CN212207492U - Current sensor - Google Patents
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- CN212207492U CN212207492U CN202020612035.1U CN202020612035U CN212207492U CN 212207492 U CN212207492 U CN 212207492U CN 202020612035 U CN202020612035 U CN 202020612035U CN 212207492 U CN212207492 U CN 212207492U
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Abstract
The embodiment of the utility model discloses current sensor, include: a first coil and a second coil are arranged in the substrate, and are connected in series and have opposite winding directions; the magnetic sensing structure comprises a first magnetic sensing element and a second magnetic sensing element which are positioned on the same surface of the substrate and have the same sensitivity direction, one magnetic sensing element is arranged right above one coil, and the product of the number of turns of the first coil and the sensitivity of the first magnetic sensing element is equal to the product of the number of turns of the second coil and the sensitivity of the second magnetic sensing element; the signal processing unit and the first magnetic sensing element are positioned on the same surface of the substrate, the signal output end of the magnetic sensing structure is electrically connected with the signal input end of the signal processing unit, and the signal output end of the signal processing unit outputs a measured voltage signal through a voltage output pin. The embodiment of the utility model provides an in, current sensor its output voltage does not receive external magnetic field's interference influence under the condition that has or not external magnetic field to disturb, has improved measurement accuracy.
Description
Technical Field
The embodiment of the utility model provides a relate to the sensor technology, especially relate to a current sensor.
Background
The current sensor is used for measuring output current, and can be widely applied to various devices or devices which need to measure current, such as a frequency converter, which is integrated with a large number of current sensors. The current sensors are various, wherein the chip type current sensor is widely applied to the frequency converter due to the advantages of small size, convenience in installation and the like.
The existing chip-type current sensor is easily interfered by an external magnetic field, the external magnetic field and a magnetic field generated when a measured current flows into the sensor are superposed, so that the measurement is inaccurate, namely the existing chip-type current sensor is easily interfered by a common-mode magnetic field signal, and the measurement precision is influenced.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a current sensor improves current sensor's measurement accuracy.
An embodiment of the utility model provides a current sensor, include: the magnetic sensor comprises a substrate, a magnetic sensitive structure and a signal processing unit;
a first coil and a second coil are arranged in the substrate, the first coil and the second coil are arranged in a direction parallel to the plane of the substrate and are connected in series, and the winding directions of the first coil and the second coil are opposite;
the magneto-sensitive structure comprises a first magneto-sensitive element and a second magneto-sensitive element which are positioned on the same surface of the substrate and have the same sensitivity direction, the first magneto-sensitive element is arranged right above the first coil, the second magneto-sensitive element is arranged right above the second coil, and the product of the number of turns of the first coil and the sensitivity of the first magneto-sensitive element is equal to the product of the number of turns of the second coil and the sensitivity of the second magneto-sensitive element;
the signal processing unit and the first magnetic sensing element are located on the same surface of the substrate, the signal output end of the magnetic sensing structure is electrically connected with the signal input end of the signal processing unit, and the signal output end of the signal processing unit outputs a measured voltage signal through a voltage output pin.
Further, the current sensor further includes: and the packaging body is used for packaging part or all of the substrate comprising the magnetic-sensing structure and the signal processing unit in the packaging body, and the pin is positioned outside the packaging body.
Further, the package form of the package body includes an LGA package, a BGA package, an SOP package, or a DFN package.
Further, the magnetic sensing structure further comprises:
a magnetizer disposed on a side of the first magnetic sensing element facing away from the substrate and a magnetizer disposed on a side of the second magnetic sensing element facing away from the substrate; and/or a magnetizer disposed on a side of the first magnetic sensing element facing the substrate and a magnetizer disposed on a side of the second magnetic sensing element facing the substrate;
wherein the magnetic permeability of the magnetizer is more than 1.
Further, the sensitive direction of the first magnetic sensing element is perpendicular to the surface of the first magnetic sensing element, and the sensitive direction of the second magnetic sensing element is perpendicular to the surface of the second magnetic sensing element.
Further, the first magneto-sensitive element and the second magneto-sensitive element are both hall effect elements, anisotropic magneto-resistive elements, giant magneto-resistive elements or tunnel magneto-resistive elements.
Further, the first coil and the second coil are both single-layer coils, and the number of turns of the single-layer coils is one or more; or,
the first coil and the second coil are both multilayer sub-coils, and the number of turns of the sub-coils is one or more.
Furthermore, the first coil receives a measured current signal through a current input pin, and the second coil outputs the measured current signal through a current output pin, wherein the measured voltage signal and the measured current signal are in a linear relationship.
Further, the signal processing unit includes: an amplification component and/or a temperature compensation component;
the temperature compensation component is used for performing temperature compensation on the voltage signal output by the magnetic-sensing structure to obtain a primary voltage signal;
the amplifying assembly is used for amplifying the primary voltage signal to obtain the measured voltage signal.
Further, the substrate is a ceramic substrate, a printed circuit substrate or a bakelite substrate.
The embodiment of the utility model provides a pair of current sensor, including the base plate inside the packaging body, magnetic-sensing structure and signal processing unit, the base plate has two sets of series connection's coil, two magnetic-sensing element are located two sets of coil centers respectively directly over, the coiling opposite direction of two sets of coils, two magnetic-sensing element sensitive directions are the same, the number of turns of one of them coil and the product of the sensitivity of a magnetic-sensing element directly over rather than equal the number of turns of another coil and the product of the sensitivity of another magnetic-sensing element directly over rather than. The current to be measured sequentially flows through the two groups of coils, the directions of the magnetic fields generated by the two magnetic sensing elements are opposite, the output voltages of the two magnetic sensing elements are opposite in positive and negative and equal in size, so that a differential structure is formed, the interference of an external magnetic field can be mutually counteracted, the output voltages of the current sensor are kept consistent under the condition of the existence of the interference of the external magnetic field, the output result is not influenced by the interference of the external magnetic field, and the measurement precision of the current sensor is improved.
Drawings
To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below of the drawings required for the embodiments or the technical solutions in the prior art, and it should be apparent that the drawings in the following description are some specific embodiments of the present invention, and it is obvious for those skilled in the art that the basic concepts of the device structure, the driving method and the manufacturing method disclosed and suggested according to the various embodiments of the present invention can be extended and extended to other structures and drawings, which should not be undoubted to be within the scope of the claims of the present invention.
Fig. 1 is a schematic diagram of a current sensor according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a sensitivity curve of a magnetic sensor provided in an embodiment of the present invention;
fig. 3 is a schematic diagram of magnetic circuit analysis provided by an embodiment of the present invention;
fig. 4A-4D are schematic diagrams of a package structure provided by an embodiment of the present invention;
fig. 5 is a schematic diagram of a magnetic sensing structure provided by an embodiment of the present invention;
fig. 6 is a schematic diagram of a magnetic sensing structure provided by an embodiment of the present invention;
fig. 7 is a schematic diagram of a magnetic sensing structure provided by an embodiment of the present invention;
fig. 8 is a schematic diagram of a coil provided by an embodiment of the present invention;
fig. 9 is a schematic diagram of a coil provided by an embodiment of the present invention;
fig. 10 is a schematic diagram of a coil provided by an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described clearly and completely through embodiments with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments obtained by a person skilled in the art based on the basic concepts disclosed and suggested by the embodiments of the present invention belong to the protection scope of the present invention.
Referring to fig. 1, a schematic diagram of a current sensor according to an embodiment of the present invention is shown. The current sensor provided by the embodiment comprises: a substrate 102, a magneto-sensitive structure and a signal processing unit 107; a first coil 103 and a second coil 104 are arranged in the substrate 102, the first coil 103 and the second coil 104 are arranged in a direction parallel to the plane of the substrate 102 and are connected in series, and the winding directions of the first coil 103 and the second coil 104 are opposite; the magnetic sensing structure comprises a first magnetic sensing element 105 and a second magnetic sensing element 106 which are positioned on the same surface of the substrate 102 and have the same sensitivity direction, the first magnetic sensing element 105 is arranged right above the first coil 103, the second magnetic sensing element 106 is arranged right above the second coil 104, and the product of the number of turns of the first coil 103 and the sensitivity of the first magnetic sensing element 105 is equal to the product of the number of turns of the second coil 104 and the sensitivity of the second magnetic sensing element 106; the signal processing unit 107 and the first magnetic sensing element 103 are located on the same surface of the substrate 102, a signal output end of the magnetic sensing structure is electrically connected with a signal input end of the signal processing unit 107, and a signal output end of the signal processing unit 107 outputs a voltage signal to be measured through a voltage output pin. Optionally, the sensitive direction of the first magnetic sensing element 105 is perpendicular to the surface of the first magnetic sensing element 105, and the sensitive direction of the second magnetic sensing element 106 is perpendicular to the surface of the second magnetic sensing element 105; wherein, the surfaces of the first magnetic sensing element 105 and the second magnetic sensing element 106 are parallel to the plane of the substrate 102.
In this embodiment, the optional substrate 102 is a ceramic substrate, a printed circuit substrate, or a bakelite substrate. The ceramic substrate, the printed circuit substrate or the bakelite substrate have excellent electrical insulation performance, can be etched with various patterns, and have large current-carrying capacity, so the ceramic substrate, the printed circuit substrate or the bakelite substrate is usually used as a basic material of a high-power electronic circuit structure and an interconnection technology. It is understood that the materials of the substrate include, but are not limited to, those described above.
A first coil 103 and a second coil 104 are arranged in the substrate 102, the first coil 103 and the second coil 104 are arranged in a direction parallel to the plane of the substrate 102 and are connected in series, and the winding directions of the first coil 103 and the second coil 104 are opposite. The current signal to be measured flows into the first coil 103 and the second coil 104 which are connected in series, specifically, pins 109 are arranged on the peripheries of the first coil 103 and the second coil 104, the first coil 103 receives the current signal to be measured through a current input pin, and the second coil 104 outputs the current signal to be measured through a current output pin. It can be understood that the current sensor is provided with a plurality of pins, and the connection structure and function of different pins are different, for example, if the current input end of the first coil 103 is electrically connected to one pin, the pin is a current input pin, all the pins are labeled as 109 in this embodiment, and the labeling of the structure of the pins is only a general name, and is not related to the structure and function of the pins.
In this embodiment, the magnetic sensing structure includes a first magnetic sensing element 105 and a second magnetic sensing element 106 which are located on the same surface of the substrate 102 and have the same sensitivity direction, the first magnetic sensing element 105 is disposed directly above the first coil 103, and the second magnetic sensing element 106 is disposed directly above the second coil 104. Specifically, the orthographic projection of the first magnetic sensing element 105 on the substrate 102 overlaps with the first coil 103, and optionally, the orthographic projection of the first magnetic sensing element 105 on the substrate 102 is located at the center of the first coil 103; the orthographic projection of the second magnetic sensing element 106 on the substrate 102 overlaps the second coil 104, and optionally the orthographic projection of the second magnetic sensing element 106 on the substrate 102 is located at the center of the second coil 104.
The product of the number of turns of the first coil 103 and the sensitivity of the first magnetic sensing element 105 is equal to the product of the number of turns of the second coil 104 and the sensitivity of the second magnetic sensing element 106, the winding directions of the first coil 103 and the second coil 104 are opposite, and the sensitivity directions of the first magnetic sensing element 105 and the second magnetic sensing element 106 are the same, so that the direction of the magnetic field generated by the first magnetic sensing element 105 and the first coil 103 is different from the direction of the magnetic field generated by the second magnetic sensing element 106 and the second coil 104, and the directions of the two magnetic fields are opposite, so that the external common-mode magnetic field interference can be counteracted, and the detection accuracy is improved.
In this embodiment, the signal processing unit 107 and the first magnetic sensing element 103 are located on the same surface of the substrate 102, the signal output end of the magnetic sensing structure is electrically connected to the signal input end of the signal processing unit 107, and the signal output end of the signal processing unit 107 outputs the voltage signal to be measured through the voltage output pin. Specifically, the signal output end of the first magnetic sensing element 105 is electrically connected to the first input end of the signal processing unit 107, and the signal output end of the second magnetic sensing element 106 is electrically connected to the second input end of the signal processing unit 107, so that the signal processing unit 107 receives the first voltage signal of the first magnetic sensing element 105 and the second voltage signal of the second magnetic sensing element 106, and processes the first voltage signal and the second voltage signal to obtain the measured voltage signal.
Referring to fig. 2, a sensitivity curve of a magnetic sensor according to an embodiment of the present invention is provided, in which an abscissa represents a magnetic field of the magnetic sensor in a sensitivity direction, and an ordinate represents an output voltage of the magnetic sensor. The first magneto-sensitive element and the second magneto-sensitive element can be selected to be Hall effect elements, anisotropic magneto-resistance elements, giant magneto-resistance elements or tunnel magneto-resistance elements. The working magnetic field range of the magnetic sensing element is-Hs- + Hs, and in the magnetic field range, the output voltage of the magnetic sensing element is in linear relation with the magnetic field of the magnetic sensing element in the sensitivity direction. It is known that the magnetic field of the magnetic sensor in the sensitivity direction is linear with the measured current flowing into the coil, and therefore the output voltage of the magnetic sensor is also linear with the measured current flowing into the coil.
Referring to fig. 3, a schematic diagram of a magnetic circuit analysis provided by an embodiment of the present invention is shown. The direction of the current to be measured is the direction in which the port 202 of the first coil 201 flows in and the port 205 of the second coil 204 flows out, i.e. from left to right in the figure. According to the right-hand screw rule, at the position of the first magnetic sensing element 203 above the first coil 201, the direction of the magnetic field generated by the first magnetic sensing element 203 is upward in the figure; at the position of the second magnetic sensing element 206 above the second coil 204, the direction of the magnetic field generated by the second magnetic sensing element 206 is downward as shown. Obviously, the two magnetic sensing elements have the same sensitivity direction and generate magnetic fields with opposite directions, so that the effect of resisting the interference of an external magnetic field can be achieved. Optionally, the first coil 201 receives a measured current signal through the current input pin, and the second coil 204 outputs the measured current signal through the current output pin, wherein the measured voltage signal and the measured current signal have a linear relationship.
In the case where the first coil 103 and the second coil 104 have the same number of turns, the product of the number of turns of the first coil 103 and the sensitivity of the first magnetic sensing element 105 is equal to the product of the number of turns of the second coil 104 and the sensitivity of the second magnetic sensing element 106, and then the sensitivities of the first magnetic sensing element 105 and the second magnetic sensing element 106 are the same.
When the measured current is I, the magnetic field generated by the first coil 103 at the first magnetic sensing element 105 is-H1, and the output voltage of the first magnetic sensing element 105 is-V1; the magnetic field generated at the second magnetic sensing element 106 by the second coil 104 is + H1, and the output voltage of the second magnetic sensing element 106 is + V1. The signal processing unit 107 receives the output voltage-V1 of the first magnetic sensing element 105 and the output voltage + V1 of the second magnetic sensing element 106, and performs subtraction calculation on the output voltages of the two magnetic sensing elements, so that the output voltage Vo of the signal processing unit 107 is (+ V1) - (-V1) 2V 1.
When the measured current is I and the external interference magnetic field is Δ H, the magnetic field generated by the first coil 103 at the first magnetic sensing element 105 is-H1 + Δ H, and the output voltage of the first magnetic sensing element 105 is-V1 + Δ V; the magnetic field generated at the second magnetic sensing element 106 by the second coil 104 is + H1+ Δ H, and the output voltage of the second magnetic sensing element 106 is + V1+ Δ V. The output voltage Vo of the signal processing unit 107 is (+ V1+ Δ V) - (-V1+ Δ V) ═ 2V 1.
Obviously, the output voltage of the current sensor is kept consistent under the condition of no external magnetic field interference, and the output result is not influenced by the external magnetic field interference.
The optional signal processing unit comprises: an amplification component and/or a temperature compensation component; the temperature compensation component is used for carrying out temperature compensation on the voltage signal output by the magnetic-sensing structure to obtain a primary voltage signal; the amplifying assembly is used for amplifying the primary voltage signal to obtain a measured voltage signal. For the current sensor with lower sensitivity, the signal processing unit receives the output voltage of the first magnetic sensing element and the output voltage of the second magnetic sensing element, and after subtraction calculation is carried out on the output voltages of the two magnetic sensing elements, the voltage signal obtained after subtraction calculation can be amplified through the amplifying component, so that interference signals in a circuit can be reduced. The temperature compensation component is used for compensating the temperature drift of the magnetic sensing element.
In the case where the first coil 103 and the second coil 104 have different numbers of turns, the product of the number of turns of the first coil 103 and the sensitivity of the first magnetic sensing element 105 is equal to the product of the number of turns of the second coil 104 and the sensitivity of the second magnetic sensing element 106, and then the sensitivities of the first magnetic sensing element 105 and the second magnetic sensing element 106 are different. For any magneto-sensitive element, the magneto-sensitive element satisfies its corresponding sensitivity curve. Therefore, the output voltage of the current sensor is consistent under the condition of no external magnetic field interference, and the output result is not influenced by the external magnetic field interference.
The embodiment of the utility model provides a pair of current sensor, including the base plate inside the packaging body, magnetic-sensing structure and signal processing unit, the base plate has two sets of series connection's coil, two magnetic-sensing element are located two sets of coil centers respectively directly over, the coiling opposite direction of two sets of coils, two magnetic-sensing element sensitive directions are the same, the number of turns of one of them coil and the product of the sensitivity of a magnetic-sensing element directly over rather than equal the number of turns of another coil and the product of the sensitivity of another magnetic-sensing element directly over rather than. The current to be measured sequentially flows through the two groups of coils, the directions of the magnetic fields generated by the two magnetic sensing elements are opposite, the output voltages of the two magnetic sensing elements are opposite in positive and negative and equal in size, so that a differential structure is formed, the interference of an external magnetic field can be mutually counteracted, the output voltages of the current sensor are kept consistent under the condition of the existence of the interference of the external magnetic field, the output result is not influenced by the interference of the external magnetic field, and the measurement precision of the current sensor is improved.
Exemplarily, on the basis of the above technical solution, the optional current sensor shown in fig. 1 further includes: the package 108, a part or all of the substrate 102 including the magneto-sensitive structure and the signal processing unit 107, is packaged in the package 108, and the leads 109 are located outside the package 108.
In this embodiment, the package 108 encapsulates the entire surface of the substrate 102 including the first magnetic sensor 105, the second magnetic sensor 106, and the signal processing unit 107. The signal output terminal of the signal processing unit 107 is led out through a pin 109, and the pin outputs a voltage signal which is proportional to the measured current flowing into the first coil 103 as an output signal of the current sensor. The leads 109 are led out from a side of the substrate 102 facing away from the package 108. In other embodiments, the package may optionally encapsulate the surface of the substrate 102 including the first magneto-sensitive element, the second magneto-sensitive element and the signal processing unit.
Alternative package forms of the package body 108 include an LGA package, a BGA package, an SOP package, or a DFN package. But is not limited thereto. The LGA package shown in fig. 4A means that the top surface of the substrate facing the magnetic sensing structure is covered by the package, the side and bottom surfaces of the substrate are exposed, and the bottom surface is provided with a plurality of lead-out pads, i.e., pins of the current sensor. As shown in fig. 4B, the BGA package means that the top surface of the substrate facing the magnetic sensing structure is covered by the package body, the side and the bottom surface of the substrate are exposed, the bottom surface is provided with a plurality of lead-out solder balls, which are the pins of the current sensor, and the solder balls have strong bonding force with the bottom surface and higher solderability. The SOP package shown in fig. 4C means that the substrate is placed on a lead frame, the electrical terminals on the substrate are electrically connected with the lead frame in a wire bonding manner, and the exposed pins of the lead frame are the pins of the current sensor. The DFN package shown in fig. 4D has a similar structure to the SOP package, except that the lead frame of the DFN package is flush with the package body, having a smaller package size.
The optional magnetically sensitive structure further comprises: a magnetizer arranged on one side of the first magnetic sensing element, which is far away from the substrate, and a magnetizer arranged on one side of the second magnetic sensing element, which is far away from the substrate; and/or a magnetizer disposed on a side of the first magnetic sensing element facing the substrate and a magnetizer disposed on a side of the second magnetic sensing element facing the substrate; wherein, the magnetic conductivity of the magnetizer is more than 1. For a magnetic sensor, the background noise is a fixed value, and if the size of the magnetic field to be measured can be increased, the signal-to-noise ratio of the sensor can be increased.
As shown in fig. 5, the optional magnetically sensitive structure further comprises: a magnetic conductor 305 provided on the side of the first magnetic sensing element 303 facing the substrate 301 and a magnetic conductor 306 provided on the side of the second magnetic sensing element 304 facing the substrate 301. Optional magnetizer 305 and magnetizer 306 are located within substrate 301. By adding the magnetizer in the sensitivity direction, the magnetic field of the magnetic sensing element in the sensitivity direction can be increased, and the signal-to-noise ratio of the magnetic sensing element is further improved.
As shown in fig. 6, the optional magnetically sensitive structure further comprises: a magnetic conductor 307 arranged on the side of the first magneto-sensitive element 303 facing away from the substrate 301 and a magnetic conductor 308 arranged on the side of the second magneto-sensitive element 304 facing away from the substrate 301. By adding the magnetizer in the sensitivity direction, the magnetic field of the magnetic sensing element in the sensitivity direction can be increased, and the signal-to-noise ratio of the magnetic sensing element is further improved.
As shown in fig. 7, the alternative magnetically sensitive structure further includes: a magnetic conductor 305 provided on the side of the first magnetic sensing element 303 facing the substrate 301 and a magnetic conductor 306 provided on the side of the second magnetic sensing element 304 facing the substrate 301; and a magnetic conductor 307 arranged on the side of the first magneto-sensitive element 303 facing away from the substrate 301 and a magnetic conductor 308 arranged on the side of the second magneto-sensitive element 304 facing away from the substrate 301. Optional magnetizer 305 and magnetizer 306 are located within substrate 301. By adding the magnetizer in the sensitivity direction, the magnetic field of the magnetic sensing element in the sensitivity direction can be increased, and the signal-to-noise ratio of the magnetic sensing element is further improved.
In the above embodiment, the magnetic sensor is provided with the magnetizer, so that the size of the magnetic field of the magnetic sensor can be increased, the signal-to-noise ratio of the current sensor is further increased, and the measurement accuracy of the current sensor is further improved.
Exemplarily, on the basis of the above technical solution, the first coil and the second coil may be both single-layer coils, and the number of turns of the single-layer coil is one or more; or the first coil and the second coil are both multilayer sub-coils, and the number of turns of the sub-coils is one or more. For a magnetic sensor, the background noise is a fixed value, and if the size of the magnetic field to be measured can be increased, the signal-to-noise ratio of the sensor can be increased. In this embodiment, the coil keeps the current constant, and the number of turns is increased to increase the magnetic field, thereby improving the signal-to-noise ratio.
As shown in fig. 8, the optional substrate includes four layers, namely a first substrate 401, a second substrate 402, a third substrate 403, and a fourth substrate 404; each layer of substrate is provided with a coil, the number of turns of the coil is one, and then four turns of the coils which are stacked are connected in series to form one coil. Taking the first coil in fig. 8 as an example, the first coils of 4 single layers are respectively the first single-layer coil 402, the second single-layer coil 406, the third single-layer coil 411 and the fourth single-layer coil 416; each single-layer coil is provided with an input end and an output end, and two adjacent single-layer coils are connected through the through hole.
Specifically, the current to be measured flows in from the input port 403 and flows out from the output port 404 of the first single-layer coil 402 in the first substrate 401; through the through hole 409, the measured current flowing out of the output port 404 flows into the input port 407 of the second single-layer coil 406 in the second substrate 405 and then flows out of the output port 408 thereof; through the through hole 414, the measured current flowing out from the output port 408 flows into the input port 412 of the third single-layer coil 411 in the third substrate 410, and then flows out from the output port 413 thereof; through the via 419, the measured current flowing from the output port 413 flows into the input port 417 of the fourth single-layer coil 416 in the fourth substrate 415 and then flows out from the output port 418 thereof.
As described above, the winding direction of the first coil in each layer is the same, so that the magnetic field generated by the first magnetic sensing element is four times that of a coil with one turn under the same current, and the effect of enhancing the magnetic field can be achieved.
As shown in fig. 9, the optional substrate 420 includes one layer; the coil 421 provided in the substrate 420 has four turns. Taking the first coil in fig. 9 as an example, the current to be measured flows in from the input port 422 and flows out from the output port 423 of the first coil 421 in the substrate 420; and then into the second coil. As described above, the number of turns of the first coil is 4, so that the magnetic field generated by the first magnetic sensing element is four times that of the one-turn coil under the same current, and the effect of enhancing the magnetic field can be achieved.
As shown in fig. 10, the alternative substrate comprises four layers; each layer of substrate is provided with a coil, the number of turns of the coil is multiple, and four layers of coils which are stacked are connected in series to form one coil. Taking the first coil in fig. 10 as an example, the 4 single-layer multi-turn first coils have input ends and output ends, and two adjacent single-layer coils are connected through a through hole. The measured current flows in from the input port 424 of the first single-layer coil and thence through the remaining three single-layer coils and out the output port 425. The winding directions of the first coils in each layer are consistent, so that the magnetic field generated by the first magnetic sensing element is multiple times of that of a coil of one turn under the same current, and the effect of enhancing the magnetic field can be achieved.
In the above embodiment, the multilayer coil and/or the multi-turn coil is/are disposed in the substrate, so that the magnetic field of the magnetic sensing element can be enhanced, the signal-to-noise ratio of the current sensor can be increased, and the measurement accuracy of the current sensor can be further improved.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. A current sensor, comprising: the magnetic sensor comprises a substrate, a magnetic sensitive structure and a signal processing unit;
a first coil and a second coil are arranged in the substrate, the first coil and the second coil are arranged in a direction parallel to the plane of the substrate and are connected in series, and the winding directions of the first coil and the second coil are opposite;
the magneto-sensitive structure comprises a first magneto-sensitive element and a second magneto-sensitive element which are positioned on the same surface of the substrate and have the same sensitivity direction, the first magneto-sensitive element is arranged right above the first coil, the second magneto-sensitive element is arranged right above the second coil, and the product of the number of turns of the first coil and the sensitivity of the first magneto-sensitive element is equal to the product of the number of turns of the second coil and the sensitivity of the second magneto-sensitive element;
the signal processing unit and the first magnetic sensing element are located on the same surface of the substrate, the signal output end of the magnetic sensing structure is electrically connected with the signal input end of the signal processing unit, and the signal output end of the signal processing unit outputs a measured voltage signal through a voltage output pin.
2. The current sensor of claim 1, further comprising: and the packaging body is used for packaging part or all of the substrate comprising the magnetic-sensing structure and the signal processing unit in the packaging body, and the pin is positioned outside the packaging body.
3. The current sensor of claim 2, wherein the package form of the package body comprises an LGA package, a BGA package, an SOP package, or a DFN package.
4. The current sensor of claim 1, wherein the magnetically sensitive structure further comprises:
a magnetizer disposed on a side of the first magnetic sensing element facing away from the substrate and a magnetizer disposed on a side of the second magnetic sensing element facing away from the substrate; and/or a magnetizer disposed on a side of the first magnetic sensing element facing the substrate and a magnetizer disposed on a side of the second magnetic sensing element facing the substrate;
wherein the magnetic permeability of the magnetizer is more than 1.
5. The current sensor of claim 1, wherein the first magnetic sensing element has a sensitive direction perpendicular to a surface of the first magnetic sensing element and the second magnetic sensing element has a sensitive direction perpendicular to a surface of the second magnetic sensing element.
6. The current sensor of claim 1, wherein the first and second magneto-sensitive elements are each a hall effect element, an anisotropic magneto-resistive element, a giant magneto-resistive element, or a tunneling magneto-resistive element.
7. The current sensor of claim 1, wherein the first coil and the second coil are both single layer coils having one or more turns; or,
the first coil and the second coil are both multilayer sub-coils, and the number of turns of the sub-coils is one or more.
8. The current sensor of claim 1, wherein the first coil receives a measured current signal through a current input pin, and the second coil outputs the measured current signal through a current output pin, wherein the measured voltage signal is linear with the measured current signal.
9. The current sensor according to claim 1, wherein the signal processing unit comprises: an amplification component and/or a temperature compensation component;
the temperature compensation component is used for performing temperature compensation on the voltage signal output by the magnetic-sensing structure to obtain a primary voltage signal;
the amplifying assembly is used for amplifying the primary voltage signal to obtain the measured voltage signal.
10. The current sensor of claim 1, wherein the substrate is a ceramic substrate, a printed circuit substrate, or a bakelite substrate.
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