mode interference), or the width of the wire 20 is set to be larger to increase the heat dissipation area, in order to further improve the capability of the current detection device to resist differential mode interference, the projections of the first magnetic resistor 11, the second magnetic resistor 12, the third magnetic resistor 13, and the fourth magnetic resistor 14 on the surface of the wire 20 may be disposed on the same side of the wire 20. The distance between two magnetic resistors on the same serial branch can be reduced, and even if the external magnetic field is not a uniform magnetic field, the difference value of the magnetic induction intensity of the position where the two magnetic resistors with extremely small distance are located is very tiny, so that the influence on the detection result is small, and the capability of the current detection device for resisting differential mode interference is improved.
In a similar embodiment, the signal processing module may be an operational amplifier and its peripheral circuit, as shown in fig. 6 and 7 (the same positions in the two figures are electrically connected); or may be a module including a processor chip, or may be other electronic circuits, the application is not limited.
Optionally, the distance between the projection of the first magnetic resistor 11 and the fourth magnetic resistor 14 on the plane of the wire 20 and the wire 20 is substantially equal, and the distance between the projection of the second magnetic resistor 12 and the third magnetic resistor 13 on the plane of the wire 20 and the wire 20 is substantially equal.
Example III
The embodiment of the invention provides a current detection device based on a PCB, which is unique in that the magnetic sensitivity directions of the four magnetic resistors are the same as those of the second embodiment.
As shown in fig. 6, the first branch where the first magnetic resistor 11 and the second magnetic resistor 12 are located may be regarded as the circuit shown in fig. 3 alone, and the second branch where the third magnetic resistor 13 and the fourth magnetic resistor 14 are located may be regarded as the circuit shown in fig. 3 alone. Since the magnetic induction intensity at the position where the first magnetic resistor 11 is located is smaller than the magnetic induction intensity at the position where the second magnetic resistor 12 is located, the magnetic induction intensity at the position where the fourth magnetic resistor 14 is located is smaller than the magnetic induction intensity at the position where the third magnetic resistor 13 is located, that is, when placed in a magnetic field environment, the variation amplitude of the first magnetic resistor is smaller than the second magnetic resistor, and the variation amplitude of the fourth magnetic resistor is smaller than the third magnetic resistor. Therefore, when no current is passed through the wires, the values of V- (i.e., the voltage between the first magnetic resistor 11 and the second magnetic resistor 12) and v+ (i.e., the voltage between the third magnetic resistor 13 and the fourth magnetic resistor 14) in fig. 6 are the same, and the difference between them is 0; when current is passed through the wires, V-and v+ in fig. 6 change in opposite directions (i.e., one increases and the other decreases), respectively, by a factor of two. Therefore, compared with the first embodiment, the current detection device provided in the embodiment can also improve the detection sensitivity while having stronger capability of resisting the interference of the external magnetic field.
As an alternative implementation manner of the first embodiment, the second embodiment or the third embodiment, the PCB-based current detection device includes at least three detection units, each detection unit includes the respective magnetic resistor and the wire described in the first embodiment, the second embodiment or the third embodiment, so that a plurality of detection units are disposed on one PCB board, and each detection unit may be used to detect one current to be detected. In particular, at least three wires may be used for passing three-phase currents, respectively. For example, in fig. 9A to 9C, the area between two dotted lines closest to each other represents a wire, three wires are used to pass A, B, C three-phase currents, two small squares on one side of each wire represent two magnetoresistors, and 30 represents a PCB body.
As an alternative implementation manner of the first embodiment, the second embodiment or the third embodiment, the PCB-based current detection apparatus further includes a metal cover, which is disposed on the second surface of the PCB board, and each of the magneto resistors and/or the signal processing module is located in the metal cover. The metal cover can shield the interference of an external electric field, and effectively eliminates the interference of the current to be detected (namely the interference of dv/dt on the magnetic resistor) and the interference of the space stray electric field on the magnetic resistor or each component of the signal processing module.
Alternatively, the magnetoresistance in the embodiments of the present application may be a TMR tunnel magnetoresistance with higher sensitivity and precision, or other magnetoresistance of the same kind, which is not limited by the present application.
Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations are within the scope of the invention as defined by the appended claims.
Claims (10)
1. A PCB-based current sensing apparatus, comprising:
a PCB body;
The lead is printed on the first surface of the PCB body and used for supplying current to be measured;
The first magnetic resistor and the second magnetic resistor are arranged on the second surface of the PCB body, and the second surface is opposite to the first surface; the projection of the first magnetic resistor and the second magnetic resistor on the plane of the lead is different from the distance between the lead; the magnetic sensitivity directions of the first magnetic resistor and the second magnetic resistor are parallel to the PCB body, and the magnetic sensitivity directions of the first magnetic resistor and the second magnetic resistor are the same; the first magnetic resistor and the second magnetic resistor are connected in series, and two ends after being connected in series are connected with a power supply;
and the input end of the signal processing module is connected between the first magnetic resistor and the second magnetic resistor, and is used for acquiring and outputting a current value to be detected according to the electric signal between the first magnetic resistor and the second magnetic resistor.
2. The PCB-based current detection device of claim 1 wherein,
The signal processing module is an operational amplifier, a first input end of the operational amplifier is connected between the first magnetic resistor and the second magnetic resistor, and a second input end of the operational amplifier is connected with a reference voltage.
3. The PCB-based current detection apparatus of claim 2 wherein the reference voltage is half the power supply voltage.
4. A PCB-based current sensing apparatus, comprising:
a PCB body;
The lead is printed on the first surface of the PCB body and used for supplying current to be measured;
The first magnetic resistor, the second magnetic resistor, the third magnetic resistor and the fourth magnetic resistor are arranged on the second surface of the PCB body, and the second surface is opposite to the first surface; the first magnetic resistor and the second magnetic resistor are connected in series, two ends of the first magnetic resistor and the second magnetic resistor after being connected in series are connected with a power supply, the third magnetic resistor and the fourth magnetic resistor are connected in series, two ends of the first magnetic resistor and the third magnetic resistor after being connected in series are connected with the power supply, and the first magnetic resistor and the third magnetic resistor are connected with the same potential of the power supply; the distance between the projection of the first magnetic resistor on the plane of the lead and the lead is larger than the distance between the projection of the second magnetic resistor on the plane of the lead and the lead, and the distance between the projection of the fourth magnetic resistor on the plane of the lead and the lead is larger than the distance between the projection of the third magnetic resistor on the plane of the lead and the lead; the magnetic sensitivity directions of the first magnetic resistor, the second magnetic resistor, the third magnetic resistor and the fourth magnetic resistor are all parallel to the PCB body; the magnetic sensitivity directions of two magnetic resistors on the same serial branch are the same, the magnetic sensitivity directions of the magnetic resistors on different serial branches are different, or the magnetic sensitivity directions of four magnetic resistors are the same;
The first input end of the signal processing module is connected between the first magnetic resistor and the second magnetic resistor, and the second input end of the signal processing module is connected between the third magnetic resistor and the fourth magnetic resistor; the signal processing module is used for acquiring a current value to be measured according to the electric signal between the first magnetic resistor and the second magnetic resistor and the electric signal between the third magnetic resistor and the fourth magnetic resistor.
5. The PCB-based current detection apparatus of claim 4, wherein the first and fourth magnetic resistances are substantially equidistant from a projection of the wire in a plane of the wire, and the second and third magnetic resistances are substantially equidistant from the wire.
6. The PCB-based current detection device of claim 4, wherein the signal processing module is an operational amplifier.
7. The PCB-based current detection apparatus of any one of claims 1 to 6, wherein the projections of each of the magnetic resistors onto the surface on which the wire is located are all located on the same side of the wire.
8. The PCB-based current detection apparatus of any one of claims 1 to 6, comprising at least three detection units including respective magneto-resistors and the wires.
9. The PCB-based current detection apparatus of claim 8, wherein at least three of the wires are each for passing a three-phase current.
10. The PCB-based current detection device of any one of claims 1 to 6, further comprising a metal cover disposed on the second surface of the PCB board, and wherein each of the magneto resistors and/or the signal processing module is located within the metal cover.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910189990.0A CN109752586B (en) | 2019-03-13 | 2019-03-13 | PCB-based current detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910189990.0A CN109752586B (en) | 2019-03-13 | 2019-03-13 | PCB-based current detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109752586A CN109752586A (en) | 2019-05-14 |
| CN109752586B true CN109752586B (en) | 2024-05-10 |
Family
ID=66408626
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910189990.0A Active CN109752586B (en) | 2019-03-13 | 2019-03-13 | PCB-based current detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109752586B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111257620A (en) * | 2020-02-28 | 2020-06-09 | 张苏 | Current detection device and method |
| CN113777384B (en) * | 2021-09-28 | 2023-12-12 | 南方电网数字电网研究院有限公司 | Method, device, computer equipment and storage medium for detecting four split conductor current |
| CN114264860A (en) * | 2021-12-21 | 2022-04-01 | 江苏多维科技有限公司 | Step type copper bar current detection device |
| CN116087588B (en) * | 2023-04-11 | 2023-10-13 | 江苏多维科技有限公司 | Current sensor for resisting external field interference |
| CN117405958B (en) * | 2023-12-14 | 2024-02-13 | 江苏多维科技有限公司 | current sensor |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005195427A (en) * | 2004-01-06 | 2005-07-21 | Asahi Kasei Electronics Co Ltd | Current measurement system, current measurement method, and current measurement program |
| CN102901858A (en) * | 2012-10-24 | 2013-01-30 | 无锡乐尔科技有限公司 | Current sensor |
| CN204989291U (en) * | 2015-08-26 | 2016-01-20 | 江苏多维科技有限公司 | Tunnel magneto resistor current sensor |
| CN107290584A (en) * | 2017-07-19 | 2017-10-24 | 无锡乐尔科技有限公司 | A kind of current sensor |
| CN208172078U (en) * | 2018-04-27 | 2018-11-30 | 宁波希磁电子科技有限公司 | A kind of current sensor |
| CN109374940A (en) * | 2018-11-30 | 2019-02-22 | 无锡乐尔科技有限公司 | The current measuring method and device of copper bar type conducting wire |
| CN209927923U (en) * | 2019-03-13 | 2020-01-10 | 无锡乐尔科技有限公司 | Current detection device based on PCB |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102012012759A1 (en) * | 2012-06-27 | 2014-01-02 | Sensitec Gmbh | Arrangement for current measurement |
| US9778288B2 (en) * | 2015-08-24 | 2017-10-03 | Texas Instruments Incorporated | Fluxgate-based current sensor |
-
2019
- 2019-03-13 CN CN201910189990.0A patent/CN109752586B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005195427A (en) * | 2004-01-06 | 2005-07-21 | Asahi Kasei Electronics Co Ltd | Current measurement system, current measurement method, and current measurement program |
| CN102901858A (en) * | 2012-10-24 | 2013-01-30 | 无锡乐尔科技有限公司 | Current sensor |
| CN204989291U (en) * | 2015-08-26 | 2016-01-20 | 江苏多维科技有限公司 | Tunnel magneto resistor current sensor |
| CN107290584A (en) * | 2017-07-19 | 2017-10-24 | 无锡乐尔科技有限公司 | A kind of current sensor |
| CN208172078U (en) * | 2018-04-27 | 2018-11-30 | 宁波希磁电子科技有限公司 | A kind of current sensor |
| CN109374940A (en) * | 2018-11-30 | 2019-02-22 | 无锡乐尔科技有限公司 | The current measuring method and device of copper bar type conducting wire |
| CN209927923U (en) * | 2019-03-13 | 2020-01-10 | 无锡乐尔科技有限公司 | Current detection device based on PCB |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109752586A (en) | 2019-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109752586B (en) | PCB-based current detection device | |
| US9176203B2 (en) | Apparatus and method for in situ current measurement in a conductor | |
| CN102016606B (en) | Arrangements for current sensing circuit and integrated current sensor | |
| US9372240B2 (en) | Current sensor | |
| US7642768B1 (en) | Current sensor having field screening arrangement including electrical conductors sandwiching magnetic permeability layer | |
| EP2174152B1 (en) | Current sensor having sandwiched magnetic permeability layer | |
| WO2023065894A1 (en) | Magnetic sensor apparatus | |
| US11022632B2 (en) | Electric current sensor | |
| US11016124B2 (en) | Integrated current sensor | |
| US11879951B2 (en) | Magnetic field sensor apparatus | |
| CN209927923U (en) | Current detection device based on PCB | |
| WO2017213003A1 (en) | Magneto-impedance sensor | |
| CN209927922U (en) | Current detection device based on PCB | |
| US11009569B2 (en) | Magnetic field sensing device | |
| US20220381805A1 (en) | Differential signal current sensor | |
| JP2012098202A (en) | Current sensor | |
| CN212207492U (en) | Current sensor | |
| US11994541B2 (en) | Current sensor assemblies for low currents | |
| US10866267B2 (en) | Electric current sensor | |
| WO2011111456A1 (en) | Current measurement device | |
| JPWO2014188669A1 (en) | Current sensor | |
| WO2015125233A1 (en) | Current detection device | |
| CN113533825A (en) | Current measurement method capable of eliminating common-mode interference based on magnetoresistive sensor | |
| JP2016142651A (en) | Power sensor | |
| JP2005321202A (en) | Current sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20210817 Address after: 315221 No. 1, Jinxi Road, Jiaochuan street, Zhenhai District, Ningbo City, Zhejiang Province Applicant after: NING BO SINOMAGS ELECTRONIC TECHNOLOGY Co.,Ltd. Address before: 214131 999-8-a2-501, gaolang East Road, Wuxi City, Jiangsu Province Applicant before: Wuxi Ler Technology Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |