A capacitive coupler, an optical coupler, and their electromagnetic shielding structure

Abstract

This invention discloses a capacitive coupler, an optocoupler, and their electromagnetic shielding structure. The electromagnetic shielding structure includes a metal support, comprising an input terminal support and an output terminal support that are insulated from each other. The output terminal support and the input terminal support each include a first die-carrying platform and a second die-carrying platform for placing an output chip and an input chip, respectively. The first die-carrying platform is electrically connected to a ground pin and has an extension that is electrically connected to the first die-carrying platform. The extension, the first die-carrying platform, and the second die-carrying platform together form an electromagnetic shielding layer covering the output chip and the input chip. The extension is insulated from the second die-carrying platform. This invention, by incorporating an electromagnetic shielding layer on the metal support, can form an effective double electromagnetic shielding space together with a chip-level Faraday shielding layer. This significantly improves the electromagnetic interference immunity of the capacitive coupler and optocoupler, enhances electromagnetic compatibility, and is simple in structure, easy to implement, and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of capacitive coupling and optical coupling, and specifically relates to a capacitive coupling, an optical coupling and their electromagnetic shielding structure. Background Technology

[0002] In electronic circuits, changes in voltage or current in a conductor cause it to radiate electromagnetic waves, generating electromagnetic interference (EMI). EMI is the interference phenomenon caused by the interaction of electromagnetic waves with electronic components. Capacitive and optocouplers, as isolation devices, are typically used in environments including generators, large electric motors, and other equipment that generate strong electromagnetic fields. When exposed to these magnetic fields, sudden changes in voltage and current will generate EMI. Therefore, for many isolation devices, users require strong electromagnetic compatibility (EMC). Electromagnetic compatibility (EMC) refers to the ability of electronic devices, electrical equipment, or systems to function normally under expected electromagnetic conditions, as designed, without causing unacceptable electromagnetic interference to other components, equipment, or systems in that environment. It is a particularly critical performance characteristic for isolation devices.

[0003] Both capacitive and optocouplers are isolation devices that achieve signal transmission while providing electrical isolation. Capacitive couplers utilize the principle of on-chip capacitors to "pass AC and block DC" for isolated signal transmission. The input terminal of the capacitive coupler serves as the signal input, converting it into a wireless radio frequency signal for high-frequency reception and processing. The received signal is then output through the output terminal. This process involves differential signal processing. However, when external electromagnetic fields are present, electromagnetic interference can affect data signal transmission or cause potential data corruption. Therefore, the EMC (Electromagnetic Compatibility) of capacitive couplers on the market is relatively weak. Optocouplers utilize light-emitting diodes and photosensitive chips to achieve "electrical-optical-electrical" conversion. In some applications, those with IC functions or logic signal processing capabilities may also be susceptible to electromagnetic interference from external circuits.

[0004] Enhanced electromagnetic interference (EMI) immunity for capacitive and optocoupler devices is typically achieved using chip-level Faraday shielding. However, at the packaging level, due to design and internal structure limitations of capacitive and optocoupler devices, existing solutions lack EMI shielding. Furthermore, relying solely on chip-level Faraday shielding is insufficient for EMI immunity in many environments with strong electromagnetic interference. Summary of the Invention

[0005] The purpose of this invention is to provide a capacitive coupler, an optical coupler, and an electromagnetic shielding structure thereof to solve the aforementioned technical problems.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: an electromagnetic shielding structure for capacitive or optocoupler coupling, comprising a metal support, the metal support including an input end support and an output end support that are insulated from each other, the output end support including a first die carrier for placing an output end chip, the first die carrier being electrically connected to a ground pin, the input end support including a second die carrier for placing an input end chip, the first die carrier having an extension portion, the extension portion being electrically connected to a ground pin through the first die carrier to achieve grounding, the extension portion, the first die carrier, and the second die carrier together forming an electromagnetic shielding layer covering the output end chip and the input end chip, the extension portion being insulated from the second die carrier.

[0007] Furthermore, the extension includes a side portion and a top portion, with the top portion positioned spaced above the first and second substrate stages.

[0008] Furthermore, the side portion of the extension is composed of multiple spaced metal strips.

[0009] Furthermore, the top of the extension is made of a metal sheet.

[0010] Furthermore, the top of the extension is arranged parallel to the first substrate stage.

[0011] Furthermore, the extension is composed of a first sub-extension and a second sub-extension, which are formed by extending from opposite sides of the first substrate stage.

[0012] Furthermore, the first sub-extension and the second sub-extension have the same structure.

[0013] Furthermore, it also includes an epoxy molding compound for encapsulating the metal support, extensions, input chips, and output chips within the epoxy molding compound.

[0014] The present invention also provides a capacitive coupling having the above-described electromagnetic shielding structure.

[0015] The present invention also provides an optical coupler having the above-mentioned electromagnetic shielding structure.

[0016] Beneficial technical effects of the present invention:

[0017] This invention provides a good shielding effect for capacitive or optocouplers in the packaging structure by incorporating an electromagnetic shielding layer on a metal support. It also attenuates electromagnetic interference from the environment. Together with the chip-level Faraday shielding layer, it forms an effective dual electromagnetic shielding space, which can significantly improve the electromagnetic interference resistance of capacitive and optocouplers, and significantly enhance their electromagnetic compatibility. Moreover, the structure is simple, easy to implement, and low in cost. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a top view of the electromagnetic shielding structure of a specific embodiment of the present invention, omitting the epoxy encapsulation layer;

[0020] Figure 2 This is a side view of the electromagnetic shielding structure of a specific embodiment of the present invention, omitting the epoxy encapsulation layer;

[0021] Figure 3 This is a front view of the electromagnetic shielding structure of a specific embodiment of the present invention, omitting the epoxy encapsulation layer;

[0022] Figure 4 This is a schematic diagram of the electromagnetic shielding structure according to a specific embodiment of the present invention;

[0023] Figure 5 This is a structural diagram of the first and second sub-extensions of a specific embodiment of the present invention without bending.

[0024] Figure 6 This is a structural diagram of the first and second sub-extensions after bending, according to a specific embodiment of the present invention. Detailed Implementation

[0025] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0026] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0027] like Figure 1-6 As shown, an electromagnetic shielding structure for capacitive or optical coupling includes a metal support. The metal support includes an input terminal support 2 and an output terminal support 1 that are insulated from each other. Specifically, the input terminal support 2 and the output terminal support 1 are positioned along the front-back direction (with...). Figure 1(For directional reference) The output support 1 includes a first wafer stage 11 and an output pin 12, and the input support 2 includes a second wafer stage 21 and an input pin 22. The first wafer stage 11 is used to place the output chip 3, and the second wafer stage 21 is used to place the input chip 4. The specific structure of the metal support, the output chip 3 and the input chip 4 can refer to the existing capacitive or optocoupler metal support, output chip and input chip structure. This is a very mature existing technology and can be easily implemented by those skilled in the art, so it will not be described in detail.

[0028] The first die carrier stage 11 is electrically connected to the ground pin GND2 in the output pin 12. The first die carrier stage 11 has an extension 5, which is electrically connected to the ground pin GND2 through the first die carrier stage 11 to achieve grounding (since the ground pin GND2 in the output pin 12 is grounded during device use). The extension 5, the first die carrier stage 11, and the second die carrier stage 21 together form an electromagnetic shielding layer covering the output chip 3 and the input chip 4. The extension 5 is insulated from the second die carrier stage 21, that is, the extension 5 and the second die carrier stage 21 are spaced apart. The extension 5 is integrally formed by extending from the first die carrier stage 11, and can be fabricated together with the lead frame. The process is simple, easy to implement, and low in cost. Moreover, the electrical connection between the extension 5 and the first die carrier stage 11 is good.

[0029] Specifically, in this embodiment, the extension 5 includes a side portion 52 and a top portion 51. The top portion 51 is disposed above the first substrate stage 11 and the second substrate stage 21 at intervals, that is, it shields and covers the top of the first substrate stage 11 and the second substrate stage 21. The side portion 52 is disposed on the left and right sides between the first substrate stage 11 and the second substrate stage 21 and the top portion 51 of the extension 5.

[0030] Preferably, in this specific embodiment, the side portion 52 of the extension portion 5 is composed of a plurality of spaced metal strips. The metal strips have a small area, are easy to bend and process, and do not significantly affect the shielding effect, but are not limited thereto.

[0031] Preferably, in this specific embodiment, the top 51 of the extension 5 is made of a metal sheet to further enhance the shielding effect, but it is not limited thereto.

[0032] In this specific embodiment, the top 51 of the extension 5 is arranged parallel to the first substrate stage 11 and the second substrate stage 21, which facilitates bending processing. However, it is not limited to this. In some embodiments, the top 51 of the extension 5 may not be parallel to the first substrate stage 11 and the second substrate stage 21.

[0033] In this specific embodiment, the extension 5 is composed of a first sub-extension 53 and a second sub-extension 54, which are integrally formed from the left and right sides of the first substrate stage 11, respectively. This structure is easy to manufacture, requiring only two right-angle bends to the first sub-extension 53 and the second sub-extension 54. However, it is not limited to this; in some embodiments, the extension 5 can also be formed by extending from the left or right side of the first substrate stage 11 and then undergoing three right-angle bends, etc.

[0034] Specifically, the first sub-extension 53 includes a first sub-side 532 and a first sub-top 531, and the second sub-extension 54 includes a second sub-side 542 and a second sub-top 541. The first sub-side 532 and the second sub-side 542 constitute the left and right sides 52 of the extension 5. The first sub-top 531 and the second sub-top 541 are both sheet-like structures, which together constitute the top 51 of the extension 5. The free ends of the first sub-top 531 and the second sub-top 541 can contact each other or have a small gap, reducing the processing difficulty.

[0035] In this specific embodiment, the first sub-extension 53 and the second sub-extension 54 have the same structure, which makes the structure simple and easy to implement, but it is not limited to this.

[0036] Furthermore, it also includes an epoxy molding layer 6, used to encapsulate the metal bracket, extension 5, input chip 4, and output chip 3 within the epoxy molding layer 6, exposing the input pin 22 and output pin 12, such as... Figure 4 As shown, the specific potting process can refer to the existing epoxy potting process for capacitive or optocoupler coupling. This is a very mature existing technology that can be easily implemented by those skilled in the art, and will not be discussed in detail here.

[0037] Packaging process: First, a lead frame 7 is provided. The lead frame 7 has a metal support unit. The metal support unit has a first die holder 11 and a second die holder 21. The left and right sides of the first die holder 11 are respectively provided with a straight, outwardly extending, unbent first sub-extension 53 and a second sub-extension 54, as shown below. Figure 5 Next, the input chip 4 and output chip 3 are mounted and wire-bonded (refer to existing capacitive or optocoupler packaging processes for details). Then, using a bending fixture, the first sub-extension 53 and the second sub-extension 54 are bent at two right angles, so that the top of the first sub-extension 531 and the top of the second sub-extension 541 are bent above the first wafer stage 11 and the second wafer stage 21, covering or substantially covering the first wafer stage 11 and the second wafer stage 21, together forming an electromagnetic shielding layer, such as... Figure 6 As shown, epoxy potting is then performed, followed by rib cutting and molding, and the finished product is output, as shown. Figure 4 As shown.

[0038] The present invention also provides an optocoupler having the above-mentioned electromagnetic shielding structure, wherein the input chip 4 is a light-emitting diode and the output chip 3 is a photosensitive chip.

[0039] The present invention also provides a capacitive coupling having the above-described electromagnetic shielding structure.

[0040] This invention provides a good shielding effect for capacitive or optocouplers in the packaging structure by incorporating an electromagnetic shielding layer on a metal support. It also attenuates electromagnetic interference from the environment. Together with the chip-level Faraday shielding layer, it forms an effective dual electromagnetic shielding space, which can significantly improve the electromagnetic interference resistance of capacitive and optocouplers, and significantly enhance their electromagnetic compatibility. Moreover, the structure is simple, easy to implement, and low in cost.

[0041] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. An electromagnetic shielding structure for capacitive or optocoupler coupling, comprising a metal support, the metal support including an input terminal support and an output terminal support insulated from each other, the output terminal support including a first die holder for placing an output terminal chip, the first die holder being electrically connected to a ground pin, and the input terminal support including a second die holder for placing an input terminal chip, characterized in that: The first wafer carrier stage has an extension, which is electrically connected to the grounding pin through the first wafer carrier stage to achieve grounding. The extension, together with the first and second wafer carrier stages, forms an electromagnetic shielding layer covering the output chip and the input chip. The extension is insulated from the second wafer carrier stage. The extension is composed of a first sub-extension and a second sub-extension, which are formed by extending from opposite sides of the first stage, respectively. The extension includes a side and a top, with the top spaced above the first and second film stages. The first sub-extension includes a first sub-side and a first sub-top, and the second sub-extension includes a second sub-side and a second sub-top. The first sub-side and the second sub-side constitute the left and right sides of the extension. The first sub-top and the second sub-top are both sheet-like structures that together constitute the top of the extension. The free ends of the first sub-top and the second sub-top have small gaps to reduce the difficulty of processing.

2. The electromagnetic shielding structure for capacitive or optical coupling according to claim 1, characterized in that: The side of the extension is composed of multiple spaced metal strips.

3. The electromagnetic shielding structure for capacitive or optical coupling according to claim 1, characterized in that: The top of the extension is made of a metal sheet.

4. The electromagnetic shielding structure for capacitive or optical coupling according to claim 3, characterized in that: The top of the extension is arranged parallel to the first substrate stage.

5. The electromagnetic shielding structure for capacitive or optical coupling according to claim 1, characterized in that: The first sub-extension and the second sub-extension have the same structure.

6. The electromagnetic shielding structure of the capacitive or optical coupler according to any one of claims 1-5, characterized in that: It also includes an epoxy molding compound for encapsulating the metal support, extensions, input chips, and output chips within the epoxy molding compound.

7. A capacitive coupling, characterized in that: The electromagnetic shielding structure described in any one of claims 1-6 is provided.

8. An optocoupler, characterized in that: The electromagnetic shielding structure described in any one of claims 1-6 is provided.

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