Electric current sensor

Current sensor

electric current sensor

The present invention relates to a sensor, and particularly relates to a current sensor.

Current sensing is one of the indispensable elements in industrial automation. In recent years, the demand for current sensing has expanded from industrial use to consumer products and applications in the field of smart homes and smart cities. High accuracy, fast response, small size, low power consumption and reliable quality have become the goals pursued by the new generation of current sensors.

There are many ways to measure the current in a conductor. For example, a shunt resistor can be used to calculate the current by measuring the voltage difference across it. However, this resistance is quite small, so the current consumption is high, and it is not suitable for small or portable devices. In addition, high currents can generate heat and cause other problems.

The invention provides a current sensor with high sensitivity, high accuracy and low power consumption.

An embodiment of the present invention provides a current sensor including a substrate, A first slope surface, a second slope surface, at least one wire, a first anisotropic magnetic resistance unit, a second anisotropic magnetic resistance unit, a first magnetization direction setting element, and a second magnetization direction setting element. The first slope surface and the second slope surface are arranged on the substrate and are arranged in a first direction. The wires extend along a second direction and are arranged on one side of the substrate. The first anisotropic magnetic resistance unit is configured on the first slope surface, and the second anisotropic magnetic resistance unit is configured on the second slope surface. The first magnetization direction setting element is used for setting the magnetization direction of the first anisotropic magnetic resistance unit, and the second magnetization direction setting element is used for setting the magnetization direction of the second anisotropic magnetic resistance unit. When a current flows through the wire, the magnetic field component in a third direction generated by the current on the first slope surface is opposite to the magnetic field component in the third direction generated by the current on the second slope surface. The first direction, the second direction and the third direction are different from each other, and the sensing directions of the first anisotropic magnetoresistive unit and the second anisotropic magnetoresistive unit are inclined with respect to the first direction and the third direction, and are different from The second direction. The first anisotropic magnetic resistance unit is electrically connected to the second anisotropic magnetic resistance unit to output a voltage signal. The voltage signal corresponds to the magnetic field component in the third direction generated by the current at the first ramp surface and the second ramp surface.

In an embodiment of the present invention, the current sensor further includes a third ramp surface, a fourth ramp surface, a third anisotropic magnetoresistance unit, and a fourth anisotropic magnetoresistance unit. The third slope surface and the fourth slope surface are provided on the substrate, wherein the third slope surface is opposite to the first slope surface, the fourth slope surface is opposite to the second slope surface, and the first slope surface, the third slope surface, and the fourth slope surface are opposite to each other. The slope surface and the second slope surface are sequentially arranged in the first direction. The third anisotropic magnetoresistive unit is arranged on the third slope surface, and the first magnetization The direction setting element is also used to set the magnetization direction of the third anisotropic magnetoresistive unit. The fourth anisotropic magnetic resistance unit is disposed on the fourth slope surface, and the second magnetization direction setting element is also used to set the magnetization direction of the fourth anisotropic magnetic resistance unit. When the current flows through the wire, due to the magnetic field generated by the current, the resistance change generated by the first anisotropic magnetoresistive unit is opposite to the resistance change generated by the third anisotropic magnetoresistive unit, and the second The change in resistance value generated by the anisotropic magnetoresistive unit is opposite to the change in resistance value generated by the fourth anisotropic magnetoresistive unit. The first, second, third, and fourth anisotropic magnetoresistive units are electrically connected to form a Wheatstone bridge to output the output corresponding to the first, second, third, and fourth anisotropic magnetoresistive units A voltage signal that changes the resistance value.

In an embodiment of the present invention, the current sensor further includes an arithmetic unit which is electrically connected to an output terminal of the Wheatstone bridge, wherein the first magnetization direction setting element and the second magnetization direction setting element connect the first The magnetization direction combination of the second, third, and fourth anisotropic magnetoresistive units is set to a first combination, so that the Wheatstone bridge outputs a first voltage signal, and the first magnetization direction setting element and the first combination The second magnetization direction setting element then sets the magnetization direction combination of the first, second, third and fourth anisotropic magnetoresistive units to a second combination opposite to the first combination, so that the Wheatstone bridge outputs A second voltage signal. The arithmetic unit is used for subtracting the second voltage signal from the first voltage signal to output an output voltage signal corresponding to the magnitude of the magnetic field generated by the current.

In an embodiment of the present invention, the arithmetic unit is used to add the first voltage signal and the second voltage signal to output an offset voltage signal.

In an embodiment of the present invention, the Wheatstone bridge corresponding to the output voltage signal of the external magnetic field component in the first direction is zero, which corresponds to the voltage output of the external magnetic field component in the second direction. The signal is zero, and the output voltage signal corresponding to the external magnetic field component in the third direction is zero.

In an embodiment of the present invention, the first anisotropic magnetoresistive unit includes a first anisotropic magnetoresistance and a second anisotropic magnetoresistance arranged in sequence along the opposite direction of the second direction, and the second The anisotropic magnetoresistive unit includes a third anisotropic magnetoresistance and a fourth anisotropic magnetoresistance arranged in sequence along the direction opposite to the second direction. The third anisotropic magnetoresistance unit includes A fifth anisotropic magnetoresistance and a sixth anisotropic magnetoresistance are arranged in sequence in a direction opposite to the direction, and the fourth anisotropic magnetoresistance unit includes a first Seven anisotropic magnetoresistance and an eighth anisotropic magnetoresistance.

In an embodiment of the present invention, at a first time, the first magnetization direction setting element sets the magnetization directions of the first anisotropic magnetoresistance and the fifth anisotropic magnetoresistor to the opposite direction of the second direction, and Set the magnetization direction of the second anisotropic magnetoresistance and the sixth anisotropic magnetoresistance to the second direction; at the first time, the second magnetization direction setting element sets the third anisotropic magnetoresistance to the seventh anisotropy The magnetization direction of the magnetoresistance is set to the opposite direction of the second direction, and the magnetization directions of the fourth anisotropic magnetoresistance and the eighth anisotropic magnetoresistance are set to the second direction; at a second time, the first magnetization direction The setting element sets the magnetization directions of the first anisotropic magnetic resistance and the fifth anisotropic magnetic resistance to the second direction, and sets the magnetization directions of the second anisotropic magnetic resistance and the sixth anisotropic magnetic resistance to the first The opposite of the two directions; at the second time, the second magnetization direction is set The element sets the magnetization directions of the third anisotropic magnetoresistance and the seventh anisotropic magnetoresistor to the second direction, and sets the magnetization directions of the fourth anisotropic magnetoresistance and the eighth anisotropic magnetoresistance to the second The opposite direction of the direction.

In an embodiment of the present invention, the first magnetization direction setting element and the second magnetization direction setting element are conductive sheets, conductive coils, wires, conductors or permanent magnets.

In an embodiment of the present invention, the first direction, the second direction and the third direction are perpendicular to each other.

In an embodiment of the present invention, the at least one wire is a wire, the first slope surface and the second slope surface are located on a first side of the substrate, and the wire is located on a second side of the substrate, and the first side is opposite to The second side.

In an embodiment of the present invention, the first slope surface and the second slope surface are respectively located on one side of opposite ends of the substrate, and the wire is located on one side of the center of the substrate.

In an embodiment of the present invention, the above-mentioned at least one wire is two wires, which are respectively disposed beside a first end and a second end of the substrate, wherein the first end is opposite to the second end, and the two wires are respectively Partially overlaps the first end and the second end.

In an embodiment of the present invention, the above-mentioned at least one wire is two wires, which are respectively disposed beside a first end and a second end of the substrate, wherein the first end is opposite to the second end, and the two wires are respectively Does not overlap with the first end and the second end.

In an embodiment of the present invention, the first anisotropic magnetoresistive unit and the second anisotropic magnetoresistive unit are electrically connected to form a Wheatstone bridge to output the output corresponding to the first anisotropic magnetoresistive unit and the second anisotropic magnetoresistive unit. Two voltage signals of resistance change generated by anisotropic magnetoresistive unit.

In the current sensor of the embodiment of the present invention, since the anisotropic magnetoresistive unit is connected to form a Wheatstone bridge to sense the magnetic field generated by the current in the wire, it is highly sensitive to current sensing Degree and high accuracy. In addition, since the current sensor in the embodiment of the present invention uses the magnetic field generated by the sensing current to reverse the magnitude of the current, the anisotropic magnetoresistive unit does not directly contact the current, so it can have a lower Power consumption.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

<p>100, 100a, 100b, 100c, 100d: current sensor</p><p>120: package body</p><p>210: substrate</p><p>212: first end</p><p>214: second end</p><p>215: Insulation layer</p><p>222: The first anisotropic magnetoresistance unit</p><p>224: The second anisotropic magnetoresistance unit</p><p>226: The third anisotropic magnetoresistance unit</p><p>228: The fourth anisotropic magnetoresistance unit</p><p>300: Anisotropic magnetoresistance</p><p>310: short bar</p><p>312: sensing direction</p><p>320: Ferromagnetic film</p><p>400: calculator</p><p>410, 420: Arithmetic Operator</p><p>C: Wire</p><p>D: Extension direction</p><p>D1: First direction</p><p>D2: second direction</p><p>D3: Third party</p><p>H: External magnetic field</p><p>HC: Magnetic field component</p><p>HE1, HE2, HE3: external magnetic field component</p><p>I, i, I1, I2: current</p><p>M, M10, M1256, M15, M15', M20, M26, M26', M30, M3478, M37, M37', M40, M48, M48': Magnetization direction</p><p>M1, M1a: the first magnetization direction setting element</p><p>M2, M2a: The second magnetization direction setting element</p><p>P1, P1', P2, P2', P3, P3', P4, P4', P5, P5', P6': contact</p><p>R1: First anisotropic magnetoresistance</p><p>R2: second anisotropic magnetoresistance</p><p>R3: third anisotropic magnetoresistance</p><p>R4: Fourth anisotropic magnetoresistance</p><p>R5: Fifth anisotropic magnetoresistance</p><p>R6: sixth anisotropic magnetoresistance</p><p>R7: seventh anisotropic magnetoresistance</p><p>R8: Eighth anisotropic magnetoresistance</p><p>R: Resistance value change</p><p>S1: The first slope</p><p>S2: second slope surface</p><p>S3: Third slope</p><p>S4: Fourth slope</p><p>V₁: The first voltage signal</p><p>V₂: The second voltage signal</p><p>V_off: Offset voltage signal</p><p>V_out: Output voltage signal</p>

FIG. 1 is a schematic top view of a current sensor according to an embodiment of the invention.

FIG. 2 is a schematic cross-sectional view of the current sensor of FIG. 1 along line AA.

3A and 3B are used to illustrate the operating principle of the anisotropic magnetoresistance in FIG. 1.

4A and 4B respectively show the magnetization direction of the anisotropic magnetoresistance at the first time and the second time of the current sensor of FIG. 1 and the resistance change thereafter.

Fig. 5 is a graph showing output voltage-current curves of the Wheatstone bridge in Figs. 4A and 4B.

FIG. 6 shows the Wheatstone bridge of FIGS. 4A and 4B coupled to an arithmetic unit.

FIG. 7 shows the magnetization direction of the anisotropic magnetoresistance of the current sensor of FIG. 1 at the first time and the resistance value changes when it receives external magnetic field components in three different directions thereafter.

Figures 8 and 9 respectively show the anisotropy of the current sensor of Figure 1 at the second time The magnetization direction of the magnetoresistance and the resistance value change when it receives external magnetic field components in three different directions.

FIG. 10 is a schematic top view of a current sensor according to another embodiment of the invention.

FIG. 11 is a schematic top view of a current sensor according to another embodiment of the invention.

FIG. 12A is a schematic top view of a current sensor according to still another embodiment of the invention.

FIG. 12B is a schematic cross-sectional view of the current sensor of FIG. 12A along the line A1-A1.

FIG. 13A is a schematic top view of a current sensor according to another embodiment of the invention.

FIG. 13B is a schematic cross-sectional view of the current sensor of FIG. 13A along the line A2-A2.

FIG. 1 is a schematic top view of a current sensor according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the current sensor of FIG. 1 along line AA. 1 and 2, the current sensor 100 of this embodiment includes a substrate 210, a first slope surface S1, a second slope surface S2, at least one wire C (in FIG. 1 is a wire C as Example) A first anisotropic magnetic resistance unit 222, a second anisotropic magnetic resistance unit 224, a first magnetization direction setting element M1, and a second magnetization direction setting element M2. The first slope surface S1 and the second slope surface S2 are disposed on the substrate 210 and arranged in a first direction D1. The wire C extends along a second direction D2 and is disposed on one side of the substrate 210. In this embodiment, an insulating layer 215 is provided on the substrate 210, and the first slope surface S1 and the second slope surface S2 are the surfaces of the insulation layer 215. However, in other embodiments, the first slope surface S1 and the second slope surface S2 may also be the surface of the substrate 210.

The wire C extends along a second direction D2 and is disposed on one side of the substrate 210. In this embodiment, the first slope surface S1 and the second slope surface S2 are located on a first side of the substrate 210 (that is, the upper side in FIG. 2), and the wire C is located on a second side of the substrate 210 (that is, in FIG.Under), where the first side is opposite to the second side. In addition, the insulating layer 215 is located on the first side of the substrate 210. In this embodiment, the first slope surface S1 and the second slope surface S2 are respectively located at one side (for example, the first side) of opposite ends (ie, the first end 212 and the second end 214) of the substrate 210, and the wire C One side (for example, the second side) located in the center of the substrate 210. In addition, in this embodiment, the distance from the wire C to the first slope surface S1 may be equal to the distance from the wire C to the second slope surface S2.

The first anisotropic magnetoresistance unit 222 is disposed on the first slope surface S1, and the second anisotropic magnetoresistance unit 224 is disposed on the second slope surface S2. The first magnetization direction setting element M1 is used to set the magnetization direction of the first anisotropic magnetoresistive unit 222. The second magnetization direction setting element M2 is used to set the magnetization direction of the second anisotropic magnetoresistive unit 224.

When a current I flows through the wire C, the magnetic field component HC in a third direction D3 generated by the current I on the first slope surface S1 (that is, the magnetic field component HC in the upper left corner of FIG. 2) is opposite to the current I on the second slope The magnetic field component HC in the third direction D3 generated at the surface S2 (that is, the magnetic field component HC in the upper right corner of FIG. 2). The first direction D1, the second direction D2, and the third direction D3 are different from each other, and the sensing directions 312 of the first anisotropic magnetoresistive unit 222 and the second anisotropic magnetoresistive unit 224 are relative to the first directions D1 and The three directions D3 are inclined and different from the second direction D2. The first anisotropic magnetic resistance unit 222 is electrically connected to the second anisotropic magnetic resistance unit 224 to output an electrical Pressure signal. This voltage signal corresponds to the magnetic field component HC in the third direction D3 generated by the current I at the first slope surface S1 and the second slope surface S2.

The space in which the current sensor 100 exists can be constructed by a first direction D1, a second direction D2, and a third direction D3 that are different from each other. In this embodiment, the first direction D1, the second direction D2, and the third direction D3 can be perpendicular to each other. However, in other embodiments, the first direction D1, the second direction D2, and the third direction D3 may also be non-perpendicular and different from each other. In this embodiment, the third direction D2 is a direction from the second side of the substrate 210 (ie, the lower side in FIG. 2) to the first side of the substrate 210 (ie, the upper side in FIG. 2).

In this embodiment, the current sensor further includes a third slope surface S3, a fourth slope surface S4, a third anisotropic magnetic resistance unit 226, and a fourth anisotropic magnetic resistance unit 228. The third slope surface S3 and the fourth slope surface S4 are provided on the substrate 210, wherein the third slope surface S3 is opposite to the first slope surface S1, the fourth slope surface S4 is opposite to the second slope surface S2, and the first slope surface S1 , The third slope surface S3, the fourth slope surface S4, and the second slope surface S2 are sequentially arranged in the first direction D1. In this embodiment, the third slope surface S3 and the fourth slope surface S4 are the surfaces of the insulating layer 215. That is, the insulating layer 215 has two grooves, the first slope surface S1 and the third slope surface S3 are the two slope sidewalls of one of the grooves, and the second slope surface S2 and the fourth slope surface S4 are the other concave surface. The two inclined side walls of the groove. However, in other embodiments, the substrate 210 may also have two grooves, and the first to fourth slope surfaces S1, S2, S3, and S4 are inclined sidewalls of the groove of the substrate 210.

The third anisotropic magnetoresistance unit 226 is disposed on the third slope surface S3, and the first A magnetization direction setting element M1 is also used to set the magnetization direction of the third anisotropic magnetoresistive unit 226. The fourth anisotropic magnetic resistance unit 228 is disposed on the fourth slope surface S4, and the second magnetization direction setting element M2 is also used to set the magnetization direction of the fourth anisotropic magnetic resistance unit 228. When the current I flows through the wire C, due to the magnetic field HC generated by the current I, the resistance change generated by the first anisotropic magnetoresistive unit 222 is opposite to the resistance generated by the third anisotropic magnetoresistive unit 226 Value changes, and the resistance value change generated by the second anisotropic magnetic resistance unit 224 is opposite to the resistance value change generated by the fourth anisotropic magnetic resistance unit 228, and the first, second, third, and fourth different The directional magnetoresistance units 222, 224, 226 and 228 are electrically connected to form a Wheatstone bridge to output corresponding to the first, second, third and fourth anisotropic magnetoresistance units 222, 224, 226 and 228 The resulting voltage signal of the change in resistance value.

In this embodiment, the first anisotropic magnetoresistive unit 222 includes a first anisotropic magnetoresistor (AMR) R1 and a second anisotropic magnetoresistor (AMR) R1 and a second anisotropic magnetoresistor (AMR) R1 arranged in sequence along the direction opposite to the second direction D2. The second anisotropic magnetoresistance R2, the second anisotropic magnetoresistance unit 224 includes a third anisotropic magnetoresistance R3 and a fourth anisotropic magnetoresistance R4 arranged in sequence along the direction opposite to the second direction D2, and the third The anisotropic magnetoresistive unit 226 includes a fifth anisotropic magnetoresistance R5 and a sixth anisotropic magnetoresistance R6 arranged in sequence along the direction opposite to the second direction D2, and a fourth anisotropic magnetoresistance unit 228 includes a seventh anisotropic magnetoresistance R7 and an eighth anisotropic magnetoresistance R8 arranged in sequence along the opposite direction of the second direction D2. The numbers of the first to eighth anisotropic magnetoresistor R1 to R8 mentioned above are each taken as an example. However, in other embodiments, each anisotropic magnetoresistance can also be connected in series with multiple anisotropic magnetoresistors. Magnetoresistance generation. For example, the first anisotropic magnetic resistance R1 can be replaced by a plurality of first anisotropic magnetic resistances R1 connected in series.

In this embodiment, the first magnetization direction setting element M1 and the second magnetization direction setting element M2, and the first to fourth anisotropic magnetoresistance units 222, 224, 226, and 228 may be disposed on the substrate 210, and the magnetization direction The setting element and the anisotropic magnetoresistance unit can be separated by an insulating layer. In this embodiment, the first magnetization direction setting element M1 is arranged under the first and third anisotropic magnetic resistance units 222, 226, and the second magnetization direction setting element M2 is arranged under the second and fourth anisotropic magnetic resistance units. Below the resistance units 224 and 228. However, in other embodiments, the first magnetization direction setting element M1 may be arranged above the first and third anisotropic magnetoresistive units 222, 226, and the second magnetization direction setting element M2 may be arranged on the second and the first The four anisotropic magnetoresistance units 224 and 228 are arranged above. Alternatively, in other embodiments, the first magnetization direction setting element M1 may also be distributed on the upper and lower sides of the first and third anisotropic magnetoresistive units 222, 226, and the second magnetization direction setting element M2 may also It may be distributed on the upper and lower sides of the second and fourth anisotropic magnetic resistance units 224 and 228.

In addition, the wire C can be covered by a package body 120, and the two ends of the wire C are exposed outside the package body 120, where the package body 120 is, for example, an insulating material. The substrate 210 may be disposed on the package body 120. In this embodiment, the wire C extends along the second direction D2.

3A and 3B are used to illustrate the operation principle of the anisotropic magnetoresistance in FIG. 1. 3A, the anisotropic magnetoresistance 300 has a barber pole-like structure, that is, its surface is provided with an extension relative to the anisotropic magnetoresistance 300 A plurality of electrical shorting bars 310 extending obliquely to D at 45 degrees. These shorting bars 310 are spaced apart from each other and arranged in parallel on a ferromagnetic film (ferromagnetic film) 320, and the ferromagnetic film 320 is anisotropic magnetic The main body of the resistor 300 extends in the direction D of the anisotropic magnetic resistor 300. In addition, the opposite ends of the ferromagnetic film 320 can be made into a pointed shape.

Before measuring the external magnetic field H of the anisotropic magnetoresistance 300, the magnetization direction can be set by the magnetization direction setting element (such as the first magnetization direction setting element M1 or the second magnetization direction setting element M2 in FIG. 1). , Wherein the magnetization direction setting element is, for example, a coil, wire, metal sheet or conductor that can generate a magnetic field by energization. In FIG. 3A, the magnetization direction setting element can generate a magnetic field along the extension direction D by energization, so that the anisotropic magnetoresistance 300 has a magnetization direction M.

Next, the magnetization direction setting element is not energized, so that the anisotropic magnetic resistance 300 starts to measure the external magnetic field H. When there is no external magnetic field H, the magnetization direction M of the anisotropic magnetoresistor 300 is maintained in the extension direction D. At this time, a current i is applied to cause the current i to flow from the left end to the right end of the anisotropic magnetoresistor 300, which is a short circuit. The direction of the current i near the bar 310 will be perpendicular to the extension direction of the shorting bar 310, so that the current i near the shorting bar 310 flows 45 degrees with the magnetization direction M. At this time, the resistance value of the anisotropic magnetoresistance 300 is R.

When an external magnetic field H faces a direction perpendicular to the extension direction D, the magnetization direction M of the anisotropic magnetoresistance 300 will be deflected to the direction of the external magnetic field H, so that the angle between the magnetization direction and the direction of the current i near the shorting bar is greater than 45 degrees, at this time the resistance value of the anisotropic magnetoresistance 300 has a change of -R, that is, it becomes R-R, which is the electric The resistance becomes smaller, and R is greater than 0.

However, as shown in FIG. 3B, when the extension direction of the shorting bar 310 of FIG. 3B is set at 90 degrees to the extension direction of the shorting bar 310 of FIG. 3A (at this time, the extension direction of the shorting bar 310 of FIG. 3B is still It is 45 degrees between the extension direction D of the anisotropic magnetoresistance 300), and when there is an external magnetic field H, the magnetic field H will still deflect the magnetization direction M to the direction of the external magnetic field H. At this time, the magnetization direction M is short-circuited The angle of the current i near the rod 310 will be less than 45 degrees, so the resistance value of the anisotropic magnetoresistor 300 will become R+ΔR, that is, the resistance value of the anisotropic magnetoresistor 300 will increase.

In addition, when the magnetization direction M of the anisotropic magnetoresistor 300 is set to the reverse direction as shown in FIG. 3A by the magnetization direction setting element, the resistance value of the anisotropic magnetoresistor 300 in FIG. 3A under the external magnetic field H will change It becomes R+R. Furthermore, when the magnetization direction M of the anisotropic magnetic resistor 300 is set to the reverse direction shown in FIG. 3B by the magnetization direction setting element, the resistance value of the anisotropic magnetic resistor 300 in FIG. 3B under the external magnetic field H is then Will become R-R.

Based on the above, when the setting direction of the shorting bar 310 changes, the resistance value R of the anisotropic magnetoresistance 300 corresponding to the change of the external magnetic field H will change from +R to -R or vice versa, and when the magnetization direction is set When the magnetization direction M set by the element is changed to the reverse, the resistance value R of the anisotropic magnetoresistor 300 will change from +ΔR to -ΔR or vice versa in response to the change of the external magnetic field H. When the direction of the external magnetic field H is reversed, the resistance value R of the anisotropic magnetoresistance 300 corresponding to the change of the external magnetic field H will change from +ΔR to -ΔR or vice versa. However, when the current i through the anisotropic magnetoresistance 300 becomes reverse, the resistance value R of the anisotropic magnetoresistor 300 will maintain the resistance value R corresponding to the change in the external magnetic field H Keep the same sign as the original, that is, if it was originally +R, it will still be +R after changing the direction of the current. If it was originally -R, it will still be -R after changing the current direction.

According to the above principles, the anisotropic magnetization can be determined by designing the extension direction of the shorting bar 310 or the magnetization direction M set by the magnetization direction setting element when the anisotropic magnetoresistance 300 receives a certain component of the external magnetic field H The direction of the change of the resistance value R of the magnetic resistance 300, that is, the resistance value R becomes larger or smaller, for example, the amount of change is +ΔR or -ΔR. In addition, the direction perpendicular to the extension direction D of the anisotropic magnetic resistance 300 is the sensing direction of the anisotropic magnetic resistance 300 (similar to the sensing direction 312 in FIGS. 1 and 2), that is, in FIGS. 3A and 3B Parallel to the direction of the external magnetic field H.

4A and 4B illustrate the magnetization direction of the anisotropic magnetoresistance at the first time and the second time of the current sensor of FIG. 1 and the resistance value changes thereafter, respectively, and illustrate the first to eighth anomalies The extension direction of the shorting bar in the directional magnetoresistance R1~R8. 4A and 4B, in this embodiment, the extension direction of the first to eighth anisotropic magnetoresistor R1 ~ R8 is the second direction D2, and the extension direction of the shorting bar 310 is as shown in FIG. 4A It is shown that in the first and fourth anisotropic magnetoresistive units 222 and 228, the shorting bars 310 of the first, second, seventh, and eighth anisotropic magnetoresistance R1, R2, R7, and R8 are respectively located in two The two different directions are sandwiched by 45 degrees with the second direction D2, and the two different directions are parallel to the first slope surface S1 and the fourth slope surface S4. In addition, in the second and third anisotropic magnetoresistive units 224 and 226, the shorting bars 310 of the third, fourth, fifth, and sixth anisotropic magnetoresistor R3, R4, R5, and R6 are in the other two, respectively. The two different directions are sandwiched by 45 degrees with the second direction D2, and the two different directions are parallel to the second slope surface S2 and the third slope surface S3. In this embodiment, the first slope The surface S1 is parallel to the fourth slope surface S4, the second slope surface S2 is parallel to the third slope surface S3, and the first slope surface S1 and the second slope surface S2 are inclined in different directions.

When the wire C is supplied with a current I (as shown in FIGS. 1, 2, 4A, and 4B), the direction of the current I in the wire C is, for example, the second direction D2. At this time, the current I generates a magnetic field component HC along the third direction D3 on the first, second, fifth, and sixth anisotropic magnetoresistor R1, R2, R5, and R6, and the current I is in the third and fourth directions. 4. The seventh and eighth anisotropic magnetic resistors R3, R4, R7, and R8 generate magnetic field components HC in the opposite direction along the third direction D3. In addition, in this embodiment, when the current I flows through the wire C, the current I is at the first slope surface S1 and the third slope surface S3 (that is, between the first anisotropic magnetoresistive unit 222 and the third anisotropic magnetoresistance unit 222). The magnetic field generated by the magnetoresistance unit 226) in the third direction D3 (ie, the magnetic field component HC on the left in Figures 2, 4A and 4B, which faces the third direction D3) is opposite to the direction of the current I in the third direction. The components of the magnetic field generated at the two slope surfaces S2 and the fourth slope surface S4 (that is, at the second anisotropic magnetoresistance unit 224 and the fourth anisotropic magnetoresistance unit 228) in the third direction D3 (as shown in the figure) 2. The magnetic field component HC on the right side of Fig. 4A and Fig. 4B faces the direction opposite to the third direction D3).

At a first time, the first magnetization direction setting element M1 sets the magnetization direction M15 of the first anisotropic magnetic resistance R1 and the fifth anisotropic magnetic resistance R5 to the opposite direction of the second direction D2, and sets the second different The magnetization direction M26 of the directional magnetic resistance R2 and the sixth anisotropic magnetic resistance R6 is set to the second direction D2. In addition, at the first time, the second magnetization direction setting element M2 sets the magnetization direction M37 of the third anisotropic magnetic resistance R3 and the seventh anisotropic magnetic resistance R7 to the opposite direction of the second direction D2, and sets the fourth The magnetization direction M48 of the anisotropic magnetic resistance R4 and the eighth anisotropic magnetic resistance R8 is set to the second direction D2. In this embodiment, the first magnetization direction setting element M1 and the second magnetization direction setting element M2 are, for example, conductive coils, wires, conductive sheets (such as metal sheets) or conductors that can generate a magnetic field by energization, as long as they are capable of generating along The conductive structure of the magnetic field in the magnetization directions M15, M26, M37, and M48 can be used as the first magnetization direction setting element M1 and the second magnetization direction setting element M2.

After the first time, the first magnetization direction setting element M1 and the second magnetization direction setting element M2 will stop generating magnetic fields. For example, the first magnetization direction setting element M1 and the second magnetization direction setting element M2 will no longer be generated by current Magnetic field, at this time, the first, second, fifth and sixth anisotropic magnetoresistance R1, R2, R5 and R6 can induce the magnetic field component HC generated by the current I (Figure 2, Figure 4A and Figure 4B left Square magnetic field component HC) and generate resistance changes of +R, +R, -R and -R, and the third, fourth, seventh and eighth anisotropic magnetoresistance R3, R4, R7 and R8 can induce the magnetic field component HC generated by the current I (the magnetic field component HC on the right in Figure 2, Figure 4A and Figure 4B) to generate -R, -R, +R and +R respectively The resistance value changes.

In this embodiment, the first anisotropic magnetic resistance R1, the second anisotropic magnetic resistance R2, the third anisotropic magnetic resistance R3, and the fourth anisotropic magnetic resistance R4 can be connected in series from the contact P1 to Contact point P2, contact point P3 can be electrically connected to the conductive path between the second anisotropic magnetic resistance R2 and the fourth anisotropic magnetic resistance R4, the fifth anisotropic magnetic resistance R5 and the sixth anisotropic magnetic resistance The resistor R6 can be connected in series from the connection point P1 to the connection point P4, and the seventh anisotropic magnetic resistance R7 and the eighth anisotropic magnetic resistance R8 can be connected in series from the connection point P2. Connect to contact P5. The contact point P3 can receive the reference voltage VDD, and the contact point P4 and the contact point P5 can be coupled to the ground. At this time, the voltage difference between the contact point P1 and the contact point P2 in the Wheatstone bridge formed will be (VDD)×(-R/R), it can be an output signal, this output signal is a differential signal, its magnitude will correspond to the magnitude of the magnetic field component HC, and then correspond to the magnitude of the current I flowing through the wire C, Hereafter this output signal is called the first voltage signal V₁. In another embodiment, the contact point P3 can also be coupled to the ground, and the contact point P4 and the contact point P5 receive the reference voltage VDD.

At a second time after this, the first magnetization direction setting element M1 sets the magnetization direction M15' of the first anisotropic magnetic resistance R1 and the fifth anisotropic magnetic resistance R5 to the second direction D2, and sets the second The magnetization direction M26' of the anisotropic magnetic resistance R2 and the sixth anisotropic magnetic resistance R6 is set to the opposite direction of the second direction D2. In addition, at the second time, the second magnetization direction setting element M2 sets the magnetization direction M37' of the third anisotropic magnetic resistance R3 and the seventh anisotropic magnetic resistance R7 to the second direction D2, and sets the fourth anisotropy The magnetization directions M48' of the linear magnetic resistance R4 and the eighth anisotropic magnetic resistance R8 are set to be opposite to the second direction D2.

After the second time, the first magnetization direction setting element M1 and the second magnetization direction setting element M2 will stop generating magnetic fields. At this time, the first, second, fifth, and sixth anisotropic magnetoresistor R1, R2, R5 And R6 can induce the magnetic field component HC generated by the current I to generate -R, -R, +R, and +R resistance changes, and the third, fourth, seventh and eighth The directional magnetoresistor R3, R4, R7, and R8 can induce the magnetic field component HC generated by the current I to generate resistance changes of +R, +R, -R and -R, respectively. The contact P1 and the contact P2 in the Wheatstone bridge formed at this time The voltage difference between will be (VDD)×(R/R), which can be an output signal, this output signal is a differential signal, and its magnitude will correspond to the magnitude of the magnetic field component HC, and then correspond to the flow through the wire C The magnitude of the current I, hereafter this output signal is called the second voltage signal V₂。

5 is a graph showing the output voltage-current curve of the Wheatstone bridge in FIGS. 4A and 4B, and FIG. 6 shows the Wheatstone bridge in FIGS. 4A and 4B coupled to an arithmetic unit. 4A, 4B, 5 and 6, in this embodiment, the current sensor 100 further includes an arithmetic unit 400, which is electrically connected to an output terminal of the Wheatstone bridge (that is, receives the first Voltage signal V₁And the second voltage signal V₂), wherein the first magnetization direction setting element M1 and the second magnetization direction setting element M2 set the combination of the magnetization directions of the first, second, third, and fourth anisotropic magnetoresistive units 222, 224, 226, and 228 to one The first combination (ie the combination of the magnetization direction M15, the magnetization direction M26, the magnetization direction M37, and the magnetization direction M48 as shown in FIG. 4A), so that the Wheatstone bridge outputs the first voltage signal V₁, And the first magnetization direction setting element M1 and the second magnetization direction setting element M2 then set the magnetization direction combinations of the first, second, third, and fourth anisotropic magnetoresistive units 222, 224, 226, and 228 to be opposite A second combination of the first combination (ie, the combination of the magnetization direction M15', the magnetization direction M26', the magnetization direction M37', and the magnetization direction M48' as shown in FIG. 4B), so that the Wheatstone bridge outputs the second voltage Signal V₂. The arithmetic unit 400 is used to convert the second voltage signal V₂And the first voltage signal V₁Subtract to output an output voltage signal V corresponding to the magnitude of the magnetic field generated by the current I_out. In addition, in this embodiment, the arithmetic unit 400 can also be used to convert the first voltage signal V₁And the second voltage signal V₂Sum to output an offset voltage signal V_off。

Specifically, the arithmetic unit 400 may include an arithmetic unit 410 and an arithmetic unit 420, where the arithmetic unit 410 is, for example, an adder, which is used to convert the first voltage signal V₁And the second voltage signal V₂Add to output offset voltage signal V_off. In addition, the arithmetic operator 420 is, for example, a subtractor, which is used to convert the second voltage signal V₂And the first voltage signal V₁Subtract to output the output voltage signal V corresponding to the magnitude of the magnetic field generated by the current I_out。

It can be seen from Figure 5 that the output voltage-current curve of the Wheatstone bridge may have an offset voltage signal V_off, And the first voltage signal V₁And the second voltage signal V₂After the addition, the offset voltage signal V is left_off, And the second voltage signal V₂And the first voltage signal V₁After subtraction, the output voltage-current curve will pass through the point where both voltage and current are zero, so that the voltage and current are almost proportional to a certain range, and the resistance change R can be accurately passed through the output voltage signal V_outTo estimate.

In this embodiment, the contacts P1 to P5 and the arithmetic unit 400 exist in the substrate 210, for example, and the substrate 210 is a circuit substrate, such as a semiconductor substrate.

FIG. 7 shows the magnetization direction of the anisotropic magnetoresistance of the current sensor of FIG. 1 at the first time and the resistance value changes when it is subjected to external magnetic field components in three different directions afterwards, and FIGS. 8 and 9 respectively It shows the magnetization direction of the anisotropic magnetoresistance of the current sensor in FIG. 1 at the second time and the resistance change when it receives external magnetic field components in three different directions. Please refer to FIG. 7 first, after the first magnetization direction setting element M1 and the second magnetization direction setting element M2 complete the setting of the magnetization directions M15, M26, M37, M48 at the first time, when there is an external direction along the first direction D1 When the magnetic field component HE1 exists, the resistance value generated by the first to eighth anisotropic magnetoresistance R1~R8 changes They are respectively -R, -R, +R, +R, -R, -R, +R and +R, so that when the contact P3 receives the reference voltage VDD, When the point P4 and the contact point P5 are coupled to the ground, the voltage difference between the contact point P1 and the contact point P2 in the Wheatstone bridge formed at this time will be zero.

Please refer to FIG. 8 again. After the first magnetization direction setting element M1 and the second magnetization direction setting element M2 complete the setting of the magnetization directions M15', M26', M37', and M48' at the second time, when there is one along the second direction When the external magnetic field component HE2 of D2 exists, the resistance changes produced by the first to eighth anisotropic magnetoresistor R1~R8 are all zero, because the second direction D2 is not the first to eighth anisotropic magnetism The direction that the resistors R1~R8 can sense. In this way, when the contact P3 receives the reference voltage VDD and the contact P4 and the contact P5 are coupled to the ground, the voltage difference between the contact P1 and the contact P2 in the Wheatstone bridge formed at this time will be Is zero.

Please refer to FIG. 9 again. After the first magnetization direction setting element M1 and the second magnetization direction setting element M2 complete the setting of the magnetization directions M15', M26', M37', and M48' at the second time, when there is one along the third direction When the external magnetic field component HE3 of D3 exists, the resistance value changes produced by the first to eighth anisotropic magnetoresistance R1~R8 are -R, -R, -R, -R, +R, respectively , +R, +R and +R. In this way, when the contact P3 receives the reference voltage VDD and the contact P4 and the contact P5 are coupled to the ground, the voltage difference between the contact P1 and the contact P2 in the Wheatstone bridge formed at this time will be Is zero.

That is, in this embodiment, the Wheatstone bridge corresponds to the external magnetic field component HE1 in the first direction D1 and the output voltage signal is zero, which corresponds to the external magnetic field component in the second direction D2. The voltage signal output by HE2 is zero, and The output voltage signal corresponding to the external magnetic field component HE3 in the third direction D3 is zero. Therefore, no matter which direction the external magnetic field is in, it will not affect the sensing result of the current sensor 100 of this embodiment, that is, it will not interfere with the output voltage of the current sensor 100.

The above response of the Wheatstone bridge to the external magnetic field component HE1 is based on the response after the first time, and the above response of the Wheatstone bridge to the external magnetic field component HE2 and HE3 is the response after the second time As an example, after the second time, that is, the first magnetization direction setting element M1 and the second magnetization direction setting element M2 complete the magnetization directions M15', M26', M37', M48' in the second time. After setting, the first to eighth anisotropic magnetoresistance R1~R8 react to the external magnetic field component HE1, and the resistance value changes are +R, +R, -R, -R, +R, respectively , +R, -R, and -R, so that when the contact P3 receives the reference voltage VDD, and the contact P4 and the contact P5 are coupled to the ground, the Wheatstone bridge formed at this time The voltage difference between the contact point P1 and the contact point P2 will be zero. After the first magnetization direction setting element M1 and the second magnetization direction setting element M2 complete the setting of the magnetization directions M15, M26, M37, and M48 in FIG. 4A at the first time, for the external magnetic field component HE2, the first to second The eight-anisotropic magnetoresistance R1~R8 will not be affected by them, so there will be no resistance change. Therefore, the voltage difference between the contact point P1 and the contact point P2 in the Wheatstone bridge will still be zero; The external magnetic field component HE3, the first to eighth anisotropic magnetoresistance R1~R8 respond to the external magnetic field component HE3, and the resistance changes are +R, +R, +R, +R, -R, -R, -R and -R, in this way, when the contact P3 receives the reference voltage VDD, and the contact P4 and the contact P5 are coupled to the ground, The voltage difference between the contact point P1 and the contact point P2 in the Wheatstone bridge formed at this time will be zero. Therefore, no matter after the first time or the second time, the current sensor 100 of this embodiment will not be interfered by external magnetic fields in any direction.

In addition, the substrate 210 may also be provided with a feedback coil (feedback coil), which at least partially overlaps the first to eighth anisotropic magnetoresistor R1 to R8, as a closed-loop control (close-loop control) the use of.

FIG. 10 is a schematic top view of a current sensor according to another embodiment of the invention. Please refer to FIG. 10, the current sensor 100a of this embodiment is similar to the current sensor 100 of FIGS. 1, 2, 4A, and 4B, and the differences between the two are as follows. In this embodiment, the first magnetization direction setting element M1a and the second magnetization direction setting element M2a of the current sensor 100a are both permanent magnets, and the first magnetization direction setting element M1a is used to set the first, second, and The magnetization directions of the fifth and sixth anisotropic magnetic resistors R1, R2, R5, and R6 are set to the magnetization direction M1256, which points to the opposite direction of the second direction D2, and the second magnetization direction setting element M2a is used to set the third and the 4. The magnetization directions of the seventh and eighth anisotropic magnetic resistors R3, R4, R7, and R8 are set to the magnetization direction M3478, which points to the opposite direction of the second direction D2.

In addition, the extension directions of the shorting bars of the first, third, fifth, and seventh anisotropic magnetoresistor R1, R3, R5, and R7 can be the same as those of the first, third, fifth, and seventh in FIG. 4A, respectively. The extension direction of the shorting bars of the anisotropic magnetoresistor R1, R3, R5, and R7 is different from FIG. 4A. In this embodiment, the extension direction of the shorting bars of the second anisotropic magnetoresistor R2 is the same as that of the first The extension direction of the shorting bar of an anisotropic magnetic resistance R1, and the extension direction of the shorting bar of the fourth anisotropic magnetic resistance R4 is the same as that of the third The extending direction of the shorting bar of the anisotropic magnetic resistance R3, the extending direction of the shorting bar of the sixth anisotropic magnetic resistance R6 is the same as the extending direction of the shorting bar of the fifth anisotropic magnetic resistance R5, and the eighth anisotropic The extending direction of the shorting bar of the magnetic resistance R8 is the same as the extending direction of the shorting bar of the seventh anisotropic magnetic resistance R7.

In this way, when the current I flows through the wire C, the Wheatstone bridge formed by connecting the first to eighth anisotropic magnetoresistor R1 to R8 can also output the corresponding voltage signal.

FIG. 11 is a schematic top view of a current sensor according to another embodiment of the invention. Please refer to FIG. 11, the current sensor 100b of this embodiment is similar to the current sensor 100 of FIG. 4A, and the difference between the two is as follows. The current sensor 100b of this embodiment includes a first anisotropic magnetoresistive unit 222 and a second anisotropic magnetoresistive unit 224, but does not include the third anisotropic magnetoresistive unit 226 and the fourth anisotropic magnetoresistive unit 226 as shown in FIG. 4A. Directional magnetic resistance unit 228.

In this embodiment, the extension direction of the shorting bar 310 of the first anisotropic magnetic resistance R1 is the same as the extension direction of the shorting bar 310 of the first anisotropic magnetic resistance R1 in FIG. 4A, and the third anisotropic magnetic resistance The extending direction of the shorting bar 310 of the resistor R3 is the same as the extending direction of the shorting bar 310 of the third anisotropic magnetic resistor R3 in FIG. 4A. However, the difference from FIG. 4A is that, in this embodiment, the extension direction of the shorting bar 310 of the second anisotropic magnetic resistance R2 is the same as the extension direction of the shorting bar 310 of the first anisotropic magnetic resistance R1, and The extending direction of the shorting bar 310 of the fourth anisotropic magnetic resistance R4 is the same as the extending direction of the shorting bar 310 of the third anisotropic magnetic resistance R3.

In addition, at the first time, the first magnetization direction setting element M1 changes the first different The magnetization direction of the anisotropic magnetoresistor R1 is set to the magnetization direction M10, which points to the opposite direction of the second direction D2; the first magnetization direction setting element M1 sets the magnetization direction of the second anisotropic magnetoresistor R2 to the magnetization direction M20, which Point to the second direction D2; the second magnetization direction setting element M2 sets the magnetization direction of the third anisotropic magnetic resistance R3 to the magnetization direction M30, which points to the opposite direction of the second direction D2; the second magnetization direction setting element M2 sets the The magnetization direction of the four-anisotropic magnetic resistance R4 is set to the magnetization direction M40, which points to the second direction D2. In this way, after the first time, when the current I flows through the wire C, and when the third contact P3' and the fourth contact P4' receive the reference voltage VDD, and the fifth contact P5' and the sixth contact When the point P6' is coupled to the ground, the resistance values of the first to fourth anisotropic magnetic resistors R1, R2, R3, and R4 will be +R, -R, -R, +R, respectively. At this time, the voltage difference between the first contact P1' and the second contact P2' will be (VDD)×(-R/R), which can be an output signal, which is a differential signal, and its magnitude will be Corresponds to the magnitude of the magnetic field component HC, which in turn corresponds to the magnitude of the current I flowing through the wire C. Similarly, at the second time, when the first magnetization direction setting element M1 and the second magnetization direction setting element M2 set the combination of the magnetization directions of the first to fourth anisotropic magnetic resistors R1 to R4 to be opposite to that of FIG. 11 When combined, the voltage difference between the first contact P1' and the second contact P2' will be (VDD)×(+R/R).

In this embodiment, the first anisotropic magnetic resistance R1 and the second anisotropic magnetic resistance R2 are connected in series from the third contact P3' to the fifth contact P5', and the third anisotropic magnetic resistance R3 is connected to the The fourth anisotropic magnetic resistance R4 is connected in series from the fourth contact P4' to the sixth contact P6', and the first contact P1' is coupled to the first anisotropic magnetic resistance R1 and the second anisotropic magnetic resistance. The conductive path between the resistor R2, and the second contact P2' is coupled to the third anisotropic magnetic The conductive path between the resistor R3 and the fourth anisotropic magnetic resistor R4.

In other words, in this embodiment, the first anisotropic magnetic resistance unit 222 and the second anisotropic magnetic resistance unit 224 are electrically connected to form a Wheatstone bridge to output a corresponding The voltage signal in which the resistance value changes generated by the second anisotropic resistance unit 224.

FIG. 12A is a schematic top view of a current sensor according to another embodiment of the present invention, and FIG. 12B is a schematic cross-sectional view of the current sensor of FIG. 12A along the line A1-A1. Please refer to FIGS. 12A and 12B. The current sensor 100c of this embodiment is similar to the current sensor 100 of FIGS. 1 and 2, and the difference between the two is as follows. In this embodiment, the current sensor 100c has two wires C1 and C2, which are respectively disposed beside the first end 212 and the second end 214 of the substrate. The first end 212 is opposite to the second end 214, and the two The wires C1 and C2 do not overlap the first end 212 and the second end 214, respectively. In this embodiment, the wires C1 and C2 both extend along the second direction D2. When the currents I1 and I2 respectively flow through the wire C1 and the wire C2 along the opposite direction of the second direction D2, the current I1 will generate a magnetic field component HC directed to the third direction D3 at the first slope surface S1 and the third slope surface S3 , And the current I2 will generate a magnetic field component HC in the opposite direction of the third direction D3 at the second slope surface S2 and the fourth slope surface S4. In this way, the Wheatstone bridge formed by connecting the first to fourth anisotropic magnetoresistive units 222, 224, 226, and 228 can output voltage signals corresponding to the currents I1 and I2. In this embodiment, the magnitude and direction of the current I1 are the same as the magnitude and direction of the current I2.

The present invention does not limit the number of wires in the current sensor 100c, and in other embodiments In an embodiment, the number of wires in the current sensor 100c may also be more than two.

FIG. 13A is a schematic top view of a current sensor according to another embodiment of the present invention, and FIG. 13B is a schematic cross-sectional view of the current sensor of FIG. 13A along the line A2-A2. Please refer to FIGS. 13A and 13B. The current sensor 100d of this embodiment is similar to the current sensor 100c of FIGS. 12A and 12B, and the difference between the two is as follows. In the current sensor 100d of this embodiment, the wire C1 and the wire C2 partially overlap the first end 212 and the second end 214 of the substrate 210, so that the first slope surface S1 and the third slope surface S3 can still be A magnetic field component HC pointing to the third direction D3 is generated, and a magnetic field component pointing to the opposite direction of the third direction D3 can be generated at the second slope surface S2 and the fourth slope surface S4.

In summary, in the current sensor of the embodiment of the present invention, the anisotropic magnetoresistance unit is connected to form a Wheatstone bridge to sense the magnetic field generated by the current in the wire, so the current The sensing has high sensitivity and high accuracy. In addition, since the current sensor in the embodiment of the present invention uses the magnetic field generated by the sensing current to reverse the magnitude of the current, the anisotropic magnetoresistive unit does not directly contact the current, so it can have a lower Power consumption.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be determined by the scope of the attached patent application.