Switching power supply with noise reduction components

Abstract

Provided is a small-sized power supply device that can reduce heat generation and power loss in a noise reduction function component and suppress EMI noise.　A noise reduction function component (20) for a power supply device comprises: inductors (L21, L22) connected in series to a first current line connecting a first input terminal (P11) and a first output terminal (P21); a capacitor (C21); and a capacitor (C22). The capacitor (C22) is structurally a feedthrough capacitor having at least three terminals: a first terminal (T1); a second terminal (T2); and a third terminal (T3). The inductor (L21) and the capacitor (C21) form a first filter, while the inductor (L22) and the capacitor (C22) form a second filter. The first filter, the second filter, and a power conversion circuit 30 form a noise equilibrating circuit that offsets and equilibrates generation of a switching noise current in two or more frequency bands generated in a switching element.

Description

[Technical Field]

[0001] The present invention relates to a power supply device having a noise source such as a switching element of a power conversion circuit. [Background technology]

[0002] In a switching power supply device, EMI noise, mainly consisting of common-mode noise current, is generated due to the switching operation in the power conversion circuit, which can cause problems with electromagnetic interference.

[0003] The power supply device described in Patent Document 1 has a common mode noise coil and a Y capacitor connected to the input and output sides of a power conversion circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-271135 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a high-impedance common mode choke coil is connected to a wiring line through which a large current flows, as in the power supply device described in Patent Document 1, the EMI filter becomes large and expensive, and the heat generation and power loss in the common mode choke coil also increase.

[0006] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a small-sized power supply device that can reduce heat generation and power loss in noise reduction functional components and suppress EMI noise. [Means for solving the problem]

[0007] The power supply device of the present invention comprises an input DC power supply, a first noise reduction component, and a power conversion circuit connected to one another. The power conversion circuit comprises an input capacitor, a switching element, an output rectifier circuit, and an output capacitor connected to a load. The first noise reduction component comprises a pair of first and second input terminals, and a pair of first and second output terminals. The first noise reduction component comprises a first inductor and a second inductor connected in series to a first current line connecting the first input terminal and the first output terminal, a node between the first inductor and the second inductor, a first capacitor connected to a second current line connecting the second input terminal and the second output terminal, and a second capacitor connected between the first and second output terminals. The first input terminal is connected to the positive terminal of the input DC power supply, and the second input terminal is connected to the negative terminal of the input DC power supply. The first output terminal is connected to the positive terminal of the input capacitor without being connected to other parts of the power conversion circuit. The second output terminal is connected to the negative terminal of the input capacitor without being connected to other parts of the power conversion circuit. The second capacitor is structurally a feedthrough capacitor having at least three terminals, namely, a first terminal, a second terminal, and a third terminal. The first terminal is connected to the second inductor, the second terminal is connected to the first output terminal, and the third terminal is connected to the second output terminal. The first inductor and the first capacitor form a first filter, and the second inductor and the second capacitor form a second filter. The first filter, the second filter, and the power conversion circuit form a first noise balancing circuit that cancels out and balances switching noise currents generated in two or more frequency bands by the switching elements.

[0008] In this configuration, the above-described configuration prevents noise current from leaking to the outside from the first noise smoothing circuit, and various noise currents flowing through the first noise balancing circuit cancel each other out at the noise generating source, resulting in balancing, which significantly reduces noise conducted or radiated from the power supply device.

[0009] The power supply device of the present invention comprises an input DC power supply, a second noise reduction component, and a power conversion circuit connected to one another. The power conversion circuit comprises an input capacitor, a switching element, an output rectifier circuit, and an output capacitor connected to a load. The second noise reduction component comprises a pair of third and fourth input terminals, a pair of third and fourth output terminals, a third inductor and a fourth inductor connected in series to a third current line connecting the third input terminal and the third output terminal, a node between the third and fourth inductors, a third capacitor connected to a fourth current line connecting the fourth input terminal and the fourth output terminal, and a fourth capacitor connected between the third and fourth output terminals. The third input terminal is connected to the positive terminal of the output capacitor without being connected to other parts of the power conversion circuit. The fourth input terminal is connected to the negative terminal of the output capacitor without being connected to other parts of the power conversion circuit. The third output terminal is connected to the positive terminal of the load, and the fourth output terminal is connected to the negative terminal of the load. The fourth capacitor is structurally a feedthrough capacitor having at least three terminals, namely, a first terminal, a second terminal, and a third terminal, and the first terminal is connected to the fourth inductor, the second terminal is connected to the third output terminal, and the third terminal is connected to the fourth output terminal. The third inductor and the third capacitor form a first filter, and the fourth inductor and the fourth capacitor form a second filter. The first filter, the second filter, and the power conversion circuit form a second noise balancing circuit that cancels out and balances switching noise currents in two or more frequency bands generated in the switching elements.

[0010] In this configuration, the above-described configuration prevents noise currents from leaking to the outside from the second noise smoothing circuit, and the various noise currents flowing through the second noise balancing circuit cancel each other out at the noise generating source, resulting in a balance, which significantly reduces noise conducted or radiated from the power supply device. [Effects of the Invention]

[0011] According to the present invention, it is possible to realize a small-sized switching power supply device that can reduce heat generation and power loss and suppress EMI noise. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an equivalent circuit diagram of a power supply device according to a first embodiment of the present invention. [Figure 2] 2A, 2B, and 2C are diagrams showing an example of the structure of a power supply device according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a plan view showing an arrangement pattern of each component of the noise reduction function part according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a graph showing frequency characteristics of insertion loss of a noise reduction function component. [Figure 5] FIG. 5 is a graph showing frequency characteristics of noise levels in the configuration of the present invention and the comparative configuration. [Figure 6] FIG. 6(A) is a graph showing the frequency characteristics of noise levels of the comparative configuration and the configuration of the present invention in the AM frequency band, and FIG. 6(B) is a graph showing the frequency characteristics of noise levels of the comparative configuration and the configuration of the present invention in the FM frequency band. [Figure 7] FIG. 7 is a graph showing the frequency characteristics of noise levels of the comparative configuration and the configuration of the present invention in the UHF frequency band. [Figure 8] FIG. 8 is an equivalent circuit diagram of a power supply device according to a second embodiment of the present invention. [Figure 9] FIG. 9 is an equivalent circuit diagram of a power supply device according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a graph showing frequency characteristics of insertion loss of a noise reduction function component. DETAILED DESCRIPTION OF THE INVENTION

[0013] [First embodiment] (Circuit configuration of power supply device 10) A power supply device according to a first embodiment of the present invention will be described with reference to the drawings. Figure 1 is an equivalent circuit diagram of the power supply device according to the first embodiment of the present invention.

[0014] 1, the power supply device 10 includes a DC power supply 90, a noise reduction function component 20, and a power conversion circuit 30. The noise reduction function component 20 corresponds to the "first noise reduction function component" of the present invention.

[0015] As a schematic circuit configuration, an input terminal of the noise reduction function component 20 is connected to a DC power supply 90. An output terminal of the noise reduction function component 20 is connected to an input terminal of a power conversion circuit 30. An output terminal of the power conversion circuit 30 is connected to a load 99.

[0016] (Circuit configuration of noise reduction function component 20) The noise reduction function component 20 has a first input terminal P11, a second input terminal P12, a first output terminal P21, and a second output terminal P22. The first input terminal P11 is connected to the positive electrode of a DC power supply 90. The second input terminal P12 is connected to the negative electrode of the DC power supply 90. The first output terminal P21 is connected to the positive input terminal of the power conversion circuit 30, and the second output terminal P22 is connected to the negative input terminal of the power conversion circuit 30.

[0017] The noise reduction function component 20 includes an inductor L21, an inductor L22, an inductor L23, a capacitor C21, and a capacitor C22. The inductors L21, L22, and L23 correspond to the "first inductor," "second inductor," and "fifth inductor" of the present invention, respectively. The capacitors C21 and C22 correspond to the "first capacitor" and "second capacitor" of the present invention, respectively.

[0018] The noise reduction function component 20 includes a pair of first input terminal P11 and second input terminal P12, a pair of first output terminal P21 and second output terminal P22, a first current line 21, and a second current line 22. The first current line 21 connects the first input terminal P11 and the first output terminal P21. The second current line 22 connects the second input terminal P12 and the second output terminal P22.

[0019] The inductor L21 and the inductor L22 are connected in series to the first current line 21. One terminal of the inductor L21 is connected to the first input terminal P11, and the other terminal of the inductor L21 is connected to one terminal of the inductor L22. The other terminal of the inductor L22 is connected to the first output terminal P21.

[0020] The capacitor C21 is connected to the node between the inductor L21 and the inductor L22 on the first current line and to the second current line L22.

[0021] The capacitor C22 is connected to a portion of the first current line 21 between the inductor L22 and the first output terminal P21, and to the second current line 22. More specifically, the capacitor C22 has a first terminal T1, a second terminal T2, and a third terminal T3. The first terminal T1 is connected to the inductor L22, and the second terminal T2 is connected to the first output terminal P21. The third terminal T3 is connected to the second current line 22.

[0022] The inductor L23 is connected in series to the second current line 22. More specifically, one terminal of the inductor L23 is connected to the second input terminal P12, and the other terminal of the inductor L23 is connected to the node where the capacitor C21 is connected to the second current line 22.

[0023] With this configuration, the noise reduction function component 20 forms a first filter with the inductors L21, L23 and the capacitor C21, and a second filter with the inductor L22 and the capacitor C22. Note that the inductor L23 may be omitted.

[0024] (Circuit configuration of power conversion circuit 30) The power conversion circuit 30 includes an input capacitor C31, a switching element Q31, a rectifying element D31, an inductor L30, and an output capacitor C32.

[0025] The input capacitor C31 is connected between the positive and negative input terminals of the power conversion circuit 30.

[0026] Switching element Q31 is a power conversion switching element, such as a p-channel MOSFET. Its source is connected to the positive wiring line that connects to the positive input terminal. In this case, the source of switching element Q31 is connected to the positive output terminal side of the node of input capacitor C31 on the positive wiring line.

[0027] Rectifier element D31 is a rectifier element for power conversion. The cathode of rectifier element D31 is connected to the drain of switching element Q31. The anode of rectifier element D31 is connected to a negative wiring line connecting the negative input terminal and output input terminal of power conversion circuit 30. Note that rectifier element D31 can be replaced with a switching element.

[0028] One terminal of inductor L30 is connected to the node between switching element Q31 and rectifier element D31, and the other terminal of inductor L30 is connected to the positive output terminal of power conversion circuit 30.

[0029] The output capacitor C32 is connected between the positive output terminal and the negative connection terminal.

[0030] (Structure of power supply unit 10) 2(A), (B), and (C) are diagrams showing an example of the structure of a power supply device according to a first embodiment of the present invention, where Fig. 2(A) is a top view, Fig. 2(B) is a side view, and Fig. 2(C) is a bottom view.

[0031] As shown in Figures 2(A), 2(B), and 2(C), the DC power supply 90 is, for example, a battery having a rectangular parallelepiped housing. The noise reduction function component 20 and the power conversion circuit 30 are chip-type electronic components. Although Figures 2(A), 2(B), and 3(C) show the load 99 in a shape having a rectangular parallelepiped housing, the shape is not limited to this as long as it can be mounted on the circuit board 80.

[0032] The power supply device 10 includes a circuit board 80. The circuit board 80 has a first surface 801 and a second surface 802. On the first surface 801 of the circuit board 80, land electrodes for mounting the DC power supply 90, the noise reduction function component 20, the power conversion circuit 30, and the load 99, and a plurality of electrode patterns 81, 82, and 83 are formed. On the second surface 802 of the circuit board 80, a ground electrode pattern 800 is formed.

[0033] The noise reduction component 20 is disposed between the DC power supply 90 and the power conversion circuit 30. The power conversion circuit 30 is disposed between the noise reduction component 20 and a load 99. The DC power supply 90, the noise reduction component 20, the power conversion circuit 30, and the load 99 are mounted on respective land electrodes formed on a first surface 801 of the circuit board 80.

[0034] The positive terminal of the DC power supply 90 and the first input terminal P11 of the noise reduction function component 20 are electrically connected by an electrode pattern 81 formed on the first surface 801.

[0035] The first output terminal P21 of the noise reduction function component 20 and the positive input terminal of the power conversion circuit 30 are connected by an electrode pattern 82 formed on the first surface 801. At this time, the first output terminal P21 and the positive terminal of the input capacitor C31 of the power conversion circuit 30 are connected without being electrically connected to other circuit components (passive electronic components and active electronic components) that constitute the power supply device 10, including the noise reduction function component 20 and the power conversion circuit 30.

[0036] The positive output terminal of the power conversion circuit 30 and the first terminal of the load 99 are connected by an electrode pattern 83 formed on the first surface 801 .

[0037] The negative terminal of the DC power supply 90, the second input terminal P12 and the second output terminal P22 of the noise reduction function component 20, the negative input terminal and the negative output terminal of the power conversion circuit 30, and the second terminal of the load 99 are connected to the ground electrode pattern 800 on the second surface 802 through a through-hole via conductor THV formed in the circuit board 80.

[0038] At this time, the second output terminal P22 and the negative terminal of the input capacitor C31 of the power conversion circuit 30 are connected without being electrically connected to other circuit components (passive electronic components and active electronic components) that constitute the power supply device 10, including the noise reduction function component 20 and the power conversion circuit 30.

[0039] (Structure and characteristics of noise reduction functional component 20) FIG. 3 is a plan view showing an arrangement pattern of each component of the noise reduction function part according to the first embodiment of the present invention.

[0040] 3, the noise reduction function component 20 includes a housing 200 that is rectangular in plan view. The inductors L21, L22, L23, and capacitors C21 and C22 are housed in the housing 200. The first input terminal P11, the second input terminal P12, the first output terminal P21, and the second output terminal P22 are partially located inside the housing 200 and exposed on the bottom surface of the housing 200. The noise reduction function component 20 also includes a first conductor 210, a second conductor 220, and a ground metal 290.

[0041] The inductors L21, L22, and L23 are formed by ferrite beads. The capacitor C21 is a chip capacitor having external electrodes on both ends of the capacitor C21. For example, the capacitor C21 is a multilayer ceramic capacitor. The capacitor C22 is a feedthrough capacitor.

[0042] The first conductor 210 connects the first input terminal P11 and the first output terminal P21. The inductors L21 and L22 are connected in series to the first conductor 210. One terminal of the capacitor C21 is connected to the first conductor 210, and the other terminal of the capacitor C21 is connected to the second conductor 220. The inductor L22 is connected in series to the second conductor 220.

[0043] Capacitor C22 has a hollow portion that passes through it, and first conductor 210 is inserted into this hollow portion. One opening of first conductor 210 from the hollow portion serves as first terminal T1, and the other opening serves as second terminal T2. The outer surface conductor of the housing in which the hollow portion is formed serves as third terminal T3. Third terminal T3 is connected to second conductor 220.

[0044] The ground metal 290 is a flat plate. The other terminal of the capacitor C21, the third terminal T3 of the capacitor C22, and the second conductor 220 are connected to the ground metal 290 by a conductive bonding material such as solder.

[0045] (Characteristics of noise reduction function component 20) The noise reduction function component 20 has the above-described circuit configuration and structure, and thus has the following characteristics: Fig. 4 is a graph showing the frequency characteristics of the insertion loss of the noise reduction function component.

[0046] As shown in the circuit configuration above, the noise reduction function component 20 includes a first filter and a second filter. By appropriately setting the inductances of inductors L21, L22, and L23 and the capacitances of capacitors C21 and C22, the first filter and the second filter are configured as filters with different pass characteristics and attenuation characteristics. For example, the first filter can be set as a low-frequency filter, and the second filter can be set as a high-frequency filter.

[0047] As a result, noise reduction function component 20 has a circuit configuration in which a first filter and a second filter with different frequency characteristics are connected in series. As a result, as shown in FIG. 4, insertion loss is suppressed in the DC region, and a desired level of insertion loss can be obtained in a specific frequency band. The specific frequency band refers to two or more frequency bands generated by power conversion switching element Q31 of power conversion circuit 30, and is composed of, for example, an AM frequency band (a frequency band of several hundred kHz) and an FM frequency band (a few tens of MHz). Note that the specific frequency band may also include a UHF frequency band (a few hundred MHz).

[0048] In this case, since the capacitor C22 is a feedthrough capacitor, the filter characteristics of the second filter are improved, and the insertion loss characteristics are improved.

[0049] (Noise reduction effect of power supply device 10) By connecting the noise reduction component 20 having the above-described characteristics to the input terminal of the power conversion circuit 30, the power supply device 10 can form a noise balancing circuit using the noise reduction component 20, which includes the first filter, second filter, and earth metal, and the power conversion circuit 30. This suppresses noise currents in specific frequency bands leaking from the input side of the power conversion circuit 30 to the DC power supply 90, and the noise currents flowing within the noise balancing circuit cancel each other out. In other words, the various noise currents flowing within the noise balancing circuit cancel each other out at the noise generation sources, resulting in balancing. This significantly reduces noise conducted or radiated from the power supply device.

[0050] Fig. 5 is a graph showing the frequency characteristics of noise levels for the configuration of the present application and the comparative configuration. Fig. 6(A) is a graph showing the frequency characteristics of noise levels for the comparative configuration and the configuration of the present application in the AM frequency band, and Fig. 6(B) is a graph showing the frequency characteristics of noise levels for the comparative configuration and the configuration of the present application in the FM frequency band. Fig. 7 is a graph showing the frequency characteristics of noise levels for the comparative configuration and the configuration of the present application in the UHF frequency band. The comparative configuration is a configuration that does not include the noise reduction function component 20 of the present application.

[0051] As shown in FIGS. 5, 6(A), 6(B), and 7, the configuration of the present invention can reduce noise levels in the AM frequency band, FM frequency band, and UHF frequency band.

[0052] In this way, the power supply device 10 can suppress noise (EMI noise) at the switching frequency of the switching elements that is radiated externally from the power supply device 10. Furthermore, the power supply device 10 can achieve a simple circuit configuration. Furthermore, because it does not require a large common mode choke coil, the power supply device 10 can be small, inexpensive, and highly efficient. That is, the power supply device 10 can reduce heat generation and power loss in noise reduction components, and cancel out noise generation at the noise source, thereby achieving a small switching power supply device that can suppress EMI noise. In particular, the power supply device 10 can effectively reduce the generation of common mode noise current while suppressing heat generation and power loss in noise reduction components for switching power supplies that are difficult to ground to the earth potential due to mobility, such as electric vehicles.

[0053] Furthermore, the power supply device 10 can further improve the noise suppression effect by having the following configuration. Specifically, the line length between the first output terminal P21 and the second output terminal P22 of the noise reduction component 20 and the input capacitor C31 of the power conversion circuit 30 is longer than the line length between the input capacitor C31 and the terminals of the switching element Q31 and the rectifying element D31 that are connected to the input capacitor C31. This improves the noise current cancellation effect, and the power supply device 10 can suppress radiated noise (EMI noise).

[0054] In the above description, a three-terminal feedthrough capacitor (three-terminal component) is used as the capacitor C22. However, the capacitor C22 may also be a four-terminal feedthrough capacitor (four-terminal component). In the case of a four-terminal feedthrough capacitor, for example, two electrode patterns may be formed with the first conductor 210 disposed therebetween, and a lead-out wiring electrode may be formed on each of these two electrode patterns. These two electrode patterns correspond to the third and fourth terminals of the four-terminal feedthrough capacitor.

[0055] [Second embodiment] A power supply device according to a second embodiment of the present invention will be described with reference to the drawings. Figure 8 is an equivalent circuit diagram of the power supply device according to the second embodiment of the present invention.

[0056] 8, the power supply device 10A according to the second embodiment differs from the power supply device 10 according to the first embodiment in the connection mode of the noise reduction function component 20A and the power conversion circuit 30. Other configurations of the power supply device 10A are similar to those of the power supply device 10, and a description of similar parts will be omitted.

[0057] The power supply device 10A includes a noise reduction function component 20A. The noise reduction function component 20A has the same configuration as the noise reduction function component 20. The noise reduction function component 20A corresponds to the "second noise reduction function component" of the present invention. The first input terminal P11 and the second input terminal P12 of the noise reduction function component 20A correspond to the "third input terminal" and the "fourth input terminal" of the present invention, respectively. The first output terminal P21 and the second output terminal P22 of the noise reduction function component 20A correspond to the "third output terminal" and the "fourth output terminal" of the present invention, respectively. Inductors L21, L22, and L23 of the noise reduction function component 20A correspond to the "third inductor," the "fourth inductor," and the "sixth inductor," respectively. Capacitors C21 and C22 of the noise reduction function component 20A correspond to the "third capacitor" and the "fourth capacitor," respectively. Furthermore, the current lines in the noise reduction function component 20A that correspond to the "first current line" and "second current line" of the noise reduction function component 20 correspond to the "third current line" and "fourth current line" of the present invention, respectively. Furthermore, the filters in the noise reduction function component 20A that correspond to the "first filter" and "second filter" of the noise reduction function component 20 correspond to the "third filter" and "fourth filter" of the present invention, respectively.

[0058] In the power supply device 10A, the positive input terminal of the power conversion circuit 30 is connected to the positive electrode of the DC power supply 90. The negative input terminal of the power conversion circuit 30 is connected to the negative electrode of the DC power supply 90.

[0059] The positive output terminal of the power conversion circuit 30 is connected to a first input terminal P11 of the noise reduction function component 20A, and the negative output terminal of the power conversion circuit 30 is connected to a second input terminal P12 of the noise reduction function component 20A.

[0060] A first output terminal P21 of the noise reduction function component 20A is connected to a first terminal of the load 99. A second output terminal P22 of the noise reduction function component 20A is connected to a second terminal of the load 99.

[0061] In this configuration, in the power supply device 10A, the first input terminal P11 of the noise reduction function component 20A and the positive terminal of the output capacitor C32 of the power conversion circuit 30 are connected without being electrically connected to the other circuit components (passive electronic components and active electronic components) that make up the power supply device 10, including the noise reduction function component 20A and the power conversion circuit 30. In addition, the second input terminal P12 of the noise reduction function component 20A and the negative terminal of the output capacitor C32 are connected without being electrically connected to the other circuit components (passive electronic components and active electronic components) that make up the power supply device 10, including the noise reduction function component 20A and the power conversion circuit 30.

[0062] Furthermore, the line length between the first input terminal P11 and the second input terminal P12 of the noise reduction function component 20A and the output capacitor C32 of the power conversion circuit 30 is longer than the line length between the output capacitor C32 and the output terminal of the inductor L30.

[0063] With this configuration, the power supply device 10A can suppress leakage of noise current to the load 99 and suppress noise (EMI noise) at the switching frequency of the switching element that is radiated externally from the power supply device 10A. Furthermore, the power supply device 10A can achieve a simple circuit configuration. Also, since it does not require the use of a large common mode choke coil, a small, inexpensive, and highly efficient power supply device 10 can be achieved.

[0064] [Third embodiment] A power supply device according to a third embodiment of the present invention will be described with reference to the drawings. Figure 9 is an equivalent circuit diagram of the power supply device according to the third embodiment of the present invention.

[0065] 9, the power supply device 10B according to the third embodiment differs from the power supply device 10 according to the first embodiment in that it further includes a common mode choke coil 50. The other configuration of the power supply device 10B is the same as that of the power supply device 10, and a description of similar parts will be omitted.

[0066] The common mode choke coil 50 is connected between the DC power supply 90 and the noise reduction function component 20. With this configuration, even if a common mode noise current leaks from the noise reduction function component 20 to the DC power supply 90 side, it can be attenuated by the common mode choke coil 50.

[0067] As a result, the power supply device 10B can suppress radiation noise caused by common-mode current. Figure 10 is a graph showing the frequency characteristics of the insertion loss of a noise reduction component. As shown in Figure 10, by incorporating the configuration of the power supply device 10B, the noise level in the 100 MHz band can be further reduced. In this way, by incorporating the configuration of the power supply device 10B, radiation noise can be further suppressed.

[0068] At this time, the noise reduction function component 20 is connected between the common mode choke coil 50 and the power conversion circuit 30, thereby suppressing the common mode noise current leaking into the common mode choke coil 50. Therefore, the common mode choke coil 50 does not need to be large, and heat generation and power loss due to the common mode choke coil 50 can be suppressed.

[0069] The configurations of the above-described embodiments can be combined as appropriate, and effects according to each combination can be achieved. [Explanation of symbols]

[0070] 10, 10A, 10B: Power supply 20, 20A: Noise reduction parts 21: First current line 210: First conductor 22: Second current line 220: Second conductor 30: Power conversion circuit 50: Common mode choke coil 80: Circuit board 81, 82, 83: Electrode patterns 90: DC power supply 99: Load 200: Cabinet 290: Earth Metal 801: Front page 800: Ground electrode pattern 802:Second side

Claims

1. A power supply device having a configuration in which an input DC power supply, a first noise reduction function component, and a power conversion circuit are connected, The power conversion circuit includes: an input capacitor, a switching element, an output rectifier circuit, and an output capacitor connected to a load; The first noise reduction function component is a pair of first and second input terminals; a pair of first and second output terminals; a first current line connecting the first input terminal and the first output terminal; a second current line connecting the second input terminal and the second output terminal; a first inductor and a second inductor connected in series in the first current line; a first capacitor connected in parallel to the input DC power supply and connecting a connection node between the first inductor and the second inductor and the second current line; a second capacitor connected in parallel to the input capacitor and connecting the first output terminal and the second output terminal; Equipped with the first input terminal is connected to the positive electrode of the input DC power supply; the second input terminal is connected to the negative electrode of the input DC power supply; the first output terminal is connected to the positive electrode of the input capacitor without being connected to other parts of the power conversion circuit; the second output terminal is connected to the negative electrode of the input capacitor without being connected to other parts of the power conversion circuit; The second capacitor is Structurally, it is a feedthrough capacitor having at least three terminals, namely, a first terminal, a second terminal, and a third terminal; the first terminal is connected to the second inductor, the second terminal is connected to the first output terminal, and the third terminal is connected to the second output terminal; the first inductor and the first capacitor form a first filter; the second inductor and the second capacitor form a second filter; the first filter, the second filter, and the power conversion circuit form a first noise balancing circuit that cancels out and balances switching noise currents in two or more frequency bands generated by the switching element. power supply.

2. the second capacitor is a three-terminal component having the first terminal, the second terminal, and the third terminal; The power supply device of claim 1 .

3. the second capacitor is a four-terminal component including the first terminal, the second terminal, the third terminal, and a fourth terminal connected to the third terminal; The power supply device of claim 1 .

4. the first noise reduction function component is a discrete component having mounting legs; The power supply device of claim 1 .

5. the first noise reduction function component is a surface-mount component having external connection electrodes that can be surface-mounted; The power supply device of claim 1 .

6. the first noise reduction function component includes a fifth inductor; the fifth inductor is connected between the second input terminal and a node where the first capacitor and the second current line are connected; The power supply device of claim 1 .

7. a line length between the input capacitor and an input end of a switching circuit including the switching element is shorter than a line length between the first output terminal and the second output terminal of the first noise reduction function component and the input capacitor of the power conversion circuit; The power supply device of claim 1 .

8. the first filter is a low-frequency filter; the second filter is a high frequency filter; The power supply device of claim 1 .

9. A power supply device having a configuration in which an input DC power supply, a second noise reduction function component, and a power conversion circuit are connected, The power conversion circuit includes: an input capacitor, a switching element, an output rectifier circuit, and an output capacitor connected to a load; The second noise reduction function component is a third input terminal and a fourth input terminal that form a pair; a pair of third and fourth output terminals; a third current line connecting the third input terminal and the third output terminal; a fourth current line connecting the fourth input terminal and the fourth output terminal; a third inductor and a fourth inductor connected in series in the third current line; a third capacitor connected in parallel to the output capacitor and connecting a connection node between the third inductor and the fourth inductor and the fourth current line; a fourth capacitor connected in parallel to the load and connecting the third output terminal and the fourth output terminal; Equipped with the third input terminal is connected to the positive electrode of the output capacitor without being connected to other parts of the power conversion circuit; the fourth input terminal is connected to the negative electrode of the output capacitor without being connected to other parts of the power conversion circuit; the third output terminal is connected to the positive electrode of the load; the fourth output terminal is connected to the negative electrode of the load; The fourth capacitor is Structurally, it is a feedthrough capacitor having at least three terminals, namely, a first terminal, a second terminal, and a third terminal; the first terminal is connected to the fourth inductor, the second terminal is connected to the third output terminal, and the third terminal is connected to the fourth output terminal; the third inductor and the third capacitor form a third filter; the fourth inductor and the fourth capacitor form a fourth filter; the third filter, the fourth filter, and the power conversion circuit form a second noise balancing circuit that cancels out and balances switching noise currents in two or more frequency bands generated by the switching elements. power supply.

10. the fourth capacitor is a three-terminal component having the first terminal, the second terminal, and the third terminal; 10. The power supply device of claim 9.

11. the fourth capacitor is a four-terminal component including the first terminal, the second terminal, the third terminal, and a fourth terminal connected to the third terminal; 10. The power supply device of claim 9.

12. the second noise reduction function component is a discrete component having mounting legs; 10. The power supply device of claim 9.

13. the second noise reduction function component is a surface-mount component having external connection electrodes that can be surface-mounted; 10. The power supply device of claim 9.

14. the second noise reduction function component includes a sixth inductor; the sixth inductor is connected between the fourth input terminal and a node where the third capacitor and the fourth current line are connected; 10. The power supply device of claim 9.

15. a line length between the third input terminal and the fourth input terminal of the second noise reduction function component and the output capacitor of the power conversion circuit is longer than a line length between the output capacitor and an output end of the output rectifier circuit; 10. The power supply device of claim 9.

16. the third filter is a low-frequency filter; the fourth filter is a high frequency filter; 10. The power supply device of claim 9.

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