WO2023087740A1 - 一种磁传感器和电子设备 - Google Patents

一种磁传感器和电子设备 Download PDF

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Publication number
WO2023087740A1
WO2023087740A1 PCT/CN2022/103840 CN2022103840W WO2023087740A1 WO 2023087740 A1 WO2023087740 A1 WO 2023087740A1 CN 2022103840 W CN2022103840 W CN 2022103840W WO 2023087740 A1 WO2023087740 A1 WO 2023087740A1
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Prior art keywords
target
magnetic sensor
magnetoresistive element
tunneling
tmr element
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PCT/CN2022/103840
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English (en)
French (fr)
Inventor
易立琼
杨泽洲
胡笑鲁
陈少娴
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华为数字能源技术有限公司
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Application filed by 华为数字能源技术有限公司 filed Critical 华为数字能源技术有限公司
Priority to EP22894283.5A priority Critical patent/EP4407333A1/en
Publication of WO2023087740A1 publication Critical patent/WO2023087740A1/zh
Priority to US18/662,985 priority patent/US20240295586A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • 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
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors

Definitions

  • the invention relates to the field of electronic and electrical technologies, in particular to a magnetic sensor and electronic equipment.
  • the current sensor can detect the current information in the circuit, and convert the current information into electrical signals or other forms of information that meet certain standards according to certain rules, so as to meet the requirements of information transmission, processing, storage, display, recording and control.
  • current sensors such as resistive shunts, current transformers, Hall current sensors, magnetoresistive effect current sensors, magnetostrictive current sensors, light current sensors and so on.
  • PCB printed circuit board
  • the current passing through each trace in the PCB is generally relatively low, around tens of milliamperes, and some are even lower, which makes it very difficult to detect the current in the traces. Therefore, how to select a current sensor with relatively high detection accuracy for the traces in the PCB is very important.
  • a magnetic sensor and an electronic device are provided in an embodiment of the present application.
  • an embodiment of the present application provides a magnetic sensor, including: a printed circuit board, including target wiring, for electrically connecting various components; a tunneling magnetoresistive element, fixed on the printed circuit board is used to detect the current value of the target wiring; wherein, the tunneling magnetoresistive element is located on the normal line on one side of the target wiring, and the tunneling magnetoresistance element
  • the ratio of the distance D between the detection unit distance and the edge of the target line closest to the tunneling magnetoresistive element to the width W of the target line is between 3.0% and 20.0%
  • the detection unit is used to detect the magnetic induction intensity
  • the width of the target trace is the length perpendicular to the current flow direction on the target trace.
  • the tunneling magnetoresistive element detects the current value of the target wiring, which will change with the frequency of the electrical signal in the target wiring. The distance between them will affect the magnitude of the current value detected by the tunneling magnetoresistive element with the frequency of the electrical signal in the target line.
  • the tunneling magnetoresistive element when installing the tunneling magnetoresistive element, the tunneling magnetoresistive element can be installed in Directly above or directly below the target line, and the distance D between the detection unit inside and the edge of the target line closest to the tunneling magnetoresistive element, and the ratio of the width W of the target line is 3.0% to Between 20.0%, the current value of the tunneling magneto-resistive element detecting the target line does not change with the frequency of the electrical signal in the target line, or the change is very small, so that the tunneling magneto-resistive element can accurately detect the target line The current value of the electrical signal in the line, thereby increasing the range of the measurement bandwidth of the tunneling magnetoresistive element.
  • the width of the tunneling magnetoresistive element is smaller than the width of the target wiring; wherein, the width of the tunneling magnetoresistive element is perpendicular to the current flow direction on the target wiring length.
  • the width of the target trace detected by the tunneling magnetoresistive element is generally larger than the width of the tunneling magnetoresistive element. If the tunneling magnetoresistive element partially exceeds the edge of the target trace, other components and traces It will affect the detection result of the tunneling magnetoresistive element, resulting in a decrease in the accuracy of the detection current.
  • the width w of the tunneling magneto-resistive element satisfies: w ⁇ W-2D; wherein, the units of D and W are mm.
  • the width of the target trace detected by the tunneling magnetoresistive element is not only It must be larger than the width of the tunneling magneto-resistance element, and larger than the sum of the width of the tunneling magneto-resistance element and twice the reserved distance, so as to ensure that the tunneling magneto-resistance element will not partially exceed the target
  • the edge of the trace will reduce the accuracy of current detection.
  • the distance between the normal direction of the tunneling magnetoresistive element on one side of the target trace and the target trace is greater than zero.
  • the target wiring is made of graphite material.
  • the target trace on the printed circuit board can be made of graphite, which can effectively suppress the skin effect in the target trace, thereby further improving the current in the target trace measured by the tunneling magnetoresistive element. value accuracy.
  • it further includes: a shielding component, disposed on the surface of the tunneling magneto-resistive element away from the printed circuit board, for shielding other traces and traces except the target trace. Magnetic fields generated by components.
  • the shielding component is generally arranged on the surface of the tunneling magnetoresistive element away from the printed circuit board, which can shield the influence of the external magnetic field on the detection result of the tunneling magnetoresistive element.
  • the shielding component is a comb structure.
  • the shielding component generally adopts a comb-shaped structure, and there are gaps between the teeth in the comb-shaped structure, which can cut off the eddy current path of the shielding body in the high-frequency magnetic field, thereby suppressing the eddy current effect of the shielding body.
  • the surrounding magnetic field will not cause distortion or the distortion is relatively weak, so that the shielding component can effectively shield the external magnetic field, and will not affect the detection result of the tunneling magnetoresistive element.
  • the size of the shielding component is larger than the size of the tunneling magnetoresistive element.
  • the size of the shielding component is larger than the size of the tunneling magnetoresistive element, so as to prevent the shielding component from being placed on the tunneling magnetoresistive element, and the external magnetic field on the side of the tunneling magnetoresistive element will affect the detection results of the tunneling magnetoresistive element. Impact.
  • an embodiment of the present application provides an electronic device, including: at least one magnetic sensor that may be implemented according to the first aspect.
  • Fig. 1(a) is a magnetic field distribution diagram when a low-frequency electrical signal is input in a PCB trace in the prior art
  • Fig. 1(b) is a magnetic field distribution diagram when a high-frequency electrical signal is input in a PCB trace in the prior art
  • Fig. 2 is a magnetic field distribution diagram at position point A and position point B when electrical signals of different frequencies are input in PCB traces in the prior art;
  • FIG. 3 is a schematic top view of a magnetic sensor structure provided in an embodiment of the present application.
  • Fig. 4 is a schematic cross-sectional structure diagram of a magnetic sensor structure provided in an embodiment of the present application.
  • Figure 5(a) is a schematic diagram of the effect when the magnetization directions of the two magnet layers are parallel to the same direction;
  • Figure 5(b) is a schematic diagram of the effect when the magnetization directions of the two magnet layers are antiparallel
  • Figure 6 shows that when the width of the target trace provided in the embodiment of the present application is 4 mm, and the distance between the TMR element and the edge of the target trace closest to the side of the TMR element is different, the magnetic field detected by the TMR element varies with the distance in the target trace.
  • FIG. 7 is an experimental diagram of flatness corresponding to different distances between the TMR element and the edge of the target trace closest to the TMR element side when the target trace width provided in the embodiment of the present application is 4mm;
  • Fig. 8 is the current distribution experimental diagram obtained by simulation using graphite and copper as the wiring material in the PCB provided in the embodiment of the present application;
  • FIG. 9 is a schematic diagram of a comb-shaped shielding assembly provided in an embodiment of the present application.
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , can also be a contradictory connection or an integrated connection; those skilled in the art can understand the specific meanings of the above terms in this application according to specific situations.
  • the magnetic sensor In modern industry and electronic products, magnetic sensors represented by Hall current sensors are most widely used. Among them, the magnetic sensor generally detects physical parameters such as current, position, and direction by sensing the intensity of the magnetic field.
  • a sensitive element for receiving magnetic field signals it can be a Hall element, anisotropic magneto resistance (AMR) element, giant Magneto resistance (giant magneto resistance, GMR) element, tunnel magneto resistance (tunnel magneto resistance, TMR) element, etc.
  • Magnetic sensor with Hall element as sensitive element. Since the operating current of each device in the existing electronic equipment is relatively low, as low as milliamps or lower, it is necessary to add a magnetic gathering ring structure in the magnetic sensor, and use the magnetic gathering ring structure to amplify the surrounding magnetic field and improve the Hall effect. The sensitivity of the electrical signal output by the component. However, adding a magnetic-gathering ring structure to the magnetic sensor will increase the volume and weight of the magnetic sensor, and the Hall element has defects such as high power consumption and poor linearity, resulting in poor performance of the magnetic sensor.
  • Magnetic sensor with AMR element as sensitive element. If the sensitive element in the magnetic sensor uses an AMR device, it is necessary to set a set/reset coil in the magnetic sensor to perform a preset/reset operation on the AMR element. Although the sensitivity of the AMR element is much higher than that of the Hall element, its linear range is relatively narrow, and the addition of set/reset coils will make the manufacturing process of the magnetic sensor more complicated, resulting in a higher cost of the magnetic sensor.
  • Magnetic sensor with GMR element as sensitive element. If the GMR element is selected as the sensitive element, compared with the magnetic sensor composed of Hall elements, although the sensitivity of the magnetic sensor is relatively high, its linear range is lower, resulting in poor performance of the magnetic sensor.
  • the TMR element is a new type of magnetoresistance effect sensor that has been applied in industry in recent years. It was originally used on the magnetic read-write head in the hard disk, so the precision, accuracy and life reliability of magnetic field detection are relatively high.
  • the TMR element detects the magnetic field generated by the current on the copper bar and the wire, and calculates the magnitude of the current through the chip.
  • the magnetic sensor composed of Hall elements Compared with the magnetic sensor composed of Hall elements, it has the advantages of better temperature stability, higher sensitivity, lower power consumption, better linearity, and no need for additional magnetic ring structures; compared The magnetic sensor composed of AMR elements has the advantages of better temperature stability, higher sensitivity, wider linear range, and no additional set/reset coil structure; compared with the magnetic sensor composed of GMR elements, it has better Excellent temperature stability, higher sensitivity, lower power consumption, wider linear range and other advantages.
  • Table 1 is a magnetic sensor composed of Hall elements, AMR elements, GMR elements, and TMR elements. It can be more intuitive to compare the six technical parameters of power consumption, size, sensitivity, linear range, resolution, and temperature characteristics. See the advantages of TMR components. Specifically:
  • the magnetic sensor composed of TMR elements has obvious advantages in six aspects of power consumption, size, sensitivity, linear range, resolution and temperature characteristics.
  • the TMR component is surface-mounted on the wiring in the PCB. It belongs to the open magnetic circuit detection mode, and the measurement accuracy is easily disturbed by external factors.
  • the current distribution inside the conductor is uneven, and the current is concentrated in the "skin" part of the conductor, that is to say, the current is concentrated in the thin layer on the outside of the conductor.
  • the current at the center of the trace in the PCB is small or zero, and the current at the two sides is relatively small. Large, so that the distribution of the magnetic field generated around the trace is not uniform.
  • the relationship between the magnetic field strength detected at the two locations and the frequency of the electrical signal is shown in the figure 2. Since the current to be measured usually contains rich harmonic content, it is necessary to find a suitable installation position so that the magnetic induction intensity B generated by currents of different frequencies remains basically constant to ensure the measurement bandwidth of the TMR element.
  • FIG. 3 and FIG. 4 are structural schematic diagrams of a magnetic sensor provided in an embodiment of the present application.
  • the magnetic sensor 300 includes a PCB 310 and a TMR element 320.
  • a large number of traces are arranged in the PCB 310 for electrically connecting various components.
  • the TMR element 320 is generally arranged on the outer surface of the PCB 310, and the TMR element 320 and the trace to be detected (hereinafter referred to as " The relationship between the target wiring 311”) is: the TMR element 320 and the target wiring 311 are located in the normal direction of the outer surface of the PCB 310.
  • PCB is generally composed of connection wires and isolation materials.
  • connection wires When making PCB, the connection wires can be laid flat on the plane, and then the isolation material is sprayed on the connection wires to isolate each connection wire from each other; Lay a layer of connecting wires on the material, and then spray the isolation material on the connecting wires; by analogy, a PCB with multiple layers of connecting wires can be produced.
  • the connecting wires in the isolation material are generally referred to as "traces".
  • the tunneling magnetoresistance effect refers to the effect that in the ferromagnetic-insulator film-ferromagnetic material, the magnitude of the tunneling resistance changes with the relative direction of the ferromagnetic materials on both sides. Because the tunneling magnetoresistance effect has unique advantages such as large magnetoresistance effect and high magnetic field sensitivity, it has broad application prospects.
  • the TMR element 320 is in a low resistance state; as shown in Figure 5(b), when the two layers The magnetization direction of the magnet layer is antiparallel, and the situation is just the opposite, that is, the electrons of the majority spin subband will enter the empty state of the minority spin subband in the other magnetic layer, and the electrons of the minority spin subband will also enter the other magnetic layer.
  • the tunneling current is small at this time, and the TMR element 320 is in a high resistance state. It can be seen that both the tunnel current and the tunnel resistance depend on the relative orientation of the magnetization of the two ferromagnetic layers. When the magnetization direction changes, the tunnel resistance changes, so it is called the tunnel magnetoresistance effect.
  • the TMR element 320 can use the principle that the change of the magnetic field causes the change of the magnetoresistance, and measure the change of the magnetic field around the TMR element 320 by detecting the change of the magnetoresistance, so as to calculate the current value of the target wire 311 .
  • the target wiring 311 is fed with a high-frequency electrical signal, skin effect will appear in the target wiring 311, so that the magnetic field generated by the target wiring 311 will change with the frequency of the input electrical signal, causing the TMR element 320 cannot accurately measure the current value in the target wire 311 , so that the range of the detection bandwidth of the TMR element 320 is greatly reduced.
  • the detected magnetic field remains unchanged at first, and then gradually decreases in a period of frequency, and then remains unchanged again after decreasing to a certain value; if the detection point is at position B, input As the frequency of the electrical signal increases, the detected magnetic field remains unchanged at first, then gradually increases within a period of frequency, and after increasing to a certain value, remains unchanged again.
  • the target trace 311 is located in the middle of the PCB 310, and the TMR element 320 can be fixed on the outer surface of the PCB 310 by means of welding, bonding, or the like.
  • the position on the PCB 310 where the TMR element 320 is fixed from the top view shown in FIG.
  • the distance D between the edges closest to the side of the TMR element 320, and the ratio of the width W of the target line 311 is between 3.0% and 20.0%, so that the current value of the tunneling magnetoresistive element detecting the target line does not follow the target line.
  • the frequency of the electrical signal in the trace changes, or changes very little, so that the tunneling magnetoresistive element can accurately detect the current value of the electrical signal in the target trace, thereby increasing the range of the measurement bandwidth of the tunneling magnetoresistive element.
  • the formula (1) is specifically:
  • D represents the distance between the detection unit in the TMR element 320 and the edge of the target line 311 closest to the TMR element 320
  • W is the width of the target line 311
  • the unit of D and W is mm.
  • the width of the target trace 311 detected by the TMR element 320 is generally between 1 mm and 40 mm. If the width of the target trace 311 is less than 1mm, its width may be smaller than the width of the TMR element 320, resulting in a reduction in the detection accuracy of the TMR element 320; if the width of the target trace 311 is greater than 40mm, it occupies a relatively large area of the PCB, resulting in Reduced PCB integration.
  • the magnetic field detected by the TMR element 320 is the most stable.
  • the frequency change of the input electrical signal in 311 is the smallest, and the flatness is also the smallest, thus verifying that the distance between the TMR element 320 and the edge of the target line 311 closest to the TMR element 320 side satisfies the formula (1), the TMR element
  • the installation position of 320 is the most ideal, and the detected magnetic field is the most stable.
  • the installation position of the TMR element 320 determined according to the formula (1) is at the mm level, the requirements for the manufacturing process of the product are relatively high.
  • the installation position of the TMR element 320 can be allowed to have a certain range of deviation.
  • the flatness ⁇ is less than 5%, it can be considered that the variation range of the magnetic field is small, and the position where the TMR element 320 is installed is an ideal position. As shown in Figure 7, when the value D is closer to 0.5 mm, the flatness ⁇ is smaller, and when the value D is farther away from 0.5 mm, the flatness ⁇ is larger.
  • the ratio of the distance D between the detection unit in the TMR element 320 and the edge of the target line 311 closest to the TMR element 320 to the width W of the target line 311 is between 5.0% and 20.0%. , conforming to the scope set by this application.
  • the ideal position where the TMR element 320 is arranged on the PCB 310 has no relationship with the height h between the TMR element 320 and the target trace 311, so the thickness of the PCB 310 of this application It can be any numerical value, and the present application does not limit it here.
  • the width of the TMR element 320 is smaller than the width of the target trace 311. From the top view, it is avoided that the TMR element 320 exceeds the target trace. The area where line 311 lies. Usually, if the TMR element 320 is located directly above or directly below the target trace 311, the distance between it and other traces is relatively far, and the influence of the magnetic field generated by other traces on the results detected by the TMR element 320 is compared.
  • the relationship between the width of the TMR element 320 and the width of the target routing 311 needs to satisfy the relationship represented by formula (2), specifically:
  • w represents the width of the TMR element 320
  • W represents the width of the target wiring 311 .
  • the TMR element of the magnetic sensor is arranged on the outer surface of the PCB, and its position is directly above or directly below the detected target trace, and is on the side closest to the TMR element of the target trace.
  • the target wiring 311 on the PCB 310 can be made of graphite, which can effectively suppress the generation of skin effect in the target wiring 311, thereby further improving the measurement of the target wiring 311 by the TMR element 320.
  • the skin effect generated in the target wiring 311 is generally related to the frequency, magnetic permeability and electrical conductivity of the electrical signal, specifically:
  • ⁇ represents the frequency of the electrical signal in the trace
  • ⁇ represents the magnetic permeability of the trace
  • ⁇ represents the electrical conductivity of the trace
  • this application uses graphite and copper elements as the wiring materials respectively, and the produced PCB is subjected to experimental simulation, and the simulation results shown in Figure 8 are obtained.
  • the frequency of the electrical signal is within 1MHz
  • the graphite wiring The current in the wire is evenly distributed in the trace, while the current distribution in the copper trace is uneven. It can be seen that the graphite trace suppresses the skin effect caused by the trace.
  • graphite is used as the material for making the wiring.
  • the TMR element 320 detects Compared with the simulation results in Figure 6, when the frequency of the electrical signal is within 10MHz, the magnetic sensor made of graphite as the material for the wiring detects the flatness of the magnetic field change. Much better.
  • the magnetic sensor 300 protected in this application further includes a shielding component 330 .
  • the shielding component 330 is generally arranged on the surface of the TMR element 320 away from the PCB 310 side, which can shield the influence of the external magnetic field on the detection result of the TMR element 320.
  • the shielding assembly 330 generally selects a comb structure, and the area of the comb structure is greater than the surface area of the surface of the TMR element 320 away from the PCB 310 side, so that the shielding assembly 330 can effectively shield the external magnetic field The impact on the detection result of the TMR element 320.
  • the shield with a comb structure because there is a gap between the teeth in the comb structure, can cut off the eddy current path of the shield in the high-frequency magnetic field, thereby inhibiting the eddy current effect of the shield, and has no effect on the surrounding magnetic field. It will cause distortion or the distortion is relatively weak, so it has little influence on the detection result of the TMR element 320 .
  • the smaller the side length of the teeth in the shielding assembly 330 and the smaller the distance between the teeth the better the effect of the shielding assembly 330 in suppressing the eddy current effect, and the smaller the impact on the detection result of the TMR element 320 .
  • the shielding assembly 330 is not limited to the structure shown in FIG. 9 , and can also be in other shapes, such as a semicircular shape, which can be buckled on the TMR element 320, and there is a gap between the TMR element 320 and the shielding assembly 330 to avoid Shielding the magnetic field generated by the target wire 311 causes the TMR element 320 to fail to detect the magnetic field generated by the target wire 311 ; and other shapes, which are not limited in this application.
  • the embodiment of the present application also provides an electronic device, the electronic device includes at least one magnetic sensor as described in Figure 3- Figure 9 and the corresponding protection scheme above, since the electronic device includes the magnetic sensor, the electronic The device has all or at least some of the advantages of the magnetic sensor.
  • the electronic device may be an electric vehicle, a computer, and the like.

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Abstract

一种磁传感器和电子设备，其中，磁传感器包括印刷电路板（310）和隧穿磁阻元件（320），印刷电路板（310）包括目标走线（311）。在安装隧穿磁阻元件（320）时，让隧穿磁阻元件（320）安装在目标走线（311）的正上方或正下方，且其内部的检测单元与目标走线（311）的距隧穿磁阻元件（320）最近一侧边缘之间的距离D，与目标走线（311）的宽度W之比为3.0％至20.0％之间，实现让隧穿磁阻元件（320）检测目标走线（311）的电流值不随目标走线（311）中电信号的频率变化而变化，或变化很小，使得隧穿磁阻元件（320）可以准确地检测出目标走线（311）中电信号的电流值，从而提高隧穿磁阻元件（320）测量带宽的范围。

Description

一种磁传感器和电子设备
本申请要求于2021年11月17日提交中国国家知识产权局、申请号为202111360274.8、申请名称为“一种磁传感器和电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及电子电气技术领域，尤其涉及一种磁传感器和电子设备。
背景技术
电流传感器可以检测电路中的电流信息，并将电流信息按一定规律变换成为符合一定标准需要的电信号或其它形式的信息，以满足信息的传输、处理、存储、显示、记录和控制等要求。其中，现有的电流传感器的种类有很多，常见的有电阻分流器、电流互感器、霍尔电流传感器、磁阻效应电流传感器、磁致伸缩电流传感器、光线电流传感器等等。
随着集成电路技术的发展，可以将大量的电路、晶体管、电阻等元器件集成在一起，形成比较小的电路板，不仅提高电子设备的集成度，还降低了电子设备的硬件成本和耗电成本。以印刷电路板(printed circuit board，PCB)为例，PCB中布置有大量的走线，各种元器件通过走线实现相互电连接。而PCB中的每个走线通过的电流一般都比较低，在几十毫安左右，有的甚至更低，导致检测走线中的电流十分困难。因此，如何为PCB中的走线选择出检测精度比较高的电流传感器是非常重要的。
发明内容
为了解决上述的问题，本申请的实施例中提供了一种磁传感器和电子设备，TMR元件布置在PCB的外表面上，其位置是处在被检测的目标走线的正上方或正下方，且与目标走线的最靠近TMR元件一侧的边缘之间的距离满足D＝0.1584W-0.1209时，TMR元件检测到磁场不会随目标走线中电信号的频率变化而变化，或变化很小，可以准确测量出目标走线的电流值，从而提高TMR元件测量带宽的范围。
为此，本申请的实施例中采用如下技术方案：
第一方面，本申请实施例中提供一种磁传感器，包括：印刷电路板，包括目标走线，用于让各个元器件之间电连接；隧穿磁阻元件，固定在所述印刷电路板的外表面上，用于检测所述目标走线的电流值；其中，所述隧穿磁阻元件位于所述目标走线的一侧侧面上的法线上，且所述隧穿磁阻元件中的检测单元距离与所述目标走线的距所述隧穿磁阻元件最近一侧边缘之间的距离D，与所述目标走线的宽度W之比为3.0％至20.0％之间，所述检测单元用于检测磁感应强度，所述目标走线的宽度为垂直于所述目标走线上电流流通方向上的长度。
在该实施方式中，通常情况下，隧穿磁阻元件检测目标走线的电流值，会随着目标走线中的电信号的频率变化而变化，但是由于隧穿磁阻元件与目标走线之间的距离，会影响到隧穿磁阻元件检测到电流值随目标走线中的电信号的频率变化的幅度，所以在安装隧穿磁阻元件时，可以让隧穿磁阻元件安装在目标走线的正上方或正下方，且其内部的检测单元与目标走线的距隧穿磁阻元件最近一侧边缘之间的距离D，与目标走线的宽度W之比为3.0％至20.0％之间，实现让隧穿磁阻元件检测目标走线的电流值不随目标走线中电信号的频率变化而变化， 或变化很小，使得隧穿磁阻元件可以准确地检测出目标走线中电信号的电流值，从而提高隧穿磁阻元件测量带宽的范围。
在一种实施方式中，所述隧穿磁阻元件位于所述目标走线的一侧侧面上的法线上，且所述隧穿磁阻元件中的检测单元与所述目标走线的距所述隧穿磁阻元件最近一侧边缘之间的距离D满足：D＝0.1584W-0.1209；其中，D和W的单位为mm，D和W的单位为mm。
在该实施方式中，通过大量的实验验证，当穿磁阻元件位于目标走线的一侧侧面上的法线上，且隧穿磁阻元件中的检测单元与所述目标走线的距隧穿磁阻元件最近一侧边缘之间的距离D为D＝0.1584W-0.1209的时候，隧穿磁阻元件检测到电流值随目标走线中的电信号的频率变化的幅度变化最小，实现隧穿磁阻元件可以准确地检测出目标走线中电信号的电流值。
在一种实施方式中，所述隧穿磁阻元件的宽度小于所述目标走线的宽度；其中，所述隧穿磁阻元件的宽度为垂直于所述目标走线上电流流通方向上的长度。
在该实施方式中，隧穿磁阻元件检测的目标走线的宽度一般比隧穿磁阻元件的宽度要大，如果隧穿磁阻元件有部分超出目标走线边缘，其它元器件和走线会对隧穿磁阻元件的检测结果有影响，造成检测电流的准确性降低。
在一种实施方式中，所述隧穿磁阻元件的宽度w满足：w＜W-2D；其中，D和W的单位为mm。
在该实施方式中，由于隧穿磁阻元件理想安装位置，与目标走线最近一侧的边缘之间需要预留设定的距离，所以隧穿磁阻元件检测的目标走线的宽度，不仅要比隧穿磁阻元件的宽度要大，还要比隧穿磁阻元件的宽度和两倍的预留设定的距离之和要大，才能保证隧穿磁阻元件不会有部分超出目标走线边缘，造成检测电流的准确性降低。
在一种实施方式中，所述隧穿磁阻元件在所述目标走线的一侧侧面上的法线方向，与所述目标走线之间的距离大于零。
在该实施方式中，隧穿磁阻元件和目标走线之间的高度h一般是大于0，如果隧穿磁阻元件和目标走线之间的高度h＝0，也即将隧穿磁阻元件嵌入目标走线中，这种安装会导致电子设备的成本比较高。
在一种实施方式中，所述目标走线是由石墨材料制作而成。
在该实施方式中，印刷电路板上的目标走线可以是由石墨制作而成，可以有效地抑制目标走线中产生集肤效应，从而进一步提高隧穿磁阻元件测量目标走线中的电流值的准确性。
在一种实施方式中，还包括：屏蔽组件，设置在所述隧穿磁阻元件的背离所述印刷电路板一侧的表面上，用于屏蔽除所述目标走线以外的其它走线和元器件产生的磁场。
在该实施方式中，屏蔽组件一般设置在隧穿磁阻元件的背离印刷电路板一侧的表面上，可以屏蔽外界磁场对隧穿磁阻元件检测结果的影响。
在一种实施方式中，所述屏蔽组件为梳状结构。
在该实施方式中，屏蔽组件一般选用梳状结构，该梳状结构中的齿与齿之间存在缝隙，可以切断屏蔽体在高频磁场中涡流的路径，从而抑制屏蔽体产生涡流效应，对周围磁场不会造成畸变或畸变比较弱，使得屏蔽组件可以有效地屏蔽外界磁场，且不会影响隧穿磁阻元件检测结果。
在一种实施方式中，所述屏蔽组件的尺寸大于所述隧穿磁阻元件的尺寸。
在该实施方式中，屏蔽组件的尺寸要大于隧穿磁阻元件的尺寸，避免屏蔽组件布置在隧穿磁阻元件上，隧穿磁阻元件侧面上的外界磁场对隧穿磁阻元件检测结果的影响。
第二方面，本申请实施例中提供一种电子设备，包括：至少一个如第一方面各个可能实现的磁传感器。
附图说明
下面对实施例或现有技术描述中所需使用的附图作简单地介绍。
图1(a)为现有技术中PCB走线中输入低频电信号时磁场分布图；
图1(b)为现有技术中PCB走线中输入高频电信号时磁场分布图；
图2为现有技术中PCB走线中输入不同频率电信号时位置点A和位置点B处磁场分布图；
图3为本申请实施例中提供的一种磁传感器结构俯视结构示意图；
图4为本申请实施例中提供的一种磁传感器结构剖面结构示意图；
图5(a)为两层的磁铁层的磁化方向同向平行时的效果示意图；
图5(b)为两层的磁铁层的磁化方向反向平行时的效果示意图；
图6为本申请实施例中提供的目标走线宽度为4mm，且TMR元件与目标走线最靠近TMR元件一侧的边缘之间的不同距离时，TMR元件检测到的磁场随目标走线中电信号的频率变化关系的实验图；
图7为本申请实施例中提供的目标走线宽度为4mm时，TMR元件与目标走线最靠近TMR元件一侧的边缘之间的不同距离对应的平坦程度的实验图；
图8为本申请实施例中提供的采用石墨和铜作为PCB中的走线材料，仿真得到电流分布实验图；
图9为本申请实施例中提供的梳状结构的屏蔽组件示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行描述。
在本申请的描述中，术语“中心”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如可以是固定连接，也可以是可拆卸连接，还可以是抵触连接或一体的连接；对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
在本说明书的描述中，具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以适合的方式结合。
在现代工业和电子产品中，以霍尔电流传感器为代表的磁传感器应用最为广泛。其中，磁传感器一般是以感应磁场强度来检测电流、位置、方向等物理参数，其作为接收磁场信号的敏感元件可以为霍尔元件、各向异性磁电阻(anisotropic magneto resistance，AMR)元件、巨磁电阻(giant magneto resistance，GMR)元件、隧穿磁阻(tunnel magneto resistance，TMR)元件等等。
以霍尔元件为敏感元件的磁传感器。由于现有的电子设备中各个器件的工作电流比较低，低至毫安级或更低，因此需要在磁传感器中增加聚磁环结构，通过聚磁环结构来放大周围的磁场，提高霍尔元件输出的电信号的灵敏度。但是，在磁传感器中增加聚磁环结构，会增大 磁传感器的体积和重量，且霍尔元件具有功耗大、线性度差等缺陷，导致该磁传感器性能比较差。
以AMR元件为敏感元件的磁传感器。如果磁传感器中的敏感元件采用AMR器件，则需要在磁传感器中设置set/reset线圈，对AMR元件进行预设/复位操作。虽然AMR元件的灵敏度比霍尔元件高很多，但是其线性范围比较窄，且增加了set/reset线圈会使得该磁传感器制造工艺比较复杂，导致该磁传感器的成本比较高。
以GMR元件为敏感元件的磁传感器。如果选用GMR元件作为敏感元件，相比较由霍尔元件构成的磁传感器，虽然该磁传感器的灵敏性比较高，但是其线性范围更低，导致该磁传感器性能比较差。
TMR元件是近年来开始工业应用的新型磁电阻效应传感器，其最初是用在硬盘中磁性读写头上的，所以对磁场检测的精度、准确度以及寿命可靠性比较高。TMR元件是通过检测铜排和导线上电流所产生的磁场，并通过芯片进行运算得到电流的大小。相比较由霍尔元件构成的磁传感器，具有更好的温度稳定性、更高的灵敏度、更低的功耗、更好的线性度、以及不需要额外的聚磁环结构等优点；相比较AMR元件构成的磁传感器，具有更好的温度稳定性、更高的灵敏度、更宽的线性范围、以及不要额外的set/reset线圈结构等优点；相比较GMR元件构成的磁传感器，具有更好的温度稳定性、更高的灵敏度、更低的功耗、更宽的线性范围等优点。
表一是由霍尔元件、AMR元件、GMR元件和TMR元件构成的磁传感器，分别从功耗、尺寸、灵敏度、线性范围、分辨率和温度特征这六个技术参数进行对比，可以更为直观的看到TMR元件的优势。具体为：
表一各种磁传感器的各个技术参数对比表
Figure PCTCN2022103840-appb-000001
根据表一可知，相比较其它磁传感器，由TMR元件构成的磁传感器在功耗、尺寸、灵敏度、线性范围、分辨率和温度特征这六个方面，都是有明显的优势。
对于表贴式TMR磁传感器，是将TMR元件表贴在PCB中的走线上，其属于开放式磁路检测模式，测量精度容易受外部因素干扰。当导体中有交流电或者交变电磁场时，导体内部的电流分布不均匀，电流集中在导体的“皮肤”部分，也就是说电流集中在导体外表的薄层，越靠近导体表面，电流密度越大，导体内部实际上电流较小，从而使导体的电阻增加，损耗功率也相应增加，这一现象称为集肤效应(skin effect)。
现有技术中，如图1(a)所示，如果PCB中的走线通入低频电信号时，走线中的电流变化率(di/dt)比较接近零，可以认为电流分布比较均匀，不会出现集肤效应；如图1(b)所示，如果PCB中的走线通入高频电信号时，由于集肤效应的存在，高频电信号在走线中产生的磁场在走线的中心区域，感应出最大的电动势，该电动势在闭合电路中产生感应电流，在走线中心的感应电流最大。由于感应电流的方向与原有电流的方向相反，且随着频率的增大感应电流越大，导致PCB中的走线的中心位置上的电流很小或者为零，两侧位置上的电流比较大， 从而使得该走线周围产生的磁场分布不均匀。
PCB中的走线通入不同频率的电信号后，在走线周围的两个测量位置点A和位置点B处，两个位置点处检测到的磁场强度与电信号频率之间关系如图2所示。由于待测的电流通常包含有丰富的谐波含量，所以需要找到合适的安装位置，使不同频率的电流产生的磁感应强度B基本保持不变，以确保TMR元件的测量带宽。
图3、图4为本申请实施例中提供的一种磁传感器的结构示意图。如图所示，该磁传感器300包括PCB 310和TMR元件320。其中，PCB 310中布置有大量的走线，用于让各个元器件进行电连接，TMR元件320一般布置在PCB 310的外表面上，且TMR元件320与待检测的走线(后续称为“目标走线311”)之间关系为：TMR元件320与目标走线311处在PCB 310的外表面法线方向上。PCB一般是由连接导线和隔离材料构成，在制作PCB时，可以将连接导线平铺在平面上，然后在连接导线上喷涂隔离材料，让每个连接导线之间相互隔离；然后在喷涂的隔离材料上再平铺一层连接导线，再在连接导线上喷涂隔离材料；以此类推，可以制作出具有多层的连接导线的PCB。其中，处在隔离材料中的连接导线，一般称之为“走线”。
当TMR元件320和目标走线311通入电信号时，由于TMR元件320与目标走线311处在PCB 310的外表面法线方向上，TMR元件320和目标走线311会在PCB 310中隔离材料之间，形成TMR元件320-隔离材料-目标走线311结构，从而产生隧穿磁阻效应。其中，隧穿磁阻效应是指在铁磁-绝缘体薄膜-铁磁材料中，隧穿电阻大小随两边铁磁材料相对方向变化的效应。由于隧穿磁阻效应具有磁电阻效应大、磁场灵敏度高等独特优势，有着广泛的应用前景。
从经典物理学观点来看，铁磁层(F1)+绝缘层(I)+铁磁层(F2)的三明治结构根本无法实现电子在磁层中穿通，而量子力学却可以完美解释这一现象。如图5(a)所示，当两层铁磁层的磁化方向同向平行，多数自旋子带的电子将进入另一磁性层中多数自旋子带的空态，少数自旋子带的电子也将进入另一磁性层中少数自旋子带的空态，总的隧穿电流较大，此时TMR元件320为低阻状态；如图5(b)所示，当两层的磁铁层的磁化方向反向平行，情况则刚好相反，即多数自旋子带的电子将进入另一磁性层中少数自旋子带的空态，而少数自旋子带的电子也进入另一磁性层中多数自旋子带的空态，此时隧穿电流较小，TMR元件320为高阻状态。由此可以看出，隧道电流和隧道电阻都依赖于两个铁磁层磁化强度的相对取向，当磁化方向发生变化时，隧穿电阻发生变化，因此称为隧穿磁阻效应。
本申请中，TMR元件320可以利用磁场变化引起磁电阻变化的原理，通过检测磁电阻的变化，来测算出TMR元件320周围的磁场变化，从而计算出目标走线311的电流值。但是，如果目标走线311通入的是高频电信号，目标走线311中会出现集肤效应，使得目标走线311产生的磁场会随着输入电信号的频率变化而变化，导致TMR元件320无法准确测量出目标走线311中的电流值，使得TMR元件320检测带宽的范围大大减小。
根据现有技术中如图2所示的输入不同频率电信号时位置点A和位置点B处磁场分布图可知，检测点如果在位置点A处，随着目标走线311中输入电信号的频率增大，检测到的磁场先保持不变，然后在一段频率中逐渐减小，减小到一定数值后，再次保持不变；检测点如果在位置B处，随着目标走线311中输入电信号的频率增大，检测到的磁场先保持不变，然后在一段频率中逐渐增大，增大到一定数值后，再次保持不变。可以想到，可能在位置点A和位置点B之间的某一位置处，随着目标走线311中输入电信号的频率增大，检测到的额外磁场始终保持不变或变化范围很小，使得TMR元件320可以准确测量出目标走线311的电流值，从而提高TMR元件320测量带宽的范围。
本申请实施例中，目标走线311处在PCB 310中间位置，TMR元件320可以通过焊接、粘接 等方式固定在PCB 310的外表面上。其中，TMR元件320固定在PCB 310上的位置，从图3所示的俯视图来看，处在目标走线311的正上方或正下方，且TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D，与目标走线311的宽度W之比为3.0％至20.0％之间，实现让隧穿磁阻元件检测目标走线的电流值不随目标走线中电信号的频率变化而变化，或变化很小，使得隧穿磁阻元件可以准确地检测出目标走线中电信号的电流值，从而提高隧穿磁阻元件测量带宽的范围。示例性地，通过大量的实验验证，当TMR元件320处在目标走线311的正上方或正下方，且TMR元件320中的检测单元与目标走线311的距TMR元件320最近一侧边缘之间的距离D满足公式(1)表示的关系，TMR元件320检测到电流值随目标走线311中的电信号的频率变化的幅度变化最小，实现TMR元件320可以准确地检测出目标走线311中电信号的电流值，公式(1)具体为：
D＝0.1584W-0.1209        (1)
其中，D表示TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离，W为目标走线311的宽度，D和W的单位为mm。
本申请中，TMR元件320检测的目标走线311，其宽度一般在1mm-40mm之间。如果目标走线311的宽度小于1mm，其宽度可能比TMR元件320的宽度要小，导致TMR元件320检测准确度降低；如果目标走线311的宽度大于40mm，其占据PCB的面积比较大，造成PCB集成度降低。示例性地，如果目标走线311的宽度W在1mm-40mm之间，根据公式(1)可以计算出，当目标走线311的宽度W＝1mm，TMR元件320中的检测单元与目标走线311的距TMR元件320最近一侧边缘之间的距离D＝0.038mm，则TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D，与目标走线311的宽度W之比为3.75％；当目标走线311的宽度W＝40mm，TMR元件320中的检测单元与目标走线311的距TMR元件320最近一侧边缘之间的距离D＝6.215mm，则TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D，与目标走线311的宽度W之比为15.54％。
TMR元件320布置在PCB 310的外表面上时，难免会出现安装误差，因此需要考虑安装误差带来的偏差。对于目标走线311的宽度W＝1mm，TMR元件320中的检测单元与目标走线311的距TMR元件320最近一侧边缘之间的距离D＝0.038mm，如果可以允许其误差在±0.008mm以内，此时TMR元件320中的检测单元与目标走线311的距TMR元件320最近一侧边缘之间的最小距离D＝0.03mm，此时TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D，与目标走线311的宽度W之比最小值为3.0％；对于目标走线311的宽度W＝40mm，TMR元件320中的检测单元与目标走线311的距TMR元件320最近一侧边缘之间的距离D＝6.215mm，如果可以允许其误差在±1.785mm以内，此时TMR元件320中的检测单元与目标走线311的距TMR元件320最近一侧边缘之间的最大距离D＝8.0mm，此时TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D，与目标走线311的宽度W之比最大值为20.0％。
本申请在实验模拟过程中，选用的PCB 310中布置有走线，且目标走线311的宽度W＝4mm；TMR元件320通过表贴方式固定在PCB 310的外表面上，从俯视图上来看，TMR元件320处在目标走线的正上方，且TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D＝0.1584×4-0.1209≈0.5mm，TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D，与目标走线311的宽度W之比为12.82％；TMR元件320的检测单元与目标走线311之间高度距离h＝1.2mm。
在有限元仿真过程中，选用不同TMR元件320中的检测单元与目标走线311的最靠近TMR 元件320一侧的边缘之间的距离D＝0,0.1mm,0.2mm，…，0.5mm，…2.0mm，得到如图6所示的结果。其中，对于D＝0.5mm的曲线中，TMR元件320检测到的最低磁场B＝1.63mT，最高磁场B＝1.66mT，平坦程度为η＝(1.66-1.63)/1.63＝1.8％，相比较其它距离D，TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D＝0.5mm时，TMR元件320检测到的磁场最稳定，随着目标走线311中输入电信号的频率变化最小，且平坦程度也最小，从而验证了TMR元件320与目标走线311的最靠近TMR元件320一侧的边缘之间的距离满足公式(1)时，TMR元件320安装位置最为理想，检测到的磁场最稳定。
由于TMR元件320根据公式(1)确定的理想安装位置在mm级别，所以对产品的制造工艺要求比较高，一般为了降低成本，可以允许TMR元件320的安装位置有一定范围的偏差。可选地，当平坦程度η小于5％，可以认为磁场变化范围很小，此时TMR元件320安装的位置即为理想位置。结合图7所示，当数值D越靠近0.5mm时，平坦度η越小，数值D越远离0.5mm时，平坦度η越大。如果设定η＜5％范围内都可以认为TMR元件320安装在理想位置上，则TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D在0.2mm-0.8mm之间均满足，因此TMR元件320在安装过程中，安装的位置相对于理想位置D＝0.1584W-0.1209可以偏差0.3mm，从而降低产品的制作难度和降低产品的成本。另外，此时TMR元件320中的检测单元与目标走线311的最靠近TMR元件320一侧的边缘之间的距离D，与目标走线311的宽度W之比为5.0％至20.0％之间，符合本申请设定的范围。
本申请中，根据公式(1)可知，TMR元件320布置在PCB 310上的理想位置，与TMR元件320和目标走线311之间的高度h之间并没有关系，因此本申请PCB 310的厚度可以为任意数值，本申请在此并不限定。优选地，TMR元件320和目标走线311之间的高度h一般是大于0，如果TMR元件320和目标走线311之间的高度h＝0，也即将TMR元件320嵌入目标走线320中，这种安装会导致电子设备的成本比较高。
结合图3所示，TMR元件320的宽度，也即与目标走线311的宽度平行方向上的边长，比目标走线311的宽度要小，从俯视图来看，避免TMR元件320超出目标走线311所在的区域。通常情况下，TMR元件320处在目标走线311的正上方或正下方，则与其它走线之间的距离比较远，其它走线产生的磁场对TMR元件320检测到的结果影响比较下，如果TMR元件320有部分超出目标走线311所在的区域，甚至从俯视图来看叠加到其它走线上，此时其它走线产生的磁场对TMR元件320检测到的结果影响比较大，会导致TMR元件320检测目标走线的电流值不准确。可选地，TMR元件320的宽度与目标走线311的宽度之间的关系，需要满足公式(2)表示的关系，具体为：
w＜W-2D       (2)
其中，w表示TMR元件320的宽度，W表示目标走线311的宽度。
本申请实施例中，磁传感器的TMR元件布置在PCB的外表面上，其位置是处在被检测的目标走线的正上方或正下方，且与目标走线的最靠近TMR元件一侧的边缘之间的距离满足D＝0.1584W-0.1209时，TMR元件检测到磁场不会随目标走线中电信号的频率变化而变化，或变化很小，可以准确测量出目标走线的电流值，从而提高TMR元件测量带宽的范围。
本申请保护的磁传感器300中，PCB 310上的目标走线311可以是由石墨制作而成，可以有效地抑制目标走线311中产生集肤效应，从而进一步提高TMR元件320测量目标走线311中的电流值的准确性。示例性地，目标走线311中产生集肤效应一般与电信号的频率、磁导率和电导率有关，具体为：
Figure PCTCN2022103840-appb-000002
其中，ω表示走线中电信号的频率，μ表示走线的磁导率，γ表示走线的电导率。
根据公式(3)可知，在频率ω保持不变的情况下，如果降低磁导率μ和电导率γ，可以有效的抑制走线产生集肤效应。如果选用石墨作为制作走线的材料，石墨的电导率γ＝7×10 4S/m，相比较金属材料的电导率γ比较小，δ 石墨大于δ 铜，所以由石墨构成的目标走线311抑制产生集肤效应的效果更好。
在有限元仿真过程中，本申请以石墨和铜元素分别作为制作走线材料，制作出的PCB进行实验仿真，得到如图8所示的仿真结果，当电信号的频率在1MHz以内，石墨走线中的电流是均匀地分布在走线中，而铜走线中的电流分布不均匀，可以看出石墨走线抑制走线产生肌肤效应更为明显。
结合图9所示，采用石墨作为制作走线的材料，当TMR元件320处在不同位置时，也即数值D＝0,0.5mm，0.6mm，1mm，1.5mm，2mm时，TMR元件320检测到磁场随走线中电信号频率变化而变化的仿真图，相比较图6的仿真结果，当电信号的频率在10MHz以内，由石墨作为制作走线的材料的磁传感器检测到磁场变化的平坦程度更好。
本申请保护的磁传感器300中，还包括屏蔽组件330。其中，屏蔽组件330一般设置在TMR元件320的背离PCB 310一侧的表面上，可以屏蔽外界磁场对TMR元件320检测结果的影响。示例性地，如图9所示，屏蔽组件330一般选用梳状结构，该梳状结构的面积要大于TMR元件320的背离PCB 310一侧表面的表面积，使得屏蔽组件330可以有效地屏蔽外界磁场对TMR元件320检测结果的影响。而且，如果采用完整结构的屏蔽体，屏蔽体内会产生涡流效应，会对周围的磁场造成严重的畸变，从而影响TMR元件320的检测结果。而采用梳状结构的屏蔽体，由于梳状结构中起到屏蔽作用的齿之间存在间隙，可以切断屏蔽体在高频磁场中涡流的路径，从而抑制屏蔽体产生涡流效应，对周围磁场不会造成畸变或畸变比较弱，从而对TMR元件320检测结果的影响很小。
优选地，屏蔽组件330中的齿的边长、齿与齿之间的距离越小，屏蔽组件330抑制产生涡流效应的效果越好，对TMR元件320检测结果的影响越小。
本申请中，屏蔽组件330，不仅限于图9所示的结构，还可以为其它形状，例如为半圆形状，可以扣在TMR元件320上，且TMR元件320与屏蔽组件330之间存在孔隙，避免屏蔽目标走线311产生的磁场，导致TMR元件320无法检测目标走线311产生的磁场；以及其它形状，本申请在此不做限定。
本申请实施例中还提供了一种电子设备，该电子设备中包括至少一个如图3-图9和上述对应保护方案中记载的磁传感器，由于该电子设备包括有该磁传感器，因此该电子设备具有该磁传感器的所有或至少部分优点。其中，电子设备可以为电动汽车、电脑等等。
在本说明书的描述中，具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以适合的方式结合。
最后说明的是：以上实施例仅用以说明本申请的技术方案，而对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例中所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或替换，并不使相应技术方案的本质脱离本申请各实施例中技术方案的精神和范围。

Claims (10)

  1. 一种磁传感器，其特征在于，包括：
    印刷电路板(310)，包括目标走线(311)，用于让各个元器件之间电连接；
    隧穿磁阻元件(320)，固定在所述印刷电路板的外表面上，用于检测所述目标走线的电流值；
    其中，所述隧穿磁阻元件位于所述目标走线的一侧侧面上的法线上，且所述隧穿磁阻元件中的检测单元距离与所述目标走线的距所述隧穿磁阻元件最近一侧边缘之间的距离D，与所述目标走线的宽度W之比为3.0％至20.0％之间，所述检测单元用于检测磁感应强度，所述目标走线的宽度为垂直于所述目标走线上电流流通方向上的长度。
  2. 根据权利要求1所述的磁传感器，其特征在于，所述隧穿磁阻元件中的检测单元与所述目标走线的距所述隧穿磁阻元件最近一侧边缘之间的距离D满足：
    D＝0.1584W-0.1209
    其中，D和W的单位为mm。
  3. 根据权利要求1或2所述的磁传感器，其特征在于，所述隧穿磁阻元件的宽度小于所述目标走线的宽度；其中，所述隧穿磁阻元件的宽度为垂直于所述目标走线上电流流通方向上的长度。
  4. 根据权利要求1-3任意一项所述的磁传感器，其特征在于，所述隧穿磁阻元件的宽度w满足：
    w＜W-2D
    其中，D和W的单位为mm。
  5. 根据权利要求1-4任意一项所述的磁传感器，其特征在于，所述隧穿磁阻元件在所述目标走线的一侧侧面上的法线方向，与所述目标走线之间的距离大于零。
  6. 根据权利要求1-5任意一项所述的磁传感器，其特征在于，所述目标走线是由石墨材料制作而成。
  7. 根据权利要求1-6任意一项所述的磁传感器，其特征在于，还包括：
    屏蔽组件(320)，设置在所述隧穿磁阻元件的背离所述印刷电路板一侧的表面上，用于屏蔽除所述目标走线以外的其它走线和元器件产生的磁场。
  8. 根据权利要求7所述的磁传感器，其特征在于，所述屏蔽组件为梳状结构。
  9. 根据权利要求7或8所述的磁传感器，其特征在于，所述屏蔽组件的尺寸大于所述隧穿磁阻元件的尺寸。
  10. 一种电子设备，其特征在于，包括：至少一个如权利要求1-9所述的磁传感器。
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