A current sensor chip

Abstract

The utility model relates to a current sensor chip, including: a substrate, a DC detection unit, a U-shaped conductor, a feedback coil, an arcing coil and an output signal processing circuit; the DC detection unit is formed by connecting a plurality of magnetoresistance elements; the U-shaped conductor, the feedback coil and a plurality of magnetoresistance elements of the DC detection unit are stacked in the Z-axis direction to form a "sandwich" structure; the arcing coil is arranged on the substrate for detecting the arcing current; the feedback coil is connected to the output signal processing circuit of the DC detection unit, and a plurality of magnetoresistance elements are made to work in a zero magnetic flux state through a closed-loop negative feedback mechanism. The utility model improves the integration of the existing current sensor by integrating the DC current and the arcing current detection functions together, and in addition, a plurality of magnetoresistance elements are made to work in a zero magnetic flux state through a closed-loop negative feedback mechanism so that the magnetoresistance elements are not easily saturated, thereby expanding the detection range and accuracy of the existing current sensor.

Description

Technical Field

[0001] The utility model relates to the field of string current and arc current detection equipment, in particular to a current sensor chip. Background Art

[0002] In a photovoltaic power generation system, several photovoltaic modules are connected in series and then merged into a combiner box or inverter. Photovoltaic systems usually operate under medium to high DC voltages and high currents. Due to factors such as system installation, module quality, cable insulation aging, and poor connector contact, arcs may occur during normal use. In addition, since DC power does not have a zero point, it is difficult to extinguish a DC arc once it occurs, which can cause a fire and pose a great safety hazard. Therefore, in addition to conventional current measurement with a certain accuracy, arc current detection is very necessary in photovoltaic systems.

[0003] The current detection method of DC arc is as follows: the current signal is divided into conventional current and arc current, wherein the conventional current refers to the current when the photovoltaic equipment is working normally, and its dynamic range is relatively large and can reach more than 20A; the arc current is an AC current with a very small amplitude superimposed on the conventional current, and its amplitude is at the mA level. When this small signal AC current is superimposed on the conventional current with a large dynamic range, it is often difficult to measure using a conventional current sensor due to its resolution limitation. It is necessary to use an AC current transformer to filter out the DC component and condition and collect the small AC current signal.

[0004] In the existing technical solutions, arc current detection adopts a method similar to electromagnetic induction current transformer or AC coupling amplification and conditioning of the current detection chip; for conventional current detection, an open-loop current sensor method is used; this combination method can be integrated into the device separately, or the two can be combined into a larger module. This causes technical problems such as large volume and inconvenience for on-board installation; in addition, the open-loop current sensor method leads to poor linearity, which affects the measurement accuracy of the current sensor. At the same time, there are problems such as the magnetic core is easily saturated and difficult to detect large current signals, and the frequency response is low.

[0005] Therefore, the existing technical solutions lack a detection device that is small in size and can simultaneously detect arc current and DC current. Utility Model Content

[0006] The utility model aims to provide a current sensor chip to solve the technical problems of the current sensor in the prior art that the volume is too large, the detection range is too low and the detection accuracy is too low.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] The utility model provides a current sensor chip, comprising:

[0009] Base, DC detection unit, U-shaped conductor, feedback coil, arc drawing coil and output signal processing circuit;

[0010] The DC detection unit is formed by connecting a number of magnetoresistive elements;

[0011] Taking the plane where the substrate is located as the XY plane, the U-shaped conductor, the feedback coil and the plurality of magnetoresistive elements of the DC detection unit are stacked in the Z-axis direction to form a "sandwich" structure;

[0012] The arc-drawing coil is arranged on the substrate and between the two arms of the U-shaped conductor, and is used to detect the arc-drawing current;

[0013] The feedback coil is connected to the output signal processing circuit and is used to pass a feedback current related to the output signal, so as to make the plurality of magnetoresistive elements operate in a zero flux state through a closed-loop negative feedback mechanism.

[0014] According to the present invention, preferably, the magnetoresistive element is an XMR magnetoresistive element, and the XMR magnetoresistive element at least includes: a TMR magnetoresistive element, a GMR magnetoresistive element, and an AMR magnetoresistive element.

[0015] According to the utility model, preferably, the DC detection unit is a push-pull full-bridge circuit composed of the plurality of magnetoresistive elements, and the push-pull full-bridge is in a balanced state of zero output when the magnetic field is zero; taking the extension direction of the two arms of the U-shaped conductor as the Y-axis direction, the plurality of magnetoresistive elements are symmetrically distributed above or below the two arms of the U-shaped conductor, and the symmetry plane is parallel to the ZY plane; the magnetoresistive elements symmetrically arranged about the symmetry plane have the same sensitive directions, and are parallel to or anti-parallel to the X-axis direction.

[0016] According to the utility model, preferably, the feedback coil is made of one or more materials selected from the group consisting of Cu, Ag, Al, and Au.

[0017] According to the utility model, preferably, the upper side, or the left and right sides and the upper side of the feedback coil are covered with a magnetic focusing layer.

[0018] According to the utility model, preferably, the material of the magnetic focusing layer is NiFe or other high magnetic permeability soft magnetic materials.

[0019] According to the utility model, preferably, the current in the feedback coil is obtained by measuring a precision resistor.

[0020] The beneficial effects of the utility model are as follows: the utility model improves the integration of existing current sensors by integrating direct current and arc current detection functions; in addition, a closed-loop negative feedback mechanism is used to make several magnetoresistive elements operate in a zero magnetic flux state so that the magnetoresistive elements are not easily saturated, thereby expanding the detection range and accuracy of existing current sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the structure of the current sensor chip provided by the utility model embodiment;

[0023] Figure 2 It is a structural schematic diagram of a closed-loop detection circuit of a current sensor chip provided by an embodiment of the utility model;

[0024] Figure 3 It is a schematic diagram of the structure cross section of a current sensor chip provided by an embodiment of the utility model at a certain magnetoresistive element;

[0025] Figure 4 It is a schematic diagram of the structure of the utility model in which the left and right sides and the upper side are covered with a magnetic concentrating layer;

[0026] Figure 5 This is a simulation diagram of the magnetic field distribution near the magnetoresistance unit when the feedback coil has no magnetic focusing layer;

[0027] Figure 6 This is a simulation diagram of the magnetic field distribution near the magnetoresistive unit when the left and right sides and the upper side of the feedback coil are covered with a magnetic focusing layer.

[0028] Icons: 1-magnetoresistance element; 2-arc-pulling coil; 3-feedback coil; 4-substrate; 5-ceramic insulation layer; 6-output signal processing circuit; 7-precision resistor; 8-U-shaped conductor; 9-DC detection unit; 10-power input terminal; 11-output terminal; 12-magnetic focusing layer; 13-insulation layer. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0032] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0033] The utility model provides a current sensor chip. The following is an embodiment to describe the current sensor chip provided by the utility model in detail.

[0034] See also Figure 1 The utility model provides a current sensor chip, specifically comprising:

[0035] A substrate 4, a DC detection unit 9, a U-shaped conductor 8, a feedback coil 3, an arc-drawing coil 2 and an output signal processing circuit 6;

[0036] The DC detection unit 9 is formed by connecting a plurality of magnetoresistive elements 1;

[0037] Taking the plane where the substrate 4 is located as the XY plane, the U-shaped conductor 8, the feedback coil 3 and the plurality of magnetoresistive elements 1 of the DC detection unit 9 are stacked in the Z-axis direction to form a "sandwich" structure, wherein the arrangement order of the U-shaped conductor 8, the feedback coil 3 and the DC detection unit 9 in the Z-axis direction is not limited to Figure 1 , in fact, as long as the three are stacked to form a "sandwich" result;

[0038] The arc-drawing coil 2 is disposed on the substrate 4 and between the two arms of the U-shaped conductor 8, and is used to detect the arc-drawing current;

[0039] The feedback coil 3 is connected to the output signal processing circuit 6 of the DC detection unit 9 and is used to pass a feedback current related to the output signal, so that a plurality of magnetoresistive elements operate in a zero flux state through a closed-loop negative feedback mechanism.

[0040] Specifically, Figure 2 The structure diagram of the closed-loop detection circuit of the current sensor chip is shown. The current to be measured flows into the U-shaped conductor 8 and generates a magnetic field at the magnetoresistive element 1 on both sides of the U-shaped conductor 8. The magnetoresistive element 1 senses the magnetic field and converts it into a voltage signal. The voltage signal output by the magnetoresistive element 1 is converted into a current signal by the output signal processing circuit 6, and then the current signal is transmitted to the feedback coil 3, and then fed back to the top of the magnetoresistive element 1 through the feedback coil 3, so that the closed-loop feedback is realized through the feedback coil 3, so that the magnetoresistive element 1 always works in a zero magnetic flux state.

[0041] Specifically, the arc coil 2, the magnetoresistive element and the feedback coil 3 are grown on the same substrate 4 through a semiconductor preparation process to form a single chip, so that the magnetoresistive unit in the magnetoresistive element 1 is precisely aligned with the feedback coil 3, so that each magnetoresistive element 1 is in a zero flux state, so that the feedback coil 3 can accurately feedback the magnetic field; in addition, the above-mentioned single chip, U-shaped conductor 8, output signal processing circuit 6, precision resistor 7 and a ceramic insulating layer 5 are packaged together through a semiconductor packaging process, so that the signal detection function of the direct current and the arc current can be realized at the same time, and the integration of the chip is improved. Since the feedback coil 3 is very close to the magnetoresistive element 1, a larger feedback magnetic field can be obtained, so it is ensured that when a larger current is input, the magnetoresistive element 1 can still be in a zero flux state. In one embodiment, the substrate 4, the output signal processing circuit 6, and the precision resistor 7 can also be integrated into the same substrate into a single chip and then packaged together to improve the integration of the chip.

[0042] See also Figure 3 The figure shows a cross-sectional schematic diagram of the current sensor at a certain magnetoresistive element. As long as the direction of the feedback coil 3 is changed, the magnetic field generated by the current in the feedback coil 3 and the input current to be measured at the magnetoresistive element 1 can be opposite. The magnetic field generated by the current in the feedback coil 3 will weaken the magnetic field generated by the input current to be measured, so that the magnetic field strength at the magnetoresistive element 1 is reduced. The magnetoresistive element 1 converts the weakened magnetic field into a deviation voltage signal again, and the feedback coil 3 corrects the deviation voltage signal by closed-loop feedback until the current in the feedback coil 3 and the magnetic field generated by the input current to be measured at the magnetoresistive element 1 cancel each other to nearly 0, so that the magnetoresistive element 1 works in a zero flux state.

[0043] Specifically, on the one hand, when the current Ip to be detected flows through the U-shaped conductor 8, the magnetoresistive element 1 constituting the DC detection unit is used as a magnetic field detection element, and the magnitude of the current to be measured is determined according to the magnetic field strength generated by the current to be measured. The current measurement signal is output by the output signal processing circuit connected to the output end of the DC detection unit 9, and is fed back to the top of the magnetoresistive element 1 by the feedback coil 3, so as to realize closed-loop negative feedback to make the magnetoresistive element 1 work in a zero magnetic flux state, and then the current in the feedback coil 3 is measured by the precision resistor 7 to realize the DC current measurement of the current Ip to be detected; on the other hand, the output end of the arc coil 2 outputs a high-frequency current detection signal to complete the high-frequency current detection of the current Ip to be detected, thereby realizing the arc detection function.

[0044] In practical applications, the current to be detected Ip can be any current that requires current measurement and high-frequency current detection at the same time, such as the DC current of a photovoltaic string, which is not limited here and is within the protection scope of this application.

[0045] In one embodiment, the magnetoresistive element 1 may be an XMR magnetoresistive element, which includes at least a TMR magnetoresistive element, a GMR magnetoresistive element, and an AMR magnetoresistive element.

[0046] In one embodiment, the DC detection unit 9 is a push-pull full-bridge circuit composed of a plurality of magnetoresistive elements, and the push-pull full-bridge is in a balanced state of zero output when the magnetic field is zero, realizing differential output, thereby resisting the interference of common-mode noise. With the extension direction of the two arms of the U-shaped conductor as the Y-axis direction, the plurality of magnetoresistive elements are symmetrically distributed above or below the two arms of the U-shaped conductor, and the symmetry plane is parallel to the ZY plane; the magnetoresistive elements symmetrically arranged about the symmetry plane have the same sensitive direction, and are parallel to or antiparallel to the X-axis direction.

[0047] In one embodiment, the feedback coil 3 is made of a metal material with relatively high electrical conductivity, such as one or more materials selected from the group consisting of Cu, Ag, Al, and Au.

[0048] In one embodiment, in order to further improve the current range during current detection and prevent the feedback coil from being burned out under a large feedback current, it is necessary to increase the ratio of the primary current to the secondary current when the magnetoresistive unit is in a zero flux state. Therefore, a magnetic concentrating layer 12 may be provided on the upper side of the feedback coil, or on both sides and the upper side. Figure 4 As shown, the ability of the feedback coil to generate a magnetic field is improved, thereby increasing the range of the detection current.

[0049] In one embodiment, the material of the magnetic focusing layer may be a soft magnetic material with high magnetic permeability, such as NiFe, so that the magnetic field generated by the feedback coil is concentrated at the magnetoresistive unit.

[0050] See also Figure 5 and Figure 6 , respectively, are simulation diagrams of the magnetic field distribution near the magnetoresistive unit when the feedback coil is without a magnetic focusing layer and when it is covered with a magnetic focusing layer. By comparison, it can be seen that the magnetic field strength of the feedback coil 3 at the magnetoresistive element can be increased by covering the magnetic focusing layer, thereby improving the ability of the feedback coil 3 to generate a magnetic field, that is, increasing the range of detected current; at the same time, the uniform area of ​​the magnetic field generated by the feedback coil 3 at the magnetoresistive element is increased, thereby further reducing the influence of the alignment error on the detection accuracy and improving the accuracy of current detection.

[0051] In one embodiment, the DC and low-frequency current signals in the input current to be measured are obtained by measuring the voltage signal on the precision resistor 7 connected to the feedback coil.

[0052] In one embodiment, the arc coil 2 is located at the center of the U-shaped gap of the U-shaped conductor, so that the magnetic fields generated by the input side and the output side of the U-shaped conductor 8 will be superimposed and increased at the arc coil 2, thereby increasing the output signal of the arc current detected by the arc coil 2.

[0053] In this embodiment, the magnetoresistive element, the feedback coil 3, and the arc-drawing coil 2 are grown on the same substrate 4 through a semiconductor preparation process to form a single chip, and then the single chip, the U-shaped conductor 8, the output signal processing circuit 6, and the precision resistor 7 are packaged together through a semiconductor packaging process to form a current sensor chip. The detection functions of the DC current and the arc-drawing current signal can be realized simultaneously, while reducing the chip size and improving the integration.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A current sensor chip, characterized in that: include: Base, DC detection unit, U-shaped conductor, feedback coil, arc drawing coil and output signal processing circuit; The DC detection unit is formed by connecting a number of magnetoresistive elements; Taking the plane where the substrate is located as the XY plane, the U-shaped conductor, the feedback coil and the plurality of magnetoresistive elements of the DC detection unit are stacked in the Z-axis direction to form a "sandwich" structure; The arc-drawing coil is arranged on the substrate and between the two arms of the U-shaped conductor, and is used to detect the arc-drawing current; The feedback coil is connected to the output signal processing circuit and is used to pass a feedback current related to the output signal, so as to make the plurality of magnetoresistive elements operate in a zero flux state through a closed-loop negative feedback mechanism.

2. The current sensor chip according to claim 1, characterized in that: The magnetoresistive element is an XMR magnetoresistive element, and the XMR magnetoresistive element at least includes: a TMR magnetoresistive element, a GMR magnetoresistive element, and an AMR magnetoresistive element.

3. The current sensor chip according to claim 2, characterized in that: The DC detection unit is a push-pull full-bridge circuit composed of the plurality of magnetoresistive elements, and the push-pull full-bridge is in a balanced state of zero output when there is a zero magnetic field; Taking the extension direction of the two arms of the U-shaped conductor as the Y-axis direction, the plurality of magnetoresistive elements are symmetrically distributed above or below the two arms of the U-shaped conductor, and the symmetry plane is parallel to the ZY plane; the magnetoresistive elements symmetrically arranged about the symmetry plane have the same sensitive direction and are parallel to or antiparallel to the X-axis direction.

4. The current sensor chip according to any one of claims 1 to 3, characterized in that: The upper side, or the left and right sides and the upper side of the feedback coil are covered with a magnetic field concentrating layer.

5. The current sensor chip according to claim 4, characterized in that: The material of the magnetic concentrating layer is NiFe or other high magnetic permeability soft magnetic materials.

6. The current sensor chip according to claim 5, characterized in that: The current in the feedback coil is measured by a precision resistor.

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