Magnetic tunnel junction signal isolator with electric shielding layer

Abstract

An embodiment of the present invention discloses a magnetic tunnel junction signal isolator with an electrical shielding layer. In the isolator, the coil is located between a magnetic shielding layer and an electric shielding layer, and the electric shielding layer is located between the coil and a magnetoresistive sensor, and the magnetoresistive sensor is composed of a plurality of magnetic tunnel junctions connected in series and parallel. The two ends of the coil are electrically connected to a circuit having a first reference ground used to send a signal, and the signal is sent from the magnetoresistive sensor to a receiving circuit connected to a second reference ground. The magnetic shielding layer is electrically connected to the first reference ground in a single-point mode or a multi-point mode, or is completely electrically isolated from the first reference ground. The electric shielding layer may alternatively be electrically connected to the second reference ground in a single-point mode or a multi-point mode, or may be completely electrically isolated from the second reference ground. That is, the electric shielding layer and the magnetic shielding layer are each electrically connected to any one or more potentials between the first reference ground and the second reference ground in a single-point mode or a multi-point mode. Embodiments of the present invention solve the problem of interference and damage caused by coils to magnetic tunnel junctions in magnetoresistive sensors by preventing electric fields from corrupting the magnetoresistive sensor signal.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to the technical field of magnetic sensors, and more particularly to magnetic tunnel junction signal isolators with electrical shielding layers. [Background technology]

[0002] The magnetoresistive isolator connects the signal transmitting circuitry at either end of the coil and the signal receiving circuitry at either end of the magnetic sensor through a non-contact relationship between the magnetic field signal source and the magnetic sensor, thereby providing physical separation between the signal transmitting circuitry and the signal receiving circuitry.

[0003] Existing patents disclose a magnetic digital signal coupler including a coil and a magnetic sensor located below or above the coil. A magnetic shielding layer is also located above or below the coil and magnetic sensor to prevent interference from external magnetic fields. Electrical isolation is achieved using an insulating layer between the coil, the magnetic sensor and the magnetic shielding layer. However, this scheme only considers the interaction of magnetic fields between the coil and the magnetic sensor. In fact, the spiral coil itself has a first reference ground and a first voltage or current source, so that the coil has a different first potential distribution along the current direction, generating an electric field distribution in the surrounding space. And the magnetic sensor itself has a second reference ground and a second voltage or current source, so that the magnetic sensor also has a certain second potential distribution.

[0004] Due to the unequal potential between the first and second reference grounds, in this case there is a potential difference between the first and second potentials. This potential difference will generate an electric field at the location of the magnetic sensor, and this electric field will have a destructive effect on the magnetic sensor. For example, for a magnetic tunnel junction sensor, the electric field may destroy the magnetic tunnel junction. Summary of the Invention [Means for solving the problem]

[0005] SUMMARY OF THE PRESENT EMBODIMENTS The present invention provides a magnetic tunnel junction signal isolator with an electric shielding layer to solve the problem that existing signal isolators based on magnetic tunnel junctions are easily disturbed by electric fields.

[0006] An embodiment of the present invention is a magnetic tunnel junction signal isolator with an electric shielding layer, comprising: a magnetic shielding layer, a coil, an electric shielding layer, and a magnetoresistive sensor, the coil being located between the magnetic shielding layer and the electric shielding layer, the electric shielding layer being located between the coil and the magnetoresistive sensor, and the magnetoresistive sensor being composed of a plurality of magnetic tunnel junctions connected in series and parallel; a signal transmission circuit electrically connected to two ends of the coil and having a first reference ground; a signal receiving circuit connected to the magnetoresistive sensor and having a second reference ground; The magnetic tunnel junction signal isolator further provides that the magnetic shielding layer is electrically connected to or completely electrically isolated from the first reference ground in single-point or multi-point mode, and the electrical shielding layer may alternatively be electrically connected to or completely electrically isolated from the second reference ground in single-point or multi-point mode, i.e., the electrical shielding layer and the magnetic shielding layer are each electrically connected to any one or more potentials between the first reference ground and the second reference ground in single-point or multi-point mode.

[0007] Furthermore, the magnetoresistive sensors are connected with push arms and / or pull arms to form a push-pull bridge structure for measuring the magnetic field gradient or magnetic field value, in which: the push arm is comprised of an interconnected array of push magnetoresistive sensor units, the array of push magnetoresistive sensor units being comprised of push magnetoresistive sensor units connected in series and in parallel, the push magnetoresistive sensor unit being comprised of a plurality of magnetoresistive sensors connected in series and in parallel; the pull arm is comprised of an interconnected array of pull magnetoresistive sensor units, the array of pull magnetoresistive sensor units being comprised of pull magnetoresistive sensor units connected in series and in parallel, the pull magnetoresistive sensor unit being comprised of a plurality of magnetoresistive sensors connected in series and in parallel; The push-pull bridge structure includes any one of a push-pull half-bridge structure, a push-pull full-bridge structure, a push-pull pseudo-bridge structure, and a single-arm electrical bridge structure.

[0008] Furthermore, an angle between the magnetic field sensing direction of the push magnetoresistive sensor unit array and the reference horizontal direction is α, and an angle between the magnetic field sensing direction of the pull magnetoresistive sensor unit array and the reference horizontal direction is β; One side surface of the coil has a first sub-region and a second sub-region, in a direction perpendicular to the coil, the push magnetoresistive sensor unit array is located in the first sub-region, and the pull magnetoresistive sensor unit array is located in the second sub-region, when a current flows through the first sub-region, a magnetic field Bα is generated along the magnetic field sensing direction of the push magnetoresistive sensor unit array, when a current flows through the second sub-region, a magnetic field Bβ is generated along the magnetic field sensing direction of the pull magnetoresistive sensor unit array, Bα and Bβ are equal in magnitude, the direction of Bα is the same as the magnetic field sensing direction of the push magnetoresistive sensor unit array, while the direction of Bβ is opposite to the magnetic field sensing direction of the pull magnetoresistive sensor unit array, and the range of α and β is 0~360°.

[0009] Furthermore, the magnetoresistive sensor is a linear magnetoresistive sensor or a switching magnetoresistive sensor, and multiple magnetic tunnel junctions in the linear magnetoresistive sensor or the switching magnetoresistive sensor are connected to form a two-port structure.

[0010] Furthermore, the magnetic tunnel junction signal isolator includes a magnetic shielding pin and / or an electrical shielding pin, where the magnetic shielding layer sets a potential through the magnetic shielding pin and the electrical shielding layer sets a potential through the electrical shielding pin.

[0011] Furthermore, a signal transmission circuit is passively or actively connected to the coil.

[0012] Furthermore, a signal receiving circuit is passively or actively connected to the magnetoresistive sensor.

[0013] Furthermore, during packaging, the grains containing the magnetic tunnel junction signal isolators can be mounted separately on a lead frame and then packaged with packaging material, or During packaging, the grain containing the magnetic tunnel junction signal isolator and the signal transmission circuitry is placed on a lead frame and then packaged with a packaging material, or During packaging, the grain containing the magnetic tunnel junction signal isolator and signal receiving circuitry is placed on a lead frame and then packaged with packaging material. During packaging, the pins of the signal transmitting circuit and the pins of the signal receiving circuit on the lead frame are located on two opposite sides of the lead frame, respectively; The packaging material is one of a polymeric material, a ceramic material, a ferromagnetic metal, and a non-magnetic metal.

[0014] The isolator further includes an electrical shielding potential setting circuit and / or a magnetic shielding potential setting circuit; the electrical shield potential setting circuit ensures that the measured potential difference between the magnetoresistive sensor and the coil is equal to the set potential difference by comparing the measured potential difference between the magnetoresistive sensor and the coil with the set potential difference and adjusting the magnitude of the potential of the electrical shield layer; The magnetic shielding potential setting circuit ensures that the measured potential difference between the magnetoresistive sensor and the coil is equal to the set potential difference by comparing the measured potential difference between the magnetoresistive sensor and the coil with the set potential difference and by adjusting the magnitude of the potential of the magnetic shielding layer.

[0015] Furthermore, the magnetic shielding layer, the coil, the magnetoresistive sensor, and the electrical shielding layer are separated by an insulating material, and the insulating material is Si3N4, Al2O3, photoresist, SiO2, or polyimide.

[0016] Furthermore, the coil has a thickness of 1 μm to 20 μm, a width of 5 μm to 40 μm, and a spacing of 10 μm to 100 μm. The magnetic shielding layer and the electric shielding layer have a thickness of 1 μm to 20 μm.

[0017] An embodiment of the present invention provides a magnetic tunnel junction signal isolator with an electric shielding layer. A coil is located between the magnetic shielding layer and the electric shielding layer, and the electric shielding layer is located between the coil and the magnetoresistive sensor. A non-magnetic electric shielding layer is added between the coil and the magnetoresistive sensor, which can shield the electric field generated by the common mode voltage difference between the coil and a second reference ground, and prevent the electric field from disturbing the magnetic field signal of the magnetoresistive sensor. Thereby, the problem of interference and damage to the magnetic tunnel junction in the magnetoresistive sensor caused by the coil is solved.

[0018] In order to more clearly show the technical solutions in the embodiments of the present invention or the prior art, the drawings required for the illustration of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are some specific embodiments of the present invention, but those skilled in the art can understand that the drawings can be expanded and extended to other structures and drawings according to the device structures disclosed and induced by the basic concepts of the various embodiments of the present invention and the driving method and the fabrication method. There is no doubt that these are within the scope of the claims of the present invention. [Brief description of the drawings]

[0019] [Figure 1a] FIG. 2 is a schematic diagram of a magnetic tunnel junction signal isolator with an electrical shielding layer provided in an embodiment of the present invention. [Figure 1b]FIG. 2 is a schematic diagram of another magnetic tunnel junction signal isolator with an electrical shielding layer provided in an embodiment of the present invention. [Figure 1c] FIG. 13 is a schematic diagram of a third magnetic tunnel junction signal isolator with an electrical shielding layer provided in an embodiment of the present invention. [Figure 1d] FIG. 13 is a schematic diagram of a fourth magnetic tunnel junction signal isolator with an electrical shielding layer provided in an embodiment of the present invention. [Figure 2a] 4 is a distribution diagram of first small regions and magnetic tunnel junctions in a coil provided in an embodiment of the present invention. FIG. [Figure 2b] FIG. 4 is a distribution diagram of second sub-regions and magnetic tunnel junctions in a coil provided in an embodiment of the present invention. [Figure 2c] FIG. 2 is a magnetic field orientation diagram of a push magnetoresistive sensor unit provided in an embodiment of the present invention. [Figure 2d] FIG. 2 is a magnetic field orientation diagram of a pull magnetoresistive sensor unit provided in an embodiment of the present invention. [Figure 3a] FIG. 2 is a diagram showing a signal-magnetic field conversion curve of a linear magnetoresistive sensor. [Figure 3b] FIG. 1 is a diagram showing a signal-magnetic field conversion curve of a switching magnetoresistive sensor. [Figure 3c] A diagram illustrating the magnetization direction, sensing direction, and magnetic field direction of the free layer of a linear push magnetoresistive sensor unit. [Figure 3d] FIG. 13 illustrates the magnetization direction, sensing direction, and magnetic field direction of the free layer of a switching-push magnetoresistive sensor unit. [Figure 3e] FIG. 13 illustrates the magnetization direction, sensing direction, and field direction of the free layer of a linear-pull magnetoresistive sensor unit. [Figure 3f] FIG. 1 illustrates the magnetization direction, sensing direction, and field direction of the free layer of a switching-pull magnetoresistive sensor unit. [Figure 4] FIG. 2 is a schematic diagram of a spiral coil. [Figure 5a]This is a circuit diagram of a push-pull full-bridge structure composed of magnetoresistive sensors. [Figure 5b] This is a circuit diagram of a push-pull half-bridge structure composed of magnetoresistive sensors. [Figure 5c] FIG. 1 is a circuit diagram of a push-pull pseudo-bridge structure formed by magnetoresistive sensors. [Figure 5d] Schematic diagram of a single push arm and bridge arm consisting of an attached push magnetoresistive sensor. [Figure 6] FIG. 2D electric field distribution of an isolator without an electrical shielding layer. [Figure 7] FIG. 2D electric field distribution diagram of an isolator having an electric shielding layer. [Figure 8] 8A and 8B are potential distribution diagrams of an isolator without / with a charging shielding layer in a magnetic tunnel junction corresponding to FIGS. 6 and 7 . [Figure 9] 8A and 8B show the distribution of the electric field E in the isolator without / with the charged shielding layer corresponding to FIGS. 6 and 7 in the magnetic tunnel junction. [Figure 10] 8A and 8B are diagrams showing the distribution of the electric field Ey in the isolator without / with the charged shielding layer corresponding to FIGS. 6 and 7 in the magnetic tunnel junction. [Figure 11] 8A and 8B are diagrams showing the distribution of potential distribution maps of the electric field Ex of an isolator without / with a charged shielding layer corresponding to FIGS. 6 and 7 in a magnetic tunnel junction. [Figure 12] FIG. 1 shows an isolator lead frame with electrical shielding layer. [Figure 13] FIG. 13 shows another lead frame of an isolator having an electrical shielding layer. [Figure 14] FIG. 13 shows a third lead frame of an isolator having an electrical shielding layer. [Figure 15] FIG. 4 shows a fourth lead frame of an isolator having an electrical shielding layer. [Figure 16] FIG. 1 is a diagram showing external potential settings of a magnetic shielding layer and an electric shielding layer in an isolator having a magnetic shielding layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly described in detail through implementation with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part, not all, of the embodiments of the present invention. Based on the basic concept disclosed and induced by the embodiments of the present invention, all other embodiments obtained by those skilled in the art are within the protection scope of the present invention.

[0021] The contents shown in FIG. 1a-FIG. 1d are schematic diagrams of a four magnetic tunnel junction signal isolator with electric shielding layer provided in an embodiment of the present invention. The four magnetic tunnel junction signal isolator with electric shielding layer provided in this embodiment are marked 1(0)-1(3) in order. Specifically, the magnetic tunnel junction signal isolator with electric shielding layer includes a magnetic shielding layer 2, a coil 3, an electric shielding layer 4, and a magnetoresistive sensor 5. The coil 3 is located between the magnetic shielding layer 2 and the electric shielding layer 4. The electric shielding layer 4 is located between the coil 3 and the magnetoresistive sensor 5. The magnetoresistive sensor 5 is composed of a plurality of magnetic tunnel junctions connected in series and in parallel. Signal transmission circuit 6: The signal transmission circuit 6 is electrically connected to both ends of the coil 3 and has a first reference ground GND1. Signal reception circuit 7: The signal reception circuit 7 is connected to the magnetoresistive sensor 5 and has a second reference ground GND. The magnetic shielding layer 2 may be electrically connected to the first reference ground GND1 in single-point or multi-point mode or may be completely electrically isolated from the first reference ground. The electrical shielding layer 4 may alternatively be electrically connected to the second reference ground GND2 in single-point or multi-point mode or may be completely electrically isolated from the second reference ground. That is, the electrical shielding layer 4 and the magnetic shielding layer 2 may each be electrically connected to any potential between the first reference ground GND1 and the second reference ground GND2 in single-point or multi-point mode.

[0022] In this embodiment, both ends of the coil 3 are electrically connected to a signal transmitting circuit 6, and both ends of the magnetoresistive sensor 5 are electrically connected to a signal receiving circuit 7. The potential at one end of the coil 3 is V1, and the potential at one end of the magnetoresistive sensor 5 is V2. There are many different connection methods between the magnetic shielding layer 2 and the electric shielding layer 4 to form various different magnetic tunnel junction signal isolators with electric shielding layers. Figures 1a-1d only show four types of magnetic tunnel junction signal isolators with electric shielding layers. According to the various connection methods between the magnetic shielding layer 2 and the electric shielding layer 4, there can be many types of magnetic tunnel junction signal isolators with electric shielding layers, not limited to those shown in Figures 1a-1d.

[0023] Refer to the magnetic tunnel junction signal isolator 1(0) with an electric shielding layer shown in FIG. 1a. In this isolator, the magnetic shielding layer 2 is electrically connected to a first reference ground GND1 of a signal transmission circuit 6 through a single point 21, and the electric shielding layer 4 is electrically connected to a second reference ground GND2 of a signal reception circuit 7 through multiple points 41 and 42. One end of the coil 3 is electrically connected to a potential V1 of the signal transmission circuit 6, and the other end is electrically connected to the first reference ground GND1. One end of the magnetoresistive sensor 5 is electrically connected to a potential V2 of the signal reception circuit 7, and the other end is electrically connected to the second reference ground GND2.

[0024] Refer to the magnetic tunnel junction signal isolator 1 (1) with an electric shielding layer shown in FIG. 1b. In this isolator, the magnetic shielding layer 2 is electrically connected to a potential V3 in a single-point mode, and the electric shielding layer 4 is connected to a potential V4 in a multi-point mode. The potentials V3 and V4 are potentials between a first reference ground GND1 of the signal transmitting circuit 6 and a second reference ground GND2 of the signal receiving circuit 7. One end of the coil 3 is electrically connected to the potential V1 of the signal transmitting circuit 6, and the other end is electrically connected to the potential V3. One end of the magnetoresistive sensor 5 is electrically connected to the potential V2 of the signal receiving circuit 7, and the other end is electrically connected to the potential V4.

[0025] Refer to the magnetic tunnel junction signal isolator 1 (2) with an electric shielding layer shown in FIG. 1c. In this isolator, the magnetic shielding layer 2 is at a floating potential, and the electric shielding layer 4 is also at a floating potential. At this time, the magnetic shielding layer 2 is completely electrically insulated from the first reference ground GND1, and the electric shielding layer 4 is completely electrically insulated from the second reference ground GND2. One end of the coil 3 is electrically connected to the potential V1 of the signal transmitting circuit 6, and the other end is electrically connected to the first reference ground GND1. One end of the magnetoresistive sensor 5 is electrically connected to the potential V2 of the signal receiving circuit 7, and the other end is electrically connected to the second reference ground GND2.

[0026] The magnetic tunnel junction signal isolator with optional electric shielding layer includes a magnetic shielding pin and / or an electric shielding pin. The magnetic shielding layer 2 sets a potential through the magnetic shielding pin, and the electric shielding layer 4 sets a potential through the electric shielding pin. Specifically, the user sets the potential for the magnetic shielding layer 2 independently through its magnetic shielding pin, and / or the user sets the potential for the electric shielding layer 4 independently through its electric shielding pin. Refer to the electrically shielded magnetic tunnel junction signal isolator 1 (3) with electric shielding layer shown in FIG. 1d. In this isolator, the magnetic shielding layer 2 is electrically connected to an external potential V5 set by the user, and the electric shielding layer 4 is electrically connected to an external potential V6 set by the user. For example, during packaging, the magnetic shielding layer 2 and the electric shielding layer 4 can also be individually pinned out, and the pins can be set to any potential to facilitate direct connection to an external potential by the user. One end of the coil 3 is electrically connected to the potential V1 of the signal transmitting circuit 6, and the other end is electrically connected to the first reference ground GND1. One end of the magnetoresistive sensor 5 is electrically connected to the potential V2 of the signal receiving circuit 7, and the other end is electrically connected to the second reference ground GND2.

[0027] The optional magnetic shielding layer 2, coil 3, magnetoresistive sensor 5, and electrical shielding layer 4 are separated by an insulating material, which is Si3N4, Al2O3, photoresist, SiO2, or polyimide. Two adjacent structures are separated by an insulating layer. The magnetic shielding layer 2 and coil 3 are separated by an insulating layer. The coil 3 and electrical shielding layer 4 are separated by an insulating layer. The magnetoresistive sensor 5 and electrical shielding layer 4 are separated by an insulating layer. The optional insulating layer may be made of, but is not limited to, Si3N4, Al2O3, photoresist, SiO2, or polyimide. The coil 3 may be a spiral coil, and the magnetoresistive sensor 5 may be a linear magnetoresistive sensor or a switching magnetoresistive sensor.

[0028] The optional magnetic shielding layer 2 is made of a high permeability ferromagnetic alloy. For example, the high permeability ferromagnetic alloy can be, but is not limited to, NiFe, CoFeSiB, CoZrNb, CoFeB, FeSiB, or FeSiBNbCu. Any high permeability ferromagnetic alloy suitable for the present invention is within the protection scope of the present invention.

[0029] The optional coil 3 and the electrical shielding layer 4 may be made of a highly conductive metal material. For example, the highly conductive metal material may be, but is not limited to, Cu, Ti, Au, Ta, Al, or Pt. Any highly conductive metal material suitable for the present invention is within the protection scope of the present invention.

[0030] The coil 3 has a thickness of 1 μm to 20 μm, a width of 5 μm to 40 μm, and a spacing of 10 μm to 100 μm. The magnetic shielding layer 2 and the electrical shielding layer 4 have a thickness of 1 μm to 20 μm. In this embodiment, the thickness of the coil 3 is 1 μm or more and 20 μm or less. The width of the coil 3 is 5 μm or more and 40 μm or less. The spacing of the coils 3 is 10 μm or more and 100 μm or less. The thickness of the magnetic shielding layer 2 is 1 μm or more and 20 μm or less. The thickness of the electrical shielding layer 4 is 1 μm or more and 20 μm or less.

[0031] The optional magnetoresistive sensor 5 is a linear magnetoresistive sensor or a switching magnetoresistive sensor. Multiple magnetic tunnel junctions in the linear magnetoresistive sensor or the switching magnetoresistive sensor are connected to form a two-port structure. The linear magnetoresistive sensor or the switching magnetoresistive sensor has a two-port structure formed by an interconnected array of magnetoresistive sensors, in which the arrayed magnetoresistive sensors have the same magnetic field sensing direction.

[0032] An embodiment of the present invention provides a magnetic tunnel junction signal isolator with an electric shielding layer. A coil is located between the magnetic shielding layer and the electric shielding layer, and the electric shielding layer is located between the coil and the magnetoresistive sensor. A non-magnetic electric shielding layer is added between the coil and the magnetoresistive sensor, which can shield the electric field generated by the common mode voltage difference between the coil and the second reference ground, and can prevent the electric field from disturbing the magnetic field signal of the magnetoresistive sensor. Thereby, the problem of interference and damage to the magnetic tunnel junction in the magnetoresistive sensor caused by the coil is solved.

[0033] The optional magnetoresistive sensors are connected at the push arm and / or the pull arm to form a push-pull bridge structure for measuring a magnetic field gradient or magnetic field value. In this structure, the push arm is comprised of an interconnected array of push magnetoresistive sensor units. The array of push magnetoresistive sensor units is comprised of push magnetoresistive sensor units connected in series and parallel. The push magnetoresistive sensor unit is comprised of a plurality of magnetoresistive sensors connected in series and parallel. The pull arm is comprised of an interconnected array of pull magnetoresistive sensor units. The array of pull magnetoresistive sensor units is comprised of pull magnetoresistive sensor units connected in series and parallel. The pull magnetoresistive sensor unit is comprised of a plurality of magnetoresistive sensors connected in series and parallel. The push-pull bridge structure includes any one of a push-pull half-bridge structure, a push-pull full-bridge structure, a push-pull pseudo-bridge structure, and a single-arm bridge structure.

[0034] The angle between the magnetic field sensing direction of the optional push magnetoresistive sensor unit array and the reference horizontal direction is α. The angle between the magnetic field sensing direction of the pull magnetoresistive sensor unit array and the reference horizontal direction is β. The surface on one side of the coil has a first sub-region and a second sub-region. In a direction perpendicular to the coil, the push magnetoresistive sensor unit array is located in the first sub-region, and the pull magnetoresistive sensor unit array is located in the second sub-region. When a current flows through the first sub-region, a magnetic field Bα is generated along the magnetic field sensing direction of the push magnetoresistive sensor unit array. When a current flows through the second sub-region, a magnetic field Bβ is generated along the magnetic field sensing direction of the pull magnetoresistive sensor unit array. Bα and Bβ are equal in magnitude. The direction of Bα is the same as the magnetic field sensing direction of the push magnetoresistive sensor unit array, while the direction of Bβ is opposite to the magnetic field sensing direction of the pull magnetoresistive sensor unit array. The range of α and β is 0 to 360°.

[0035] The contents shown in FIG. 2a to FIG. 2d are distribution diagrams of a coil and a magnetic tunnel junction provided in an embodiment of the present invention. The contents shown in FIG. 2a are distribution diagrams of a first sub-region and a magnetic tunnel junction in a coil provided in an embodiment of the present invention. The contents shown in FIG. 2b are distribution diagrams of a second sub-region and a magnetic tunnel junction in a coil provided in an embodiment of the present invention. The contents shown in FIG. 2c are magnetic field orientation diagrams of a push magnetoresistive sensor unit provided in an embodiment of the present invention. The contents shown in FIG. 2d are magnetic field orientation diagrams of a pull magnetoresistive sensor unit provided in an embodiment of the present invention. The coil includes two sub-regions. One of the sub-regions is the first sub-region 8 shown in FIG. 2a, which includes a plurality of first conductive wires 81, and the other is the second sub-region 9 shown in FIG. 2b, which includes a plurality of second conductive wires 91. The first sub-region 8 includes N straight conductive wires arranged at equal distances in parallel, where N is an integer equal to or greater than 3. The second sub-region 9 includes N straight conductors arranged in parallel and equidistantly, where N is an integer greater than or equal to 3.

[0036] In this embodiment, magnetoresistive sensors comprised of multiple magnetic tunnel structures are connected by push arms and / or pull arms to form a push-pull bridge structure. In this structure, the push arms in the push-pull bridge structure are comprised of push magnetoresistive sensing units as shown in FIG. 2, connected in series and in parallel to form a push magnetoresistive sensing unit array 82. The push magnetoresistive sensing units are comprised of multiple magnetoresistive sensors connected in series and in parallel. The pull arms in the push-pull bridge structure are comprised of pull magnetoresistive sensing units as shown in FIG. 2b, connected in series and in parallel to form a pull magnetoresistive sensing unit array 92. The pull magnetoresistive sensing units are comprised of multiple magnetoresistive sensors connected in series and in parallel.

[0037] The push magnetoresistance sensing unit array 82 is located above or below the first sub-region 8, and the pull magnetoresistance sensing unit array 92 is located above or below the second sub-region 9. For any push magnetoresistance sensing unit in FIG. 2a, the magnetic field sensing direction S1 is the α direction. The magnetic field generated along the magnetic field sensing direction when the current I1 flows through the first sub-region 8 is Bα, in this case, the magnetic field sensing direction is actually an angle of the reference horizontal direction x. For any pull magnetoresistance sensing unit in FIG. 2b, the magnetic field sensing direction S2 is the β direction. The magnetic field generated along the magnetic field sensing direction when the current I2 flows through the second sub-region 9 is Bβ, in this case, the magnetic field sensing direction is actually an angle of the reference horizontal direction x. Bα and Bβ are the same in magnitude. The direction of Bα is the same as the corresponding magnetic field sensing direction α, while the direction of Bβ is opposite to the corresponding magnetic field sensing direction β. The range of α and β is from 0 degrees to 360 degrees, and α and β can be the same or different.

[0038] The magnetoresistive sensor can be of two types: linear magnetoresistive sensor and switching magnetoresistive sensor, as shown in Fig. 3a-3f. Fig. 3a is the signal-magnetic field characteristic curve of the linear magnetoresistive sensor, where the magnetic field and the signal are in a linear relationship. Fig. 3b is the signal-magnetic field characteristic curve of the switching magnetoresistive sensor, where the magnetic field and the signal are in a rectangular hysteresis relationship. In this way, the sensor can have a latch function and can memorize the polarity and direction of the previous magnetic field signal. Fig. 3c and Fig. 3e show the magnetization direction and sensing direction of the free layer of the linear push magnetoresistive sensing unit and the linear pull magnetoresistive sensing unit, as well as the magnetic field direction of the external magnetic field. The magnetization direction Hk of the free layer is perpendicular to the sensing directions S2 and S1. Fig. 3d and Fig. 3f show the magnetization direction and sensing direction of the free layer of the switching push magnetoresistive sensing unit and the switching pull magnetoresistive sensing unit, as well as the magnetic field direction of the external magnetic field. The magnetization direction Hk' of the free layer is parallel to the sensing directions S1' and S2'. The difference between the linear and switched magnetoresistive sensors lies in the variation characteristic, in which it can be seen that the magnetic field of the hysteresis loop in the free layer caused by the difference in the orientation of the free layer changes, but the orientation of the sensing direction remains unchanged.

[0039] Some examples of α and β are given below.

[0040] Taking α=0, β=0 as an example, when the directions of Bα and Bβ need to be opposite, the corresponding push magnetoresistance sensing unit and the pull magnetoresistance sensing unit are of the same orientation, and the first sub-region 8 and the second sub-region 9 need to have opposite magnetic field directions. The content shown in FIG. 4 is a schematic diagram of a spiral coil. Based on the spiral coil 3(0), the push magnetoresistance sensor unit and the pull magnetoresistance sensor unit have the same magnetic field sensing direction. The first sub-region 31 and the second sub-region 32 of the spiral coil have opposite current directions. The push magnetoresistance sensor unit array is located above or below the first sub-region 31, and the pull magnetoresistance sensor unit array is located above or below the second sub-region 32.

[0041] Taking α=0, β=180 as an example, if the magnetic field directions of Bα and Bβ need to be the same, the corresponding push magnetoresistive sensing unit and pull magnetoresistive sensing unit are of opposite orientation. For example, the two sensing units are 180 degrees reversed from each other. The first sub-region 8 and the second sub-region 9 can have the same magnetic field direction and be located in the same region of the coil.

[0042] The sensing direction of the magnetoresistive sensor can be manipulated by magnetic field annealing with a laser to achieve a 180 degree reversal or other values ​​of α and β.

[0043] The contents shown in FIG. 5a-FIG. 5d are structure diagrams of magnetoresistive sensors based on magnetic tunnel junctions. The magnetoresistive sensors in FIG. 5a are connected with push arms and pull arms to form a push-pull full-bridge structure. The magnetoresistive sensors in FIG. 5b are connected with push arms and pull arms to form a push-pull half-bridge structure. The magnetoresistive sensors in FIG. 5c are connected with push arms and pull arms to form a push-pull pseudo-bridge structure. The push-pull pseudo-bridge structure includes two identical current sources, as well as a pull arm and a push arm. The two current sources are connected to the pull arm and push arm respectively to form a push-pull pseudo-bridge structure. The push magnetoresistive sensors in FIG. 5d are connected to form a single push-arm bridge structure.

[0044] Figure 6 shows a two-dimensional electric field distribution diagram of an isolator without an electric shielding layer. In this figure, 2 is the magnetic shielding layer, and 3 is the cross section of the coil. GND1 is the first reference ground. 4(0) is defined as the air material. 5 is the location of the magnetoresistive sensor composed of a magnetic tunnel junction. 100 is the power line.

[0045] The content shown in Figure 7 is a two-dimensional electric field distribution diagram of an isolator with an electric shielding layer. In this figure, 2 is the magnetic shielding layer, and 3 is the cross section of the coil. GND1 is the first reference ground. 4(1) is defined as the air material. 5 is the location of the magnetoresistive sensor composed of a magnetic tunnel junction. 101 is the power line.

[0046] Comparing FIG. 6 with FIG. 7, it can be seen that when the electrical shielding material 4(1) is installed, the power lines are obviously concentrated below the electrical shielding layer 4(1).

[0047] Figure 8 shows the potential distribution map of the isolator without / with the electric shielding layer corresponding to Figure 6 and Figure 7 at the magnetic tunnel junction. As shown in Figure 8, it can be seen that the potential of the isolator with the electric shielding layer increases at the position of the magnetic tunnel. The reason is that the electric field inside the electric shielding layer itself is 0, which is equivalent to shortening the length of the power line, thereby increasing the potential.

[0048] FIG. 9 shows the distribution of the electric field E of the isolator without / with the charging shielding layer corresponding to FIG. 6 and FIG. 7 at the magnetic tunnel junction. As shown in FIG. 9, when there is no electric shielding layer, it can be seen that there are many high values ​​of the electric field strength E of the isolator at the location of the magnetoresistive sensor composed of the magnetic tunnel junction. However, when there is an electric shielding layer, the electric field strength E of the isolator is greatly reduced at the location of the magnetoresistive sensor composed of the magnetic tunnel junction, and the area is flat.

[0049] FIG. 10 shows the distribution of the electric field Ey of the isolator without / with the charging shielding layer corresponding to FIG. 6 and FIG. 7 at the magnetic tunnel junction. As shown in FIG. 10, when there is no electric shielding layer, it can be seen that the electric field strength E of the isolator fluctuates between positive and negative values ​​at the location of the magnetoresistive sensor composed of the magnetic tunnel junction. However, when there is an electric shielding layer, the electric field strength E of the isolator is greatly reduced at the location of the magnetoresistive sensor composed of the magnetic tunnel junction, and the area is flat. By adding the magnetic shielding layer, the possibility of destruction of the magnetic tunnel junction is greatly reduced, since Ey mainly corresponds to the current direction of the magnetic tunnel junction, which is also the direction most likely to cause destruction.

[0050] FIG. 11 shows the distribution of the electric field Ex of the isolator without / with the charging shielding layer corresponding to FIG. 6 and FIG. 7 in the magnetic tunnel junction. As shown in FIG. 11, it can be seen that when there is no electric shielding layer, the electric field strength E of the isolator fluctuates between positive and negative values ​​at the location of the magnetoresistive sensor composed of the magnetic tunnel junction. However, after adding the electric shielding layer, the electric field strength E of the isolator is greatly reduced at the location of the magnetoresistive sensor composed of the magnetic tunnel junction, and the area is flat at the location of the magnetoresistive sensor formed by the magnetic tunnel structure.

[0051] The optional signal transmitting circuitry is passively or actively connected to the coil and the optional signal receiving circuitry is passively or actively connected to the magnetoresistive sensor. The optional coil is a spiral coil and the magnetoresistive sensor is a linear magnetoresistive sensor.

[0052] During the optional packaging, the grain including the magnetic tunnel junction signal isolator is separately mounted on a lead frame and then packaged with a packaging material, or during the packaging, the grain including the magnetic tunnel junction signal isolator and the signal transmitting circuit is mounted on a lead frame and then packaged with a packaging material, or during the packaging, the grain including the magnetic tunnel junction signal isolator and the signal receiving circuit is mounted on a lead frame and then packaged with a packaging material, and during the packaging, the pins of the signal transmitting circuit and the pins of the signal receiving circuit on the lead frame are respectively located on opposite sides of the lead frame, and the packaging material is any one of a polymer material, a ceramic material, a ferromagnetic metal, and a non-magnetic metal.

[0053] If the magnetic tunnel junction signal isolator with electrical shielding layer is a passive method, the grains can be separately placed on the lead frame for packaging. Alternatively, the grains of the magnetic tunnel junction signal isolator with electrical shielding layer and the ASIC grains of the signal receiving circuit are placed together on the lead frame for packaging. Alternatively, the grains of the magnetic tunnel junction signal isolator with electrical shielding layer and the ASIC grains of the signal transmitting circuit are placed together on the lead frame for packaging. Alternatively, the grains of the magnetic tunnel junction signal isolator with electrical shielding layer, the ASIC grains of the signal transmitting circuit and the ASIC grains of the signal receiving circuit are placed together on the lead frame for packaging.

[0054] The optional magnetic tunnel junction signal isolator also includes an electrical shielding potential setting circuit and / or a magnetic shielding potential setting circuit, which ensures that the measured potential difference between the magnetoresistive sensor and the coil is equal to the set potential difference by comparing the measured potential difference between the magnetoresistive sensor and the coil with the set potential difference and adjusting the magnitude of the potential of the electrical shielding layer, and the magnetic shielding potential setting circuit ensures that the measured potential difference is equal to the set potential difference by comparing the measured potential difference between the magnetoresistive sensor and the coil with the set potential difference and adjusting the magnitude of the potential of the magnetic shielding layer.

[0055] The electrical shielding potential setting circuit calculates the measured potential difference between the magnetoresistive sensor and the coil, and also pre-stores a set potential difference between the magnetoresistive sensor and the coil, and then compares the measured potential difference with the set potential difference.The electrical shielding potential setting circuit then adjusts the magnitude of the potential of the electrical shielding layer so that the measured potential difference is equal to the set potential difference.

[0056] The magnetic shielding potential setting circuit calculates the measured potential difference between the magnetoresistive sensor and the coil, and also pre-stores the set potential difference between the magnetoresistive sensor and the coil, and then compares the measured potential difference with the set potential difference.The magnetic shielding potential setting circuit then adjusts the magnitude of the potential of the magnetic shielding layer so that the measured potential difference is equal to the set potential difference.

[0057] 12 shows a lead frame of an isolator with an electrical shielding layer. As shown in FIG. 12, a lead frame 200 includes an isolator grain 201 with an electrical shielding layer, and the isolator grain 201 is placed on a lead frame 202. The pins of the lead frame 202 include a coil pin, a GND1 pin, a power supply Vcc pin of the magnetic tunnel junction sensor, a GND2 pin, and output signal terminals V+ and V-. The ground 300 of the magnetic tunnel junction sensor of the isolator grain 201 with an electrical shielding layer is wire-bonded to the lead frame pin GND2 of the lead frame 202.

[0058] FIG. 13 shows another lead frame of an isolator with an electrical shielding layer. As shown in FIG. 13, a lead frame 200(1) includes an isolator grain with an electrical shielding layer 201(1) disposed on a lead frame 202(1). The isolator grain with an electrical shielding layer 201(1) includes a grain electrical shielding layer pin 198 and a grain magnetic shielding layer pin 199. The grain electrical shielding layer pin 198 is wire bonded to a lead frame pin Ve, and the grain magnetic shielding layer pin 199 is wire bonded to a lead frame pin Vm. A user can set the potential of the electrical shielding layer through pin Ve and the potential of the magnetic shielding layer through pin Vm. The ground 300(1) of the magnetic tunnel junction sensor of the isolator die with electrical shielding 201(1) is wire bonded to a lead frame pin GND2 of the lead frame 202(1).

[0059] Figure 14 shows a third lead frame of an isolator with an electrical shielding layer. As shown in Figure 14, a lead frame 200(2) includes an isolator grain with an electrical shielding layer 201(2) and a signal receiving circuit ASCI grain 203. The two grains are placed together on a lead frame 202(2). In this lead frame, the grain ground pin 300(2) of the isolator grain with an electrical shielding layer 201(2) is wired to the lead frame 202(2), and the grain ground pin 301 of the signal receiving circuit ASCI grain 203 is wired to the lead frame 202(2). The grain signal output pins 303 and 304 of the isolator grain with an electrical shielding layer 201(2) are wired to the input end of the signal receiving circuit ASIC grain 203, and the signal receiving circuit ASIC grain 203 and the isolator grain with an electrical shielding layer 201(2) have the same power supply Vcc.

[0060] FIG. 15 shows a fourth lead frame of an isolator with an electrical shielding layer. As shown in FIG. 15, a lead frame 200(3) includes an isolator grain 201(3) with an electrical shielding layer, a signal receiving circuit ASIC chip 203(1), and a signal transmitting circuit ASIC chip 204. In this lead frame, 201(3) and 203(1) are mounted together on a lead frame 202(3), and 204 is mounted on a lead frame 205. 203(3) and 205 are electrically isolated. The grain ground pin 304 of the signal transmitting circuit ASIC grain 204 is connected to the pin GND1 of the lead frame 200(3) after being wired to the lead frame 205, and the power pin 206 of the signal transmitting circuit ASIC grain 204 is electrically connected to the pin Vcc1 of the lead frame 200(3). The grain ground pin 300(3) of the isolator grain 201(3) with the electrical shielding layer and the grain ground pin 301(1) of the signal receiving circuit ASCI grain 203(1) are both wired to the lead frame 202(3).

[0061] Furthermore, the pins on the lead frame corresponding to the signal transmitting circuit and the pins on the lead frame corresponding to the signal receiving circuit are located on opposite sides of the lead frame, i.e., on the left and right sides in the figure, respectively, to avoid mutual interference.

[0062] FIG. 16 shows the external potential setting of the magnetic shielding layer and the electric shielding layer in the isolator with the magnetic shielding layer. As shown in FIG. 16, a closed loop control is implemented to keep the isolator within a reasonable operating range. The set potential difference between the coil and the magnetic tunnel junction sensor is preset, and then the actual measured potential difference between the coil and the magnetic tunnel junction sensor is calculated, and then the set potential difference is compared with the measured potential difference. According to the comparison result, the method circuit including the amplifier is controlled to adjust the potential Vm of the magnetic shielding layer pin or the potential Ve of the electric shielding layer pin, and finally ensure that the set potential difference between the coil and the magnetic tunnel junction sensor is equal to the actual measured potential difference.

[0063] It should be noted that the above description is merely a preferred embodiment and technical principle of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the specific embodiments described herein, and various obvious modifications, rearrangements, combinations, and substitutions are possible for those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, it is not limited to the above embodiments. Many other equivalent embodiments may also be included without departing from the concept of the present invention, and the scope of the present invention is defined by the appended claims.

Claims

1. 1. A magnetic tunnel junction signal isolator having an electric shield layer, comprising: a magnetic shielding layer, a coil, an electric shielding layer, and a magnetoresistive sensor, the coil being located between the magnetic shielding layer and the electric shielding layer, the electric shielding layer being located between the coil and the magnetoresistive sensor, and the magnetoresistive sensor being composed of a plurality of magnetic tunnel junctions connected in series and parallel; a signal transmission circuit electrically connected to two ends of the coil and having a first reference ground; a signal receiving circuit connected to the magnetoresistive sensor and having a second reference ground; It is composed of A magnetic tunnel junction signal isolator, characterized in that the magnetic shielding layer is electrically connected to the first reference ground in a single-point mode or a multi-point mode or is completely electrically isolated from the first reference ground, and the electrical shielding layer can alternatively be electrically connected to the second reference ground in a single-point mode or a multi-point mode or be completely electrically isolated from the second reference ground, i.e., the electrical shielding layer and the magnetic shielding layer are each electrically connected to any one or more potentials between the first reference ground and the second reference ground in a single-point mode or a multi-point mode.

2. the magnetoresistive sensors are connected with push and / or pull arms to form a push-pull bridge structure for measuring a magnetic field gradient or a magnetic field value; the push arm is comprised of an interconnected array of push magnetoresistive sensor units, the array of push magnetoresistive sensor units being comprised of push magnetoresistive sensor units connected in series and in parallel, the push magnetoresistive sensor unit being comprised of a plurality of said magnetoresistive sensors connected in series and in parallel; the pull arm is comprised of an interconnected array of pull magnetoresistive sensor units, the array of pull magnetoresistive sensor units being comprised of pull magnetoresistive sensor units connected in series and in parallel, the pull magnetoresistive sensor unit being comprised of said plurality of magnetoresistive sensors connected in series and in parallel; 2. The magnetic tunnel junction signal isolator of claim 1, wherein the push-pull bridge structure includes any one of a push-pull half-bridge structure, a push-pull full-bridge structure, a push-pull pseudo-bridge structure, and a single-arm electrical bridge structure.

3. The angle between the magnetic field sensing direction of the push magnetoresistive sensing unit array and the reference horizontal direction is α, and the angle between the magnetic field sensing direction of the pull magnetoresistive sensing unit array and the reference horizontal direction is β; A surface on one side of the coil has a first sub-region and a second sub-region, in a direction perpendicular to the coil, the push magnetoresistive sensor unit array is located in the first sub-region, and the pull magnetoresistive sensor unit array is located in the second sub-region, when a current flows through the first sub-region, a magnetic field Bα is generated along the magnetic field sensing direction of the push magnetoresistive sensor unit array, and when a current flows through the second sub-region, a magnetic field Bβ is generated along the magnetic field sensing direction of the pull magnetoresistive sensor unit array; 3. The magnetic tunnel junction signal isolator of claim 2, characterized in that Bα and Bβ are equal in magnitude, the direction of Bα is the same as the magnetic field sensing direction of the push magnetoresistive sensor unit array, but the direction of Bβ is opposite to the magnetic field sensing direction of the pull magnetoresistive sensor unit array, and α and β range from 0 to 360°C.

4. 2. The magnetic tunnel junction signal isolator of claim 1, wherein the magnetoresistive sensor is a linear magnetoresistive sensor or a switching magnetoresistive sensor, and multiple magnetic tunnel junctions in the linear magnetoresistive sensor or the switching magnetoresistive sensor are connected to form a two-port structure.

5. 2. The magnetic tunnel junction signal isolator of claim 1, wherein the magnetic tunnel junction signal isolator includes a magnetic shielding pin and / or an electrical shielding pin, the magnetic shielding layer sets a potential through the magnetic shielding pin, and the electrical shielding layer sets a potential through the electrical shielding pin.

6. The magnetic tunnel junction signal isolator of claim 1 , wherein the signal transmission circuit is passively or actively connected to the coil.

7. 2. The magnetic tunnel junction signal isolator of claim 1, wherein the signal receiving circuit is passively or actively connected to the magnetoresistive sensor.

8. During packaging, the grains including the magnetic tunnel junction signal isolators are separately mounted on a lead frame and then packaged with a packaging material; or During packaging, the grain including the magnetic tunnel junction signal isolator and the signal transmission circuit is placed on a lead frame and then packaged with a packaging material; or During packaging, the grain including the magnetic tunnel junction signal isolator and the signal receiving circuit is placed on a lead frame and then packaged with a packaging material; During packaging, the pins of the signal transmitting circuit and the pins of the signal receiving circuit on the lead frame are located on two opposite sides of the lead frame, respectively; 8. The magnetic tunnel junction signal isolator of claim 6 or 7, wherein the packaging material is one of a polymer material, a ceramic material, a ferromagnetic metal, and a non-magnetic metal.

9. The electric shielding potential setting circuit and / or the magnetic shielding potential setting circuit are included, the electrical shielding potential setting circuit ensures that the measured potential difference between the magnetoresistive sensor and the coil is equal to the set potential difference by comparing the measured potential difference between the magnetoresistive sensor and the coil with the set potential difference and adjusting the magnitude of the potential of the electrical shielding layer; 6. The magnetic tunnel junction signal isolator of claim 5, wherein the magnetic shielding potential setting circuit ensures that the measured potential difference between the magnetoresistive sensor and the coil is equal to the set potential difference by comparing the measured potential difference between the magnetoresistive sensor and the coil with the set potential difference and adjusting the magnitude of the potential of the magnetic shielding layer.

10. The magnetic shielding layer, the coil, the magnetoresistive sensor, and the electrical shielding layer are separated by an insulating material, the insulating material being Si ３ N ４ , Al ２ O ３ , photoresist, SiO ２ 2. The magnetic tunnel junction signal isolator of claim 1, wherein the material is a polyimide or a polyimide.

11. The coil has a thickness of 1 μm to 20 μm, a width of 5 μm to 40 μm, and a spacing of 10 μm to 100 μm; The magnetic tunnel junction signal isolator of claim 1 , wherein the thickness of the magnetic shielding layer and the electrical shielding layer varies from 1 μm to 20 μm.

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