Current sensor and preparation method thereof

Abstract

The invention provides a current sensor and a preparation method thereof, the current sensor comprises an overcurrent conductor, a first Hall component and a second Hall component, the magnetic field sensing directions of the first Hall component and the second Hall component are the same, the output polarities of the first Hall component and the second Hall component are opposite, and the first Hall component and the second Hall component are connected in parallel or in series; the first Hall component and the second Hall component are aligned along a second plane perpendicular to the first plane; the first plane is the plane where the overcurrent conductor is located, and an insulating layer is arranged between the first Hall component and the second Hall component. According to the scheme, the distance between the two Hall components and the shape and the size of the overcurrent conductor can be flexibly set by adopting a vertical arrangement mode, so that the sensing voltages of the two Hall components on a common-mode magnetic field are closer, and the suppression effect of the current sensor on the common-mode magnetic field is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of current sensing, and in particular to a current sensor and a method for preparing the same. Background Art

[0002] Hall current sensors are an indispensable part of many application fields and play an important role in industrial automation, automotive electronics, medical and health systems, etc. At present, most related technologies use differential Hall current sensors for current detection.

[0003] The differential Hall current sensor uses two sets of Hall components with different polarity output modes to amplify the differential signal given by the measured current and suppress the external common-mode interference signal. However, since the two sets of Hall components used by the differential Hall current sensor need to be set on both sides of the overcurrent bar, the width of the overcurrent bar will affect the distance between the two Hall components. In some scenarios, in order to allow the overcurrent bar to pass a larger current, the width of the overcurrent bar will be appropriately increased, so that the distance between the two sets of Hall components will also increase, so that the two sets of Hall components have different perceived voltages for the interference magnetic field, resulting in poor suppression of the common-mode magnetic field. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a current sensor and a method for manufacturing the same, so as to improve the common-mode magnetic field suppression effect of the Hall current sensor.

[0005] In a first aspect, an embodiment of the present application provides a current sensor, the current sensor comprising: a current-carrying conductor and a first Hall element and a second Hall element having the same magnetic field sensing direction and opposite output polarities, wherein: The first Hall element and the second Hall element are connected in parallel or in series; The first Hall element and the second Hall element are aligned and arranged along a second plane perpendicular to the first plane; wherein the first plane is the plane where the current-carrying conductor is located; an insulating layer is arranged between the first Hall element and the second Hall element; The first penetration angle of the first Hall element is not equal to the second penetration angle of the second Hall element, and / or the first distance between the first Hall element and the overcurrent conductor is not equal to the second distance between the second Hall element and the overcurrent conductor; wherein the first penetration angle and the second penetration angle are respectively the magnetic field penetration angles at the first Hall element and the second Hall element of the magnetic field to be measured generated when the measured current flows through the overcurrent conductor.

[0006] In the implementation process of the above scheme, the two Hall elements in the sensor are aligned and arranged on a vertical plane perpendicular to the plane where the current conductor is located, and the two Hall elements have the same magnetic field sensing direction and opposite output polarities. Due to the vertical arrangement, the distance between the two Hall elements and the shape and size of the current conductor can be flexibly set, so that the sensing voltages of the two Hall elements to the common-mode magnetic field are closer, thereby improving the suppression effect of the current sensor on the common-mode magnetic field and the current carrying capacity of the current sensor.

[0007] In an implementation of the first aspect, the first distance is 1 to 500 ; and / or, the second distance is 1 to 500 .

[0008] In the process of implementing the above solution, by controlling the distance between the Hall element and the current conductor, the above current sensor has better magnetic properties.

[0009] In an implementation of the first aspect, the current sensor further includes: a lead frame and an insulating substrate arranged along the second plane, wherein: The insulating substrate is fixed on the lead frame; The insulating substrate is provided with an on-board circuit for powering the Hall element and realizing parallel connection or series connection of the first Hall element and the second Hall element; the first Hall element and the second Hall element are respectively connected to the on-board circuit.

[0010] In the process of implementing the above scheme, the power supply of the Hall element and the series or parallel connection between the two Hall elements are realized by means of an on-board circuit arranged on an insulating substrate. On the one hand, the integration degree of the above-mentioned current sensor is higher. On the other hand, since the on-board circuit can be customized, it is conducive to improving the flexibility of the above-mentioned current sensor.

[0011] In an implementation of the first aspect, the first Hall component adopts a multi-layer Hall chip stacking structure; and / or the second Hall component adopts a multi-layer chip stacking structure.

[0012] In the process of implementing the above scheme, the Hall components can stack multiple Hall sensor chips together to form a common sensor unit. On the one hand, it is beneficial to improve the performance of the above current sensor; on the other hand, it can also enable the above current sensor to integrate more functions, which is beneficial to improve the applicability of the above current sensor.

[0013] In an implementation of the first aspect, the Hall sensing core of the Hall chip in the first Hall component adopts a Wheatstone bridge structure; and / or the Hall sensing core of the Hall chip in the second Hall component adopts a Wheatstone bridge structure.

[0014] In the process of implementing the above scheme, the Hall sensing core of the Hall chip in the Hall component can adopt a Wheatstone bridge structure, which is beneficial to improving the magnetic characteristics of the above current sensor and the common-mode interference magnetic field suppression effect.

[0015] In a second aspect, an embodiment of the present application provides a method for preparing a current sensor, the method comprising: setting a current conductor on a first plane; setting a lead frame on a second plane perpendicular to the first plane; fixing an insulating substrate with an on-board circuit to the lead frame; fixing a first Hall component to the insulating substrate; aligning a second Hall component with the first Hall component and fixing it on the first Hall component; performing wire bonding connection; and obtaining a current sensor after plastic sealing.

[0016] In an implementation manner of the second aspect, the method further includes: when the first Hall element is fixedly connected to the insulating substrate, controlling the distance between the first Hall element and the current conductor to control the sensitivity of the current sensor.

[0017] In an implementation of the second aspect, aligning the second Hall component with the first Hall component and fixing the second Hall component on the first Hall component comprises: aligning the second Hall component with the first Hall component; fixing the second Hall component on the first Hall component by using insulating glue; The method further includes: when the second Hall element is fixed on the first Hall element by using insulating glue, controlling the thickness of the insulating glue to control the resolution of the current sensor.

[0018] In an implementation of the second aspect, the fixing and connecting the first Hall element to the insulating substrate comprises: electrically connecting the first Hall element to the on-board circuit of the insulating substrate using a conductive adhesive so that the first Hall element is fixed on the insulating substrate; Alternatively, the fixed connection of the first Hall component to the insulating substrate includes: fixing the first Hall component on the insulating substrate using insulating glue; the wire bonding includes: wire bonding the first Hall component to the on-board circuit of the insulating substrate.

[0019] In a third aspect, an embodiment of the present application provides a current sensor, the current sensor comprising: a current conductor and a first magnetoresistive element and a second magnetoresistive element having the same magnetic field sensing direction and opposite output polarities, wherein: The first magnetoresistive element is connected in parallel or in series with the second magnetoresistive element; The first magnetoresistive element and the second magnetoresistive element are aligned and arranged along a second plane perpendicular to the first plane; wherein the first plane is the plane where the current-carrying conductor is located; The third penetration angle of the first magnetoresistance element is not equal to the fourth penetration angle of the second magnetoresistance element, and / or the third distance between the first magnetoresistance element and the current conductor is not equal to the third distance between the second magnetoresistance element and the current conductor; wherein the third penetration angle and the fourth penetration angle are respectively the magnetic field penetration angles at the first magnetoresistance element and the second magnetoresistance element of the magnetic field to be measured generated when the current to be measured flows through the current conductor.

[0020] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the embodiments of the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a structural schematic diagram of a differential Hall current sensor in the related art; Figure 2 A schematic diagram of the structure of a current sensor provided in an embodiment of the present application; Figure 3 A schematic diagram of experimental results of a control experiment provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of the insulating layer provided in an embodiment of the present application; Figure 5 Another schematic diagram of the structure of the current sensor provided in the embodiment of the present application; Figure 6 A schematic diagram of the structure of the Hall chip provided in the embodiment of the present application; Figure 7 A schematic diagram of a process for preparing a current sensor provided in an embodiment of the present application; Figure 8 A schematic diagram of a bonding method between a first Hall element and a lead frame provided in an embodiment of the present application; Fig. 9 A schematic diagram of the wire bonding method of the current sensor in the first scenario provided in the embodiment of the present application; Fig.10 A schematic diagram of the wire bonding method of the current sensor in the second scenario provided in the embodiment of the present application; Fig.11 A schematic diagram of the structure of a magnetoresistive current sensor provided in an embodiment of the present application; Fig.12 A schematic diagram of the working principle of the magnetoresistive current sensor provided in an embodiment of the present application when it is directly arranged on the surface of a current-carrying conductor. DETAILED DESCRIPTION

[0023] The following will describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0024] See also Figure 1 The differential Hall current sensor in the related art includes an overcurrent copper bar and two Hall components Hall1 and Hall2 arranged in the same plane as the overcurrent copper bar and on the opposite sides of the overcurrent bar. The principle of the differential Hall current sensor is as follows: (1) Suppress the common mode magnetic field (also known as the interference magnetic field): Since the two Hall elements are located close to each other, the sensing voltages of the two Hall elements to the common-mode magnetic field are also close. The common-mode magnetic field can be suppressed by subtracting the output voltages of the two Hall elements. (2) Amplification of differential mode signals: When the current to be measured flows through the current busbar, a magnetic field to be measured is generated. The directions of the magnetic fields at the two Hall elements are opposite, but the output polarities of the two Hall elements are opposite. Therefore, the two Hall elements can output two voltage values ​​of equal magnitude and direction. The current to be measured can be detected by calculating the voltage values.

[0025] In the implementation scheme of the above-mentioned differential Hall current sensor, since an overcurrent bar needs to be arranged between the two Hall components, and in some scenarios, since the overcurrent bar needs to pass a large current, the width of the overcurrent bar will be appropriately increased; in addition, the magnetic field direction of the magnetic field to be measured at the two Hall components also needs to be set in opposite directions, so there will be a certain distance between the two Hall components. On the one hand, setting a larger width of the overcurrent bar will reduce the strength of the magnetic field signal sensed by the Hall component; in addition, since the Hall components are set at a certain distance, the perceived voltages of the two Hall components to the common-mode magnetic field will also have a large difference, resulting in the differential Hall current sensor having a poor suppression effect on the common-mode magnetic field. Generally, the differential Hall current sensor in the related art can only achieve a common-mode magnetic field suppression ratio of -40dB.

[0026] In addition, since there are certain differences in the magnetic sensitivity of the Hall elements, this difference will further increase the difference in the perceived voltage of the two Hall elements to the common-mode magnetic field, thereby making the differential Hall current sensor's suppression of the common-mode magnetic field even worse.

[0027] Based on this, an embodiment of the present application provides a current sensor, in which two Hall elements in the sensor are aligned and arranged on a vertical plane perpendicular to the plane in which the current conductor is located, and the two Hall elements have the same magnetic field sensing direction and opposite output polarities. Due to the vertical arrangement, the distance between the two Hall elements and the shape and size of the current conductor can be flexibly set, so that the sensing voltages of the two Hall elements to the common-mode magnetic field are closer, thereby improving the current sensor's suppression effect on the common-mode magnetic field and the current sensor's current-carrying capacity.

[0028] The following is a detailed description of the above current sensors, see Figure 2 The present application embodiment provides a current sensor 100, which includes: a current conductor 130 and a first Hall element 110 and a second Hall element 120 having the same magnetic field sensing direction and opposite output polarities, wherein: The first Hall element 110 and the second Hall element 120 are connected in parallel or in series; The first Hall element 110 and the second Hall element 120 are aligned along a second plane perpendicular to the first plane; wherein the first plane is the plane where the current conductor 130 is located, and an insulating layer 140 is arranged between the first Hall element 110 and the second Hall element 120 .

[0029] The first penetration angle of the first Hall element 110 is not equal to the second penetration angle of the second Hall element 120, and / or the first distance between the first Hall element 110 and the current conductor 130 is not equal to the second distance between the second Hall element 120 and the current conductor 130; wherein the first penetration angle and the second penetration angle are respectively the magnetic field penetration angles at the first Hall element 110 and the second Hall element 120 of the magnetic field to be measured generated when the current to be measured flows through the current conductor 130.

[0030] It can be understood that the Hall sensing cores of the first Hall element 110 and the second Hall element 120 can be arranged on the upper surfaces of the Hall elements.

[0031] Understandably, Figure 2 FIG. 1 shows only a positional relationship between the first Hall element 110 , the second Hall element 120 and the current-carrying conductor 130 , and includes the following schematic contents: (1) The circular portion in the figure is a schematic diagram of the magnetic field to be measured generated when the current to be measured flows through the current conductor 130; (2) In the figure is a first distance between the first Hall element 110 and the current conductor 130, is a second distance between the second Hall element 120 and the current conductor 130; (3) The first Hall element 110 and the second Hall element 120 are aligned and arranged on a second plane perpendicular to the first plane; (4) The first penetration angle of the first Hall element 110 is 0, and the second penetration angle of the second Hall element 120 is .

[0032] The working principle of the current sensor is described below by taking the first Hall element 110 and the second Hall element 120 connected in parallel as an example: When the current to be measured flows through the current conductor 130, a magnetic field to be measured is generated. The magnetic field to be measured generates a Hall effect at the first Hall element 110 and the second Hall element 120. Assuming that the output voltage of the first Hall element 110 is , the output voltage of the second Hall element 120 is , the output voltage after the two Hall elements are connected in parallel is ,So:

[0033]

[0034]

[0035] in, and are respectively the sensed voltages of the first Hall element 110 and the second Hall element 120 to the magnetic field to be measured, and They are respectively the sensed voltages of the first Hall element 110 and the second Hall element 120 to the interfering magnetic field.

[0036] Since the distance between the two Hall elements is relatively close, although the sensing voltage of the two Hall elements to the interfering magnetic field is and There is a slight difference, but the two values ​​can still be considered to be approximately equal. Since the output polarities of the two Hall elements are opposite, it can be considered that: ,So:

[0037] It can be seen from the above formula that the above arrangement scheme of the current sensor 100 suppresses the interference of the common mode magnetic field to a large extent; Assume that the magnitude of the magnetic field to be measured at the first Hall element 110 is , the magnitude of the magnetic field at the second Hall element 120 is , since the magnitude of the magnetic field at a certain position is inversely proportional to the distance from the current-carrying conductor, that is:

[0038]

[0039]

[0040] So:

[0041] in, is the magnetic permeability in vacuum, is the current flowing through the conductor, is the effective magnetic field of the magnetic field to be measured at the second Hall element 120, and are the magnetic sensitivities of the first Hall element 110 and the second Hall element 120 respectively. Generally, and are approximately equal, so the above equation can be simplified to:

[0042] in, for and The approximate equivalent of From the above equation, we can see that the magnetic sensitivity of the Hall element , a first distance between the first Hall element 110 and the current conductor 130 , a second distance between the second Hall element 120 and the current conductor 130 , a first penetration angle of the first Hall element 110 and a second penetration angle of the second Hall element 120 When the value is fixed, the output voltage of two Hall elements connected in parallel is The magnetic field magnitude of the effective magnetic field at the first Hall element 110 of the magnetic field to be measured Of course, it can also be said that the output voltage of two Hall elements connected in parallel is The magnetic field magnitude of the effective magnetic field of the magnetic field to be measured at the second Hall element 120 is proportional to the voltage To determine the current value to be measured, thereby realizing the detection of the current to be measured.

[0043] In addition, it can be understood that from the above formula, the smaller R1 / R2 is, that is, the larger the distance between the Hall element 110 and the Hall element 120 is, the output voltage V * The bigger.

[0044] In addition, it should be pointed out that the above output voltage The calculation formula is only for the first penetration angle of the first Hall element 110 When the first penetration angle of the first Hall element 11 is 0, Not 0, output voltage The calculation method can be:

[0045] The output voltage The calculation formula shows that: voltage The value depends on the parameter ,parameter And parameters , in the parameters is 1, and When the voltage The value of is 0, and the current to be measured cannot be detected at this time. Therefore, the parameters of the two Hall elements can be constrained as follows: (1) First penetration angle of the first Hall element 110 The second penetration angle of the second Hall element 120 unequal, and / or, a first distance between the first Hall element 110 and the current conductor 130 The second distance between the second Hall element 120 and the current conductor 130 Not equal, that is: Equation And the equation Not established at the same time.

[0046] (2) The effective magnetic field value of the magnetic field to be measured penetrating into the two Hall elements is not zero.

[0047] It can be understood that, in consideration of the above two constraints, the distance between the two Hall elements and the positions of the two Hall elements relative to the current conductor 130 can be set according to the actual application scenario.

[0048] In addition, it should be pointed out that the alignment configuration of the first Hall component 110 and the second Hall component 120 means that the central axes of the Hall sensing cores of the Hall chips in the two Hall components are both in the second plane, and the Hall components can be rotated along the central axis according to the actual application scenario. For example, in order to facilitate wire bonding, the second Hall component 120 can be rotated 45° along the central axis of the Hall sensing core.

[0049] Through experiments, it is found that the above-mentioned current sensor 100 has a good suppression effect on the common-mode interference magnetic field, which can reach above -60dB. In addition, the embodiment of the present application also conducted a comparative experiment on the magnetic common-mode suppression ratio when two Hall elements are arranged vertically and horizontally, specifically: An interference source is set 10 mm away from the first Hall element. The two Hall elements can be arranged vertically or horizontally. The horizontal arrangement includes: (1) Horizontal layout mode 1: The first Hall element is located close to the interference source, and the second Hall element is located far away from the interference source; (2) Horizontal layout method 2: The second Hall element is located close to the interference source, and the first Hall element is located far away from the interference source.

[0050] In the experiment, the distance between the two Hall elements was adjusted to determine the common-mode interference suppression effect of the vertical arrangement, horizontal arrangement 1, and horizontal arrangement 2. The results are shown in the figure. Figure 3 As shown by Figure 3 The following conclusions can be drawn: (1) With the same spacing between Hall elements, the common-mode suppression effect of the vertical arrangement is better than that of the horizontal arrangement; (2) The distance between the two Hall elements will affect the common-mode rejection effect of the current sensor.

[0051] The following is a further introduction to the parameters of the two Hall components and their positional relationship: As an optional implementation of the current sensor, the third distance between the first Hall element 110 and the second Hall element 120 is 0 to 350 .

[0052] It is understandable that, on the one hand, since the current sensor 100 is arranged vertically, the distance between the two Hall elements can be shortened as much as possible in theory, so that the sensing voltage of the two Hall elements to the common-mode interference magnetic field is as close as possible. On the other hand, considering the actual product requirements, the distance between the two Hall elements may not be set to 0. It has been found through experiments that the third distance between the two Hall elements is 350 When the sensing voltage of the two Hall elements to the common-mode interference magnetic field is within an acceptable error, the third distance between the first Hall element 110 and the second Hall element 120 can be 0 to 350. To achieve better common-mode interference magnetic field suppression effect.

[0053] In the above solution, the third distance between the first Hall element 110 and the second Hall element 120 is 0 to 350 , which is beneficial to improving the common-mode interference magnetic field suppression effect of the current sensor 100.

[0054] Optionally, the target gain of the first Hall element 110 is the same as the target gain of the second Hall element 120 .

[0055] It is understandable that since the target gains of the two Hall elements need to be approximately equal, two Hall elements with the same target gain can be selected. Although the actual magnetic sensitivity may deviate from the nominal value, it can be adjusted by calibrating the sensor, etc. Therefore, two Hall elements with the same target gain can be selected.

[0056] The current sensor 100 in the above solution can select two Hall elements with the same target gain, which is beneficial to improving the common-mode interference magnetic field suppression effect of the current sensor 100.

[0057] Optionally, the difference between the actual gain of the first Hall element 110 and the actual gain of the second Hall element 120 is within the range of ±0.1% of the target gain.

[0058] Experiments have shown that when the actual gain difference between the two Hall elements is within ±0.1% of the target gain, the effect on the common-mode interference magnetic field suppression effect is small.

[0059] In addition, when the difference between the actual gains of the two Hall elements is within ±0.1% of the target gain, the Hall elements do not need to be calibrated.

[0060] The above-mentioned current sensor 100 can select two Hall elements with the same target gain and the difference between the actual gains is within the range of ±0.1% of the target gain. On the first hand, it is beneficial to improve the common-mode interference magnetic field suppression effect of the current sensor 100; on the second hand, the Hall element does not need to be calibrated, which is beneficial to reducing the sensor calibration cost; on the third hand, it can also avoid the generation of calibration errors, which is beneficial to further improve the common-mode interference magnetic field suppression effect of the current sensor 100.

[0061] See also Figure 4 The current sensor 100 may further include an insulating layer 140 disposed between the first Hall element 110 and the second Hall element 120 .

[0062] It is understandable that the insulating layer 140 may be an insulating layer formed by applying insulating glue on the first Hall element 110, and the insulating layer may play the following roles: (1) Fix the Hall element in a specific position to fix and position it; (2) Prevent electrical short circuits between Hall elements and other conductive parts; (3) Protect Hall components from or reduce physical damage and erosion by environmental factors; (4) Providing overall mechanical stability for the current sensor 100, which is beneficial to improving the reliability and life of the sensor.

[0063] The above solution provides an insulating layer 140 between the first Hall element 110 and the second Hall element 120 to fix and protect the Hall elements, which is beneficial to improving the performance stability of the above current sensor 100.

[0064] It is understandable that, in addition to the above functions, the insulating layer 140 can also be used to adjust the third distance between the first Hall element 110 and the second Hall element 120. The specific scheme is as follows: As an optional implementation of the current sensor, the thickness of the insulating layer 140 is 1-200 μm. .

[0065] It is understandable that the third distance between the first Hall element 110 and the second Hall element 120 is 0 to 350°. , and the thickness of the insulating layer 140 used to adjust the third distance is 1-200 There is no conflict between the two because: in actual application scenarios, the Hall element itself has a certain thickness. The thickness range of the insulating layer 140 is set based on the thickness of the Hall element itself, the insulation performance of the insulating layer, the fixing strength of the insulating layer, the stress relief of the insulating layer, and the cost-effectiveness. The third distance adjusted by the insulating layer 140 can still be between 0 and 350 within the range.

[0066] The above solution controls the third distance between the two Hall elements by controlling the thickness of the insulating layer 140 , so that the current sensor 100 obtains a better common-mode interference magnetic field suppression effect and is beneficial to improving the performance stability of the current sensor 100 .

[0067] The positional relationship between the two Hall elements and the current-carrying conductor 130 is described below: As an optional implementation of the above current sensor, the above first distance is 1~500 ; and / or, the second distance is 1 to 500 .

[0068] It can be understood that when setting the distance between the Hall element and the overcurrent conductor 130, the balance between the sensor magnetic properties and the sensor saturation can be considered. Specifically: setting an appropriate distance between the Hall element and the overcurrent conductor 130 can make the Hall element have sufficient response to the magnetic field to be measured, while reducing the probability of sensor saturation caused by excessive magnetic field strength.

[0069] In addition to the balance between the magnetic characteristics of the sensor and the saturation of the sensor, the electrical isolation between the current conductor 130 and the Hall element, the capacitance effect, etc. may also be considered.

[0070] The above solution controls the distance between the Hall element and the current conductor 130 so that the current sensor 100 has better magnetic properties.

[0071] The other components of the current sensor 100 are introduced below: See also Figure 5 As an optional implementation of the above current sensor, the above current sensor 100 further includes: a lead frame 150 and an insulating substrate 160 arranged along the second plane, wherein: The insulating substrate 160 is fixed on the lead frame 150; An on-board circuit for powering the Hall element and realizing parallel connection or series connection of the first Hall element 110 and the second Hall element 120 is provided on the insulating substrate 160; the first Hall element 110 and the second Hall element 120 are respectively connected to the on-board circuit.

[0072] It is understandable that the insulating substrate 160 may be a ceramic substrate (such as an Al 2 O 3 substrate), a glass substrate, an epoxy resin substrate, a polyimide substrate, a silicon substrate or a DAF film.

[0073] In the process of implementing the above scheme, the power supply of the Hall element and the series or parallel connection between the two Hall elements are realized by the on-board circuit arranged on the insulating substrate 160. On the one hand, the integration degree of the above-mentioned current sensor 100 is higher. On the other hand, since the on-board circuit can be customized, it is conducive to improving the flexibility of the above-mentioned current sensor 100.

[0074] The internal structure of the Hall element is introduced below: As an optional implementation of the above-mentioned current sensor, the above-mentioned first Hall element 110 adopts a multi-layer Hall chip stacking structure; and / or the second Hall element 120 adopts a multi-layer chip stacking structure.

[0075] In the process of implementing the above scheme, the Hall element can stack multiple Hall sensor chips together to form a common sensor unit. On the one hand, it is beneficial to improve the performance of the above current sensor 100; on the other hand, it can also enable the above current sensor 100 to integrate more functions, which is beneficial to improve the applicability of the above current sensor.

[0076] As an optional implementation of the above-mentioned current sensor, the Hall sensing core of the Hall chip in the above-mentioned first Hall component 110 adopts a Wheatstone bridge structure; and / or, the Hall sensing core of the Hall chip in the second Hall component 120 adopts a Wheatstone bridge structure. This implementation is, for example: See also Figure 6 The Hall chip includes four wafer surface pads No. 1, No. 2, No. 3 and No. 4 for bonding and a Hall sensor core (i.e., the "cross" part shown in the figure). The Hall sensor core can be made of semiconductor materials, such as GaAs (gallium arsenide), InAs (indium arsenide), InSb (indium antimonide) or other ternary or quaternary semiconductor materials. The Hall sensor core can adopt a Wheatstone bridge structure. For the implementation of the Wheatstone bridge, please refer to the relevant technology, which will not be repeated in the embodiments of this application.

[0077] In the above solution, the Hall sensing core of the Hall chip in the Hall component can adopt a Wheatstone bridge structure, which is beneficial to improving the magnetic characteristics of the above current sensor 100 and the common-mode interference magnetic field suppression effect.

[0078] See also Figure 7 Based on the same inventive concept, an embodiment of the present application further provides a method for preparing the above-mentioned current sensor 100, the method comprising: Step S210: Arranging a current-carrying conductor 130 on a first plane; Step S220: Arranging the lead frame 150 on a second plane perpendicular to the first plane; Step S230: Fixing and connecting the insulating substrate 160 with the on-board circuit to the lead frame 150; Step S240: fixing and connecting the first Hall element 110 to the insulating substrate 160; Step S250: aligning the second Hall element 120 with the first Hall element 110 and fixing the second Hall element 120 on the first Hall element; Step S260: perform wire connection; Step S270: Obtain the current sensor 100 after plastic packaging.

[0079] It can be understood that sensitivity and resolution are two important performance parameters of current sensors, among which: Sensitivity: refers to the ratio between the change in the output signal of the current sensor and the change in the magnetic field strength of the measured magnetic field. It describes the degree of response of the sensor to changes in the measured value. Resolution: refers to the minimum change in current (or the minimum change in magnetic field) that the current sensor can detect, that is, the minimum difference in the smallest measured value that the current sensor can distinguish. It describes the minimum step or minimum change that the sensor output signal can achieve, which represents the fineness of the current sensor.

[0080] The control scheme of the above preparation method on sensor sensitivity and sensor resolution is introduced below: As an optional implementation of the method for preparing the current sensor, the method further includes: When the first Hall element 110 is fixedly connected to the insulating substrate 160 , the distance between the first Hall element 110 and the current conductor 130 is controlled to control the sensitivity of the current sensor 100 .

[0081] It can be understood that in the current sensor, the Hall voltage generated by the Hall element can be used as an indication of the magnitude of the current to be measured. Therefore, the range of the Hall voltage that can be obtained by the Hall element in the current sensor 100, that is, the sensitivity of the current sensor 100, can be controlled by controlling the distance between the Hall element and the current conductor 130.

[0082] As an optional implementation of the method for preparing the current sensor, the step S250 includes: aligning the second Hall component 120 with the first Hall component 110; and fixing the second Hall component 120 on the first Hall component 110 by using insulating glue.

[0083] The above-mentioned preparation method further includes: when the second Hall element 120 is fixed on the first Hall element 110 by using the insulating glue, controlling the thickness of the insulating glue to control the resolution of the current sensor.

[0084] It can be understood that the layered structure formed by the insulating glue between the first Hall element 110 and the second Hall element 120 is the insulating layer 140 .

[0085] In addition, it can be understood that, if the sensing voltage of the two Hall elements to the common-mode interference magnetic field is not considered, the greater the distance between the first Hall element 110 and the second Hall element 120, the greater the output voltage of the current sensor to the same magnetic field to be measured. The larger the value is, the weaker the current can be identified. Therefore, the resolution of the current sensor 100 can be controlled by controlling the thickness of the insulating layer 140 .

[0086] Of course, when setting the distance between the two Hall elements, the sensitivity and resolution must be considered. It is unreasonable to set a value that is too large or too small.

[0087] The connection relationship between the first Hall element 110 and the insulating substrate 160 is described below: It can be understood that, since the first Hall element 110 is fixed on the insulating substrate 160, and the first Hall element 110 is electrically connected to the on-board circuit arranged on the insulating substrate 160, there are the following two implementations of the connection between the first Hall element 110 and the insulating substrate 160: The first implementation mode: directly use conductive glue to electrically connect the first Hall element 110 to the on-board circuit on the insulating substrate 160 , so that the first Hall element 110 is fixed on the insulating substrate 160 .

[0088] The second implementation mode: the first Hall element 110 is fixed on the insulating substrate 160 by using insulating glue, and then the first Hall element 110 is connected to the on-board circuit arranged on the insulating substrate 160 by wire bonding.

[0089] The following describes the solution of fixing the first Hall element 110 on the insulating substrate 160 in step S240, the solution of fixing the second Hall element 120 on the first Hall element 110 in step 250, and the wire bonding solution in step S260 in a certain scenario: Step 1: Before preparing the current sensor 100, pre-design the size of each component; In some embodiments of the present application, the size of the first Hall element 110 and the second Hall element 120 can be designed to be 500*500. The layout thickness of the first Hall element 110 can be designed to be 50~100 The layout thickness of the second Hall element 120 can be designed to be 200~400 ; In addition, if the Hall element needs to adopt a multi-layer stacked chip design, more layouts can be designed, and the sizes of multiple layouts can be designed as the basic layout size (500*500 ) is 0.5~0.65 times the size of the Hall chip, and the Hall chip is prepared through processes such as photolithography, etching, and metal evaporation.

[0090] Step 2: Use a die bonding process to attach the first Hall element 110 to the insulating substrate 160. The thickness of the insulating substrate 160 can be 50 to 100 μm. , the thickness of glue can be controlled between 1 and 200 The distance between the first Hall element 110 and the current conductor 130 can be controlled within a range of 1 to 500 ; Before attaching the first Hall element 110 to the insulating substrate 160 , the Hall chip may be cut into individual core particles by dicing, and then the first Hall element 110 may be attached to the insulating substrate 160 by die bonding.

[0091] Step 3: Rotate the second Hall element 120 45° along the central axis of the Hall sensor core and attach it to the first Hall element 110 .

[0092] Step 4: After the different layers are fixed, the circuit connection in the current sensor 100 is established by bonding wires, including: (1) The first Hall element 110 and the second Hall element 120 are connected by wire bonding, and the output polarities of the two Hall elements are opposite; In addition, the first Hall element 110 and the second Hall element 120 may be powered and connected in series or in parallel via an on-board circuit disposed on the insulating substrate 160 .

[0093] (2) The circuit board arranged on the insulating substrate 160 is connected to the lead frame 150, or the first Hall element 110 is directly connected to the lead frame 150 by wire bonding. The wire bonding method is as follows: Figure 8 In addition, Figure 8 The Busbar shown in the figure is the current-carrying conductor.

[0094] In order to facilitate understanding of the above preparation method, the present application embodiment provides the following three preparation method implementations in different scenarios: The first scenario: See Fig. 9An on-board circuit is arranged on the insulating substrate 160 to realize the parallel connection of the first Hall element 110 and the second Hall element 120. There is no specific requirement for the size of the Hall element. In this scenario, Hall elements of the same size are used. The preparation method of the current sensor 100 in this scenario includes: Step 1: Fix the insulating substrate 160 with the on-board circuit on the lead frame 150 with glue. There are 12 pads on the insulating substrate 160 for wiring, of which 4 pads are used for connecting with the 4 pins of the first Hall element 110, 4 pads are used for connecting with the 4 pins of the second Hall element 120, and 4 pads are used for external output wiring. The on-board circuit is used to realize the parallel connection of 1, 2, 3, 4 of the first Hall element 110 and 1, 4, 3, 2 of the second Hall element 120; Step 2: fix the first Hall element 110 on the upper surface of the insulating substrate 160; Step 3: Bond the four pads of the first Hall element 110 to the circuit board on the surface of the insulating substrate 160 respectively; Step 4: After the wire bonding is completed, a layer of glue is fixed on the upper surface of the first Hall element 110 to form an insulating layer 140; The insulating layer 140 can play a certain protective role on the bonding wires, and can increase the vertical distance between the surface sensing portion of the first Hall element 110 and the second Hall element 120 to increase the differential mode signal; Step 5: After the glue is cured, fix the second Hall element 120 on the upper surface of the insulating layer 140; Step 6: Bond the four pads of the second Hall element 120 to the on-board circuit on the surface of the insulating substrate 160 respectively; Step 7: After the two Hall elements are connected in parallel, wires are bonded to the lead frame 150 through the on-board circuit on the insulating substrate 160; Step eight, after wire bonding, plastic sealing is performed to obtain the current sensor 100.

[0095] Second scenario: See Fig.10 , an on-board circuit is arranged on the insulating substrate 160 to realize the parallel connection between the first Hall element 110 and the second Hall element 120, and the first Hall element 110 is directly fixed on the upper surface of the insulating substrate 160 by a conductive adhesive. The preparation method of the current sensor 100 in this scenario includes: Step 1: Fix the insulating substrate 160 with the on-board circuit on the lead frame 150 with glue. There are 12 pads on the insulating substrate 160 for wiring, of which 4 pads are used for connecting with the 4 pins of the first Hall element 110, 4 pads are used for connecting with the 4 pins of the second Hall element 120, and 4 pads are used for external output wiring. The on-board circuit is used to realize the parallel connection of 1, 2, 3, 4 of the first Hall element 110 and 1, 4, 3, 2 of the second Hall element 120; Step 2: Use conductive glue to directly fix the second Hall element 120 on the upper surface of the insulating substrate 160 by flipping it upside down, so that the second Hall element 120 is directly connected to the on-board circuit arranged on the insulating substrate 160; Step 3: fix the second Hall element 120 on the bottom surface of the first Hall element 110; Step 4: Bond the four pads of the second Hall element 120 to the on-board circuit on the surface of the insulating substrate 160 respectively; Step 5: After the two Hall elements are connected in parallel, the on-board circuit on the insulating substrate 160 is wired to the lead frame 150; Step 6: After wire bonding, plastic sealing is performed to obtain the current sensor 100.

[0096] The third scenario: the on-board circuit of the insulating substrate 160 is used to separately power two Hall elements. In this case, the first Hall element 110 and the second Hall element 120 can be connected in series to suppress the common-mode interference magnetic field. The preparation method of the current sensor 100 in this scenario includes: Step 1: Fix the insulating substrate 160 with the on-board circuit on the lead frame 150 with glue. There are 12 pads on the insulating substrate 160 for wiring, of which 4 pads are used to connect with the 4 pins of the first Hall element 110, 4 pads are used to connect with the 4 pins of the second Hall element 120, and 4 pads are used for external output wiring. The on-board circuit is used to realize the separation of the first Hall element 110 and the second Hall element 120, and connect the No. 4 pin of the first Hall element 110 with the No. 2 pin of the second Hall element 120; Step 2: Use conductive glue to directly fix the second Hall element 120 on the upper surface of the insulating substrate 160 by flipping it upside down, so that the second Hall element 120 is directly connected to the on-board circuit arranged on the insulating substrate 160; Step 3: fix the second Hall element 120 on the bottom surface of the first Hall element 110; Step 4: Bond the four pads of the second Hall element 120 to the on-board circuit on the surface of the insulating substrate 160 respectively; Step 5: After the two Hall elements are connected in parallel, the on-board circuit on the insulating substrate 160 is wired to the lead frame 150; Step 6: After wire bonding, plastic sealing is performed to obtain the current sensor 100.

[0097] It can be understood that the wiring diagram of the current sensor preparation method in this scenario is similar to the wiring diagram of the current sensor preparation method in the second scenario, so the wiring diagram in the third scenario can be referred to. Fig.10 .

[0098] See also Fig.11 Based on the same inventive concept, the embodiment of the present application further provides a magnetoresistive current sensor 300 which is different from the above-mentioned Hall current sensor 100. The sensor comprises: a current-carrying conductor 130 and a first magnetoresistive element 310 and a second magnetoresistive element 320 having the same magnetic field sensing direction and opposite output polarities, wherein: The first magnetoresistive element 310 and the second magnetoresistive element 320 are connected in parallel or in series; The first magnetoresistive element 310 and the second magnetoresistive element 320 are aligned and arranged along a second plane perpendicular to the first plane; wherein the first plane is a plane where the current-carrying conductor is located; The third penetration angle of the first magnetoresistance element 310 is not equal to the fourth penetration angle of the second magnetoresistance element 320, and / or the third distance between the first magnetoresistance element 310 and the current conductor 130 is not equal to the third distance between the second magnetoresistance element 320 and the current conductor 130; wherein the third penetration angle and the fourth penetration angle are respectively the magnetic field penetration angles of the magnetic field to be measured generated when the current to be measured flows through the current conductor 130 at the first magnetoresistance element 310 and the magnetic field penetration angles at the second magnetoresistance element 320.

[0099] It is understandable that, compared with the Hall current sensor 100, the above magnetoresistive current sensor 300 is different in that: (1) The magnetoresistive current sensor 300 uses a magnetoresistive element to detect the magnitude of the magnetic field to be measured where the element is located; (2) Compared with Hall elements, the magnetic field sensing direction of magnetoresistive elements is more flexible and can be set according to the direction of the magnetic field to be measured.

[0100] See also Fig.12 , the magnetoresistive current sensor 300 can be directly arranged on the surface of the current conductor 130. At this time, the magnetic field sensing direction of the magnetoresistive element in the magnetoresistive current sensor 300 can be the magnetic field direction when the magnetic field to be measured passes through the magnetoresistive element, that is, Fig.12 The left-to-right direction or the right-to-left direction.

[0101] It is understandable that other structures, wire bonding methods and working principles of the magnetoresistive current sensor 300 are similar to those of the Hall current sensor 100. For example, the magnetoresistive current sensor may also set an insulating layer between the first magnetoresistive element 310 and the second magnetoresistive element 320 to control the distance between the first magnetoresistive element 310 and the second magnetoresistive element 320. The first magnetoresistive element 310 may also be directly electrically connected to the on-board circuit on the insulating substrate 160 using conductive glue. Therefore, for the specific implementation of the magnetoresistive current sensor 300, please refer to the implementation of the Hall current sensor 100 above, and the present application embodiment will not be repeated.

[0102] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0103] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0104] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0105] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0106] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A current sensor, characterized in that: The current sensor comprises: a current conductor and a first Hall element and a second Hall element with the same magnetic field sensing direction and opposite output polarities, wherein: The first Hall element and the second Hall element are aligned and arranged along a second plane perpendicular to the first plane; wherein the first plane is the plane where the current-carrying conductor is located; an insulating layer is arranged between the first Hall element and the second Hall element; The first penetration angle of the first Hall element is not equal to the second penetration angle of the second Hall element, and / or the first distance between the first Hall element and the overcurrent conductor is not equal to the second distance between the second Hall element and the overcurrent conductor; wherein the first penetration angle and the second penetration angle are respectively the magnetic field penetration angles at the first Hall element and the second Hall element of the magnetic field to be measured generated when the measured current flows through the overcurrent conductor.

2. The current sensor according to claim 1, characterized in that: The first distance is 1~500 ; And / or, the second distance is 1 to 500 .

3. The current sensor according to claim 1, characterized in that: The current sensor further comprises: a lead frame and an insulating substrate arranged along the second plane, wherein: The insulating substrate is fixed on the lead frame; The insulating substrate is provided with an on-board circuit for powering the Hall element and realizing parallel connection or series connection of the first Hall element and the second Hall element; the first Hall element and the second Hall element are respectively connected to the on-board circuit.

4. The current sensor according to any one of claims 1 to 3, characterized in that: The first Hall element adopts a multi-layer Hall chip stacking structure; And / or, the second Hall element adopts a multi-layer chip stacking structure.

5. The current sensor according to any one of claims 1 to 3, characterized in that: The Hall sensing core of the Hall chip in the first Hall component adopts a Wheatstone bridge structure; And / or, the Hall sensing core of the Hall chip in the second Hall component adopts a Wheatstone bridge structure.

6. A method for preparing a current sensor according to any one of claims 1 to 5, characterized in that: The method comprises: Arranging a current-carrying conductor on the first plane; Disposing a lead frame on a second plane perpendicular to the first plane; The insulating substrate with the on-board circuit is fixedly connected to the lead frame; Fixedly connecting the first Hall element to the insulating substrate; Aligning a second Hall element with the first Hall element and fixing the second Hall element on the first Hall element; Make wire connections; Get the current sensor after plastic sealing.

7. The method for preparing the current sensor according to claim 6, characterized in that: The method further comprises: When the first Hall element is fixedly connected to the insulating substrate, the distance between the first Hall element and the current conductor is controlled to control the sensitivity of the current sensor.

8. The method for preparing the current sensor according to claim 6, characterized in that: The method of aligning the second Hall element with the first Hall element and fixing the second Hall element on the first Hall element comprises: Aligning a second Hall element with the first Hall element; Fixing the second Hall element on the first Hall element by using insulating glue; The method further comprises: When the second Hall element is fixed on the first Hall element by using insulating glue, the thickness of the insulating glue is controlled to control the resolution of the current sensor.

9. The method for preparing the current sensor according to claim 6, characterized in that: The method of fixedly connecting the first Hall element to the insulating substrate comprises: Using conductive glue to electrically connect the first Hall element to the on-board circuit of the insulating substrate so that the first Hall element is fixed on the insulating substrate; Alternatively, the first Hall element is fixed on the insulating substrate by using insulating glue; the wire bonding includes: connecting the first Hall element to the on-board circuit of the insulating substrate by wire bonding.

10. A current sensor, characterized in that: The current sensor comprises: a current conductor and a first magnetoresistive element and a second magnetoresistive element having the same magnetic field sensing direction and opposite output polarities, wherein: The first magnetoresistive element is connected in parallel or in series with the second magnetoresistive element; The first magnetoresistive element and the second magnetoresistive element are aligned and arranged along a second plane perpendicular to the first plane; wherein the first plane is the plane where the current-carrying conductor is located; The third penetration angle of the first magnetoresistance element is not equal to the fourth penetration angle of the second magnetoresistance element, and / or the third distance between the first magnetoresistance element and the current conductor is not equal to the third distance between the second magnetoresistance element and the current conductor; wherein the third penetration angle and the fourth penetration angle are respectively the magnetic field penetration angles at the first magnetoresistance element and the second magnetoresistance element of the magnetic field to be measured generated when the current to be measured flows through the current conductor.

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