Power supply device

Abstract

This makes it possible to suppress and prevent deterioration of noise terminal voltage while ensuring the necessary insulation distance. [Solution] The power supply unit 1 has an isolation transformer 12 equipped with a ferrite core and windings mounted on a mounting board, and a fuse 14 and a cement resistor 16 mounted on the mounting board 10 at a distance between components from which noise from the isolation transformer 12 propagates. A shielding substrate 22 having a copper pattern and an insulator, with the insulator located on the outermost surface, is placed between the isolation transformer 12 and the fuse 14 and between the isolation transformer 12 and the cement resistor 16, and the shielding substrate 22 is connected to the mounting board 10.

Description

TECHNICAL FIELD

[0001] The present invention relates to a power supply apparatus including noise-generating components such as transformers and inductors each having a ferrite core and windings. BACKGROUND ART

[0002] Conventionally, the Electrical Appliance and Material Safety Act requires securing a required insulation distance between the front stage and the rear stage of rectification, and international standards (such as IEC62368) require an insulation distance between a fuse and other components. In addition, international standards (such as CISPR11 and EN55011) set standard values for the noise terminal voltage, which refers to the noise generated by a power supply apparatus that adversely affects peripheral devices via input lines, and power supply apparatuses are required to meet these requirements.

[0003] In a power supply apparatus, for example as shown in FIG. 7, an input connector 180 to which an input line 600 is connected, a fuse 140, and an insulation transformer 120 are mounted on a mounting substrate 100. The fuse 140 is mounted on a second mounting substrate 200, and is mounted on the mounting substrate 100 by mounting the second mounting substrate 200 on which the fuse 140 is mounted to the mounting substrate 100.

[0004] Here, the insulation transformer 120 is a noise-generating component including a ferrite core 121 and windings (a primary winding and a secondary winding) 122. The ferrite core 121 is known as a component with potential variation, and when another component is arranged in the vicinity thereof, the ferrite core propagates noise through electrostatic coupling or magnetic field coupling with the other component arranged in the vicinity.

[0005] Furthermore, the fuse 140 is mounted near the isolation transformer 120 and is a noise-affecting component mounted at a distance from the ferrite core 121 of the isolation transformer 120 through which noise propagates. As shown in Figure 7, a stray capacitance C5 is generated between the ferrite core 121 of the isolation transformer 120 and the fuse 140, and stray capacitances C1 and C2 are also generated between the winding 122 of the isolation transformer 120 and the ferrite core 121, and between the ferrite core 121 and the mounting substrate 100. Through these capacitances, each part is electrostatically and magnetically coupled, and voltage fluctuations in the winding 122 of the isolation transformer 120 propagate as noise through the ferrite core 121 and fuse 140 to the input line 600, causing the noise terminal voltage to deteriorate.

[0006] Furthermore, in power supply units, noise countermeasures are generally implemented to reduce noise propagated to the input line 600 by providing noise suppression circuits such as noise filters in the electrical circuit. However, since the fuse 140 is a component that protects the electrical circuit located downstream from high currents exceeding its rating, it needs to be placed in the electrical circuit at the position closest to the input line 600 (on the primary side). Noise propagated to the fuse 140 through electrostatic or magnetic coupling with the isolation transformer 12 cannot be reduced by the noise suppression circuit located downstream of the fuse 140 (on the secondary side). Moreover, not limited to the fuse 140, noise propagated to noise-affecting components that are located on the input line 600 side (primary side) of the noise suppression circuit and are mounted near noise-generating components such as the isolation transformer 120 at the inter-component distance from which noise propagates cannot be reduced by the noise suppression circuit.

[0007] Therefore, noise that propagates to the input line 600 via components located on the input line 600 side of the noise suppression circuit has conventionally been countered by placing a shielding member made of conductive material such as copper or aluminum between the noise-generating component and the noise-affecting component. For example, as shown in Figure 8, there is a shielding plate 220 placed as a shielding member between the isolation transformer 120 and the fuse 140.

[0008] As shown in Figure 8, when a shield plate 220 is placed between the isolation transformer 120 and the fuse 140, stray capacitances C6 and C7 are generated between the ferrite core 121 of the isolation transformer 120 and the shield plate 220, and between the shield plate 220 and the fuse 140, resulting in electrostatic and magnetic field coupling. However, since the shield plate 220 is connected to the stable potential of the mounting substrate 100, its potential remains stable without fluctuation. This suppresses and prevents charge transfer from the ferrite core 121 to the fuse 140, and suppresses and prevents potential fluctuations in the fuse 140. As a result, noise propagation from the ferrite core 121 through the fuse 140 to the input line 600 is suppressed and prevented, and deterioration of the noise terminal voltage can be suppressed and prevented. Note that when using electrostatic coupling countermeasures, the shield plate 220 is placed connected to the stable potential of the mounting substrate 100, but when using magnetic field coupling countermeasures, it is not necessarily required to connect to the stable potential, and the shield plate 220 may be placed floating on the mounting substrate 100. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2002-281738 [Patent Document 2] Japanese Patent Publication No. 2016-122747 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] However, if a shielding member is placed between a noise-generating component and a noise-affecting component to prevent deterioration of the noise terminal voltage, it may become difficult to ensure sufficient insulation distance between the noise-generating component and the noise-affecting component, depending on the distance between the components, because the shielding member is a conductor. In particular, if the distance between the noise-generating component and the noise-affecting component is 3 mm or less, it becomes difficult to ensure the necessary insulation distance when a shielding member is placed between the noise-generating component and the noise-affecting component. Therefore, it becomes necessary to increase the insulation distance by placing an insulator between the noise-generating component and the shielding member, and between the noise-affecting component and the shielding member.

[0011] Therefore, it is conceivable to apply insulating paint to the surface of the shielding member, or to place insulating paper, which is an insulating material, between the noise-generating component and the shielding member, and between the noise-affecting component and the shielding member.

[0012] However, when insulating paint is applied to shielding members, there are several problems, including the fact that the process of applying the insulating paint to the shielding members is complex, and that controlling the thickness of the insulating layer applied to the shielding members is troublesome, which increases the cost of the materials, as well as the difficulty of soldering shielding members coated with insulating paint.

[0013] Furthermore, when additional insulating paper is added, space is required equal to the thickness of the additional insulating paper, and depending on the distance between noise-generating components and noise-affecting components, placement may not be possible. In addition, the insulating paper and shielding material must be aligned and fixed with adhesive, etc., which complicates the process, similar to when insulating paint is applied to the shielding material. Thus, this also presents multiple problems.

[0014] Furthermore, in order to connect the shielding member to the stable potential of the mounting board, it is necessary to solder the shielding member to the mounting board using a crimping terminal for connection. This requires sufficient space to crimp the crimping terminal to the shielding member and connect it to the mounting board, making it physically difficult to place the shielding member in a confined space.

[0015] Furthermore, one might consider mounting components on the circuit board with increased distance between noise-generating components and noise-affecting components to eliminate the need for insulating paint or insulating paper. However, this would contradict the market demand for miniaturization of power supply units and is therefore undesirable as a countermeasure.

[0016] Furthermore, as a countermeasure that does not use shielding material, as shown in Figure 9, the deterioration of the noise terminal voltage can also be prevented by connecting the ferrite core 121 of the isolation transformer 120 itself to the stable potential of the mounting substrate 100. This is because, by connecting the ferrite core 121 of the isolation transformer 120 to the stable potential of the mounting substrate 100, potential fluctuations of the ferrite core 121 are suppressed and prevented, and charge transfer to the fuse 140 is suppressed and prevented.

[0017] However, when the ferrite core 121 is connected to the stable potential of the mounting board 100, the winding 122, which is capacitively coupled to the ferrite core 121, becomes electrostatically coupled to the stable potential of the mounting board 100. This leads to increased capacitance loss and increased heat generation during power supply switching.

[0018] As described above, conventional measures to suppress and prevent the deterioration of noise terminal voltage while maintaining insulation distance inevitably lead to various problems, such as increased complexity of processes and control, difficulty in placement in confined spaces, larger power supply units, and increased heat generation.

[0019] The present invention aims to provide a power supply device that solves the problems that arise with conventional measures, ensures the necessary insulation distance, and suppresses and prevents deterioration of noise terminal voltage. [Means for solving the problem]

[0020] (Power supply device) The present invention relates to a power supply device provided with a noise-generating component, The noise-generating component having a ferrite core and a winding is mounted on a mounting board, and a noise-affected component is mounted on the mounting board at an inter-component distance through which noise from the noise-generating component propagates, A shield substrate having a conductor pattern and an insulator, with the insulator located on the outermost surface, is disposed between the noise-generating component and the noise-affected component, and the shield substrate is connected to the mounting board.

[0021] (Inter-component distance between noise-generating component and noise-affected component) The inter-component distance between the noise-generating component and the noise-affected component is 3 mm or less.

[0022] (Noise-generating component) The noise-generating component includes a transformer and an inductor.

[0023] (Noise-affected component) The noise-affected component is a component located on the input line side relative to the noise countermeasure circuit unit in the electric circuit, and includes a fuse, a thermistor, and a cement resistor.

[0024] (Connection 1 between mounting board and shield board) The shield board has a board connection portion protruding in a predetermined direction, The mounting board has a through hole through which the board connection portion of the noise countermeasure board is inserted, By inserting the board connection portion of the shield board into the through hole of the mounting board to connect the shield board and the mounting board, the conductor pattern of the shield board is connected to the stable potential of the mounting board, and the shield board is arranged perpendicular to the mounting board.

[0025] (Connection 2 between mounting board and shield board) The shield board has a board connection portion protruding in a predetermined direction, The mounting board has a through hole through which the board connection portion of the noise countermeasure board is inserted, By inserting the board connection portion of the shield board into the through-hole of the mounting board and connecting the shield board and the mounting board, the shield board is positioned perpendicular to the mounting board. [Effects of the Invention]

[0026] (Effects of the power supply) The present invention relates to a power supply device equipped with a noise generating component, wherein the noise generating component, which has a ferrite core and windings, is mounted on a mounting board, and noise-affecting components are mounted on the mounting board at a distance between components over which noise from the noise generating component propagates, and a shielding substrate having a conductor pattern and an insulator with the insulator on its outermost surface is placed between the noise generating component and the noise-affecting components, and the shielding substrate is connected to the mounting board. Because a substrate is used, the noise suppression component (shielding substrate) can be connected to the mounting board without requiring crimping like a shielding member, and it is possible to secure an insulating distance without adding insulating paper, so it can be placed in a narrower space than the space in which conventional shielding members can be placed.

[0027] Furthermore, while substrates are used to suppress and prevent the propagation of noise from noise-generating components to noise-affecting components, the process of manufacturing substrates—wiring a conductor pattern onto the surface of the substrate itself, which is an insulator, and then applying a resist, which is also an insulator—is already a common and established process. Compared to cases where insulating distance is ensured by applying insulating paint to the shielding member or by aligning and fixing insulating paper to the shielding member, the process and management are simpler, and material costs can be reduced.

[0028] Furthermore, since the shielding substrate has an insulator on its outermost surface, it is possible to secure the necessary insulation distance without having to increase the distance between noise-generating components and noise-affecting components, and this does not hinder the miniaturization of the power supply unit.

[0029] Furthermore, since the ferrite core, which is a noise-generating component, does not need to be connected to the stable potential of the mounting board, capacitance loss does not increase and heat generation does not increase during power supply switching.

[0030] As described above, the present invention eliminates all the problems that arose with conventional measures, and while ensuring the necessary insulation distance, it is possible to suppress and prevent the deterioration of noise terminal voltage. [Brief explanation of the drawing]

[0031] [Figure 1] This is an explanatory diagram showing an example of a power supply unit in a perspective view. [Figure 2] This is an explanatory diagram showing an example of a power supply unit in a top view. [Figure 3] This is an explanatory diagram showing an example of a power supply unit from a rear view. [Figure 4] This is an explanatory diagram showing an example of a circuit block diagram for a power supply unit. [Figure 5] This is an explanatory diagram showing an example of a shielding substrate. [Figure 6] This is an explanatory diagram illustrating the concept of a power supply unit with a shielding substrate. [Figure 7] This is an explanatory diagram showing a conceptual diagram of a conventional power supply unit. [Figure 8] This is an explanatory diagram illustrating the concept of a conventional power supply unit that incorporates noise countermeasures using shielding plates. [Figure 9] This is an explanatory diagram illustrating the concept of a conventional power supply device that incorporates noise countermeasures by connecting a ferrite core to a stable potential. [Modes for carrying out the invention]

[0032] Embodiments of the power supply device according to the present invention are described below. However, the present invention is not limited to the following embodiments.

[0033] [Basic Concepts of the Embodiment] First, the basic concept of the embodiment will be explained. The embodiment generally relates to a power supply device equipped with noise-generating components. In the power supply device of the embodiment, the noise-generating components are mounted on a mounting board, and noise-affecting components are mounted on the mounting board at a distance between components over which noise propagates from the noise-generating components. As a noise countermeasure to prevent deterioration of the noise terminal voltage by suppressing and preventing noise propagation from the noise-generating components to the noise-affecting components through electrostatic or magnetic field coupling, a shielding substrate having a conductor pattern and an insulator on its outermost surface is placed between the noise-generating components and the noise-affecting components, and the shielding substrate is connected to the mounting board.

[0034] "Noise-generating components" are components that have a ferrite core and windings, and whose ferrite cores electrostatically or magnetically couple with other components located nearby, causing noise to propagate to the input line and worsening the noise terminal voltage. Examples of such components include transformers and inductors.

[0035] "Noise-affected components" are components that, in a state where noise countermeasures are not implemented, or in the embodiment where a shielding substrate is not provided, are affected by noise from the aforementioned noise-generating components due to electrostatic or magnetic coupling. For example, in an electrical circuit, components located on the input line side of the noise countermeasure circuit section include fuses, thermistors and cement resistors used in inrush current prevention circuits.

[0036] Furthermore, this does not preclude including components that have noise suppression measures implemented by the noise suppression circuit section as "noise-affected components" that have noise suppression measures implemented by the shielding substrate of the embodiment; in other words, there may be components that have noise suppression measures implemented by both the shielding substrate and the noise suppression circuit section of the embodiment.

[0037] A "substrate" is a substrate made of an insulating material such as glass epoxy resin, on which conductive wiring (conductor patterns) of copper or other materials are applied to the surface or inside. In the power supply device of this embodiment, there are two types of substrates: a "mounting substrate" and a "shielding substrate".

[0038] A "mounted circuit board" is a circuit board on which predetermined components constituting a power supply device, including the aforementioned noise-generating and noise-affecting components, are mounted. This includes various types of circuit boards, such as single-sided circuit boards with wiring on one side of the board, double-sided circuit boards with wiring on both sides of the board, and multilayer circuit boards with wiring inside the board.

[0039] A "shielded substrate" is a substrate having a laminated structure in which a conductive pattern and an insulator are located on the outermost surface, meaning that layers of conductive patterns exist between layers of insulators. It has a structure similar to conventional shielding members made of conductive material coated with insulating paint or shielding members sandwiched between insulating paper. A "shielded substrate" can be realized as a single-sided substrate with a laminated structure of solder resist (an insulator), a conductive pattern, and the substrate body (an insulator), but it does not prevent the use of double-sided or multi-layer substrates as long as the insulator is located on the outermost surface.

[0040] Furthermore, the "shielding substrate" is placed between noise-generating components and noise-affecting components and connected to the mounting board. It can be placed as long as the distance between the noise-generating components and noise-affecting components is equal to the thickness of the shielding substrate. Also, because an insulator is located on the outermost surface, the necessary insulation distance can be secured even with component distances of 3 mm or less, where securing insulation distance becomes difficult if conductive materials are placed.

[0041] Furthermore, regarding the connection between the shielding substrate and the mounting substrate, for example, in the case of electrostatic coupling countermeasures, the shielding substrate has a substrate connection portion that protrudes in a predetermined direction, the mounting substrate has a through hole through which the substrate connection portion of the shielding substrate is inserted, and the substrate connection portion of the noise suppression substrate is inserted through the through hole of the mounting substrate to connect the shielding substrate and the mounting substrate. As a result, the conductor pattern of the shielding substrate is connected to the stable potential of the mounting substrate, for example, the ground potential of the mounting substrate, and the shielding substrate is positioned perpendicular to the mounting substrate.

[0042] Furthermore, when implementing magnetic field coupling countermeasures, the conductor pattern of the shielding substrate does not need to be connected to the stable potential of the mounting substrate. The shielding substrate can be positioned perpendicular to the mounting substrate by inserting the substrate connection portion of the noise suppression substrate through a through-hole in the mounting substrate to connect the shielding substrate and the mounting substrate.

[0043] The specific details of the embodiment will be explained below with reference to examples. In the specific details of the embodiment, the case where the "noise generating component" is an "isolation transformer equipped with a ferrite core and windings (primary winding, secondary winding)", the "noise affecting component" is a "fuse and cement resistor", and the "shielding substrate" is a "single-sided substrate" will be explained.

[0044] [Specific details of the embodiment] The specific details of the embodiments shown below will be explained by presenting examples and dividing them as follows. a. Power supply a1. Component layout of the power supply unit a2. Circuit configuration of the power supply unit b. Shielding substrate b1. Structure of the shielding substrate b2. Function of the shielding substrate c. Modified form of the present invention

[0045] [a.Power supply] First, we will describe a power supply unit equipped with an isolation transformer (noise-generating component), a fuse, and a cement resistor (noise-affecting component).

[0046] (a1. Component layout of the power supply unit) First, we will explain the component layout of the power supply unit. For this explanation, please refer to Figure 1, which shows an example of a power supply unit in a perspective view; Figure 2, which shows an example of a power supply unit in a top view; and Figure 3, which shows an example of a power supply unit in a rear view.

[0047] Furthermore, in the explanation of Figure 1, the XYZ directions are mutually orthogonal directions. In the X direction, the +X side is the right side and the -X side is the left side. In the Y direction, the +Y side is the upper side and the -Y side is the lower side. In the Z direction, the +Z side is the front side and the -Z side is the rear side. Each direction shown in Figure 1 is used as the reference, and the same applies to Figures 2 and 3 as to Figure 1.

[0048] In power supply unit 1, components constituting the power supply unit are mounted on the mounting board 10. An isolation transformer 12, which is a noise generating component, is mounted near the center of the rear side of the mounting board 10. A fuse 14 and a cement resistor 16 are mounted to the left of the isolation transformer 12, and an input connector 18 to which input wires are connected is mounted on the left side of the mounting board 10. In addition, certain components such as electrolytic capacitors, switching elements, and output connectors are also mounted on the mounting board 10, but since their relationship to the present invention is minor, the explanation of the arrangement of other components is omitted.

[0049] The isolation transformer 12 is a component that electrically isolates the primary side (input side) and secondary side (output side, load side) of the power supply unit, enabling the safe use of the power supply unit 1. The primary winding and secondary winding are wound onto a bobbin made of insulating material while ensuring mutual insulation, a ferrite core, which is a magnetic material, is attached to the bobbin, the primary winding wound on the bobbin is wrapped around the primary connection terminal and soldered, the secondary winding is wrapped around the secondary connection terminal and soldered, and the primary and secondary connection terminals are inserted into predetermined mounting holes on the mounting board 10 and soldered, thereby electrically connecting to the pattern on the mounting board 10 and being mounted.

[0050] The fuse 14 is a component that protects the downstream circuit from currents exceeding the rated value. Various types of fuses are included, such as tube fuses made of glass or ceramic tubes, and surface-mount fuses that can be surface-mounted on a circuit board. In this embodiment, a surface-mount fuse is used. The cement resistor 16 is a countermeasure component that prevents an inrush current larger than the rated current from flowing instantaneously to the downstream circuit when the power supply unit 1 starts operating. Furthermore, the fuse 14 is not directly mounted on the mounting board 10, but is mounted so as to be electrically connected to the pattern of the second mounting board 20. The second mounting board 20 with the fuse 14 mounted on it is positioned perpendicular to the mounting board 10 and soldered together, thereby electrically connecting the pattern of the second mounting board 20 and the pattern of the mounting board 10, and thus mounted on the mounting board 10.

[0051] Furthermore, since the isolation transformer 12 is a noise-generating component having windings (primary and secondary windings) and a ferrite core, the ferrite core electrostatically and magnetically couples with the fuse 14 and cement resistor 16 located nearby, and noise propagates from the fuse 14 and cement resistor 16 to the input line connected to the input connector 18, worsening the noise terminal voltage. In this embodiment, the shielding substrate 22 is positioned between the isolation transformer 12 and the fuse 14, and between the isolation transformer 12 and the cement resistor 16, thereby suppressing and preventing the propagation of noise from the isolation transformer 12 to the fuse 14 and cement resistor 16, and thus suppressing and preventing the deterioration of the noise terminal voltage. The shielding substrate 22 will be described separately later.

[0052] (a2. Circuit configuration of the power supply unit) Next, the circuit configuration of the power supply unit will be described. For this description, please refer to Figure 4, which shows an example of a circuit block diagram of the power supply unit.

[0053] Power supply unit 1 is an AC / DC power supply unit that, for example, converts a predetermined AC voltage to a predetermined DC voltage to supply DC power. The primary rectifier and smoothing circuit unit 32 smooths and rectifies the AC voltage of the AC power supply input via the fuse 14 and the inrush current prevention circuit unit 30 into a DC power supply of a predetermined voltage. The cement resistor 16 is a component included in the inrush current prevention circuit unit 32.

[0054] The inverter unit 34 pulses the DC power supply that has been smoothed and rectified by the primary rectifier and smoothing circuit unit 32 and outputs it to the isolation transformer 12. The isolation transformer 12 converts the primary DC power supply pulsed by the inverter unit 34 into a DC power supply of a predetermined secondary voltage. The secondary rectifier and smoothing circuit unit 36 ​​smooths and rectifies the DC power supply whose voltage has been converted by the isolation transformer 12 and supplies it to a predetermined load connected to the secondary side.

[0055] Furthermore, the switching operation of the inverter section 34 in the power supply unit 1 is controlled by the control circuit section 38. The control circuit section 38 controls the switching operation of the inverter section 34 by receiving signals from the feedback circuit section 40, which is connected to the output side via the photocoupler 41.

[0056] Furthermore, in the power supply unit 1, a current detection circuit unit 42 is provided for the inverter unit 34 to detect overcurrents flowing through the inverter unit 34, and an overvoltage protection circuit 44 is provided on the output side to detect overvoltages on the output side. The control circuit unit 38 controls the operation of the inverter unit 34 by receiving a signal when an abnormal current or voltage is detected by the current detection circuit unit 42 or the overvoltage protection circuit 44. In addition, the signal from the overvoltage protection circuit unit 44 located on the output side passes through a photocoupler 45, similar to the feedback circuit unit 40, so that the primary and secondary sides are electrically isolated.

[0057] Here, the inrush current prevention circuit section 32, which includes the fuse 14 and cement resistor 16, protects the circuit located downstream. Therefore, it is located at the very top (input line side) of the electrical circuit of the power supply unit 1. Noise propagating from the isolation transformer 12 to the fuse 14 and cement resistor 16 cannot be countered by noise suppression circuits such as noise filters. As mentioned above, noise from the isolation transformer 12 requires noise suppression by the shielding board 22.

[0058] [b. Shielding substrate] Next, we will explain the shielding board that suppresses and prevents noise propagation from the isolation transformer to the fuse and cement resistor.

[0059] (b1. Structure of the shielding substrate) First, the structure of the shielding substrate will be explained. For this explanation, please refer to Figure 5, which shows an example of a shielding substrate.

[0060] The shield substrate 22 is a single-sided substrate made by impregnating a substrate body such as glass or paper with a resin such as epoxy resin, wiring a copper pattern 2210 as a conductive pattern on one side, as shown in Figure 5, and applying solder resist to the other side on which the copper pattern 2210 is wired. Since the substrate body and solder resist are insulators and the copper pattern 2210 is a conductor, its cross-section has a structure in which insulator, conductor, insulator are layered in that order. In other words, the structure of the shield substrate 22 is similar to that of conventional shield members made of conductive materials with insulating paint applied to the surface or with insulating paper added, but the process of wiring the copper pattern 2210 on the surface of the substrate body which is an insulator and applying an insulating resist is already a generalized and established process, and it is easier to process and manage than applying insulating paint to a shield member or aligning and fixing insulating paper to a shield member, and it is possible to reduce material costs.

[0061] Furthermore, the shield substrate 22 has a thickness of approximately 1 mm, which is almost the same as the thickness of a conventional shielding plate, which is a shielding component that ensures a certain degree of strength. However, unlike a shielding plate, it is not necessary to add insulating paper of about 0.5 mm on both sides to ensure the insulation distance. Therefore, the shield substrate 22 can be placed in a narrower space than the shielding component while ensuring the insulation distance.

[0062] Furthermore, the copper pattern 2210 of the shield substrate 22 will be connected to a pattern that is at a stable potential on the mounting substrate 10, for example, the ground potential. The method of connection is arbitrary, but for example, as shown in Figure 5, the shield substrate 22 has a substrate connection projection 2220 that protrudes downward from the lower left of the substrate in Figure 5. By inserting this substrate connection projection 2220 into a predetermined mounting hole on the mounting substrate 10 and soldering it, the copper pattern 2210 of the shield substrate 22 and the pattern that is at the ground potential on the mounting substrate 10 are electrically connected. In addition, as shown in Figures 1 to 3, it will be positioned perpendicular to the mounting substrate 10 between the isolation transformer 12, the fuse 14, and the cement resistor 16.

[0063] Therefore, when connecting the shield substrate 22 to the mounting substrate 10, there is no need for space to crimp the connecting crimp terminals to the shield member as in the conventional method, and from this point of view, it is advantageous for placement in a space narrower than that of the shield member. In addition, the solder resist is not applied to the substrate connection portion 2220, or the solder resist has been removed by etching or the like, exposing the copper pattern 2210.

[0064] Furthermore, the substrate contact portion 2230 protrudes downward from the lower right of the substrate in Figure 5, opposite to the position of the substrate connection portion 2220. When the shield substrate 22 is connected to the mounting substrate 10 by inserting the substrate connection portion 2220 into a predetermined mounting hole in the mounting substrate 10, the substrate contact portion 2230 contacts the substrate surface of the mounting substrate 10, thereby stabilizing the position of the shield substrate 22 mounted on the mounting substrate 10.

[0065] (b2. Function of the shielding substrate) Next, the function of the shielding substrate will be explained. For this explanation, please refer to Figure 6, which shows a conceptual diagram of the power supply unit on which the shielding substrate is placed.

[0066] As explained in the prior art section, stray capacitances C1 and C2 are generated between the winding 1220 of the isolation transformer 12 and the ferrite core 1210, and between the ferrite core 1210 and the mounting substrate 10. Furthermore, if there is no shield substrate 22 and stray capacitance is generated between the ferrite core 1210 of the isolation transformer 12 and the fuse 14, causing electrostatic or magnetic field coupling of each part, voltage fluctuations in the winding 1220 of the isolation transformer 12 will propagate as noise through the ferrite core 1210 and fuse 14 to the input line 60, worsening the noise terminal voltage.

[0067] Therefore, in this embodiment, as shown in Figure 6, a shielding substrate 22 is placed between the isolation transformer 12 and the fuse 14. Stray capacitances C3 and C4 are generated between the ferrite core 1210 of the isolation transformer 12 and the shielding substrate 22, and between the shielding substrate 22 and the fuse 14, causing electrostatic and magnetic field coupling between the parts. However, since the shielding substrate 22 is connected to the stable potential of the mounting substrate 10, its potential remains stable without fluctuation. Charge transfer from the ferrite core 1210 to the fuse 14 is suppressed and prevented, and potential fluctuations of the fuse 14 are suppressed and prevented. As a result, noise propagation from the ferrite core 1210 to the input line 60 via the fuse 14 is suppressed and prevented, and deterioration of the noise terminal voltage is suppressed and prevented. Thus, it functions as a noise countermeasure, similar to when a shielding member is placed.

[0068] Furthermore, since the shield substrate has the substrate body, which is an insulator, and the resist located on the outermost surface, it is possible to secure the necessary insulation distance without having to widen the distance between noise-generating components and noise-affecting components. Also, since it is not necessary to connect the ferrite core 1210 to the stable potential of the mounting substrate 10, capacitance loss does not increase and heat generation does not increase during switching.

[0069] [c. Variations of the present invention] Modifications of the power supply device according to the present invention will now be described. In addition to the embodiments described above, the power supply device of the present invention includes the following modifications.

[0070] (power supply) In the above embodiment, a type of AC / DC power supply was used as an example, but the power supply to which the present invention can be applied is not limited to this, and it is applicable to any power supply in which a noise-generating component having a ferrite core and windings is mounted on a circuit board, and noise-influencing components are mounted at a distance between components that allows noise to propagate through electrostatic or magnetic field coupling with the noise-generating component.

[0071] (Noise-generating component) In the above embodiment, the noise-generating component was an isolation transformer, but it is not limited to this; any component having a ferrite core and windings is acceptable, and other transformers, inductors, etc., are included.

[0072] (Noise-affected components) In the above embodiment, the noise-affected components were a fuse located on the input line side of the electrical circuit and a cement resistor in the inrush current prevention circuit. However, the components are not limited to these, and include any component mounted near a noise-generating component that is affected by noise from the noise-generating component through electrostatic or magnetic field coupling.

[0073] (Connection between the shield board and the mounted board) In the above embodiment, the shielding substrate and the mounting substrate were connected such that the copper pattern of the shielding substrate was connected to the stable potential of the mounting substrate. However, the invention is not limited to this, and the shielding substrate and the mounting substrate may be connected without connecting the copper pattern of the shielding substrate to the stable potential of the mounting substrate. By wiring the copper pattern wired to the substrate connection part for connecting to the mounting substrate and the copper pattern wired to substantially the entire surface of the shielding substrate, which functions as a noise suppression measure, as separate, electrically isolated patterns, it is possible to connect the shielding substrate and the mounting substrate without connecting the copper pattern of the shielding substrate, which functions as a noise suppression measure, to the stable potential of the mounting substrate.

[0074] (others) Furthermore, the present invention includes appropriate modifications that do not impair its purpose and advantages, and is not limited by the numerical values ​​shown in the above embodiments. [Explanation of symbols]

[0075] 1: Power supply 10: Implemented circuit board 12: Isolation transformer 1210: Ferrite core 1220: Winding 14: Fuse 16: Cement Resistor 18: Input Connector 20: Second mounting board 22: Shielding board 2210: Copper pattern 2220: Circuit board connection section 2230: Substrate contact area 30: Inrush current prevention circuit section 32: Primary rectifier smoothing circuit section 34: Inverter section 36: Secondary rectifier smoothing circuit section 38: Control circuit section 40: Feedback circuit section 41,45: Photocoupler 42: Current detection circuit section 44: Overvoltage protection circuit section 60: Input line

Claims

1. A noise-generating component comprising a ferrite core and windings is mounted on the mounting board, and noise-affecting components are mounted on the mounting board at a distance between components over which noise from the noise-generating component propagates. A power supply device characterized in that a shielding substrate having a conductor pattern and an insulator, with the insulator located on the outermost surface, is placed between the noise generating component and the noise affecting component, and the shielding substrate is connected to the mounting substrate.

2. A power supply device according to claim 1, A power supply device characterized in that the distance between the noise-generating component and the noise-affecting component is 3 mm or less.

3. A power supply device according to claim 1, The power supply device is characterized in that the noise generating components include a transformer and an inductor.

4. A power supply device according to claim 1, The power supply device is characterized in that the noise-influencing component is located on the input line side of the electrical circuit, rather than on the noise suppression circuit section.

5. A power supply device according to claim 4, The power supply device is characterized in that the noise-influencing components include fuses, thermistors, and cement resistors.

6. A power supply device according to claim 1, The shield substrate has a substrate connection portion that protrudes in a predetermined direction, The mounting board has a through hole through which the board connection portion of the noise suppression board is inserted. A power supply device characterized in that the conductor pattern of the shielding substrate is connected to the stable potential of the mounting substrate by inserting the substrate connection portion of the shielding substrate into the through hole of the mounting substrate, and the shielding substrate is positioned perpendicular to the mounting substrate.

7. A power supply device according to claim 1, The shield substrate has a substrate connection portion that protrudes in a predetermined direction, The mounting board has a through hole through which the board connection portion of the noise suppression board is inserted. A power supply device characterized in that the shielding substrate is positioned perpendicular to the mounting substrate by inserting the substrate connection portion of the shielding substrate into the through hole of the mounting substrate and connecting the shielding substrate and the mounting substrate.

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