A closed loop current sensor

Abstract

The application discloses a kind of closed loop current sensors.The closed loop current sensor by setting magnetic sensing chip is located on the packaging base island, and with the first distance between packaging base island, setting metal component is located on the magnetic sensing chip, and with the second distance between magnetic sensing chip;So in the process of magnetic balance type operation, when the distance ratio of primary side and secondary side of known closed loop current sensor, by measuring the size of secondary side compensation current, the value of primary side current can be calculated, so as to realize the isolation measurement of primary side current.The application can realize without borrowing external magnetic core coil to form closed loop passage, thereby reducing overall volume and reducing cost;By adopting semiconductor packaging technology, the full integrated single-chip of closed loop current sensor is realized, with smaller volume, reduced space and reduced cost, also realizing high consistency and reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of current sensor, in particular to a closed-loop current sensor with full integration, single-chip, no magnetic core and no coil. BACKGROUND

[0002] The sensor can be used as a detection device to detect the relevant information of the detected equipment and convert it into an electrical signal or other required form of information output according to a certain rule, to meet the requirements of information transmission, processing, storage, display, recording and control. Since the discovery of magnetic sensing effect, magnetic sensing technology has been increasingly applied in various fields of industrial control. With the development of component technology, the closed-loop magnetic sensing current sensor developed from magnetic sensor components has been greatly improved, which has greatly supported and developed this technology in this application field.

[0003] The closed-loop magnetic sensing current sensor in the prior art needs to use a magnetic core to strengthen the aggregation of the magnetic field generated by the current line, which can generally be increased by about 5 times. Meanwhile, the traditional scheme needs to use a compensation coil, which is generally much larger than the number of turns of the original lead. The zero-magnetic flux closed-loop path is formed by the original measured current lead and the compensation coil, which occupies a large volume space and has limitations in installation mode, is not convenient for users to use flexibly, and has serious problems in consistency and reliability. SUMMARY

[0004] The present application aims to provide a closed-loop current sensor solution to solve the technical problems of the existing closed-loop magnetic sensor occupying a large volume space and having limitations in installation mode, and to realize full integration, single-chip, no magnetic core and no coil of the closed-loop current sensor.

[0005] In order to achieve the above-mentioned purpose, the present application provides a closed-loop current sensor, comprising: a packaging base island; a magnetic sensing chip located above the packaging base island and having a first distance from the packaging base island; and a metal member located above the magnetic sensing chip and having a second distance from the magnetic sensing chip; wherein the original side current flows through the packaging base island and generates an original side magnetic field on the packaging base island, the compensation current flows through the metal member and generates a compensation magnetic field on the metal member, the magnetic sensing chip senses the compensation magnetic field to balance the original side magnetic field, and realizes the isolated measurement of the original side current.

[0006] In some embodiments, the metal member is a gold wire connecting the chip packaging pin and the magnetic sensing chip, or the metal member is a metal wire layer on the surface of the chip.

[0007] In some embodiments, the magnetic sensing chip is selected from one of a Hall element, a III-V compound semiconductor material type element, and a magnetoresistance element.

[0008] In some embodiments, the material of the packaging base island is copper.

[0009] In some embodiments, the shape of the packaging base island is U-shaped or strip-shaped.

[0010] In some embodiments, the packaging base island, the magnetic sensing chip and the metal member are packaged in the same chip packaging structure.

[0011] In some embodiments, the first distance is greater than the second distance.

[0012] In some embodiments, the strength of the primary magnetic field is adjusted by adjusting the first distance.

[0013] In some embodiments, when the primary magnetic field and the secondary magnetic field reach equilibrium, the product of the primary current and the first distance is equal to the product of the compensation current and the second distance.

[0014] The present application sets the magnetic sensing chip above the packaging base island with a first distance, and sets the metal member above the magnetic sensing chip with a second distance; thereby in the magnetic balance type working process, the packaging base island serves as the primary current wire, the metal member serves as the secondary compensation current wire, and the ratio of the first distance and the second distance replaces the primary-secondary coil turn ratio of the existing closed-loop current sensor in the form of magnetic core coil. When the distance ratio of the primary and secondary sides of the closed-loop current sensor is known, the value of the primary current can be calculated by measuring the size of the secondary compensation current, thereby realizing the isolated measurement of the primary current. The present application can realize the closed-loop path without borrowing external magnetic core coil, thereby reducing the overall volume and cost. Further, by using semiconductor packaging technology, the closed-loop current sensor is fully integrated into a single chip, and the high-integrated semiconductor packaging has smaller volume than the existing technology, thereby further reducing space and cost. At the same time, based on the semiconductor packaging technology, the insulating layer has no physical contact and realizes high isolation voltage, and the semiconductor process production also realizes high consistency and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The structure schematic diagram of the closed-loop current sensor provided by an embodiment of the present application is shown in the figure;

[0016] Figure 2 The side view schematic diagram of the closed-loop current sensor provided by an embodiment of the present application is shown in the figure;

[0017] Figure 3 The top view schematic diagram of the closed-loop current sensor provided by an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0019] The closed-loop magnetic sensor sensor adopts a magnetic balance principle, and the specific working process is as follows: when the primary side coil has a primary side current IN passing through, the magnetic field generated on the wire is gathered and sensed on the magnetic sensor device, and the generated signal output is used to drive the corresponding power tube and make it conductive, so as to obtain a compensation current IM. This compensation current IM generates a magnetic field through the secondary side coil, which is just opposite to the magnetic field generated by the measured current, so as to compensate the original magnetic field and make the output of the magnetic sensor device gradually decrease. That is, the primary side magnetic field generated by the primary side current IN is compensated by the secondary side magnetic field generated by the compensation current IM of the secondary side coil, so that the magnetic sensor device is always in a working state of detecting zero magnetic flux. When the magnetic field generated by the primary and secondary side currents reaches balance in the magnetic core, the compensation current IM no longer increases, at which time the magnetic sensor device plays a role of zero magnetic flux, and at this time, the compensation current IM can be used for balance. Any change of the measured current will destroy this balance, and once the magnetic field loses balance, the magnetic sensor device will have a signal output. After power amplification, the corresponding current immediately flows through the secondary side coil to compensate for the unbalanced magnetic field. However, the existing closed-loop magnetic sensor sensor which forms a closed-loop path by borrowing an external magnetic core coil occupies a large volume space, has limitations in installation mode, is not convenient for users to use flexibly, and has serious problems of consistency and reliability. Accordingly, the present application provides a closed-loop current sensor which can realize full integration of single chip and has no magnetic core and coil. The following gives an explanation.

[0020] Please refer to Figures 1-3 , wherein Figure 1 is a structural schematic diagram of a closed-loop current sensor provided by an embodiment of the present application, Figure 2 is a side view schematic diagram of a closed-loop current sensor provided by an embodiment of the present application, Figure 3 is a top view schematic diagram of a closed-loop current sensor provided by an embodiment of the present application.

[0021] As Figure 1 shown, the closed-loop current sensor 10 described in the embodiment includes at least one packaging base island 11, a magnetic sensor chip 12 and a metal member 13. Specifically, the magnetic sensor chip 12 is located on the packaging base island 11 and has a first distance D1 (shown in Figure 2(in the middle); the metal component 13 is located on the magnetic sensing chip 12 and has a second distance D2 between it and the magnetic sensing chip 12 (shown in the middle); Figure 2 middle).

[0022] like Figures 2-3 As shown, the primary current IN flows through the packaged base island 11 and generates a primary magnetic field on the packaged base island 11. The compensation current IM flows through the metal component 13 and generates a compensation magnetic field on the metal component 13. The magnetic sensing chip 12 senses the compensation magnetic field to balance the primary magnetic field, thereby achieving isolated measurement of the primary current. Compared with the existing highly complex closed-loop magnetic sensing sensors that use external magnetic core coils to form a closed-loop path, this invention saves a lot of components and reduces the overall bill of materials (BOM) cost.

[0023] In some embodiments, the magnetic sensing chip 12 is selected from one of the following: Hall element, group III-V compound semiconductor material element, and magnetoresistive element.

[0024] In some embodiments, the material of the packaging base island 11 is copper. Generally, the impedance of the packaging base island is below 5mΩ. The shape of the packaging base island 11 is U-shaped or strip-shaped. It should be noted that the present invention does not limit the number of packaging base islands; it can be a single base island or two or more base islands. Multiple chips can be disposed on the packaging base island 11, such as... Figure 3 As shown, two magnetic sensing chips 12 are disposed on the packaging base island 11.

[0025] In some embodiments, the packaging base island 11, the magnetic sensing chip 12, and the metal component 13 are packaged within the same chip packaging structure. Semiconductor packaging technology achieves fully integrated single-chip packaging. Compared to existing technologies, highly integrated semiconductor packaging has a smaller volume, further reducing space and cost. Simultaneously, based on semiconductor packaging technology, the insulating layers have no physical contact, achieving high isolation withstand voltage, and semiconductor manufacturing processes also achieve high consistency and reliability.

[0026] In some embodiments, the first distance D1 is greater than the second distance D2. Thus, the ratio of the first distance D1 to the second distance D2 replaces the turns ratio of the primary and secondary coils in existing closed-loop current sensors using magnetic core coils. Furthermore, the first distance D1 is related to the voltage isolation distance of the measured conductor; generally, a semiconductor encapsulation material of >50µm is required to obtain an isolation voltage >3kV.

[0027] In some embodiments, the strength of the primary magnetic field is adjusted by adjusting the first distance D1, thereby improving sampling accuracy while taking into account the requirements of isolation voltage.

[0028] In some embodiments, when the primary and secondary magnetic fields are in equilibrium, the product of the primary current and the first distance can be considered equivalent to the product of the compensation current and the second distance. That is, by adjusting the relationship of the closed-loop current through distance, a magnetic field effect of D1 / IN = D2 / IM can be achieved.

[0029] In some embodiments, such as Figure 1 As shown, the closed-loop current sensor is an integrated chip package structure. The package base island 11 is a current-carrying frame at the bottom of the integrated chip package structure. The metal component 13 is a gold wire connecting the chip package pins to the magnetic sensing chip 12, or the metal component 13 is a metal wire layer located on the chip surface. The material of the metal wire layer can be copper, aluminum, gold, or their alloys. During magnetic balance operation, the package base island 11 serves as the primary current conductor, and the metal component 13 serves as the secondary compensation current conductor. The ratio of the first distance D1 to the second distance D2 replaces the turns ratio of the primary and secondary coils in existing closed-loop current sensors using magnetic core coils. By adjusting the distance, the relationship of the closed-loop current is adjusted, thereby achieving a magnetic field effect of D1 / IN = D2 / IM. This eliminates the need for external magnetic cores and coils to form a closed-loop path, thus reducing the overall size and cost, while also achieving high consistency and reliability.

[0030] The working principle of a closed-loop magnetic current sensor is magnetic balance-based. The magnetic field generated by the primary current IN is compensated by the magnetic field generated by a compensating current IM, ensuring the sensor always operates in a zero-flux detection state. For a closed-loop current sensor using a magnetic core coil, when the magnetic fields generated by the primary and secondary currents reach equilibrium within the core, the following formula applies:

[0031] N1 * IN = N2 * IM (Formula 1)

[0032] In the formula, IN is the primary current, N1 is the number of turns of the primary coil; IM is the secondary compensation current, and N2 is the number of turns of the secondary compensation coil.

[0033] This invention utilizes the packaged base island as the primary current conductor to replace the traditional primary magnetic core coil; and the packaged gold wire or the metal conductor layer on the chip surface as the secondary compensation current conductor to replace the traditional secondary compensation coil; therefore, the above formula 1 can be replaced with:

[0034] D1 / IN = D2 / IM (Formula 2)

[0035] This achieves an equivalent substitution of D2 / D1 = N1 / N2. When the magnetic field generated by the primary and secondary currents reaches equilibrium in the magnetic core, the compensation current IM no longer increases. At this point, the magnetic sensor acts as a zero-flux device, and the equilibrium can be maintained by the compensation current IM. Any change in the measured current will disrupt this equilibrium. Once the magnetic field is unbalanced, the magnetic sensor will output a signal. After power amplification, a corresponding current immediately flows through the secondary coil to compensate for the unbalanced magnetic field. When the distance ratio between the primary and secondary sides of the closed-loop current sensor is known, the value of the primary current IN can be calculated by measuring the magnitude of the secondary compensation current IM, thus achieving isolated measurement of the primary current.

[0036] As can be seen from the above, the closed-loop current sensor provided in this embodiment, by setting the magnetic sensing chip on top of the packaging base island and maintaining a first distance between them, and setting the metal component on top of the magnetic sensing chip and maintaining a second distance between them, allows the packaging base island to act as the primary current conductor and the metal component to act as the secondary compensation current conductor during magnetic balance operation. The ratio of the first distance to the second distance replaces the turns ratio of the primary and secondary coils in existing closed-loop current sensors using magnetic core coils. When the distance ratio between the primary and secondary sides of the closed-loop current sensor is known, the value of the primary current can be calculated by measuring the magnitude of the secondary compensation current, thus achieving isolated measurement of the primary current. This embodiment can achieve closed-loop path formation without the need for an external magnetic core coil, thereby reducing the overall size and cost. Furthermore, by adopting semiconductor packaging technology, a fully integrated single-chip closed-loop current sensor has been achieved. The highly integrated semiconductor packaging has a smaller volume compared to existing technologies, thereby further reducing space and cost. At the same time, based on semiconductor packaging technology, the insulating layer has no physical contact, achieving high isolation withstand voltage, and the semiconductor process manufacturing also achieves high consistency and reliability.

[0037] Furthermore, to address practical application issues, as seen in the invention above, current sensors are not immune to external magnetic field interference and are therefore susceptible to such interference. In practical implementation, two magnetic sensors are used simultaneously: one for positive primary-side magnetic field induction and the other for negative primary-side magnetic field induction, with differential calculation between the two. This allows the removal of external interfering magnetic fields (co-directional interfering magnetic fields).

[0038] It should be noted that the above embodiments are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The terms "comprising" and "having," and their variations, used in this invention document are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context. It should be understood that such data can be used interchangeably where appropriate. Furthermore, embodiments and features within embodiments of this invention can be combined with each other unless otherwise specified. In addition, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this invention.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A closed-loop current sensor, characterized in that, include: At least one encapsulation base island; A magnetic sensing chip is located on the packaging base island and has a first distance between it and the packaging base island; A metal component is located on the magnetic sensing chip and has a second distance from it. The metal component is a gold wire connecting the chip package pins to the magnetic sensing chip, or the metal component is a metal wire layer located on the surface of the magnetic sensing chip. The primary current flows through the package base island and generates a primary magnetic field on the package base island. The compensation current flows through the metal component and generates a compensation magnetic field on the metal component. The magnetic sensing chip senses and obtains the compensation magnetic field to balance the primary magnetic field, thereby realizing isolated measurement of the primary current.

2. The closed-loop current sensor according to claim 1, characterized in that, The magnetic sensing chip is selected from one of the following: Hall element, group III-V compound semiconductor material element, and magnetoresistive element.

3. The closed-loop current sensor according to claim 1, characterized in that, The material of the encapsulation base island is copper.

4. The closed-loop current sensor according to claim 1, characterized in that, The shape of the encapsulation base island is U-shaped or strip-shaped.

5. The closed-loop current sensor according to claim 1, characterized in that, The packaging base island, the magnetic sensing chip, and the metal component are packaged within the same chip packaging structure.

6. The closed-loop current sensor according to claim 1, characterized in that, The first distance is greater than the second distance.

7. The closed-loop current sensor according to claim 1, characterized in that, The strength of the primary magnetic field is adjusted by adjusting the first distance.

8. The closed-loop current sensor according to claim 1, characterized in that, When the primary magnetic field and the secondary magnetic field reach equilibrium, the product of the primary current and the first distance is equal to the product of the compensation current and the second distance.

Images