A stacked integrated inductor

Abstract

The utility model discloses a kind of integrated inductors of stacking type, including inductance main body and adhesive layer. Inductance main body is by first inductance part and second inductance part laminated, first inductance part connects first electrode and second electrode, second inductance part connects third electrode and fourth electrode, electrode extends from inductance part side and is bent to bottom. The inductor of the application is integrated in single structure by three-dimensional stacking design two independent inductors, four electrode layout at bottom makes overall size reduce, mounting density improves;Low dielectric properties of adhesive layer reduce distributed capacitance, mutual-inductance interference is reduced by magnetic circuit symmetry design, optimize high-frequency electrical performance;Without multilayer sintering process, only need to bond after single body forming, process is simple and cost is low.

Description

Technical Field

[0001] This utility model relates to the technical field of inductors, and in particular to a stacked, integrally molded inductor. Background Technology

[0002] As electronic devices evolve towards miniaturization and high integration, the miniaturization and high-density mounting of surface mount devices (SMDs) have become key technological requirements. Inductors, as core components for power conversion and signal filtering, directly impact the overall size and performance of electronic devices through their size and mounting density.

[0003] Currently, traditional molded inductors are formed by embedding the winding coil in magnetic powder using powder metallurgy. They have advantages such as good magnetic shielding, high mechanical strength, and stable inductance, and are widely used in various electronic devices. However, the size of a single molded inductor is still relatively large. In scenarios that require the integration of multiple inductors (such as multi-phase power modules and multi-channel signal filtering circuits), multiple independent inductors need to be distributed on the PCB board, which increases the PCB footprint, reduces mounting efficiency, and may introduce longer lead inductance, affecting high-frequency performance.

[0004] While multilayer inductors (such as multilayer ceramic inductors) exist in the existing technology, their structure is usually formed by alternating stacking and sintering of multiple layers of magnetic thin films and windings. This results in high complexity and cost due to the need for precise control of the thickness and alignment accuracy of each layer in the multilayer structure; the windings are segmented, resulting in large parasitic inductance and distributed capacitance, and poor high-frequency characteristics; and the magnetic materials are mainly ceramic or ferrite, which limits heat dissipation performance and makes them prone to overheating and failure under high current conditions. Utility Model Content

[0005] This invention aims to at least partially solve one of the problems in related technologies. Therefore, one objective of this invention is to provide a stacked, integrally molded inductor for achieving high-density inductor mounting, optimized electrical performance, simple and low-cost manufacturing process, and high reliability.

[0006] A stacked, integrally molded inductor, the stacked, integrally molded inductor comprising:

[0007] An inductor body includes a first inductor portion and a second inductor portion. The first inductor portion is connected to a first electrode and a second electrode, and the second inductor portion is connected to a third electrode and a fourth electrode. The first inductor portion and the second inductor portion are stacked. The first electrode and the second electrode extend from two sides of the first inductor portion and are bent at the bottom of the first inductor portion. The third electrode and the fourth electrode extend from the other two sides of the first inductor portion and are bent at the bottom of the first inductor portion.

[0008] An adhesive layer is disposed between the first inductor and the second inductor for connecting the first inductor and the second inductor.

[0009] Furthermore, the first electrode, the second electrode, the third electrode, and the fourth electrode are arranged in a rectangular pattern at the bottom of the first inductor.

[0010] Furthermore, the spacing between two adjacent electrodes is ≥0.2mm.

[0011] Furthermore, the adhesive layer is made of epoxy resin.

[0012] Furthermore, the thickness of the adhesive layer ranges from 0.05 mm to 0.1 mm.

[0013] Furthermore, the inductor body is made of iron powder, iron-silicon-chromium powder, iron-silicon-aluminum, or a composite material of iron-nickel powder and epoxy resin.

[0014] Furthermore, the bent portions of the first electrode, the second electrode, the third electrode, and the fourth electrode are rounded bends.

[0015] Furthermore, the first electrode, the second electrode, the third electrode, and the fourth electrode are each provided with silver-plated pads on the bottom surface of the first inductor, and the edges of the silver-plated pads protrude beyond the electrode edges.

[0016] Furthermore, the stacked integral molded inductor is also provided with a shielding layer, which is disposed between the first inductor and the second inductor, and the shielding layer is made of iron-nickel alloy magnet.

[0017] Furthermore, the shielding layer covers the stacked surface of the first inductor and the second inductor.

[0018] The technical solutions provided in this application have the following advantages compared with the prior art:

[0019] This application combines two independent, integrally molded inductors with epoxy resin adhesive to form a structure with four electrodes integrated at the bottom. After the two inductors are stacked, the overall size is only 0.9-1.2 times that of a single inductor, while the traditional distributed layout requires more than twice the area, thus increasing the mounting density. The low dielectric properties of epoxy resin reduce distributed capacitance, and the symmetrical magnetic circuit of the stacked structure reduces mutual inductance interference, optimizing electrical performance. Furthermore, instead of requiring a multi-layer sintering process, only individual molding and bonding are needed, making the process simple and low-cost. In addition, the bonding layer enhances mechanical strength, provides excellent heat dissipation, and ensures high reliability. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] In the attached image:

[0023] Figure 1 This is a schematic diagram of the structure of an embodiment of the stacked integral molded inductor of this application;

[0024] Figure 2 This is a schematic diagram of the structure of another embodiment of the stacked integral molded inductor of this application;

[0025] Figure 3 This is a schematic diagram of another embodiment of the stacked integral molded inductor of this application.

[0026] Figure label:

[0027] 1. A stacked, integrally molded inductor; 10. Inductor body; 11. First inductor section; 111. First electrode; 112. Second electrode; 12. Second inductor section; 121. Third electrode; 122. Fourth electrode; 30. Adhesive layer; 50. Silver-plated pad; 70. Shielding layer. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] like Figure 1 , Figure 2 As shown, the stacked integral molded inductor 1 provided in this application includes:

[0031] An inductor body 10 includes a first inductor portion 11 and a second inductor portion 12. The first inductor portion 11 is connected to a first electrode 111 and a second electrode 112. The second inductor portion 12 is connected to a third electrode 121 and a fourth electrode 122. The first inductor portion 11 and the second inductor portion 12 are stacked. The first electrode 111 and the second electrode 112 extend from both sides of the first inductor portion 11 and are bent at the bottom of the first inductor portion 11. The third electrode 121 and the fourth electrode 122 extend from the other two sides of the first inductor portion 11 and are bent at the bottom of the first inductor portion 11.

[0032] An adhesive layer 30 is disposed between the first inductor 11 and the second inductor 12 for connecting the first inductor 11 and the second inductor 12.

[0033] The first inductor 11 and the second inductor 12 are stacked and integrated at the bottom through an electrode bending design, while the positions of the two are fixed by an adhesive layer 30. By stacking the two inductors and integrating the bottom electrodes, the integration of electronic devices is significantly improved, solving the problem of large space occupation by traditional scattered layouts. This structure can flexibly adapt to different circuit requirements. For example, in multi-phase power modules, the stacked structure can achieve a compact layout of two inductors, reducing PCB wiring complexity; in mobile phone fast charging chips, the stacked structure can integrate filter inductors and energy storage inductors, reducing the size of the power management module.

[0034] The stacked arrangement of the first inductor 11 and the second inductor 12 transforms the traditional planar two-dimensional structure into a three-dimensional structure, utilizing vertical space to compress the horizontal area occupied. The design of the electrodes extending from the sides and bending to the bottom forms a "bottom electrode array," concentrating the electrical connection on a single plane, while also providing mechanical support and conductivity. The adhesive layer 30, as the interlayer medium, must meet both mechanical strength and electrical insulation requirements in its physical connection properties.

[0035] By stacking two inductor units, the overall size is only 0.9-1.2 times that of a single inductor, significantly increasing the mounting density compared to the traditional distributed layout (which requires more than twice the area). The first electrode 111 and the second electrode 112 extend from both sides of the first inductor unit 11 and bend to the bottom, while the third electrode 121 and the fourth electrode 122 extend from the other two sides, forming a four-electrode structure at the bottom. This design concentrates the electrodes at the bottom, adapting to standard SMD soldering processes. Compared to traditional distributed electrodes, it is easier to automate mounting, and the lead paths are shorter, reducing the impact of lead inductance on high-frequency performance. The adhesive layer 30 connects the two inductor units, not only fixing their physical position but also enhancing the overall mechanical strength through the bonding force of materials such as epoxy resin, preventing the stacked structure from loosening under vibration or impact.

[0036] The electrode bending design is adapted to the coplanar welding requirements of surface mount technology. The bending angle and the vertical transition to the bottom plane can reduce welding stress concentration. The adhesive layer 30 is bonded by curing with epoxy resin and other materials to form a rigid integral structure, which can resist mechanical stress in the vibration environment and suppress interlayer parasitic capacitance through the low dielectric properties of the material, thus achieving the dual goal of "mechanical connection and electrical performance optimization".

[0037] Furthermore, the first electrode 111, the second electrode 112, the third electrode 121, and the fourth electrode 122 are located at the bottom of the first inductor 11 and are arranged in a rectangular pattern.

[0038] The four electrodes are arranged in a rectangular pattern at the bottom of the first inductor section 11. From a layout logic perspective, the rectangular distribution is the optimal solution that balances electrical performance and structural compactness. If the electrodes are arranged arbitrarily, it may lead to uneven spacing between adjacent electrodes, increasing the risk of short circuits; if they are arranged linearly, the bottom plane space cannot be fully utilized. The rectangular layout can achieve a symmetrical distribution of electrodes within a limited area, satisfying both electrical safety spacing and facilitating the standardized design of PCB pads.

[0039] The rectangular distribution allows the four electrodes to form a regular quadrilateral array. The pads on the PCB can be designed according to a standard rectangular grid, adapting to the positioning system of automated pick-and-place machines and reducing placement errors. With a rectangular layout, the distance from each electrode to its corresponding inductor is equal, resulting in a more symmetrical magnetic circuit distribution and reducing mutual inductive coupling between inductors. In high-frequency applications, reduced mutual inductance leads to more stable inductance values, preventing a decrease in filtering performance due to signal crosstalk.

[0040] Furthermore, the spacing between two adjacent electrodes is ≥0.2mm.

[0041] The minimum spacing between adjacent electrodes is 0.2mm, a requirement governed by both electrical safety and manufacturing process constraints. From a safety perspective, insufficient spacing can easily lead to short circuits due to solder bridging. From a process perspective, 0.2mm is the minimum spacing that can be reliably controlled in current SMD soldering processes (such as reflow soldering)—if the spacing is less than 0.2mm, the solder paste printing precision requirements become too high, increasing production costs and defect rates. Furthermore, a 0.2mm spacing effectively prevents electrode short circuits caused by solder overflow during the soldering process.

[0042] Furthermore, the adhesive layer 30 is made of epoxy resin.

[0043] The adhesive layer 30 is made of epoxy resin, a choice that considers both electrical and mechanical properties and cost. As a common adhesive, epoxy resin has a low dielectric constant (ε≈3-4), which is crucial for the high-frequency performance of inductors. Simultaneously, epoxy resin exhibits high hardness and strong bonding strength after curing, meeting the mechanical stability requirements of stacked structures. The low dielectric properties of epoxy resin reduce parasitic capacitance between the two inductor components. The tensile strength of cured epoxy resin can reach 50-70 MPa, effectively resisting delamination caused by vibration or thermal cycling. Epoxy resin adhesives are inexpensive and do not require complex curing equipment (such as high-temperature sintering), requiring only room temperature or low-temperature curing, thus reducing production costs and energy consumption. Therefore, using epoxy resin for the adhesive layer 30 offers advantages such as reduced distributed capacitance, optimized high-frequency characteristics, high bonding strength and temperature resistance, improved reliability, low cost, and simple process.

[0044] The adhesive layer 30 can also be made of silicone rubber. Addition-cured silicone rubber has a lower dielectric constant and is more elastic, making it suitable for applications requiring vibration damping. However, the thickness of the adhesive layer 30 needs to be increased (to 0.2 mm) to compensate for insufficient mechanical strength. Alternatively, it can be made of UV-cured acrylate. Acrylic adhesives cure quickly and are suitable for mass production.

[0045] Furthermore, the thickness of the adhesive layer 30 ranges from 0.05 mm to 0.1 mm.

[0046] The defined thickness range reflects a balance between mechanical strength and volume optimization. If the thickness is less than 0.05 mm, the adhesive layer 30 may be too thin, leading to localized insufficient adhesive and affecting bond strength. If the thickness is greater than 0.1 mm, it not only increases the overall inductance thickness but may also increase distributed capacitance due to the dielectric constant of the epoxy resin. The 0.05-0.1 mm range ensures effective bonding while minimizing the impact on electrical performance. A thickness of 0.05 mm ensures that the epoxy resin fully fills the interlayer gaps while avoiding increased capacitance due to excessive thickness. Furthermore, this thickness range matches the precision (±0.02 mm) of automated dispensing processes, allowing for precise control through quantitative dispensing equipment, avoiding uneven thickness caused by manual operation, and improving production yield.

[0047] Furthermore, the inductor body 10 is made of iron powder, iron-silicon-chromium powder, iron-silicon-aluminum, or iron-nickel powder and epoxy resin composite material.

[0048] The inductor body 10 is made of a composite material of iron powder, iron-silicon-chromium powder, iron-silicon-aluminum powder, or iron-nickel powder and epoxy resin, a choice that covers the needs of different application scenarios. The metal magnetic powder provides high permeability, and the epoxy resin acts as a matrix to fix the magnetic powder particles and isolate eddy currents. The two are combined to form a "soft magnetic particle-insulating matrix" structure, which has both high permeability and low eddy current loss.

[0049] The choice of this composite material not only optimizes the electromagnetic performance of the inductor but also enhances its mechanical stability and heat resistance. The use of metallic magnetic powders such as iron powder, iron-silicon-chromium powder, iron-silicon-aluminum powder, or iron-nickel powder ensures that the inductor body 10 possesses high saturation magnetic induction and low coercivity, which is crucial for improving inductor efficiency and reducing energy loss. Simultaneously, the epoxy resin matrix effectively fixes the magnetic powder particles, preventing displacement under high-frequency vibration or temperature changes, and also effectively isolates eddy currents through its insulation properties, reducing unnecessary energy loss. This "soft magnetic particle-insulating matrix" structure design allows the inductor to maintain good performance stability even in high-frequency, high-power applications.

[0050] Furthermore, the bent portions of the first electrode 111, the second electrode 112, the third electrode 121, and the fourth electrode 122 are rounded bends.

[0051] The rounded corner design of the electrode bending section optimizes mechanical reliability. Traditional right-angle bends are prone to stress concentration points at the corners. When the inductor is subjected to external impact or thermal expansion and contraction, the right-angle corner may crack or even break. The rounded corner design, by increasing the radius of curvature, distributes stress evenly in the rounded corner area, improving the fatigue strength of the electrode.

[0052] Rounded corner bending design improves structural reliability and process adaptability through geometric optimization. Traditional right-angle bends create stress concentration points at the corners, making them prone to cracking or even breakage when the inductor is subjected to mechanical vibration or thermal expansion and contraction. Rounded corner design, by increasing the radius of curvature at the corner, distributes stress evenly across the rounded area, reducing the stress concentration coefficient according to the principles of material mechanics. This design offers significant advantages in automated manufacturing: rounded corners can be formed in one step using a mold, avoiding the secondary deburring process required for right-angle bends and eliminating the risk of metal burrs scratching the PCB. In soldering processes, rounded corner transitions create a smoother contact surface between the electrode and the pad, resulting in more uniform solder flow and reducing the probability of cold solder joints. This is particularly suitable for the surface tension characteristics of solder in high-speed reflow soldering processes, improving production yield.

[0053] Furthermore, such as Figure 3 As shown, the first electrode 111, the second electrode 112, the third electrode 121 and the fourth electrode 122 are respectively provided with silver-plated pads 50 on the bottom surface of the first inductor 11, and the edges of the silver-plated pads 50 protrude from the electrode edges.

[0054] Silver-plated pads 50 are added to the surfaces of the four bottom electrodes, with the edges of the pads extending beyond the electrode body. This is intended to improve soldering reliability and reduce the risk of cold solder joints; at the same time, it increases the contact area between the pads and the PCB, enhancing the high-current carrying capacity. Through dual optimization of material properties and structural design, the silver-plated pads 50 significantly improve soldering performance. Silver's conductivity is second only to copper, and the silver plating layer effectively reduces the contact resistance between the electrode and the PCB pads, significantly reducing heat generation in high-current scenarios.

[0055] The design of the pad edges protruding beyond the electrodes creates a "soldering margin"—when the placement machine's positioning error is within ±0.1mm, the protruding silver layer still ensures full contact between the electrode and the pads, thereby improving soldering yield. This design essentially utilizes "physical redundancy" to compensate for process errors.

[0056] In addition, the oxide film (Ag2O) formed on the surface of the silver layer has good conductivity, which is completely different from the high resistance characteristics of the copper oxide film (CuO). It can maintain the stability of contact resistance for a long time, thereby extending the service life of the inductor in humid and hot environments.

[0057] Furthermore, such as Figure 3 As shown, the stacked integral molded inductor also has a shielding layer 70, which is disposed between the first inductor part 11 and the second inductor part 12, and the shielding layer 70 is made of iron-nickel alloy magnet.

[0058] Adding a nickel-iron alloy magnetic shielding layer 70 between the two inductor sections is a specific optimization to address high-frequency mutual inductance interference. Nickel-iron alloys (such as permalloy) have extremely high permeability, which guides magnetic field lines through the shielding layer 70 instead of penetrating to the other inductor section, thereby suppressing magnetic coupling between the two inductor sections. Suppressing magnetic coupling interference between the two inductor sections reduces the mutual inductance coefficient; it also reduces the influence of external magnetic fields on the inductance value, improving inductor stability.

[0059] Furthermore, the iron-nickel alloy magnetic shielding layer 70 effectively isolates external electromagnetic interference, providing the inductor with a relatively enclosed electromagnetic environment. This design is particularly important in high-sensitivity circuits or complex electromagnetic environments, ensuring that the inductor's performance is unaffected by external fluctuations. Simultaneously, the iron-nickel alloy magnetic shielding layer 70 also possesses a certain degree of thermal stability, maintaining stable permeability at high temperatures, further enhancing the inductor's reliability and lifespan.

[0060] Furthermore, the shielding layer 70 covers the stacked surface of the first inductor 11 and the second inductor 12.

[0061] The shielding layer 70 must completely cover the stacked surface of the first inductor 11 and the second inductor 12, which is crucial to ensuring the shielding effect. If the shielding layer 70 does not completely cover the surface, magnetic lines of force at the edge of the stacked surface can still penetrate, resulting in incomplete suppression of mutual inductance. The full-coverage design can form a complete magnetic shielding barrier between the two inductors, blocking the coupling path of magnetic lines of force from a physical structure perspective.

[0062] Furthermore, the shielding layer 70 is seamlessly welded to the inductor to enhance structural stability and the continuity of electromagnetic shielding. This seamless welding not only improves overall mechanical strength, preventing the shielding layer 70 from detaching or deforming during use, but also ensures the integrity of the electromagnetic shielding layer 70, avoiding electromagnetic leakage problems caused by connection gaps. This design further enhances the inductor's anti-interference capability, enabling it to maintain stable performance in various complex electromagnetic environments.

[0063] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A stacked, integrally molded inductor, characterized in that, include: An inductor body includes a first inductor portion and a second inductor portion. The first inductor portion is connected to a first electrode and a second electrode, and the second inductor portion is connected to a third electrode and a fourth electrode. The first inductor portion and the second inductor portion are stacked. The first electrode and the second electrode extend from two sides of the first inductor portion and are bent at the bottom of the first inductor portion. The third electrode and the fourth electrode extend from the other two sides of the first inductor portion and are bent at the bottom of the first inductor portion. An adhesive layer is disposed between the first inductor and the second inductor for connecting the first inductor and the second inductor.

2. The stacked monolithically integrated inductor of claim 1, wherein, The first electrode, the second electrode, the third electrode, and the fourth electrode are located at the bottom of the first inductor and are arranged in a rectangular shape.

3. The stacked monolithically integrated inductor of claim 2, wherein, The distance between two adjacent electrodes is ≥0.2mm.

4. The stacked monolithically integrated inductor of claim 1, wherein, The adhesive layer is made of epoxy resin.

5. The stacked monolithically integrated inductor of claim 1, wherein, The thickness of the adhesive layer ranges from 0.05 mm to 0.1 mm.

6. The stacked monolithically integrated inductor of claim 1, wherein, The inductor body is made of iron powder, iron-silicon-chromium powder, iron-silicon-aluminum, or iron-nickel powder and epoxy resin composite material.

7. The stacked monolithically integrated inductor of claim 1, wherein, The bent portions of the first electrode, the second electrode, the third electrode, and the fourth electrode are rounded bends.

8. The stacked monolithically integrated inductor of claim 1, wherein, The first electrode, the second electrode, the third electrode, and the fourth electrode are each provided with silver-plated pads on the bottom surface of the first inductor, and the edges of the silver-plated pads protrude beyond the electrode edges.

9. The stacked monolithically integrated inductor of claim 1, wherein, The stacked integral molded inductor also has a shielding layer, which is disposed between the first inductor and the second inductor, and the shielding layer is made of iron-nickel alloy magnet.

10. A stacked, integrally molded inductor according to claim 9, characterized in that, The shielding layer covers the stacked surface of the first inductor and the second inductor.

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