Switching power supply circuit, medical power supply and medical equipment
By bridging the capacitors in the switching power supply circuit with a shielding sheet spaced apart from the circuit module, the problems of reduced shielding effect and safety hazards caused by the reduction in the area of traditional shielding sheets are solved, achieving better EMI performance and heat dissipation.
Patent Information
- Application Number
- CN202520132616.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-01-20
AI Technical Summary
In switching power supply products, especially AC-DC power adapters, the shielding effect of traditional shielding sheets is reduced due to the smaller area, which cannot meet EMI requirements. At the same time, traditional connection methods increase safety hazards and thermal resistance.
By bridging the first and second capacitors of the switching power supply circuit with a shielding sheet made of metal and spaced apart from the circuit module, only a 1 MOPP insulation distance is required. Combined with an insulation layer, this ensures safety and heat dissipation.
Offering a larger shielding area in products of the same size improves EMI performance and heat dissipation, while reducing safety hazards and thermal resistance, thus enhancing product reliability.
Smart Images
Figure CN223872192U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electronic technology, and in particular to a switching power supply circuit, a medical power supply, and a medical device. Background Technology
[0002] In switching power supply products, especially AC-DC power adapters, shielding sheets are added to improve EMI (electromagnetic interference). Various electromagnetic interferences generated by switching components, transformers, and high-frequency circuits are also shielded and filtered out by these sheets to meet EMI requirements. In some technologies, due to safety regulations, the area of the metal shielding sheet must be reduced. However, as the size of the metal shielding sheet decreases, its shielding effectiveness also decreases. Utility Model Content
[0003] This application provides a switching power supply circuit, a medical power supply, and a medical device, aiming to improve the problem of poor shielding effect in switching power supply products.
[0004] To achieve the above-mentioned technical effects, one technical solution adopted in this application is: to provide a switching power supply circuit, comprising:
[0005] The circuit module includes a first capacitor and a second capacitor. One end of the first capacitor is connected to the static point on the primary side of the circuit module, and one end of the second capacitor is connected to the static point on the secondary side of the circuit module.
[0006] A shielding sheet is spaced apart from the circuit module. The other end of the first capacitor is connected to the shielding sheet, and the other end of the second capacitor is connected to the end of the shielding sheet away from the first capacitor. The shielding sheet is at least partially made of metal and is used to suppress electromagnetic interference from the circuit module.
[0007] In this application example, the connection point of the shielding sheet is connected between the first capacitor and the second capacitor on the primary and secondary sides. Only 1 MOPP (patient protection) is needed from the shielding sheet to both the primary and secondary sides. This allows for a larger shielding sheet area in a product design of the same size, resulting in better heat dissipation and EMI performance.
[0008] Among them, the first capacitor and / or the second capacitor are Y1 capacitors.
[0009] The shielding sheet is also connected to the protective grounding wire of the circuit module.
[0010] The switching power supply circuit also includes:
[0011] An insulating layer is placed between the shielding sheet and the circuit module.
[0012] The circuit module has a component surface and a solder surface that are positioned opposite each other; the shielding sheet includes:
[0013] The first chip is provided on the side of the component face away from the soldering face. The other end of the first capacitor is connected to the first chip, and the other end of the second capacitor is connected to the end of the first chip away from the first capacitor. The first chip is at least partially made of metal. The first chip is used to suppress electromagnetic interference on the side of the component face.
[0014] The circuit module has a component surface and a solder surface that are positioned opposite each other; the shielding sheet includes:
[0015] The second plate is provided on the side of the soldering surface away from the component surface. The other end of the first capacitor is connected to the second plate, and the other end of the second capacitor is connected to the end of the second plate away from the first capacitor. The second plate is at least partially made of metal. The second plate is used to suppress electromagnetic interference on the side of the soldering surface.
[0016] The circuit module has a component surface and a solder surface that are positioned opposite each other; the shielding sheet includes:
[0017] The third plate is located on the outside of the circuit module. The third plate has an inner surface that is set at an angle to the component surface. The other end of the first capacitor is connected to the third plate, and the other end of the second capacitor is connected to the end of the third plate away from the first capacitor. The third plate is at least partially made of metal.
[0018] The shielding sheet also includes:
[0019] The first chip is provided on the side of the component face away from the soldering surface. The other end of the first capacitor is also connected to the first chip. The other end of the second capacitor is also connected to the end of the first chip away from the first capacitor. The first chip is at least partially made of metal.
[0020] The shielding sheet also includes:
[0021] The second plate has a solder surface facing away from the component surface. The other end of the first capacitor is also connected to the second plate, and the other end of the second capacitor is also connected to the end of the second plate away from the first capacitor. The second plate is at least partially made of metal.
[0022] The circuit module has a component surface and a soldering surface that are positioned opposite each other. The shielding sheet has a hollow structure and is fitted onto the outside of the circuit module.
[0023] This application also provides an example of a medical device, including a switching power supply circuit as in any of the examples above. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a circuit diagram of an example of a switching power supply circuit of this application;
[0026] Figure 2 This is a schematic diagram of a module of an example of the switching power supply circuit of this application;
[0027] Figure 3 This is a schematic diagram of an example of a switching power supply circuit according to this application;
[0028] Figure 4 This is a schematic diagram of the installation state of an example of the shielding sheet of the switching power supply circuit of this application;
[0029] Figure 5 This is a schematic diagram of the installation state of another example of the shielding sheet of the switching power supply circuit of this application;
[0030] Figure 6 This is a schematic diagram of an example of the shielding sheet and circuit module being separated in this application.
[0031] Figure 7 This is an exploded view of an example of a switching power supply circuit according to this application;
[0032] Figure 8 This is a schematic diagram of another example of the switching power supply circuit of this application;
[0033] Figure 9 This is a schematic diagram of another example of the switching power supply circuit of this application;
[0034] Figure 10 This is a schematic diagram of another example of the shielding sheet and circuit module being separated in this application;
[0035] Figure 11 This is a schematic diagram of another example of the switching power supply circuit of this application.
[0036] Among them: 100, switching power supply circuit;
[0037] 10. Circuit module; 11. Rectifier module; 12. Filter module; 13. Power conversion module; 14. Output module; 15. Component side; 16. Soldering side; CY1, First capacitor; CY2, Second capacitor;
[0038] 20. Shielding sheet; 21. First sheet body; 22. Second sheet body; 23. Third sheet body;
[0039] 30. Insulation layer;
[0040] 40. Outer shell; 41. First shell; 42. Second shell;
[0041] 4a. First direction. Detailed Implementation
[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0043] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" in this application description should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this document based on the specific circumstances.
[0044] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.
[0045] Because AC-DC and DC-DC isolated switching power supplies require safe isolation between the primary and secondary sides, the addition of shielding must meet insulation requirements such as safety distances and withstand voltage tests. The design must consider eliminating safety risks and hazards during end-use. In some technologies, the shielding is connected by directly soldering pins to the static points (ground) on the primary and secondary sides to achieve EMI improvement. This is especially true in medical power supply designs, where safety distances, withstand voltage requirements, and temperature limits are even higher. Traditional shielding requires sufficient safety distances, necessitating a reduction in shielding area, which weakens the shielding effect.
[0046] This application addresses the aforementioned problems by proposing an example of a switching power supply circuit. The switching power supply circuit can be used in medical devices or other electrical equipment, and can serve as a power adapter for medical devices.
[0047] Please see Figures 1 to 6 In this application example, the switching power supply circuit 100 includes a circuit module 10 and a shielding sheet 20. The circuit module 10 includes a first capacitor CY1 and a second capacitor CY2. One end of the first capacitor CY1 is connected to the static point of the primary side of the circuit module 10, and one end of the second capacitor CY2 is connected to the static point of the secondary side of the circuit module 10. The shielding sheet 20 is spaced apart from the circuit module 10. The other end of the first capacitor CY1 is connected to the shielding sheet 20, and the other end of the second capacitor CY2 is connected to the end of the shielding sheet 20 away from the first capacitor CY1. The shielding sheet 20 is at least partially made of metal and is used to suppress electromagnetic interference of the circuit module 10.
[0048] The circuit module 10 may include electrical components of the switching power supply circuit 100. Optionally, the circuit module 10 may include a filter module 12, a rectifier module 11, a power conversion module 13, and an output module 14. The filter module 12 can be used to reduce electromagnetic interference in the circuit; the rectifier module 11 can be used to rectify AC power into DC power; the power conversion module 13 can step down the voltage through a transformer, where the primary side of the transformer is a high-voltage area and the secondary side of the transformer is a low-voltage area; the output module 14 can be used to connect to external electronic devices.
[0049] The first capacitor CY1 is used to connect to the primary side of the circuit module 10. One end of the first capacitor CY1 can be used to connect to the static point PGND (Power Ground) of the primary side, and the other end of the first capacitor CY1 is used to connect to the shielding sheet 20.
[0050] The second capacitor CY2 is used to connect the static point SGND (Signal Ground) on the secondary side of the circuit module 10. At the same time, the other end of the second capacitor CY2 is connected to the end of the shield 20 away from the first capacitor CY1, so that the shield 20 is connected in series between the first capacitor CY1 and the second capacitor CY2.
[0051] The shielding sheet 20 is at least partially made of metal, meaning it can be entirely made of metal, or it can be a layered structure combining metal and non-metal materials. In this example, the shielding sheet 20 can be made of metal such as copper or aluminum. In this example, the shielding sheet 20 is connected between the first capacitor CY1 and the second capacitor CY2. The shielding sheet 20, the first capacitor CY1, and the second capacitor CY2 form a series circuit across the primary and secondary sides. The first capacitor CY1 and the second capacitor CY2 provide a current path to address EMI common-mode interference noise, allowing the common-mode noise to form a loop within the power supply, reducing interference from external conduction and radiation. The shielding sheet 20 is spaced apart from the circuit module 10 to ensure mutual insulation between them. In this example, the position of the shielding sheet 20 can be determined according to the shielding requirements. The shielding sheet 20 can be placed at any position outside the circuit module 10. The shielding sheet 20 only needs to provide EMI shielding performance. Optionally, the circuit module 10 includes a circuit board, wherein the circuit board has a soldering surface 16 and a component surface 15 arranged opposite to each other. The component surface 15 and the soldering surface 16 can be two surfaces of the circuit board along a first direction 4a. The first direction 4a can be the thickness direction of the circuit board. The shielding sheet 20 can be placed outside the soldering surface 16 or the component surface 15. The shielding sheet 20 can also be placed on the side of the circuit board so that the shielding sheet 20 is set at an angle to the circuit board.
[0052] Traditional shielding plate 20 connection methods require a 2 MOPP (Mean Interval) requirement to reach the other side and functional insulation from the same side. For Class I safety protection products, a 1 MOPP requirement is also needed between the shielding plate 20 and the PE (protective earth) wire, effectively doubling the space required for safety distance. In this example, the shielding plate 20 is connected to the primary and secondary sides via a first capacitor CY1 and a second capacitor CY2, respectively. Since the shielding plate 20 is connected between the first capacitor CY1 and the second capacitor CY2, only a 1 MOPP is needed to reach both the primary and secondary sides. Therefore, the connection method provided in this example allows for a larger shielding plate 20 area in a product design of the same size, resulting in better heat dissipation and EMI performance.
[0053] In some examples, the first capacitor CY1 and / or the second capacitor CY2 are Y1 capacitors. In this example, by using safety capacitors, the shielding sheet 20 can be substantially insulated from the primary and / or secondary sides, thereby further improving the reliability of the shielding sheet 20.
[0054] In some examples, the shield 20 is also connected to the protective grounding wire of the circuit module 10 to provide grounding protection.
[0055] In some examples, the switching power supply circuit 100 further includes an insulating layer 30 disposed between the shielding sheet 20 and the circuit module 10. In this example, the insulating layer 30 can be disposed between the shielding sheet 20 and the circuit module 10 to provide insulation between them. The insulating layer 30 can be a sheet-like or film-like structure. In this example, the position of the insulating layer 30 corresponds to the shape and position of the shielding layer, and the insulating layer 30 acts as a barrier between the shielding layer and the circuit module 10.
[0056] In a traditional switching power supply circuit 100, due to the need to meet the requirements of reinforced insulation or double insulation, on the one hand, the middle insulation layer 30 needs to be thicker. The middle insulation layer 30 needs to meet the requirements of reinforced insulation, and its thickness is twice that of the basic insulation, which increases the thermal resistance and thus reduces the thermal conductivity of the power device. On the other hand, if the insulation layer 30 is damaged, cracked, or punctured by the pins of the device during the production process, it will pose a serious risk to the personal safety of the user.
[0057] Since only 1 MOPP of insulation is required from the shield 20 to both the primary and secondary sides in this example, and the insulation layer 30 between the shield 20 and the circuit board only needs to meet basic insulation requirements, compared to traditional connection methods, the insulation layer 30 can be thinner and have lower thermal resistance using the connection method in this example. The heat from the power devices in the circuit module 10 can be transferred to the shield 20 for heat dissipation more efficiently, resulting in lower power device temperatures, higher product efficiency, and better reliability. When a safety failure occurs where the insulation layer 30 is damaged or punctured by a pin at a point on the primary or secondary side, this example can still provide 1 MOPP of basic insulation protection, while traditional connection methods would directly lead to catastrophic personal safety risks if a point of failure occurs.
[0058] Please see Figure 7 and Figure 8 In some examples, the circuit module 10 has a component surface 15 and a solder surface 16 arranged opposite to each other; a shielding sheet 20 is provided on the side of the component surface 15 facing away from the solder surface 16.
[0059] The component surface 15 and the solder surface 16 are two opposing surfaces on the circuit module 10, and the power devices of the circuit module 10 are mounted on the component surface 15. In this example, a shielding sheet 20 is provided on the side of the component surface 15 away from the solder surface 16 so that the shielding sheet 20 can serve as a shield and heat dissipation device on one side of the component surface 15. Optionally, an insulating layer 30 can be provided on the side of the shielding sheet 20 facing the component surface 15. In some examples, the shielding sheet 20 includes a first sheet 21, which is provided on the side of the component surface 15 away from the solder surface 16. The other end of the first capacitor CY1 is connected to the first sheet 21, and the other end of the second capacitor CY2 is connected to the end of the first sheet 21 away from the first capacitor CY1. The first sheet 21 is at least partially made of metal. The first sheet 21 can be substantially the same in shape and volume as the component surface 15 of the circuit module 10, and the first sheet 21 can be independently provided on one side of the component surface 15 of the circuit module 10.
[0060] In some examples, unlike the previous example, a shielding sheet 20 is provided on the side of the solder surface 16 facing away from the component surface 15. This shielding sheet 20 serves to provide shielding and heat dissipation on the side of the solder surface 16 facing away from the component surface 15. Optionally, an insulating layer 30 may be provided on the side of the shielding sheet 20 facing the solder surface 16. In some examples, a second sheet 22 is provided on the side of the solder surface 16 facing away from the component surface 15. The other end of the first capacitor CY1 is connected to the second sheet 22, and the other end of the second capacitor CY2 is connected to the end of the second sheet 22 away from the first capacitor CY1. The second sheet 22 is at least partially made of metal. The second sheet 22 can be used to suppress electromagnetic interference on the side of the solder surface 16, and it can also improve the heat dissipation performance on the side of the solder surface 16. In this example, the second sheet 22 can be independently provided on the side of the solder surface 16 of the circuit module 10.
[0061] In some examples, shielding sheets 20 can be respectively provided on the outer side of the component surface 15 and the outer side of the soldering surface 16 to form shielding and heat dissipation structures on the outer sides of the component surface 15 and the soldering surface 16, respectively. In some examples, a first sheet 21 is provided on the outer side of the component surface 15, and a second sheet 22 is provided on the outer side of the soldering surface 16. The first sheet 21 and the second sheet 22 can be connected to a first capacitor CY1 and a second capacitor CY2, respectively, so that the first sheet 21 and the second sheet 22 can be used to form shielding structures on the outer sides of the component surface 15 and the soldering surface 16, respectively. Optionally, in this example, the first sheet 21 can also be interconnected with the second sheet 22 to form a whole.
[0062] Please see Figure 9 , Figure 10 as well as Figure 11 In some examples, the circuit module 10 has a component surface 15 and a solder surface 16 arranged opposite to each other; the shielding sheet 20 includes a third sheet 23, which is located on the outside of the circuit module 10. The third sheet 23 has an inner surface that is angled to the component surface 15. The other end of the first capacitor CY1 is connected to the third sheet 23, and the other end of the second capacitor CY2 is connected to the end of the third sheet 23 away from the first capacitor CY1. The third sheet 23 is at least partially made of metal.
[0063] The inner surface of the third sheet 23 is the side of the third sheet 23 facing the circuit module 10. The inner surface of the third sheet 23 is angled to the component surface 15, meaning it is not parallel to the component surface 15. In this example, the inner surface of the third sheet 23 is perpendicular to the component surface 15. The third sheet 23 can be used for shielding and heat dissipation on the side of the circuit module 10. The third sheet 23 is spaced apart from the circuit module 10. The third sheet 23 is at least partially made of metal, meaning it can be entirely made of metal, or it can be a layered structure with a metal layer.
[0064] The third chip 23 is connected in series between the first capacitor CY1 and the second capacitor CY2, so that the third chip 23 can be connected across the primary and secondary sides. In this example, the number of third chips 23 can be determined according to the specific circumstances of the switching power supply circuit 100 to improve the shielding and heat dissipation performance of the switching power supply circuit 100. In some examples, there are multiple third chips 23, which can be respectively disposed on opposite sides of the circuit module 10. In some examples, there are multiple third chips 23, which can all be disposed on the same side of the circuit module 10, and the multiple third chips 23 can be combined on the same side of the circuit module 10 to form a shielding and heat dissipation structure. Optionally, the third chip 23 is spaced apart from the circuit module 10 to form insulation; in some examples, an insulating layer 30 is provided on the side of the third chip 23 facing the circuit module 10.
[0065] In some examples, the shielding sheet 20 further includes a first sheet 21. The first sheet 21 is provided on the side of the component surface 15 facing away from the soldering surface 16. The other end of the first capacitor CY1 is also connected to the first sheet 21, and the other end of the second capacitor CY2 is also connected to the end of the first sheet 21 away from the first capacitor CY1. The first sheet 21 is at least partially made of metal. The first sheet 21 can be connected to a third sheet 23. In this example, the connection between the first sheet 21 and the third sheet 23 includes the first sheet 21 and the third sheet 23 being connected to form a whole, or the first sheet 21 and the third sheet 23 being connected in parallel between the first capacitor CY1 and the second capacitor CY2. In this example, the first sheet 21 and the third sheet 23 can be used to form shielding and heat dissipation structures in two directions of the circuit module 10, respectively, to improve the electromagnetic shielding and heat dissipation performance of the switching power supply circuit 100. In some examples, an insulating layer 30 can be provided on the side of the first sheet 21 and the third sheet 23 facing the circuit module 10.
[0066] In some examples, unlike the previous example, the shielding sheet 20 further includes a second sheet 22. The second sheet 22 is located on the side of the soldering surface 16 facing away from the component surface 15. The other end of the first capacitor CY1 is also connected to the second sheet 22, and the other end of the second capacitor CY2 is also connected to the end of the second sheet 22 away from the first capacitor CY1. The second sheet 22 is at least partially made of metal. The second sheet 22 can be connected to a third sheet 23. The second sheet 22 can be positioned opposite to the first sheet 21. The second sheet 22 and the third sheet 23 can form a shielding and heat dissipation structure in two directions of the circuit module 10 to improve the electromagnetic shielding and heat dissipation performance of the switching power supply circuit 100. In some examples, an insulating layer 30 can be provided on the side of the third sheet 23 and the second sheet 22 facing the circuit module 10.
[0067] In some examples, the shielding sheet 20 further includes a first sheet 21 and a second sheet 22, wherein the first sheet 21 and the second sheet 22 are respectively disposed one-to-one on the component side and the soldering side of the circuit module 10, and at least one of the first sheet 21 and the second sheet 22 is connected to a third sheet 23, so that the first sheet 21, the second sheet 22 and the third sheet 23 form shielding and heat dissipation structures in multiple directions on the outside of the circuit module 10.
[0068] In some examples, the circuit module 10 has a component surface 15 and a solder surface 16 arranged opposite each other, and the shielding sheet 20 has a hollow structure and is fitted over the outside of the circuit module 10. In this example, the shielding sheet 20 may have a hollow cylindrical structure, and the shielding sheet 20 is fitted over the outside of the circuit module 10 so that the shielding sheet 20 at least partially surrounds the outer periphery of the circuit module 10.
[0069] Based on the aforementioned switching power supply circuit 100, this application also proposes an example of a medical power supply, which includes the switching power supply circuit 100 as described in any of the above examples. The medical power supply can be connected to mains power and can be connected to medical equipment.
[0070] Based on the aforementioned medical power supply, this application also proposes an example of a medical device, which includes the medical power supply as described in any of the above examples. In this example, the medical power supply can be separately located on the outside of the medical device, or it can be integrated into the medical device.
[0071] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.
Claims
1. A switching power supply circuit, characterized in that, include: A circuit module, comprising a first capacitor and a second capacitor, wherein one end of the first capacitor is connected to the static point on the primary side of the circuit module, and one end of the second capacitor is connected to the static point on the secondary side of the circuit module. as well as A shielding sheet is disposed at a distance from the circuit module. The other end of the first capacitor is connected to the shielding sheet, and the other end of the second capacitor is connected to the end of the shielding sheet away from the first capacitor. The shielding sheet is at least partially made of metal and is used to suppress electromagnetic interference of the circuit module.
2. The switching power supply circuit as described in claim 1, characterized in that, The first capacitor and / or the second capacitor are Y1 capacitors.
3. The switching power supply circuit as described in claim 1, characterized in that, The shielding sheet is also connected to the protective grounding wire of the circuit module.
4. The switching power supply circuit as described in claim 1, characterized in that, The switching power supply circuit also includes: An insulating layer is disposed between the shielding sheet and the circuit module.
5. The switching power supply circuit according to any one of claims 1 to 4, characterized in that, The circuit module has a component surface and a solder surface arranged opposite to each other; the shielding sheet includes: The first plate is provided on the side of the component surface away from the welding surface. The other end of the first capacitor is connected to the first plate, and the other end of the second capacitor is connected to the end of the first plate away from the first capacitor. The first plate is at least partially made of metal. The first plate is used to suppress electromagnetic interference on the side of the component surface. And / or, a second plate is provided on the side of the welding surface away from the component surface, the other end of the first capacitor is connected to the second plate, the other end of the second capacitor is connected to the end of the second plate away from the first capacitor, the second plate is at least partially made of metal, and the second plate is used to suppress electromagnetic interference on the side of the welding surface.
6. The switching power supply circuit according to any one of claims 1 to 4, characterized in that, The circuit module has a component surface and a solder surface arranged opposite to each other; the shielding sheet includes: The third piece is disposed on the outside of the circuit module. The third piece has an inner surface that is angled to the component surface. The other end of the first capacitor is connected to the third piece, and the other end of the second capacitor is connected to the end of the third piece away from the first capacitor. The third piece is at least partially made of metal.
7. The switching power supply circuit as described in claim 6, characterized in that, The shielding sheet also includes: The first plate is provided on the side of the component surface opposite to the welding surface. The other end of the first capacitor is also connected to the first plate. The other end of the second capacitor is also connected to the end of the first plate away from the first capacitor. The first plate is at least partially made of metal. And / or, a second plate, wherein the welding surface is provided on the side opposite to the component surface, the other end of the first capacitor is also connected to the second plate, and the other end of the second capacitor is also connected to the end of the second plate away from the first capacitor, and the second plate is at least partially made of metal.
8. The switching power supply circuit according to any one of claims 1 to 4, characterized in that, The circuit module has a component surface and a solder surface arranged opposite to each other, and the shielding sheet has a hollow structure and is sleeved on the outside of the circuit module.
9. A medical power supply, characterized in that, Includes the switching power supply circuit as described in any one of claims 1 to 8.
10. A medical device, characterized in that, Includes the medical power supply as described in claim 9.