CN117890651A - Series magnetic current sensor capable of eliminating influence of external interference magnetic field - Google Patents
Series magnetic current sensor capable of eliminating influence of external interference magnetic field Download PDFInfo
- Publication number
- CN117890651A CN117890651A CN202410049272.4A CN202410049272A CN117890651A CN 117890651 A CN117890651 A CN 117890651A CN 202410049272 A CN202410049272 A CN 202410049272A CN 117890651 A CN117890651 A CN 117890651A
- Authority
- CN
- China
- Prior art keywords
- magnetic
- magnetoresistive
- unit
- magnetic resistance
- magnetic field
- 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.)
- Pending
Links
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 280
- 230000008859 change Effects 0.000 claims abstract description 17
- 239000004020 conductor Substances 0.000 claims description 9
- 238000002955 isolation Methods 0.000 claims description 6
- 230000005290 antiferromagnetic effect Effects 0.000 claims description 5
- 230000035945 sensitivity Effects 0.000 abstract description 13
- 238000001514 detection method Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 9
- 230000005415 magnetization Effects 0.000 description 9
- 239000000758 substrate Substances 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000005224 laser annealing Methods 0.000 description 3
- 230000004075 alteration Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000002885 antiferromagnetic material Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
- G01R15/205—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using magneto-resistance devices, e.g. field plates
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R17/00—Measuring arrangements involving comparison with a reference value, e.g. bridge
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
The invention belongs to the technical field of current sensors, and particularly relates to a serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field, which comprises a first magnetic resistance unit and a second magnetic resistance unit, wherein the first magnetic resistance unit and the second magnetic resistance unit are connected to a power supply pin, and the third magnetic resistance unit and the fourth magnetic resistance unit are connected to a grounding pin; the first magnetic resistance unit is connected in series with the seventh magnetic resistance unit, the fourth magnetic resistance unit is connected in series with the sixth magnetic resistance unit, and a signal output pin Vout2 is led out between the seventh magnetic resistance unit and the sixth magnetic resistance unit; the second magnetic resistance unit is connected with the eighth magnetic resistance unit in series, the third magnetic resistance unit is connected with the fifth magnetic resistance unit in series, and a signal output pin Vout1 is led out between the eighth magnetic resistance unit and the fifth magnetic resistance unit. According to the invention, V mid is not interfered by an external interference magnetic field component H x by changing the Wheatstone bridge structure; the bias magnetic field with opposite directions generated by the magnetic field generating device is increased, and the sensitivity change caused by the external disturbance magnetic field component H y is reduced.
Description
Technical Field
The invention belongs to the technical field of current sensors, and particularly relates to a serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field.
Background
The magnetic sensor is a sensor that converts a magnetic field generated by a magnet, a current, or the like into a voltage signal. In modern industry and in electronics applications, magnetic sensors are most widely used to measure physical parameters such as current, position, orientation, etc. In the prior art, there are many different types of magnetic sensors, most commonly those using Hall (Hall) elements, anisotropic magnetoresistance (Anisotropic Magneto-Resistance, AMR), giant magnetoresistance (Giant Magneto-Resistance, GMR), tunnel Magnetoresistance (TMR) as the core.
Sensors with anisotropic magnetoresistance as the core are called AMR magnetoresistive sensors. When the magnetic metal encounters an external magnetic field, the resistance value of the magnetic metal changes along with the change of the external magnetic field (as shown in fig. 1). Based on this characteristic, the basic structure of the AMR magnetoresistive sensor is composed of four magnetoresistors forming a wheatstone bridge (as shown in fig. 2 and 3), with the magnetoresistors R1 and R2 on the left side of the chip and the magnetoresistors R3 and R4 on the right side of the chip. When the magnetic field generated by the detected current needs to be detected, if the magnetization direction of the magnetic resistance R1 rotates in the direction opposite to the current, the resistance value is reduced, and if the magnetization direction of the magnetic resistance R2 rotates in the direction opposite to the current, the resistance value is increased, the Vout1 voltage signal can be obtained according to a voltage division formula, the Vout2 voltage signal can be obtained by the same, and the detected magnetic field value can be obtained by testing the Vout1 and Vout2 output voltage difference signals, so that the purpose of measuring the current is achieved.
Patent application number 201811600055.0, chinese patent entitled integrated current sensor, describes a novel current sensor structure, the sensor basic principle is: as shown in fig. 4, the directions of the detected magnetic fields applied to the first group of magnetoresistive units and the second group of magnetoresistive units on the left and right sides are different, and the sensor generates signal output to achieve the purpose of detecting current. But also has the following drawbacks in that it exhibits superior performance: 1. when the external disturbance magnetic field exists in the constant current driving, the external disturbance magnetic field component H x causes the V mid (signal output value when the detected magnetic field is 0), vout1 and Vout2 to change, and the detection accuracy of the current sensor is further reduced. 2. The ambient disturbing magnetic field component H y causes a large change in sensitivity, deteriorating detection accuracy, but we expect that the ambient disturbing magnetic field component H y does not affect the sensitivity of the sensor. 3. The first magnet and the second magnet are large in size, and outside the chip, the process flow is complex, the manufacturing cost is high, and the period is long.
Disclosure of Invention
The invention aims to solve the problems in the prior art, and provides a serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field, wherein V mid is not interfered by an external interference magnetic field component H x by changing the structure of a Wheatstone bridge; by increasing the bias magnetic field generated by the magnetic field generating device in opposite directions, the sensitivity change caused by the external disturbance magnetic field component H y can be reduced.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
A serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field comprises a conductor, an isolation device and a magnetic resistance sensing device, wherein the isolation device is positioned between the magnetic resistance sensing device and the conductor; the magnetic resistance sensing device comprises a first left-side set of magnetic resistance units and a second right-side set of magnetic resistance units, a Wheatstone bridge is formed, and the current flowing through the conductor senses detected magnetic fields with equal magnitudes and opposite directions in the first set of magnetic resistance units and the second set of magnetic resistance units; the first group of magnetoresistive units comprises a first magnetoresistive unit, a second magnetoresistive unit, a third magnetoresistive unit and a fourth magnetoresistive unit from left to right, the second group of magnetoresistive units comprises a fifth magnetoresistive unit, a sixth magnetoresistive unit, a seventh magnetoresistive unit and an eighth magnetoresistive unit from left to right, the first magnetoresistive unit and the second magnetoresistive unit are connected to a power supply pin, and the third magnetoresistive unit and the fourth magnetoresistive unit are connected to a grounding pin; the first magnetic resistance unit is connected with the seventh magnetic resistance unit in series, the fourth magnetic resistance unit is connected with the sixth magnetic resistance unit in series, and a signal output pin Vout2 is led out between the seventh magnetic resistance unit and the sixth magnetic resistance unit; the second magnetic resistance unit is connected with the eighth magnetic resistance unit in series, the third magnetic resistance unit is connected with the fifth magnetic resistance unit in series, and a signal output pin Vout1 is led out between the eighth magnetic resistance unit and the fifth magnetic resistance unit.
According to the serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field, further, each magnetoresistive unit comprises a magnetoresistive strip and a plurality of mutually parallel shorting strips which are arranged on the magnetoresistive strip and form a preset angle with the magnetoresistive strip.
According to the serial magnetic current sensor capable of eliminating the influence of the external interference magnetic field, the directions of the short circuit strips of the first group of magnetic resistance units and the second group of magnetic resistance units are symmetrical along the central axis of the long axis of the magnetic resistance sensing device.
According to the serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field, the inclination directions and angles of the short circuit strips of the first magnetic resistance unit, the sixth magnetic resistance unit, the eighth magnetic resistance unit and the third magnetic resistance unit are consistent; and the inclination directions and angles of the short circuit strips of the seventh magnetic resistance unit, the fourth magnetic resistance unit, the second magnetic resistance unit and the fifth magnetic resistance unit are consistent.
According to the serial magnetic current sensor capable of eliminating the influence of the external interference magnetic field, further, the resistance values of the first and seventh magnetoresistive units, the second and eighth magnetoresistive units, the sixth and fourth magnetoresistive units and the third and fifth magnetoresistive units are increased or decreased together under the influence of the detected magnetic field.
According to the serial magnetic current sensor capable of eliminating the influence of the external disturbance magnetic field, further, when the external disturbance magnetic field component H x parallel to the width direction of the magnetoresistive strip exists, the resistance value change trend of the first magnetoresistive unit and the seventh magnetoresistive unit, the second magnetoresistive unit and the eighth magnetoresistive unit, the sixth magnetoresistive unit and the fourth magnetoresistive unit and the third magnetoresistive unit and the fifth magnetoresistive unit are opposite.
The serial magnetic current sensor capable of eliminating the influence of external interference magnetic fields further comprises a magnetic field generating device arranged below the magnetic resistance sensing device, wherein the magnetic field generating device adopts a two-pole magnet or a four-pole magnet to generate bias magnetic fields with opposite magnetic field directions for the first group of magnetic resistance units and the second group of magnetic resistance units.
According to the serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field, further, the coil is arranged in the magnetic resistance sensing device, and the directions of coil currents in the first group of magnetic resistance units on the left side and the second group of magnetic resistance units on the right side are opposite, so that the directions of bias magnetic fields generated by the coil currents are opposite.
According to the serial magnetic current sensor capable of eliminating the influence of the external interference magnetic field, an antiferromagnetic layer is additionally arranged below the magnetoresistive strips, and the exchange bias magnetic field is applied to the first group of magnetoresistive units and the second group of magnetoresistive units, and the directions of the exchange bias magnetic fields are opposite.
According to the serial magnetic current sensor capable of eliminating the influence of the external interference magnetic field, further, the first group of magnetic resistance units and the second group of magnetic resistance units do not cross each other in a physical space.
Compared with the prior art, the invention has the following advantages:
1. when the serial magnetic current sensor is driven by constant current and has the external interference magnetic field component H x, if the midpoint potential V mid, vout1 and Vout2 are changed, the detection precision of the sensor is reduced, and the structure of the Wheatstone bridge is changed, so that V mid is not interfered by the external interference magnetic field component H x, and the detection accuracy and reliability of the sensor are improved.
2. When the external disturbance magnetic field component H y exists, the sensitivity of the sensor is changed, in order to solve the problem, the bias magnetic field with opposite directions is generated by the magnetic field generating device, the magnetization direction in each magnetoresistive unit is changed by using the bias magnetic field, when the external disturbance magnetic field component H y is in the same direction with the magnetization direction, the sensitivity is reduced, if the external disturbance magnetic field component H y is in the opposite directions, the sensitivity is increased, and the bias magnetic field with opposite directions is sensed by the left magnetoresistive unit and the right magnetoresistive unit, so that the sensitivity change of the whole sensor is small, and the detection precision is improved.
3. The invention realizes that the first group of magnetoresistive units and the second group of magnetoresistive units generate bias magnetic fields with opposite magnetic field directions by arranging the magnetic field generating device below the magnetoresistive sensing device, inside the magnetoresistive sensing device or below the magnetoresistive strips, wherein the magnetic field generating device can adopt a dipolar magnet/quadrupole magnet, an electrified coil or an antiferromagnetic layer. The arrangement mode of the magnetic field generating device occupies small volume, and realizes miniaturization of the current sensor.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a graph showing the relationship between the resistance value and the applied magnetic field of the prior AMR magnetoresistive structure;
FIG. 2 is a circuit diagram of a Wheatstone bridge of a prior art AMR magnetoresistive sensor;
FIG. 3 is a practical block diagram of a Wheatstone bridge of a prior art AMR magnetoresistive sensor;
FIG. 4 is a schematic diagram of a prior art integrated current sensor showing the direction of a sensed current and a sensed magnetic field;
FIG. 5 is a schematic diagram of a Wheatstone bridge of a first set of magnetoresistive cells and a second set of magnetoresistive cells in accordance with an embodiment of the invention;
FIG. 6 is a circuit diagram of a Wheatstone bridge of a first set of magnetoresistive cells and a second set of magnetoresistive cells in accordance with an embodiment of the invention;
FIG. 7 is a graph of the resistance of each magnetoresistive cell of the first set of magnetoresistive cells versus the magnetic field being sensed in accordance with an embodiment of the invention;
FIG. 8 is a graph showing the variation of the resistance of each magnetoresistive cell of the first set of magnetoresistive cells under the influence of the external disturbance magnetic field component H x in accordance with an embodiment of the present invention;
FIG. 9 is a circuit diagram of a Wheatstone bridge of a prior art magnetoresistive sensing device;
FIG. 10 is a graph showing the variation of the resistance of each magnetoresistive cell of the first group of magnetoresistive cells under the influence of an external disturbing magnetic field component H x in the prior art;
FIG. 11 is a graph of a prior art signal output Vout versus current generation of a sensed magnetic field;
FIG. 12 is a graph showing the relationship between the signal output Vout and the current generated magnetic field to be detected according to an embodiment of the present invention;
FIG. 13 is an exemplary diagram of a magnetic field generating device employing a magnet in accordance with an embodiment of the present invention;
FIG. 14 is an exemplary diagram of a magnetic field generating device embodying the present invention employing a built-in energized coil;
FIG. 15 is an exemplary illustration of a magnetic field generating device employing antiferromagnetic material in accordance with an embodiment of the invention;
FIG. 16 is a schematic diagram of the principle of eliminating the influence of H y by using a bias magnetic field with opposite directions according to an embodiment of the present invention;
FIG. 17 is a graph comparing sensitivity variation trends of an embodiment of the present invention with the prior art.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. 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 be within the scope of the invention.
The serial magnetic current sensor capable of eliminating the influence of external interference magnetic fields in this embodiment includes a conductor, an isolation device and a magnetoresistive sensing device, the isolation device is located between the magnetoresistive sensing device and the conductor, the magnetoresistive sensing device includes a substrate, a first group of magnetoresistive units arranged on the left side of the substrate and a second group of magnetoresistive units arranged on the right side of the substrate, the two groups of magnetoresistive units do not intersect in physical space (so that bias magnetic fields in different directions can be conveniently set), the first group of magnetoresistive units and the second group of magnetoresistive units form a wheatstone bridge, and currents flowing through the conductor sense detected magnetic fields with equal magnitudes and opposite directions in the first group of magnetoresistive units and the second group of magnetoresistive units (refer to fig. 4). The key improvement point of this embodiment is that the first group of magnetoresistive units and the second group of magnetoresistive units are shown in fig. 5 and 6, the first group of magnetoresistive units comprises a first magnetoresistive unit R11, a second magnetoresistive unit R31, a third magnetoresistive unit R42 and a fourth magnetoresistive unit R22 which are distributed from left to right, the second group of magnetoresistive units comprises a fifth magnetoresistive unit R41, a sixth magnetoresistive unit R21, a seventh magnetoresistive unit R12 and an eighth magnetoresistive unit R32 which are distributed from left to right, the first magnetoresistive unit R11 and the second magnetoresistive unit R31 are connected to a power supply pin, the third magnetoresistive unit R42 is connected with a fourth magnetoresistive unit R22 to a ground pin, the first magnetoresistive unit R11 is connected with the seventh magnetoresistive unit R12 in series, the fourth magnetoresistive unit R22 is connected with the sixth magnetoresistive unit R21 in series, a signal output pin 2 is led out between the seventh magnetoresistive unit R12 and the sixth magnetoresistive unit R21, the second magnetoresistive unit R31 is connected with the eighth magnetoresistive unit R32 in series, and the fifth magnetoresistive unit R41 is led out between the fifth magnetoresistive unit R41 and the fifth magnetoresistive unit R32.
Each of the above magnetoresistive units comprises a magnetoresistive strip and a plurality of mutually parallel short-circuit strips which are arranged on the magnetoresistive strip and form a preset angle with the magnetoresistive strip, and the direction of working current is changed by utilizing the obliquely placed short-circuit strips. When the direction of the operating current is changed by the shorting bar, the resistance of the magnetoresistive cell exhibits an opposite trend of change with the value of the applied magnetic field, which is inherent to the magnetic resistance, as shown in fig. 1. It is desirable to define the xyz axis as used herein below, with the x axis representing the direction parallel to the width of the magnetoresistive strips, the y axis representing the direction parallel to the length of the magnetoresistive strips, and the z axis representing the direction parallel to the thickness of the magnetoresistive strips.
As shown in fig. 5, the shorting bar directions of the first and second sets of magnetoresistive cells are symmetrical along the major axis of the magnetoresistive sensor device.
Further, the shorting bars of the first, sixth, eighth, and third magnetoresistive units R11, R21, R32, R42 are identical in inclination direction and angle. The shorting bar inclination directions and angles of the seventh magnetoresistive unit R12, the fourth magnetoresistive unit R22, the second magnetoresistive unit R31 and the fifth magnetoresistive unit R41 are identical. As can be seen from fig. 5 and 6, the two directions are opposite.
In the present embodiment, the directions of the detected magnetic fields sensed by the first, second, third and fourth magnetoresistive units R11, R31, R42 and R22 located at the left side of the substrate are rightward, and the directions of the detected magnetic fields sensed by the fifth, sixth, seventh and eighth magnetoresistive units R41, R21, R12 and R32 located at the right side of the substrate are leftward. As shown in fig. 7, when the magnetoresistive cells are subjected to the detected magnetic field, the resistance values of the first magnetoresistive cell R11 and the seventh magnetoresistive cell R12 become large together, the resistance values of the sixth magnetoresistive cell R21 and the fourth magnetoresistive cell R22 become small together, the resistance values of the second magnetoresistive cell R31 and the eighth magnetoresistive cell R32 become small together, and the resistance values of the fifth magnetoresistive cell R41 and the third magnetoresistive cell R42 become large together, so that the resistance values on both sides of Vout2 (Vout 1) become large one by one, and the change in signal output occurs with the change in the detected magnetic field, and the detected magnetic field value is detected. For example, under constant current driving, the total resistance R1 of the detected magnetic fields H, R11 and R12 is changed from 1000 ohms to 1020 ohms, and the total resistance R2 of the R21 and R22 is changed from 1000 ohms to 980 ohms, so that it is assumed that icc=2ma according to the calculation formula , vout2 is changed from 1000mV to 980mV, and similarly, the signal change analysis of Vout1 on the right side in fig. 6 is referred to above, and the detected magnetic field is detected through the signal output change, so the wheatstone bridge structure is designed to satisfy the most basic current detection purpose of the current sensor.
When there is an external disturbing magnetic field component H x parallel to the width direction of the magnetoresistive strip, the resistance value change trends of the first magnetoresistive unit R11 and the seventh magnetoresistive unit R12, the second magnetoresistive unit R31 and the eighth magnetoresistive unit R32, the sixth magnetoresistive unit R21 and the fourth magnetoresistive unit R22, and the third magnetoresistive unit R42 and the fifth magnetoresistive unit R41 are opposite, so that the design can effectively reduce the influence of the external disturbing magnetic field component H x.
A wheatstone bridge circuit of the prior art design (the patent mentioned in the background) is shown in fig. 9. As shown in fig. 10, when the detected magnetic field is equal to 0 and is influenced by the external disturbing magnetic field component H x (H x =2mt) in the rightward direction, the resistance value of R205 is changed from 500 ohms to 510 ohms and the resistance value of R202 is changed from 500 ohms to 490 ohms, it is assumed from the calculation formula that icc=2ma, vout1 is changed from 500mV to 490mV, so that when the external influence of H x exists, V mid (signal output value when the detected magnetic field is 0) in the prior art changes, and the analysis of the change in Vout2 signal is referred to the analysis of Vout1 above, as shown in fig. 11, the signal output of H x =0 is shown by the solid line, the signal output of H x =2mt is shown by the broken line, and the change in the midpoint potentials V mid, vout1 and Vout2 causes the deterioration of the detection accuracy of the whole system. To solve this problem, the wheatstone bridge is redesigned in this embodiment, and the structure after design is shown in fig. 5 and 6, and the specific analysis is as follows: as shown in fig. 8, when the detected magnetic field is equal to 0 with constant current driving, the detected magnetic field is affected by an external disturbing magnetic field component H x (H x =2mt) directed to the right, the resistance value of R11 is changed from 500 ohms to 510 ohms, the resistance value of R12 is changed from 500 ohms to 490 ohms, and one resistance value is increased and one resistance value is reduced, so that the error generated by the external H x is reduced. Similarly, when the detected magnetic field is equal to 0, the resistance value of R21 is changed from 500 ohms to 490 ohms, the resistance value of R22 is changed from 500 ohms to 510 ohms, one resistance value is reduced and one resistance value is increased, so that errors generated by the outside H x are reduced, and R31 and R32, and R41 and R42 also accord with the rules above. Therefore, when the influence of H x exists outside, the midpoint potential V mid of the new design is unchanged as can be seen from FIG. 12. Therefore, the newly designed Wheatstone bridge can prevent the midpoint potential V mid from being influenced by the external interference magnetic field component H x during constant current driving, so that the detection precision of the current sensor is improved.
In addition to the above structure, the current sensor of the present embodiment further includes a magnetic field generating device, and three different structural forms of the magnetic field generating device will be described below.
① First magnetic field generating device
As shown in fig. 13, the magnetic field generating device adopts a two-pole magnet or a four-pole magnet, the magnets are arranged below the magnetoresistive sensor, the magnetic poles of the magnets on the left side and the right side are opposite, if the N pole on the left side is up and the S pole is down, the S pole on the right side is up and the N pole is down, and the magnets are used as the first group of magnetoresistive units and the second group of magnetoresistive units to generate bias magnetic fields with opposite magnetic field directions.
② Second type magnetic field generating device
As shown in fig. 14, the magnetic field generating device adopts a structure that a coil is arranged inside a magnetic resistance sensing device, and the directions of coil currents in a first group of magnetic resistance units on the left side are opposite to those of a second group of magnetic resistance units on the right side, so that the directions of bias magnetic fields generated by the coil currents are opposite.
③ Third kind of magnetic field generating device
As shown in fig. 15, an antiferromagnetic layer (AFM) is added below the magnetoresistive strips and above the substrate, and exchange bias magnetic fields are applied to the first and second sets of magnetoresistive cells, with the exchange bias magnetic fields being opposite in direction. The direction of the magnetic field is determined by the method of laser annealing. The antiferromagnetic layer may be IrMn, feMn, niO, ptMn or the like. The method of laser annealing can be summarized as applying an upward (positive Hy direction) magnetic field to the magnetoresistive sensing device as a whole, and rapidly heating the magnetoresistive strips (R11, R31, R42, R22) on the left side with a laser to bring the temperature of the AFM layer above the neel temperature, followed by cooling in the magnetic field. A downward (negative Hy direction) magnetic field is then applied to the magnetoresistive sensor device as a whole, and the magnetoresistive strips (R41, R21, R12, R32) on the right are rapidly heated with a laser to bring the temperature of the AFM layer above the neel temperature, followed by cooling in the magnetic field. By the above-described laser annealing method, the directions of the exchange bias magnetic fields of the left and right magnetoresistive elements can be reversed.
The magnetic field generating devices with the three structures are all used for generating bias magnetic fields with opposite directions, one magnetic field is upward, the other magnetic field is downward, and the direction of the bias magnetic field can influence the magnetization direction of the magnetic resistance unit to be consistent with the direction of the bias magnetic field. As shown in fig. 16, assuming that there is an external disturbing magnetic field component H y in the upward direction, the left bias magnetic field direction is upward to cause the magnetization direction M to be upward, the right bias magnetic field direction is downward to cause the magnetization direction M to be downward, when H y is in the same direction as the magnetization direction, the sensitivity is reduced, when H y is in the opposite direction to the magnetization direction, the sensitivity is increased, and the two parts are added together to ensure that the sensitivity is basically unchanged (as shown in fig. 17), so that the detection accuracy is improved. Meanwhile, the magnetic field generating device and the magnetic resistance sensing device are integrated together, so that the internal space of the sensor is prevented from being occupied, the miniaturized design is realized, the appearance is smaller, and the magnetic resistance sensor is economical and practical.
In summary, the invention makes the neutral point potential V mid not interfered by the external disturbing magnetic field component H x by changing the structure of the Wheatstone bridge; the sensitivity change caused by the external interference magnetic field component H y can be reduced by increasing the bias magnetic field with opposite directions generated by the magnetic field generating device; the invention eliminates the influence of external interference magnetic fields in the x direction and the y direction from the two aspects, improves the detection precision, and has wide application prospect in the field of current sensors.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (10)
1. A serial magnetic current sensor capable of eliminating the influence of an external interference magnetic field comprises a conductor, an isolation device and a magnetic resistance sensing device, wherein the isolation device is positioned between the magnetic resistance sensing device and the conductor; the magnetic resistance sensing device comprises a first left-side set of magnetic resistance units and a second right-side set of magnetic resistance units, a Wheatstone bridge is formed, and the current flowing through the conductor senses detected magnetic fields with equal magnitudes and opposite directions in the first set of magnetic resistance units and the second set of magnetic resistance units; the magnetic resistor device is characterized in that the first group of magnetic resistor units comprises a first magnetic resistor unit, a second magnetic resistor unit, a third magnetic resistor unit and a fourth magnetic resistor unit from left to right, the second group of magnetic resistor units comprises a fifth magnetic resistor unit, a sixth magnetic resistor unit, a seventh magnetic resistor unit and an eighth magnetic resistor unit from left to right, the first magnetic resistor unit and the second magnetic resistor unit are connected to a power supply pin, and the third magnetic resistor unit and the fourth magnetic resistor unit are connected to a grounding pin; the first magnetic resistance unit is connected with the seventh magnetic resistance unit in series, the fourth magnetic resistance unit is connected with the sixth magnetic resistance unit in series, and a signal output pin Vout2 is led out between the seventh magnetic resistance unit and the sixth magnetic resistance unit; the second magnetic resistance unit is connected with the eighth magnetic resistance unit in series, the third magnetic resistance unit is connected with the fifth magnetic resistance unit in series, and a signal output pin Vout1 is led out between the eighth magnetic resistance unit and the fifth magnetic resistance unit.
2. The serial-type magnetic current sensor capable of eliminating influence of external disturbing magnetic field according to claim 1, wherein each magnetoresistive unit comprises a magnetoresistive strip and a plurality of shorting strips disposed on the magnetoresistive strip and parallel to each other at a predetermined angle to the magnetoresistive strip.
3. The series-type magnetic current sensor capable of eliminating influence of external disturbing magnetic field according to claim 2, wherein the shorting bar directions of the first group of magnetoresistive units and the second group of magnetoresistive units are symmetrical along the central axis of the major axis of the magnetoresistive sensing device.
4. The serial magnetic current sensor capable of eliminating influence of external disturbing magnetic field according to claim 3, wherein the shorting bars of the first magnetoresistive unit, the sixth magnetoresistive unit, the eighth magnetoresistive unit and the third magnetoresistive unit are identical in inclination direction and angle; and the inclination directions and angles of the short circuit strips of the seventh magnetic resistance unit, the fourth magnetic resistance unit, the second magnetic resistance unit and the fifth magnetic resistance unit are consistent.
5. The tandem type magnetic current sensor according to claim 4, wherein the resistance values of the first and seventh magnetoresistive units, the second and eighth magnetoresistive units, the sixth and fourth magnetoresistive units, and the third and fifth magnetoresistive units become larger or smaller together under the influence of the detected magnetic field.
6. The serial-type magnetic current sensor capable of eliminating influence of external disturbing magnetic field according to claim 4, wherein when external disturbing magnetic field component H x parallel to the width direction of magnetoresistive strip exists, the resistance value change trend of the first magnetoresistive unit and the seventh magnetoresistive unit, the second magnetoresistive unit and the eighth magnetoresistive unit, the sixth magnetoresistive unit and the fourth magnetoresistive unit, and the third magnetoresistive unit and the fifth magnetoresistive unit are opposite.
7. The serial magnetic current sensor capable of eliminating influence of external disturbance magnetic field according to claim 1, further comprising a magnetic field generating device arranged below the magnetoresistive sensing device, wherein the magnetic field generating device adopts a two-pole magnet or a four-pole magnet to generate bias magnetic fields with opposite magnetic field directions for the first group of magnetoresistive units and the second group of magnetoresistive units.
8. The series-type magnetic current sensor capable of eliminating influence of external disturbance magnetic field according to claim 1, wherein the inside of the magnetic resistance sensor is provided with coils, and the directions of coil currents in the first group of magnetic resistance units on the left side are opposite to those of the second group of magnetic resistance units on the right side, so that the directions of bias magnetic fields generated by the coil currents are opposite.
9. The series-type magnetic current sensor according to claim 2, wherein an antiferromagnetic layer is added under the magnetoresistive strips, and a switching bias magnetic field is applied to the first group of magnetoresistive cells and the second group of magnetoresistive cells, and the switching bias magnetic fields are opposite in direction.
10. The series-type magnetic current sensor capable of eliminating influence of external disturbing magnetic field according to claim 1, wherein the first group of magnetoresistive cells and the second group of magnetoresistive cells do not cross each other in physical space.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410049272.4A CN117890651A (en) | 2024-01-12 | 2024-01-12 | Series magnetic current sensor capable of eliminating influence of external interference magnetic field |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410049272.4A CN117890651A (en) | 2024-01-12 | 2024-01-12 | Series magnetic current sensor capable of eliminating influence of external interference magnetic field |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117890651A true CN117890651A (en) | 2024-04-16 |
Family
ID=90648558
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410049272.4A Pending CN117890651A (en) | 2024-01-12 | 2024-01-12 | Series magnetic current sensor capable of eliminating influence of external interference magnetic field |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117890651A (en) |
-
2024
- 2024-01-12 CN CN202410049272.4A patent/CN117890651A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2801834B1 (en) | Current sensor | |
| US10168397B2 (en) | Magnetic field sensor with increased field linearity | |
| US10996292B2 (en) | Magnetic sensor circuits and systems and methods for forming magnetic sensor circuits | |
| CN100541222C (en) | Magnetic field detector and the detection means of using this magnetic field detector | |
| EP2696210B1 (en) | Single-chip two-axis bridge-type magnetic field sensor | |
| EP2442117B1 (en) | Magnetic balance current sensor | |
| US9632150B2 (en) | Magnetic field sensor with increased field range | |
| CN112082579B (en) | Wide-range tunnel magneto-resistance sensor and Wheatstone half-bridge | |
| CN102435963B (en) | Monolithic dual-axis bridge-type magnetic field sensor | |
| CN105785290A (en) | Magnetic field sensor | |
| EP2978131A1 (en) | Low-power magnetic resistance switch sensor | |
| CN101988956A (en) | Magnetic sensor with bridge circuit including magnetoresistance effect elements | |
| CN101088019A (en) | Bridge type magnetic sensor with tunable characteristic | |
| WO2004074855A2 (en) | Magnetic field sensor | |
| EP2610630A2 (en) | Low hysteresis high sensitivity magnetic field sensor | |
| CN112363097B (en) | Magneto-resistance sensor chip | |
| US20090251830A1 (en) | Magnetic detector | |
| CN115541960A (en) | Magneto-resistance sensor, chip and preparation method of chip | |
| CN112083211A (en) | Current sensor | |
| CN212008887U (en) | Single-chip full-bridge TMR magnetic field sensor | |
| CN110837066B (en) | Magnetic field sensing device | |
| CN111707977A (en) | Magnetic field sensing device | |
| JP2015075362A (en) | Unit element pair and thin film magnetic sensor | |
| CN117890651A (en) | Series magnetic current sensor capable of eliminating influence of external interference magnetic field | |
| CN117871923A (en) | Parallel magnetic current sensor capable of eliminating influence of external interference magnetic field |
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 |