Reinforced insulation for current sensors with magnetic field converters

Abstract

Current sensor, which includes the following: a conductor frame (16) with a first part (16a) which has power lines connected in such a way as to form a current conductor for carrying a primary current, and a second part (16b) which contains signal lines (20); a shaped body (21) which is coupled to the second conductor frame part by a connection (32) and which contains a magnetic field sensor circuit (60) to detect a magnetic field associated with the primary current and generates an output on a signal line based on the detected magnetic field; an insulating structure (64, 64') which is arranged between the conductor and the shaped body and includes a first insulating layer (66a, 66a') and a second insulating layer (66b, 66b'); Plastic material (24) which surrounds the molded body, the connection and at least a part of the conductor frame to form a cast packing body; and wherein the conductor has a curved edge region, wherein the insulation construction covers at least part of the conductor and extends beyond the curved edge region of the conductor, and wherein the insulation construction has a substantially semicircular shape with a curved area extending laterally beyond the curved edge region of the conductor in a direction towards at least one of the signal lines with a projection dimension of at least 0.4 mm including all tolerances.

Description

AREA OF INVENTION

[0001] The present invention relates generally to current sensors as integrated circuits which contain magnetic field sensor elements and current conductors, and in particular to safety insulation solutions for such current sensors. BACKGROUND

[0002] Safety insulation is a crucial aspect in the design of all electrical products that could potentially expose their users to dangerous voltage levels. Manufacturers of such products must ensure that their products are designed to provide adequate protection against electric shock.

[0003] All safety insulation principles require a certain degree of insulation to create a protective barrier between primary and secondary circuits. A primary circuit is one that is directly connected to mains voltage and therefore has the potential to reach dangerous voltage levels. A secondary circuit is not electrically connected to the primary circuit (i.e., there is no conductive connection between the secondary and primary circuits), but dangerous voltage levels can still occur if the insulation fails.

[0004] Underwriters Laboratories Inc. (UL) has developed a safety standard known as UL 60950-1 (Second Edition), which specifies a high level of safety insulation to provide protection against the risk of injury from electric shock. The UL 60950-1 standard is based on the International Electrotechnical Commission (IEC) standard IEC 60950-1 (Second Edition). The UL 60950-1 standard defines five insulation categories: functional insulation; basic insulation; supplementary insulation; double insulation; and reinforced insulation. Functional insulation does not protect against electric shock. Basic insulation is a single level of insulation that provides fundamental protection against electric shock.Supplemental insulation is independent insulation that can be applied in addition to basic insulation to reduce the risk of electric shock if the basic insulation fails. Double insulation incorporates both basic and supplemental insulation. Basic insulation provides a single layer of insulating barrier between the primary and secondary circuits, while double insulation provides two layers of insulating barrier between them. Reinforced insulation is a single insulation system that provides protection against electric shock equivalent to double insulation.

[0005] If a secondary circuit is not accessible to the user, a basic level of insulation protection, i.e., basic insulation, may be acceptable. However, the safety requirements for products containing user-accessible secondary circuits necessitate two levels of protection, provided by double insulation or its equivalent reinforced insulation.

[0006] Although the UL 60950-1 standard is intended for use in information technology equipment, it has been adopted for many other products and is considered the primary standard for product designs requiring galvanic isolation. One product requiring galvanic isolation is the current sensor. Some current sensors use a magnetic field transducer (for example, a Hall-effect transducer or a magnetoresistive transducer) in close proximity to a current-carrying conductor. The magnetic field transducer generates an output signal with a magnitude proportional to the magnetic field induced by the current flowing through the conductor.

[0007] The magnetic field transducer is sometimes provided as an integrated circuit (IC) within an integrated circuit package that also includes a current conductor. Examples of such current conductors are marketed under part numbers ACS712 and ACS758xCB by Allegro MicroSystems, Inc., Worcester, MA 01615, the assignee of this application.

[0008] Several parameters characterize the operation of such current sensors, including their sensitivity. Sensitivity is related to the magnitude of the change in the output voltage of the magnetic field transformer as a function of the current being detected. The sensitivity of a current sensor is related to a multitude of factors. One important factor is the physical distance between the magnetic field transformer and the current-carrying conductor. Integrating the current-carrying conductor into an integrated circuit package allows for a close and precise positioning of the conductor relative to the magnetic field sensor.

[0009] To meet the stricter requirements for double or enhanced insulation, current applications using current sensors as integrated circuits rely on the basic insulation provided by the packing arrangement of the current sensors, for example in the form of plastic castings or other insulations, in conjunction with an external, supplementary level of insulation provided by the use of a separate opto-isolator or similar device.

[0010] US Patent 2005 / 0 224 248 A1 discloses an integrated current sensor comprising a terminal frame with at least two terminals connected to form a current conductor section and a substrate with a first surface on which one or more magnetic field transducers are arranged, the first surface being located near the current conductor section and a second surface being located away from the current conductor section. In a particular embodiment, the substrate is arranged such that the first surface of the substrate is located above the current conductor section and the second surface of the substrate is located above the first surface. In this particular embodiment, the substrate is oriented in reverse within the integrated circuit compared to a conventional orientation. A current conductor section can be placed near a substrate surface and near one or more magnetic field transducers.This arrangement provides a current sensor in which one or more magnetic field transducers are located very close to the current-carrying conductor section, resulting in a current sensor with improved sensitivity. An insulating layer can be placed between the current-carrying conductor section and the substrate.

[0011] Further prior art is disclosed in “Electrical, Electronic and EM1, Shielding Tapes Selection Guide,” 3M Electrical Markets Product Brochure, 3M Electrical Market Division, 6801 River Place Blvd., Austin, TX78726-900, 2007.

[0012] It is an object of the present invention to create a current sensor that avoids or mitigates the aforementioned disadvantages in safety insulation.

[0013] This problem is solved by the features of independent claims 1 and 2. Advantageous embodiments of the invention are described in the dependent claims. SUMMARY OF THE INVENTION

[0014] In general, the invention relates to a current sensor according to one aspect. The current sensor comprises a conductor frame with a first part containing current conductors connected to form a conductor for carrying the primary current, and a second part containing signal lines. The current sensor further comprises a molded part coupled to the second conductor frame part via a connection. The molded part forms a magnetic field sensor circuit for detecting a magnetic field coupled to the primary current and generates an output on one of the signal lines based on the detected magnetic field. The current sensor also includes an insulating structure and plastic material. The insulating structure is arranged between the current conductor and the molded part and comprises a first insulating layer and a second insulating layer.The plastic material surrounds the molded body, the connection, and at least part of the conductor frame to form a molded body packing. The insulation structure is dimensioned such that the plastic material provides enhanced insulation.

[0015] Embodiments of the invention may include one or more of the following features. Each of the first and second insulating layers may contain a polyimide film. Each of the first and second insulating layers may further contain an adhesive layer. The polyimide film and the adhesive layer may be provided in a tape material. The tape material may have a thickness of approximately 40 µm. The polyimide film may have a thickness of approximately 25 µm. The polyimide film may have insulating properties and a thickness that enables it to withstand an insulating voltage of at least 7000 volts. The first insulating layer and the second insulating layer may have substantially the same thickness. The magnetic field sensor circuit may include a magnetic field transducer comprising a sensor element that is either a Hall effect element or a magnetoresistive sensor element.The coupling of the molded body to the second conductor frame part via the connection may include a flip-chip arrangement. The connection may include soldered copper pins formed on a surface of the molded body. Alternatively, the coupling of the molded body to the second conductor frame part via the connection may include a molded body arrangement where the connection incorporates wire terminations. The thickness of the first and second insulation layers may be sufficient to meet the requirements for a minimum operating voltage rating of 500 VRMS according to UL 60950-1. The insulation design may cover at least a portion of the current conductor and extend laterally beyond an edge region of this part by a distance required by the plastic molding material to form a single insulating layer, thus achieving the required enhanced insulation rating according to UL 60950-1.The plastic material may contain a cast plastic compound classified as a Group II material according to UL 60950-1. The packing body may be dimensioned to meet the creep tolerance and clearance requirements of UL 60950-1. The first insulating layer may be in contact with a top surface of the conductor and the second insulating layer. The conductor may have a curved edge, and the insulating assembly may be substantially semicircular, with a curved section extending laterally over the curved edge of the conductor by a minimum of 0.4 mm, including all tolerances. The first and second insulating layers each contain a strip comprising a polyimide film layer and an adhesive layer. The polyimide film layer may have a minimum thickness of 25 µm. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The features of the invention described above, as well as the invention itself, will be further clarified by the following detailed description of the drawings. These depict: Fig. 1A a perspective view of a state-of-the-art current sensor with an integrated current path connected to an external current conductor in a current sensor configuration; Fig. 1B a partial cross-sectional view of the current sensor according to Fig. 1A; Fig. 2. A circuit diagram of a current sensor application according to the state of the art, which includes a current sensor of the type described below. Fig. 1A and Fig. 1B uses and employs the current sensor packing in conjunction with opto-isolators to achieve double insulation for this arrangement; Fig. 3A to 3C, for example, a current sensor design with an integrated current path, which includes an insulation design for enhanced insulation; Fig. 4A to 4C an alternative, for example, design of a current sensor with an integrated current path which includes an insulation design for enhanced insulation; Fig. 5 a cross-section of an insulation construction according to the Fig. 3A to 3C and 4A to 4C according to an exemplary embodiment; Fig. 6A to 6B a supervision of the current sensor pack (for the current sensor according to the Fig. 3A to 3C and 4A to 4C) with dimensions relating to creep behavior and clearances; Fig. 7A and Fig. 7B Top views of an example of a fixed printed circuit board (PCB) assembly ( Fig. 7A) and a slotted PCB design ( Fig. 7B) to achieve different creep properties in the current sensor packing according to the Fig. 6A and Fig. 6B; and Fig. 8 A simplified example function block diagram for a current sensor according to the Fig. 3A to 3C and 4A to 4C. DETAILED DESCRIPTION

[0017] A current sensor with an internal insulator or insulation design that meets the requirements of Underwriters Laboratories Inc. (UL) Standard UL 60950-1, Second Edition (hereinafter referred to as "UL 60950-1" or "the Standard") for enhanced insulation is presented here. Embodiments of the present sensor design can achieve enhanced insulation in a single packaging system with, for example, minimal outline, surface mounting, in a small package of a single integrated circuit (SOIC), for operating voltages not less than 500 VRMS, as described below.

[0018] Before describing the details of the current sensor and its insulation construction, it may be helpful to explain some specification terms, insulation requirements and test procedures of the “standard”.

[0019] First, the "standard" describes four types or levels of isolation barriers: Basic insulation; additional insulation; double insulation; and reinforced insulation. The definition of these terms is given in section 1.2.9 of the "Standard" and is described above in the section "Background of the Invention".

[0020] The standard does not specify a maximum thickness through the insulation for the base insulation. However, to be considered as supplementary or reinforced insulation under the standard, the insulation must have a minimum thickness of 0.4 mm. Insulation in the form of thin sheet material, such as thin-film material, can be considered supplementary and reinforced insulation regardless of its thickness, provided that at least two layers of such material are used. Requirements for thin sheet materials are discussed in section 2.10.5 of the standard.

[0021] Other terms of importance relate to the insulation voltage of a particular component or package. The terms "operating voltage", "RMS operating voltage", "peak operating voltage", and "required dielectric strength" are all defined in Section 1 of the "Standard" and are briefly discussed here.

[0022] The term "operating voltage" refers to the highest voltage level that a given insulation must withstand when a device, such as a current sensor, operates under normal conditions. Typically, the operating voltage is the mains voltage and varies from country to country. For example, the operating voltage is approximately 120 VRMS in the United States and 240 VRMS in Europe from phase to neutral, or 240 VRMS in the United States and 480 VRMS in Europe from phase line to phase line. The device must undergo various tests, described in the "standard," to obtain a specific operating voltage qualification. A very useful operating voltage qualification is 500 VRMS. A device certified with an operating voltage qualification of 500 VRMS can be used in many applications worldwide.

[0023] The term "RMS operating voltage" refers to the effective or RMS value of the operating voltage including any DC components and is often used interchangeably with the term "operating voltage".

[0024] The term "operating voltage peak" refers to the peak value of the operating voltage, including any DC components or recurring peak pulses generated by the device. This voltage is often called the peak value or DC voltage value. If the device must withstand a voltage of 120 VRMS, then the peak value of the operating voltage or operating voltage is 1.414 × 120 VRMS, or 170 V peak value. If the device is rated for 170 V peak value, it can operate on 170 V DC.

[0025] The term "required dielectric strength" refers to the peak voltage that the insulation in question must withstand. This voltage is also known as the insulation voltage. The required dielectric strength is of great importance because it determines the operating voltage rating of the device, which the device must achieve under the test conditions of the "standard". The required dielectric strength is generally significantly higher, for example, in the range of 3000 to 4800 V RMS. The device does not need to operate continuously at this voltage. It only needs to withstand this voltage for 60 seconds.

[0026] The testing or inspection according to the procedures specified in the "Standard" determines the working voltage or operating voltage of a device and therefore the mains voltage that can be applied to the device. For example, a current sensor can achieve a working voltage rating that ensures it can be connected to a specific mains voltage, such as 120, 240, or 480 VRMS, depending on how the device is designed and how well it meets the requirements of the "Standard".

[0027] Current sensors with integrated current conductors and magnetic field transducers have a primary conductor (i.e., the current conductor with leads connected to a high-voltage line, for example, via an external current conductor) in close proximity to a secondary conductor (i.e., a lower-voltage sensor circuit and signal connection pins). In applications where the primary conductor of the device is connected to a mains voltage (e.g., 120, 240, or 480 V RMS), maintaining galvanic isolation between the primary and secondary conductors is important.

[0028] Some earlier Hall-effect current sensors are designed to provide galvanic isolation and, furthermore, basic insulation between the current conductor (which, as mentioned above, connects to the mains voltage and can be considered the primary conductor or primary circuit) and other conductive parts of the device that can be considered electrically independent of the primary conductor, given their design (for example, sensor circuits, connections, and signal pins, which can be considered the secondary conductor or secondary circuit). An example of such a design is found in the Fig. 1A and Fig. 1B is shown.

[0029] Referring to Fig. Figure 1A contains, for example, a current sensor assembly 10 with a current sensor 12 coupled to a conductor 14. The conductor can be, for example, a conductor path on a printed circuit board (PCB) or a layer, as shown, or a busbar. Current flows into or out of the current sensor 12 via the external current path provided by the conductor 14. The drawing provides a phantom view, i.e., a view that depicts the internal structure of the current sensor 12. It can be seen from this view that the current sensor 12 consists of a conductor frame 16 with a first part 16a, which serves as the internal current path or conductor and contains primary current lines 18, and a second conductor frame part 16b, which contains signal lines 20. The integrated conductor connects to a mains voltage (via the conductor 14).

[0030] For this reason, the integrated current switch is part of a primary circuit and can be referred to as a primary conductor. The current sensor 12 also includes a molded body 21 as an integrated circuit (IC) with at least one magnetic field transducer or sensing element 22, for example, a Hall effect element, and interface circuits (not shown) for a magnetic field sensor provided therein. The molded body 21 is arranged above the conductor frame 16, such that the sensing element 22 is located near the inner current conductor, part of which is arranged below the molded body 21. This part is designed such that current flowing through the current conductor passes close to the magnetic field transducer 22. The molded body 21 is attached to or coupled to the second conductor frame part 16b. The molded body and part of the conductor frame are enclosed in plastic material 24.The integrated power conductor lines 18 are coupled to the power conductor 14 and the signal lines 20 are coupled to the PCB signal lines 26 via solder points 28a and solder points 28b respectively.

[0031] The packaging type shown is a SOIC. A current sensor with an integrated current conductor and the sensor body (such as body 21), which are combined in a single package, for example a surface-mounted IC package, such as the SOIC, is referred to here as an IC current sensor or simply as a current sensor.

[0032] In the present sensor design, a current to be measured by the current sensor 12, which is labelled “I senseThe current is connected to conductor 14. The current flows through the current sensor into those lines 18 that are used as input pins (shown as electrically connected in parallel), flows through a loop section and beyond those lines 18 that are used as output pins (also shown as electrically connected in parallel). The current I sense With reference to current sensor 12, current flows in and out on the primary side of the device and is referred to as the "primary current".

[0033] Fig. Figure 1B shows a cross-sectional view of part of the current sensor 12. The cross-section is positioned through the magnetic field transformer 22 and is viewed from the primary side of the device. As can be seen from this view, the shaped body 21 is positioned above the current conductor but is not in contact with it. The magnetic field transformer 22 is also visible, as is a portion of the inner current conductor, which flows near the magnetic field transformer 22 (and is detected by it). Magnetic flux lines linked to the magnetic field generated by the primary current flowing through the current conductor are labeled with the reference number 30.

[0034] When a primary current flows through the conductor during operation, the magnetic field converter 22 converts the detected magnetic field into a proportional voltage. An output based on this voltage is available on one of the signal lines 20.

[0035] In the depicted construction according to the Fig. 1A and Fig. In 1B, the chip body 21 is attached to the signal lines 20 of the second conductor frame part 16b via a connection 32, which is represented by solder bumps. The solder bumps can be formed on a top or active surface of the chip body, namely the surface 34. To attach the chip body to the conductor frame in the arrangement shown, the chip body 21 is actually flipped over so that the chip body faces downwards, i.e., its surface 34 faces downwards (in the present example, it faces towards the current conductor). This type of arrangement, in which a chip body is oriented downwards for connection (i.e., towards a conductor frame, as shown, or a substrate, circuit board, etc.), is known as a "flip-chip" arrangement.The connection 32 can be a solder bump or another type of structure, for example, a solder-coated (or covered) copper socket formed on the mold body. When the mold body is turned over, the bumps come into contact with the sides of the conductor frame. The connection can be formed in the form of solder bumps or paste applied to the conductor frame (before the mold body is turned over onto the conductor frame). A connection is formed between the bump (or the mold body structure) and the conductor frame during the assembly process. The mold body 21, the conductor frame signal lines 20, and the connection (for example, the solder bumps) 32 together form a secondary circuit or conductor, since this circuit or conductor is not connected to the mains voltage and is electrically independent of the primary circuit or conductor (i.e., independent of the current conductor).Points on the molded body, the signal lines and the connection can all be regarded and referred to as secondary contacts, connections or conductive parts of the current sensor.

[0036] In the current sensor design according to the Fig. 1A and Fig. 1B The space or distance formed between the molded body (secondary conductor) and the current conductor (primary conductor) in the "flip-chip" construction is filled with a transmission plastic casting material, i.e., the plastic material 24, which possesses insulating properties. Thus, this type of current sensor construction has galvanic isolation (between the primary and secondary circuits), and the plastic material acts as the basic insulation.

[0037] The insulating properties of the plastic material determine how much voltage can be applied to the primary conductors 18 before the insulation barrier breaks down and becomes faulty. Typically, a high voltage on the primary side of the device causes dendrites to grow through the insulation, creating a low-resistance path from the mains voltage to the secondary side. In some applications, the sensor's secondary signal lines are connected to user-accessible circuitry, such as a microprocessor, without any insulation provided, thus exposing the user to the risk of electric shock injury if this type of fault occurs. In such applications, a redundant level of protection is required in the form of a second or additional layer or level of insulation.

[0038] Although the illustrated current sensor 12 uses only a plastic material for insulation between the molded body and the conductor, it should be noted that some conventional current sensors use a layer of backing material or an insulating tape between the molded body and the conductor. Examples of such devices are described in U.S. Patent No. 6,356,068 and U.S. Patent No. 7,075,287 (the assignee of the latter is Allegro Microsystems, Inc., which is also the assignee of the present application). Such designs (including those described in the Fig. 1A and Fig. (as shown in 1B) do not achieve more than a basic level of isolation.

[0039] It was now on Fig. 2. Reference is made to this. Here is an example of a usage circuit 40 which uses a current sensor 12 and provides two levels of isolation. The current sensor 12 is connected in series with a mains voltage source 42 (for supplying a mains voltage in the range of 120 to 480 VRMS) and a load 44. The primary current flows through the current sensor 12, as shown in the _ Fig. 1A and Fig. The current, shown in Figure 1B (i.e., through the integrated current conductor), feeds the consumer or load 44 and then returns to the neutral conductor. Each of the PCB signal lines 26 (which are connected to the signal lines of the current sensor 12) is fed via an opto-isolator 46, so that a user can safely access circuits (not shown) connected to the insulated side 46a of the opto-isolator 46. The opto-isolator 46 is shown schematically here as containing a light-emitting diode and a phototransistor, which are kept separated from each other by a dielectric barrier.

[0040] Safety protection provided by the base insulation is available on the secondary lines because the secondary and primary circuits are separated from each other by the packaging material (or, if a base layer of insulation, such as a single tape or polyimide layer, is used, these are then separated by one of these two insulators at each secondary contact point). If an opto-isolater, for example, the opto-isolater 46 (or any other insulating component), is connected to the current sensor's signal lines as secondary or additional insulation, then a double insulation design is achieved. It should be noted that a single system provides the protection of double insulation and that the circuit 40 according to Fig. 2 can be viewed as a single system.

[0041] According to the present invention, as described in detail below, a level of enhanced insulation can be achieved in a single integrated circuit package by incorporating an insulator into the integrated circuit of a current sensor, wherein the insulator is designed to meet the requirements of the "standard" for enhanced insulation. By incorporating such an insulator into a current sensor in the form of an integrated circuit, additional insulation, for example, costly external components such as opto-isolators (as in [reference to relevant document]), can be avoided. Fig. 2 shown) can be omitted from the circuit board design.

[0042] A current sensor with an integrated conductor and an insulation structure for enhanced insulation is described below. The insulation structure is applicable to various types of fully integrated current sensor assemblies. For example, as shown in the Fig. As shown in 3A to 3C, the insulation construction is used in a “flip-chip” arrangement (as described above with reference to the Fig. 1A and Fig. 1B was described). According to another example, as described in the Fig. As shown in 4A to 4C, the insulation construction can be used in an "upward-facing" arrangement.

[0043] First, let's focus on the Fig. Reference is made to 3A to 3C. A current sensor 50 in an SOIC package in a "flip-chip" arrangement is shown here. Fig. 3A and Fig. 3B shows a "phantom" view and Fig. 3C is a cross-sectional side view of part of the current sensor 50. As shown in the diagram. Fig. As can be seen in Figure 3A, the current sensor 50 has a conductor frame 52 with a first part 52a and a second part 52b. The first part 52a forms a current conductor with primary current lines or pins 54, and the second part 52b forms signal lines 56, the outer parts of which are designated as corresponding signal lines or pins 56a. Some of the primary current lines 54 are incoming current lines, and the others are outgoing current lines. The current sensor 50 includes a molded body 58, which contains a magnetic field sensor circuit with a magnetic field converter 60 (and circuit components not shown). The magnetic field sensor circuit is an integrated circuit. Lines of magnetic flux, which are linked to that caused by the primary current in the current conductor 52a, are designated by the reference number 61.The shaped body 58 is inverted (with an upper or active surface 62 facing downwards) and is in contact with the second part 52b of the conductor frame, i.e., the internal signal lines 56, via a connection 63, which are shown here as solder-covered copper prongs. Other suitable types of prongs or similar structures may be used instead of the solder-covered copper supports or copper prongs.

[0044] An insulating structure 64 is located between the IC body and the conductor 52a. The insulating structure 64 can be formed or attached to the conductor 52a and the IC body 58 according to a possible arrangement technique, and is located on the top side of the insulating conductor. The insulating structure 64 is formed by two layers of insulating material, namely a first layer 66a and a second layer 66b. Each layer contains thin sheet material, for example, an organic polymer such as polyimide or benzocyclobutene (BCB), or an insulating oxide material, for example, silicon dioxide (if such a material can be provided in two layers). The double-layer structure provides a base insulation and supplementary insulation as layers, or enhanced insulation in a single package. The two layers can be separable or non-separable.Each layer must be capable of undergoing a high-voltage test at the required dielectric strength. If the layers are non-separable, the two-layer insulation is tested at 200% of the required dielectric strength. If the layers are separable, each layer of insulation can be tested at 100% of the required dielectric strength. The layers may be of the same or different material and / or thickness. For example, an insulating tape material may be used for both layers according to an exemplary embodiment, as described below with reference to [reference to figure]. Fig. 5 is described.

[0045] The conductor frame, the insulation structure, and the arrangement of the molded body without the external leads (signal pins 56a and power pins 54) are enclosed in plastic material 68. For illustrative purposes only, the package is shown as a twenty-pin SOIC package (with 10 pins serving as primary power pins and 10 pins serving as secondary signal pins). For simplification and clarity, the plastic material 68 is shown in the illustrations of the Fig. 3B and Fig. 3C omitted (as in the representations after the Fig. 4B and Fig. 4C, which are explained below).

[0046] It is from the representation in Fig. 3A shows that the package is a fully integrated package. The primary current enters either through the left or the right five conductors of the package and flows out through the current conductor and the other five conductors. In this design, viewed from above ( Fig. 3A to 3B) the double-layer insulation construction has a semicircular shape, but the shape can change according to the shape of the underlying conductor (conductor frame).

[0047] As previously mentioned, enhanced insulation requires that any paths between the primary and secondary conductors have a minimum thickness of 0.4 mm across a single insulating layer. This 0.4 mm measurement refers to a single insulating layer (not a thin sheet of insulating material that doesn't have a minimum thickness requirement, as mentioned above), and the plastic casting material of the packing is considered a single layer of insulation. Fig. 3B and Fig. Figure 3C shows that the insulation assembly 64 can be used to create a path of at least 0.4 mm from the primary to the secondary conductor through the plastic casting material. This minimum path of 0.4 mm is achieved by the insulation assembly 64 overlapping the primary conductor by a minimum dimension of 0.4 mm. This overlap dimension is designated by the reference numeral 70. As a result, there is no path from any point of the primary conductor to any secondary point, including the molded body, the soldered copper supports, or the signal lines, through the plastic material that would be less than 0.4 mm.

[0048] In a second embodiment, and here we will now turn to the Fig. Referring to 4A to 4C, a version of the current sensor with an upward-facing body, designated as current sensor 50', may also be constructed to include an insulation construction which exhibits certain features of the insulation construction 64 as described in the Fig. 3A to 3C is shown, i.e., the double layers of thin insulating sheet material and the 0.4 mm protrusion (relative to the primary conductor). Likewise, the current sensor 50 according to the Fig. The 3A to 3C current sensor 50' is a current sensor in a SOIC package. Fig. 4A and Fig. 4B each show a supervisor and Fig. Figure 4C shows a cross-sectional side view of part of the current sensor 50'. How to... Fig. 4A detects, the current sensor 50' has a conductor frame 52' with a first part 52a' and a second part 52b'. The first part 52a' forms a current conductor with primary current lines or pins 54', and the second part 52b' forms signal lines 56', the outer parts of which are designated as corresponding signal lines or connection pins 56a'. Some of the primary current lines 54' are the input current lines, and the others are the primary current output lines. The current sensor 50' includes a molded body 58' which contains a magnetic field sensor circuit or integrated circuit with a magnetic field transducer 60 (as well as circuits not shown). In the upward-facing design of the present embodiment, the contacts between the molded body 58' and the secondary signal lines 56a' are formed by conventional gold wire connections 72. The molded body 58 is oriented upwards, i.e.,An upper or active surface 62 faces upwards. An insulating structure 64' is located between the shaped body 58' and the current conductor 52a'. As with the insulating structure 64 according to the . Fig. In sections 3A to 3C, the insulation structure 64' is formed by two layers of thin sheet material, namely a first layer 66a' and a second layer 66b'. The layers may be of the same or different material composition and / or thickness, as further described with reference to Fig. 5 is discussed. The conductor frame, the insulation construction and the molded body as an arrangement apart from the outer conductors (signal pins 56a' and current pins 54) are enclosed in a plastic casting material 68'.

[0049] As with the insulation construction 64 according to the Fig. In 3A to 3C, the insulation structure 64' is dimensioned to have an overhang extending beyond the primary conductor 52a', providing a path of at least 0.4 mm across the cast plastic with respect to the distance from the primary to the secondary conductor. Consequently, there is no path from any point on the primary conductor 52a' to any point, including the molded body, connecting wires, and signal lines, across the plastic material that is less than 0.4 mm.

[0050] The overall size and shape of the insulation structure varies with the size and shape of the underlying conductor. One dimension considered critical is the 0.4 mm overhang, which is the amount by which the structure extends beyond the conductor. The overhang may vary within certain practical limits, such as a tolerance of ±0.15 mm, to account for any imperfections or characteristic variations in the manufacturing process. The 0.4 mm dimension is a required minimum that includes all tolerances. Thus, the overhang may be larger but must be at least 0.4 mm after accounting for tolerances. At a minimum, the insulation structure 64 or 64' must be sized and shaped to cover at least that portion of the conductor located beneath the molded body.In both illustrated designs, this part of the insulation structure has a semicircular shape. The curved edge of the insulation structure extends beyond a corresponding curved edge of the conductor by at least 0.4 mm (after accounting for the tolerances described above). The curved portion of the semicircular shape may be slightly extended to cover an additional portion of the conductor not located beneath the molded body, as shown in the illustrated examples, to ensure that the required 0.4 mm dimension is adequately maintained.

[0051] The use of a double layer of insulation between the shaped body and the current conductor in this design is key, as the operating characteristic of the IC current sensor is a function of the physical separation between the magnetic field-generating source and the magnetic field transformer. As mentioned above, the signal coupling is more optimal the smaller the distance between the shaped body (more precisely, the magnetic field transformer) and the current conductor. If a single layer of insulation were used in this area, it would have to meet the requirement of 0.4 mm, and a 0.4 mm separation distance between the shaped body and the current conductor would result in extremely poor signal coupling between the current conductor and the magnetic field transformer. At the same time, the shape, or rather theThe size of the insulation construction with an overhang area ensures that the dimension of 0.4 mm is met in areas of the packaging that only have a single layer of plastic in the packaging body as protective insulation. Thus, a construction dimensioned to have a thickness and composition chosen to provide double insulation between some primary and secondary conductive parts or areas where close proximity between the two parts is important, and an area (size) that ensures the distance across the insulation between all other primary and secondary conductive parts or areas is at least 0.4 mm, meets the design requirements under the "standard" for reinforced insulation.

[0052] For illustrative purposes only, the package is shown as a 20-pin SOIC (with 10 pins used as primary power contacts and 10 pins used as secondary signal contacts) in both flip-chip and top-up configurations. The form factor is 3.7 mm × 1.9 mm for the flip-chip configuration ( Fig. 3B) and with 1.9 mm × 1.9 mm for the upward-pointing shaped body construction ( Fig. 4B). Other pack sizes with different numbers of contact pins and different body sizes can be used.

[0053] A key advantage of the flip-chip design ( Fig. 3A to 3C) consists of the fact that the magnetic field transmitter, which is located on the active surface of the molded body, is in significantly closer proximity to the primary conductor. By positioning the magnetic field transmitter closer to the primary conductor, the magnetic field signal coupling is increased, resulting in a higher signal-to-noise ratio as well as improved sensor resolution and accuracy. A disadvantage of the flip-chip design is that the molded body size is increased and has a minimum size that is larger than in the design with the molded body facing upwards. The flip-chip design requires the molded body to be large enough to align with the secondary conductors and also to provide a minimum distance between the secondary contact of the molded body and the primary conductor. Increasing the molded body area increases the cost of the molded body and therefore the overall cost of the sensor. A brief investigation of the Fig. 3A to 3B and 4A to 4B clearly show that the primary conductor loop area of ​​the primary conductors is narrower (in terms of width) in the flip-chip design according to the Fig. 3A to 3C. A narrower primary conductor has higher resistance and therefore, for a given current, higher power loss within the package. The design with the molded body facing upwards according to the Fig. 4A to 4C allows the use of a significantly wider and therefore lower-resistance primary conductor loop. The upward-facing design also accommodates a larger tape overhang to create a slightly larger safety margin, as the 0.4 mm dimension is a minimum requirement. Even a slight increase in this overhang substantially improves the packing's insulation properties.

[0054] Fig. Figure 5 shows an enlarged cross-sectional view of the insulation structure 64 (or 64') according to an exemplary embodiment. In this embodiment, each layer is formed as a strip material layer. The first strip material layer 66a (or 66a') contains a first polyimide film layer 80a and a first adhesive layer 82a. The second strip material layer 66b (or 66b') contains a second polyimide film layer 80b and a second adhesive layer 82b. From bottom to top, the sequence of layers is the adhesive layer 82a, which is in contact with the conductor 52a, the polyimide film layer 80a, the adhesive layer 82b, and the polyimide film layer 80b. The shaped body 58 (or 58') is in contact with the polyimide film layer 80b. The first layer of tape material 66a has a thickness “T, tape 1” 84a and the second layer of tape material 66b has a thickness “T, tape material 2” 84b.The first polyimide film layer 80a has a thickness T1 86a, and the second polyimide film layer 80b has a thickness T1 86b. The first adhesive layer 82a and the second adhesive layer 82b have thicknesses T2 88a and 88b, respectively. The thicknesses 84a and 84b of the tape material layers can be the same (or substantially the same) or they can be different. Similarly, the thicknesses of the adhesive layer and the polyimide film layer in one layer can be the same or different from the corresponding layers in the other tape material layer. For example, the thickness T1 86a can be less than the thickness T1 86b. The same type of tape material can be used for both layers, in which case the composition and dimensions of the two layers are the same (or substantially the same). Each layer can contain only one polyimide film.

[0055] One type of tape material that can be used for each of the tape material layers 66a and 66b is the R-series semiconductor adhesive tape material available from Tomegawa Co., Ltd., Japan. One of these tape materials, designated with the product number "R-740," has a polyimide layer thickness of 25 µm and an adhesive layer thickness of 15 µm. This tape material offers a particularly high level of insulation per layer. It has an insulation property of approximately 330 kV per mm of thickness. Each layer of the polyimide film is 25 µm thick and can therefore provide 330 kV × 0.025, or 8.25 kV, of insulation between the primary and secondary conductors.

[0056] If the tape material is used as the thin sheet material insulating layer, then each layer can be applied separately, i.e., the first layer is applied to the top surface of the conductor and the second layer is applied to the first layer, or the layers can be applied together (double layer of tape material applied to the conductor).

[0057] In a flip-chip design, the tape material can be applied to the molded body before it is attached to the conductor frame, instead of being applied to the conductor itself. Alternatively, in a tape-less design, each layer of the thin sheet material can be deposited onto the top surface of the conductor or formed in some other way using conventional deposition processes, such as spin coating or spraying. Such methods must also coat the sides of the conductor to form the insulation overhang.

[0058] For the current sensor to pass the "standard" test for reinforced insulation and achieve a high operating voltage rating of 500 VRMS, each individual layer of the tape material (or other thin sheet material) must withstand a voltage of 4800 VRMS for 60 seconds. This voltage is the required dielectric strength, as defined above. A signal of 4800 VRMS has a peak voltage of approximately 6800 V. Each insulation layer should withstand this test. Thus, although each layer may be slightly thinner or thicker, it should be thick enough to withstand a voltage of 7 kV or above to achieve high reliability. The use of double layers achieves the supplementary insulation, which, as mentioned above, enables the reinforced insulation rating.

[0059] The plastic packing material has significantly lower insulating properties than the thin sheet material, but provides good insulation. The plastic packing material is classified into one of three categories according to the UL60950-1 standard: Material I, II, and III. An insulating material is classified into a material group based on its CTI (Comparative Tracking Index) test result. If the insulating material is not CTI-tested, the UL60950-1 standard considers it to be a material in group III. Material group III represents the lowest classification and results in the lowest operating voltage rating. Accordingly, a molded material from material group II, such as Sumitomo E670C, can be selected for use in the current sensor.Other cast compounds, such as Henkel MG-52F, can also be suitable materials if they have been tested according to the CTI standard to obtain classification as a Group II material. Selecting a plastic classified as a Group II material is important because the 500 VRMS operating voltage rating could not be achieved in a design using a Group III insulating material.

[0060] The 60-second high-voltage insulation test (required dielectric strength) that the component must survive is referred to as the type test. To achieve the operating voltage assignment of 500 VRMS, all current-sensing devices must withstand a voltage of 4800 VRMS for 60 seconds. The type test is inherently destructive, as applying 4800 VRMS to the packing exceeds what is known as the corona discharge voltage, the voltage at which dendrites begin to grow, creating a faulty conduction path from the primary to the secondary conductor of the device. The standard requires that a sample of three devices undergo this type test for certification. The voltage level at which the device passes the test is converted into an assigned operating voltage in the manner described above.For quality control of such devices in production, the standard requires a significantly shorter second high-voltage test for package integrity. This test is called the routine test. The routine test is generally performed at 3000 VRMS for one second, and all production units must be tested. The routine test is also a destructive test, but its duration is short enough that it does not substantially impair the integrity of the package.

[0061] So far, the discussion about insulation has focused on the insulating properties within the package. Turning attention to the outside of the package, creep and clearance must also be considered when determining the operating voltage of the current sensor. The term "clearance" refers to the shortest distance through the air between two conductive parts, such as the primary and secondary leads. The term "creep" refers to the shortest distance between two conductive parts along the surface of any insulating material common to both parts. The required clearance between components that must withstand a given operating voltage is determined by the creep and clearance.

[0062] To achieve a high operating voltage rating according to the "Standard," the SOIC package of the 50 or 50' current sensor must meet the required minimum creepage and clearance dimensions for the desired operating voltage as specified in the "Standard." The creepage and clearance requirements are given in Table 2N and Tables 2K to 2M (of the "Standard"), respectively. Since the minimum clearance required for a high operating voltage rating is smaller than the creepage requirement and therefore easier to meet, the clearance is not discussed in detail. According to Table 2N, to achieve an RMS or effective operating voltage rating of 500 V for reinforced or double insulation using a material from material group II, a minimum creepage distance of 7.2 mm must be achieved.To determine whether the packaging meets this minimum requirement, both the packaging and the packaging outline on the printed circuit board must be examined.

[0063] The Fig. 6A and Fig. Figure 6B shows a top view of the current sensor 50 (or 50'). These views show only the outside of the current sensor's SOIC package (again represented as a 20-pin SOIC). In particular, the figures show the physical limitations of this example of the SOIC package with respect to creep behavior. As in Fig. Figure 6A shows, for example, a packing with a body length of 12.8 mm ± 0.2 mm, a tip-to-tip width of 10.3 mm ± 0.33 mm, and a body width of 7.5 mm ± 0.10 mm. To determine the creepage distance, and here reference is made to a part of the packing identified by the reference number 92, the total distance along the plastic body (the insulation) from the primary current contact pins to the secondary current contact pins must be determined. Fig. Figure 6B shows an enlargement of part 92. The creepage distance is determined by adding the dimensions of spaces 100a and 100b (shown as 0.48 mm in the drawing) to the body width, which is the sum of the widths 102a and 102b (shown as 3.65 mm in the drawing). It should be noted that any burrs (shown as 0.21 mm wide in the drawing) are excluded from the measurement. Thus, when traveling along the packing from the primary to the secondary side, a creepage distance of 8.26 mm is obtained. This is the maximum creepage value achievable for this particular packing. The packing therefore easily meets the maximum creepage distance of 7.2 mm required for a rating of 500 V RMS or 500 V RMS.

[0064] If the packing is soldered to a printed circuit board, the solder bumps of the printed circuit board further reduce the creepage distance (and the gap). It should be noted that... Fig. Reference is made to 7A. In a mechanical layout 110 of a printed circuit board for the SOIC with 20 contact pins according to the Fig. 6A and Fig. 6B, using standard solder pads 112 for the secondary contact pins and standard solder pads 113 for the primary contact pins on a portion of a solid printed circuit board 114, results in a distance of 7.25 mm between the primary and secondary solder pads along the printed circuit board. In this embodiment, this distance between the solder pads 112 and 113 is the actual creepage distance for the packing. Although this distance is still greater than the required minimum of 7.2 mm, the safety margin is significantly reduced relative to the 7.2 mm minimum. The creepage distance can be improved somewhat by providing a slot in the printed circuit board to increase the distance along the printed circuit board from the primary to the secondary solder pads. Such a solution is described in Fig. Figure 7B shows a mechanical layout of the printed circuit board 120 with solder pads 122 for the secondary contact pins and solder pads 124 for the primary contact pins, as well as an area of ​​a printed circuit board 126 with a slot 130. The width of the slot 130 is denoted by 132. For example, this width 132 is 2.00 mm. The distance from the primary-side solder pads 124 to the slot 130 is denoted as the distance or space 134. The distance from the secondary-side solder pads 122 to the slot is denoted as the distance or space 136. These two distances are 3.30 mm in the present example. The total creepage distance in mm for the solution with the slotted printed circuit board is therefore (2 x 3.00) + 2.00 or 8.60. This means that the creepage distance on the printed circuit board can be improved to a maximum of 8.26 mm by using the slotted printed circuit board.This solution provides a substantial safety margin relative to the minimum value of 7.2 mm for an RMS operating voltage of 500 V. If a larger creepage distance is required for an even higher operating voltage rating in a Group II cast material connection, a wider packing body could be used. The dimensions of the printed circuit board slot could also be adjusted to improve the creepage distance.

[0065] Fig. Figure 8 shows a simplified functional circuit diagram of the current sensor 50 (or 50') according to an exemplary embodiment. The current sensor 50 includes the magnetic field converter 60 (according to the Fig. 3A to 3C and 4A to 4C), which is represented as a magnetic field sensor device 60. The magnetic field sensor device 60 can be formed by one or more sensor elements, for example, a Hall-effect sensor element or a magnetoresistive (MR) sensor element. The sensor elements can be arranged in a bridge circuit. The magnetic field sensor device 60 is coupled to an interface circuit 140. Together, the magnetic field sensor device 60 and the interface circuit 140 form the circuit which is enclosed by the shaped body 58 ( Fig. 3A to 3C) and is referred to above as a magnetic field sensor circuit. The current sensor 50 also contains the internal or integrated current conductor 52a. In Fig. 8 are the primary power lines (which are in Fig. 3A (as the primary current lines 54 were shown) are shown here as two groups of lines, namely a group of input line pins, which together are designated IPIN by 142a, and a group of output contact pins, which together are designated IPOUT by 142b. This drawing is to be regarded as a functional block diagram and is not intended to represent the physical positions of the current conductor 52a relative to the magnetic field converter 60.

[0066] During operation, the current to be measured by sensor 50 is applied to the conductor path 52a via the primary current lines or contact pins 142a, flows through a "loop" section 144 of the path, which brings the current close to the magnetic field sensor 60, and exits the current sensor 50 via the primary current output contact pins 142b. The applied current flowing through conductor path 52a generates a magnetic field, which is detected by the magnetic field sensor 60 and converted into a proportional voltage at the output 146 of the device. The interface circuit 140 contains various circuit blocks for conditioning and processing the output 146.For example, as shown, the circuit 140 contains a magnetic field signal generator 148, an output-generating circuit block 150, an interface which is represented as a general interface 152, and a type of non-volatile memory 154, for example in the form of an EEPROM.

[0067] In addition to the primary-side lines 142a, 142b, the current sensor includes signal contact pins or terminals for connecting the current sensor to power, ground, and external circuitry that controls and / or utilizes the current sensor's measurement characteristics and capabilities, for example, an external microcontroller. These other signal contact pins, which are located in the Fig. The secondary signal pins 56a, shown as 3A to 3C, each contain at least one contact pin (terminal or line) corresponding to the following: a VCC terminal 156 (for connection to an external power source), a GND terminal 158 (for connection to ground), at least one input 160, and at least one output 162. The output enables the use of an external current sensor, for example, as a ground fault interrupter (GFCI) or for other current monitoring purposes, to receive and utilize the information generated by the current sensor. Power is supplied to the current sensor 50 via the VCC terminal 156, which is internally connected to the various sub-circuits as shown. The GND terminal 158 is internally wired to provide a ground connection for the sensor's sub-circuits.Other terminals or pins, shown collectively as pins 164, can correspond to input terminals, such as data inputs, clock signal inputs, and other control signal inputs, like a programming controller (for example, to program the EEPROM), as shown, or they can also include other output signal pins or power supply or ground lines. It can be seen that the functionality of the current sensor and the sensor's output contact pins can be varied to meet the needs of specific applications.

[0068] The magnetic field signal generator 148, which is coupled to the magnetic field sensor device 60, and the output generation circuit block 150 can contain various conventional circuits that work together to generate the output signal 166 (or the magnetic field signal) of a magnetic field signal generator at the output 146 of the sensor device. Generally, the circuit 148 contains at least one amplifier for amplifying the output signal of the sensor device 60. Other circuits may be included in the magnetic field signal generator 148. For example, it may contain a circuit for implementing dynamic zero-point displacement cancellation. If the sensor element is a Hall-effect plate element, then a copper stabilization circuit may be provided to minimize the offset voltage of the Hall-effect plate element, along with an associated amplifier.In addition, or alternatively, the circuit 148 can implement an offset setting and / or a gain setting as features.

[0069] In a simple embodiment, the output generation circuit block 150 can include a low-pass filter and an output amplifier / buffer, which process the magnetic field signal 166 to generate an output signal 168. The output signal would be a value indicating the amplitude of the detected current. To support processing functions and an even higher level of programmability, the output generation circuit block 150 could be designed to include a processor, microcontroller, or data signal processing circuit. The microcontroller could be programmed to perform calculations and other tasks.

[0070] The general interface 152 receives at least one input on input line 170, which is connected to terminal pin 160. It can also receive other inputs via terminal pins 164 if they are defined as input terminal pins. These inputs can be used by external control devices or other application circuits to set or program user-defined input parameters, such as gain and temperature compensation, and can also provide input data and control information required by the operating modes of the general interface 152, the output generation circuit block 150, and / or the non-volatile memory 154. The general interface 152 can be configured to follow various protocols, such as serial communication protocols, for example, Inter-Integrated Circuit (IIC). 2C), Single-Edge Nibble Transmission (SENT), Peripheral Sensor Interface 5 (PSI5), Serial Peripheral Interface (SPI), or RS232. The general interface 152 is connected to the output signal circuit block 150 and the non-volatile memory 154 via connections or lines 172 and 174, respectively. The non-volatile memory is coupled to the magnetic field signal generator 148 via connection 176. Connection 176 can be used to transmit user-defined values, such as a gain setting, stored in the non-volatile memory 154 to the circuits of the magnetic field signal generator 148. Signal paths of the sensor IC can be implemented in the analog or digital domain.

[0071] Although the device, for example, according to the Fig. 3A to 3C, 4A to 4C, according to the Fig. 6A and Fig. 6B as well as 7A and 7B and after Fig. While it has 820 connection pins, other pin counts are possible, with some lines forming the primary current path and others forming the connections for signals (for example, output, power supply, and ground). It is also understood that additional functions can be added via those listed below. Fig. 8 can also be included in the sensor IC.

[0072] Sensor elements forming the magnetic field sensor device 60 can be made of silicon or semiconductor material other than silicon, for example gallium arsenide (GaAs) or an indium compound, for example indium arsenide (InAs) or indium antimonide (InSb).

[0073] Overall, the current sensor 50 (or 50') has a design capable of achieving a reinforced insulation rating, particularly for high operating voltages (e.g., an operating voltage of at least 500 V RMS). The current sensor 50 (or 50') incorporates a uniform insulation structure comprising: a) a double layer of thin sheet material; and b) an overhang dimension providing a minimum clearance of 0.4 mm between the primary and secondary components above the packing material. Therefore, due to this insulation design, the double layer of thin sheet material and the packing material meet the reinforced insulation requirements of the standard. Furthermore, the packing material is selected as a Group II material according to the standard.Finally, as mentioned above with reference to the . Fig. 6A and Fig. 6B as well as 7A and 7B has been discussed, the current sensor is packed in a SOIC, the dimensions and use in conjunction with a design of the solder points of the printed circuit board are such that a minimum creepage distance of 7.2 mm is maintained.

[0074] The current sensor and its specific packaging adhere to the design requirements of the "standard" to withstand rigorous testing. They provide a minimum galvanic isolation rating of 3000 V RMS with dual protection and an operating voltage rating of up to 500 V RMS. The packaging also features a dimension through the insulation material from the primary to the secondary side, enabling it to withstand a destructive high-voltage test of 4800 V RMS for 60 seconds to achieve a galvanic isolation rating of 3000 V RMS. This test is also required for a high operating voltage rating and allows the device to operate at higher voltages, up to 500 V RMS.

[0075] After describing preferred embodiments of the invention, it is obvious to those skilled in the art that other embodiments can be used incorporating the respective concepts. It can therefore be assumed that these embodiments are not limited to those disclosed here, but rather only by the general concept set forth in the attached claims.

Claims

[1] Current sensor, which includes the following: a conductor frame (16) with a first part (16a) which has power lines connected in such a way as to form a current conductor for carrying a primary current, and a second part (16b) which contains signal lines (20); a shaped body (21) which is coupled to the second conductor frame part by a connection (32) and which contains a magnetic field sensor circuit (60) to detect a magnetic field associated with the primary current and generates an output on a signal line based on the detected magnetic field; an insulating structure (64, 64') which is arranged between the conductor and the shaped body and includes a first insulating layer (66a, 66a') and a second insulating layer (66b, 66b'); Plastic material (24) which surrounds the molded body, the connection and at least a part of the conductor frame to form a cast packing body; and wherein the conductor has a curved edge region, wherein the insulation construction covers at least part of the conductor and extends beyond the curved edge region of the conductor, and wherein the insulation construction has a substantially semicircular shape with a curved area extending laterally beyond the curved edge region of the conductor in a direction towards at least one of the signal lines with a projection dimension of at least 0.4 mm including all tolerances. [2] Current sensor which includes the following: a conductor frame (16) with a first part (16a) which has power lines (18) connected in such a way as to form a current conductor for carrying a primary current, and a second part (16b) which contains signal lines (20), wherein the current conductor has a curved outer edge region adjacent to at least one of the power lines; a shaped body (21) which is coupled to the second conductor frame part by a connection (32) and which contains a magnetic field sensor circuit (60) to detect a magnetic field associated with the primary current and generates an output on a signal line based on the detected magnetic field; a substantially planar insulation structure (64, 64') which is arranged between the conductor and the shaped body and includes a first insulating layer (66a, 66a') and a second insulating layer (66b, 66b'); Plastic material (24) which surrounds the molded body, the connection and at least a part of the conductor frame to form a cast packing body; and wherein the insulation construction has an essentially semicircular shape with a curved area extending laterally beyond the curved outer edge of the conductor in a direction towards at least one of the signal lines with a projection dimension of at least 0.4 mm including all tolerances. [3] Current sensor according to claim 1 or 2, wherein both the first and the second insulating layer contain a polyimide film. [4] Current sensor according to claim 3, wherein both the first and the second insulating layer further contain an adhesive layer. [5] Current sensor according to claim 4, wherein the polyimide film and the adhesive layer are provided as tape material. [6] Current sensor according to claim 5, wherein the tape material has a thickness of approximately 40 µm. [7] Current sensor according to claim 6, wherein the polyimide film has a thickness of approximately 25 µm. [8] Current sensor according to claim 3, wherein the polyimide film has an insulating property and a thickness which enables the polyimide film to withstand an insulation voltage of at least 7 kV. [9] Current sensor according to claim 1 or 2, wherein the first and the second insulating layer have substantially the same thickness. [10] Current sensor according to claim 1 or 2, wherein the magnetic field sensor circuit includes a magnetic field converter (22) which has a sensor element that is either a Hall effect sensor element or a magnetoresistive sensor element. [11] Current sensor according to claim 1 or 2, wherein the coupling of the shaped body with the second conductor frame part by the connection includes a flip-chip arrangement. [12] Current sensor according to claim 11, wherein the connection includes solder-coated copper supports formed on a surface of the molded body. [13] Current sensor according to claim 1 or 2, wherein the coupling of the shaped body with the second conductor frame part by the connection has an arrangement with the shaped body facing upwards, wherein the connection includes wire connections. [14] Current sensor according to claim 1 or 2, wherein the thickness of both the first and the second insulation layer is sufficient to achieve a minimum operating voltage rating of 500 V RMS to enable compliance with the UL 60950-1 standard. [15] Current sensor according to claim 1 or 2, wherein the distance from each path from the shaped body (21) to the current conductor area of ​​the conductor frame around the insulation structure is at least 0.4 mm. [16] Current sensor according to claim 1 or 2, wherein the plastic material contains a casting material which is classified as a Group II material under the UL 60950-1 standard. [17] Current sensor according to claim 1 or 2, wherein the packing body is dimensioned to meet tracking distances and gap distances according to the requirements of standard UL 60950-1. [18] Current sensor according to claim 1 or 2, wherein the first insulating layer is in contact with an upper surface of the current conductor and the second insulating layer. [19] Current sensor according to claim 1 or 2, wherein the first and second insulating layers each contain a tape material comprising a polyimide film layer and an adhesive layer. [20] Current sensor according to claim 19, wherein the polyimide film layer has a thickness of at least 25 µm.

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