Power supply device and lighting fixture

Abstract

To provide a power supply device and a lighting fixture capable of improving reliability.SOLUTION: A power supply device 2 includes: a switching element Q1 that uses a semiconductor including silicon carbide as a material and performs high frequency switching operation; and a shielding structure S1 that shields the switching element Q1 from the outside air. The switching element Q1 has a conductive portion, a guard ring portion, and a protective film. A current flows through the conductive portion in accordance with switching operation of the switching element Q1. The guard ring portion is provided around the conductive portion. The protective film is made of polyimide and covers at least the guard ring portion.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure generally relates to a power supply device and a lighting fixture, and more particularly to a power supply device and a lighting fixture including a switching element that performs a high-frequency switching operation.

Background Art

[0002] Conventionally, lighting fixtures installed outdoors are known (see, for example, Patent Document 1).

[0003] The lighting fixture described in Patent Document 1 includes a fixture body that irradiates illumination light, and a support arm portion that supports the fixture body. The support arm portion is a hollow columnar body, and a power supply device having a power supply circuit that supplies power to the fixture body is housed therein.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a lighting fixture as described in Patent Document 1, electronic components included in the power supply device are exposed to the outside air, which may cause corrosion of the electronic components and a decrease in reliability.

[0006] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a power supply device and a lighting fixture capable of improving reliability.

Means for Solving the Problems

[0007] A power supply device according to one aspect of the present disclosure includes a switching element that uses a semiconductor containing silicon carbide as a material and performs a high-frequency switching operation, and a shielding structure that shields the switching element from the outside air. The switching element has a conduction portion through which current flows in response to the high-frequency switching operation, a guard ring portion provided around the conduction portion, and a protective film made of polyimide that covers at least the guard ring portion.

[0008] A lighting fixture according to one aspect of the present disclosure includes the power supply device and a light source module to which power is supplied from the power supply device.

Advantages of the Invention

[0009] The power supply device and the lighting fixture of the present disclosure can improve reliability.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0011] The power supply device 2 according to an embodiment of the present disclosure and the lighting fixture A1 including the power supply device 2 will be described in detail with reference to the drawings. However, each drawing described in the following embodiments is a schematic diagram, and the respective ratios of the sizes and thicknesses of the respective components do not necessarily reflect the actual dimensional ratios. Note that the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications can be made according to the design and the like as long as the effects of the present disclosure can be achieved.

[0012] (1) Overview As shown in FIG. 3, the power supply device 2 according to the embodiment includes a switching element Q1 that performs a high-frequency switching operation using a semiconductor containing silicon carbide (SiC) as a material, and a shielding structure S1 that shields the switching element Q1 from the outside air.

[0013] The switching element Q1 has a conduction portion C1 (see FIG. 4), a guard ring portion G1 (see FIG. 4), and a protective film 73 (see FIG. 4).

[0014] A current flows through the conduction portion C1 according to the switching operation of the switching element Q1.

[0015] The guard ring portion G1 is provided around the conduction portion C1.

[0016] The protective film 73 is made of polyimide and covers at least the guard ring portion G1.

[0017] Here, the guard ring portion G1 relaxes the electric field concentration around the conduction portion C1 and suppresses a decrease in the breakdown voltage performance of the switching element Q1.

[0018] According to the above configuration, since the power supply device 2 includes the shielding structure S1, it is possible to suppress moisture contained in the outside air from permeating through the protective film 73 and reaching the guard ring portion G1, and thus suppressing corrosion of the guard ring portion G1. As a result, it is possible to suppress a decrease in the breakdown voltage performance of the switching element Q1, and as a result, improve the reliability of the power supply device 2.

[0019] (2) Details The lighting fixture A1 according to the embodiment (hereinafter abbreviated as the lighting fixture A1) is a floodlight mainly used for lighting (floodlighting) soccer stadiums, various stadiums, school playgrounds, etc. In the following description, unless otherwise specified, the up-down, front-back, and left-right directions indicated by arrows in FIG. 1 and the like are defined as the up-down, front-back, and left-right directions of the lighting fixture A1, respectively.

[0020] The lighting fixture A1 includes a power supply device 2 and, for example, two light source units 1. The lighting fixture A1 further includes a pair of connecting members 4 that connect the two light source units 1 and a support member 3 that supports the two light source units 1 (see FIGS. 1 and 2). It is assumed that the two light source units 1 have the same structure. The lighting fixture A1 may include one light source unit 1 or three or more light source units 1.

[0021] (2-1) Light Source Unit The two light source units 1 have the same configuration.

[0022] As shown in FIG. 1, each light source unit 1 includes a light source module 10, a cover 11, a heat dissipation block 12, and a frame body 13.

[0023] The light source module 10 is, for example, a light source module in which a plurality of light emitting elements (LEDs) 100 are mounted on the front surface (surface) of a flat substrate 101. The plurality of light emitting elements 100 mounted on the light source module 10 emit light by the electric power supplied from the power supply device 2 to the light source unit 1. However, the light emitting element 100 is not limited to an LED, and may be an organic electroluminescence element, a semiconductor laser element, or the like. The substrate 101 is, for example, a metal base substrate based on an aluminum plate.

[0024] As shown in Fig. 1, the cover 11 is arranged to cover the light source module 10 from the front. The cover 11 is formed of a synthetic resin having translucency such as acrylic resin or polycarbonate resin. A plurality of lenses corresponding one-to-one to the plurality of light-emitting elements 100 are provided on the rear surface of the cover 11 (not shown). Each of the plurality of lenses provided on the rear surface of the cover 11 has, for example, a collimating function of making the light output from the corresponding light-emitting element 100 approach parallel light.

[0025] The heat dissipation block 12 has a base portion 120 and a plurality of heat dissipation plates 121 (see Figs. 1 and 2). The base portion 120 is formed, for example, in a rectangular flat plate shape of an aluminum alloy. The light source module 10 is attached to the front surface of the base portion 120 using a plurality of screws, so that the substrate 101 of the light source module 10 and the base portion 120 are mechanically and thermally connected.

[0026] The plurality of heat dissipation plates 121 are formed, for example, in a flat plate shape of an aluminum alloy. As shown in Fig. 2, these plurality of heat dissipation plates 121 are attached to the rear surface of the base portion 120 at regular intervals.

[0027] The heat dissipation block 12 can suppress the temperature rise of the light source module 10 and improve the luminous efficiency by efficiently dissipating the heat generated by the plurality of light-emitting elements 100 during lighting.

[0028] The frame body 13 is formed in a rectangular cylindrical shape. The frame body 13 is formed, for example, by aluminum die casting or the like. The frame body 13 holds the cover 11 inside.

[0029] (2-2) Connecting member The pair of connecting members 4 have the same configuration.

[0030] The connecting member 4 is fastened to the side surfaces of the base portions 120 of the two light source units 1 arranged one above the other with a plurality of fastening parts (hexagon bolts or the like) 46.

[0031] As a result, the two light source units 1 are connected by a pair of connecting members 4 in a state of being arranged in two upper and lower rows (see FIG. 1).

[0032] (2-3) Power supply device As shown in FIG. 1, the power supply device 2 is fixed to the two light source units 1 by a pair of fixing bases 6.

[0033] As shown in FIGS. 2 and 3, the power supply device 2 includes a housing 20, a power supply circuit board B1 and a control circuit board B2 housed in the housing 20. In this embodiment, the power supply device 2 includes two power supply circuit boards B1 corresponding to the two light source modules 10 respectively.

[0034] The housing 20 has a box-shaped case body 21 with one side (the rear side) open, and a case lid 22 that closes the opening surface (the rear side) of the case body 21. Both the case body 21 and the case lid 22 are formed of an aluminum alloy.

[0035] A case side attachment portion 23 is provided on each of the left and right side surfaces of the case body 21. Each case side attachment portion 23 is formed in a columnar shape and is integrally formed with the case body 21 so as to protrude in the left-right direction from approximately the center in the vertical direction on the left and right side surfaces of the case body 21.

[0036] Two power supply lines P1 are led out from the bottom surface of the housing 20 (see FIG. 2). One power supply line P1 is electrically connected to the lower light source unit 1 to supply the DC current output from the power supply device 2 to the lower light source unit 1. The other power supply line P1 is electrically connected to the upper light source unit 1 to supply the DC current output from the power supply device 2 to the upper light source unit 1.

[0037] The case lid 22 is formed in a rectangular flat plate shape. The case lid 22 is placed on the opening surface of the case body 21 so as to overlap with the rear end surface of the case body 21, and is screwed to the case body 21 with a plurality of screws (see Fig. 2). Thereby, an internal space Sp1 surrounded by the case body 21 and the case lid 22 is formed. The power circuit board B1 and the control circuit board B2 are housed in the internal space Sp1.

[0038] The power circuit board B1 is configured by mounting various electronic components on a printed wiring board. Various electronic components that are components of the power circuit board B1 include a switching element Q1 that performs a high-frequency switching operation. In other words, the power supply device 2 includes a power circuit board B1 on which the switching element Q1 is mounted. The switching element Q1 is, for example, an n-channel type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Note that the switching element Q1 is not limited to an n-channel type MOSFET, and may be a p-channel type MOSFET or an IGBT (Insulated Gate Bipolar Transistor) or the like.

[0039] The power circuit board B1 is a board that supplies a direct current to the light source module 10. The power circuit board B1 has, for example, a power conversion circuit section and a constant current circuit section.

[0040] The power conversion circuit section has a rectifying circuit such as a diode bridge and a boost chopper circuit (power factor improvement circuit) including a switching element Q1 (see Fig. 3). The power conversion circuit section converts alternating current power supplied from a commercial power system into direct current power. However, the power conversion circuit section may be provided with a switching power supply circuit having a power factor improvement function such as a buck chopper circuit, a buck-boost chopper circuit, or a flyback converter instead of the boost chopper circuit.

[0041] The constant current circuit section has, for example, a buck chopper circuit (buck converter) including a switching element Q1. Note that the switching element Q1 included in the boost chopper circuit of the power conversion circuit section and the switching element Q1 included in the buck chopper circuit of the constant current circuit section are different elements. The constant current circuit section steps down the DC voltage output from the power conversion circuit and applies it to the light source module 10, and adjusts the DC current flowing through the light source module 10. However, the constant current circuit section may be provided with various chopper circuits, series regulators, etc. instead of the buck chopper circuit.

[0042] The switching element Q1 includes a semiconductor chip 7 (see FIG. 4) mainly made of a semiconductor containing silicon carbide (SiC). The semiconductor chip 7 is housed in the package of the switching element Q1. Note that FIG. 4 is a cross-sectional view of the peripheral portion of the semiconductor chip 7.

[0043] As shown in FIG. 4, the semiconductor chip 7 has a semiconductor layer 70 made of silicon carbide, a first electrode 71, a second electrode 72, and a protective film 73.

[0044] The semiconductor layer 70 has a first layer L1 made of an n-type semiconductor doped with impurities (such as aluminum and boron) in silicon carbide, a second layer L2 made of a p-type semiconductor doped with impurities (such as phosphorus and arsenic) in silicon carbide, and a third layer L3 made of an n-type semiconductor. More specifically, the semiconductor layer 70 is formed by providing the second layer L2 on the surface F1 of the first layer L1 and providing the third layer L3 on the surface F2 of the second layer L2. Note that the structure of the semiconductor chip 7 described above is an example when the switching element Q1 is an n-channel MOSFET, and when the switching element Q1 is an element different from the n-channel MOSFET, the structure of the semiconductor chip 7 is different from the above structure.

[0045] The first electrode 71 is provided so as to contact the back surface R1 of the first layer L1. In this embodiment, the switching element Q1 is an n-channel MOSFET, and the first electrode 71 is the drain electrode of the n-channel MOSFET.

[0046] The second electrode 72 is provided in contact with the second layer L2 and the third layer L3. In the present embodiment, the second electrode 72 is the source electrode of an n-channel type MOSFET.

[0047] Although not shown, the semiconductor chip 7 has a third electrode that contacts the second layer L2 and the third layer L3 via an insulating layer. The third electrode is the gate electrode of an n-channel type MOSFET.

[0048] When a voltage (gate voltage) equal to or higher than a predetermined value is applied between the second electrode 72 as the source electrode and the third electrode as the gate electrode, a channel that electrically connects the first layer L1 and the third layer L3 is formed in the second layer L2. As a result, the first electrode 71 and the second electrode 72 are electrically connected via the channel formed in the second layer L2. That is, when a voltage is applied between the second electrode 72 and the third electrode, the switching element Q1 is turned on, and current flows from the first electrode 71 to the second electrode 72. On the other hand, when a voltage equal to or higher than a predetermined value is not applied between the second electrode 72 and the third electrode, the first electrode 71 and the second electrode 72 are insulated from each other. That is, when a voltage equal to or higher than a predetermined value is not applied between the second electrode 72 and the third electrode, the switching element Q1 is turned off, and no current flows from the first electrode 71 to the second electrode 72. In other words, the second layer L2 in which the channel is formed is a conduction portion C1 through which current flows in response to a high-frequency switching operation in the switching element Q1.

[0049] The semiconductor layer 70 further has a guard ring portion G1. The guard ring portion G1 is provided around the second layer L2 that is the conduction portion C1. The guard ring portion G1 is composed of a p-type semiconductor formed in an annular shape. The p-type semiconductor constituting the guard ring portion G1 is, for example, a p-type semiconductor made of silicon carbide. The guard ring portion G1 suppresses a decrease in the breakdown voltage performance of the switching element Q1 by alleviating electric field concentration at the peripheral portion of the semiconductor chip 7.

[0050] The protective film 73 is a so-called passivation film formed on the semiconductor layer 70 so as to cover at least the guard ring portion G1. The protective film 73 is a passivation film made of polyimide.

[0051] As shown in FIG. 3, the control circuit board B2 is configured by mounting various electronic components on a printed wiring board. Various electronic components that are components of the control circuit board B2 include, for example, a microcontroller M1. The control circuit board B2 controls the power conversion circuit section so as to maintain the output voltage of the power conversion circuit section of the power supply circuit board B1 at a constant DC voltage. Further, the control circuit board B2 controls the step-down chopper circuit of the constant current circuit section so that the DC current supplied from the constant current circuit section of the power supply circuit board B1 to the light source module 10 matches the target value. Note that the control circuit board B2 changes the target value of the DC current supplied to the light source module 10 according to a dimming signal received from a wireless communication section (not shown) via a signal connector.

[0052] Here, the power supply device 2 further includes a shielding structure S1 that shields the switching element Q1 from the outside air. In the present embodiment, as shown in FIG. 3, the shielding structure S1 is a covering member 8 that covers the switching element Q1. The covering member 8 includes a synthetic resin such as polyurethane. Note that the synthetic resin used as the covering member 8 is not limited to polyurethane.

[0053] The covering member 8 is provided on the power supply circuit board B1 so as to cover the entire switching element Q1. Thereby, it is possible to suppress the guard ring portion G1 of the semiconductor chip 7 included in the switching element Q1 from being corroded by moisture contained in the outside air.

[0054] The power supply device 2 further includes a container (case 24) in which the power supply circuit board B1 is housed and a container (case 25) in which the control circuit board B2 is housed. Note that in the present embodiment, the power supply device 2 includes two cases 24 corresponding to the two power supply circuit boards B1 respectively. The two cases 24 and the case 25 are housed in the internal space Sp1 of the housing 20.

[0055] The case 24 is a flat rectangular parallelepiped with an open rear surface. The power circuit board B1 is housed in the case 24 such that the switching element Q1 faces the front panel 240 of the case 24 with a space therebetween. The case 24 housing the power circuit board B1 is fixed to the case body 21 such that the front panel 240 contacts the front panel 211 of the case body 21 of the housing 20.

[0056] The case 25 is a flat rectangular parallelepiped with an open rear surface. The control circuit board B2 is housed in the case 25 such that the microcontroller M1 faces the front panel 250 of the case 25. The case 25 housing the control circuit board B2 is fixed to the case body 21 with the front panel 250 separated from the front panel 211 of the case body 21.

[0057] (2-4) Support member As shown in FIGS. 1 and 2, the support member 3 has a fixing portion 30, a pair of arm portions 31 rising obliquely upward from both the left and right ends of the fixing portion 30, and mounting portions 32 provided at the tips (upper ends) of the pair of arm portions 31 (see FIG. 1). However, the support member 3 integrally forms the fixing portion 30, the pair of arm portions 31, and the pair of mounting portions 32 by processing a metal plate.

[0058] The fixing portion 30 is fixed to a gantry Z1 (see FIG. 1), which is a surface to be fixed, using bolts or the like.

[0059] The pair of arm portions 31 rise forward and obliquely upward from both the left and right ends of the fixing portion 30. The mounting portions 32 are integrally provided at the tips of the respective arm portions 31.

[0060] The pair of mounting portions 32 are respectively attached to a pair of case-side attachment portions 23 of the housing 20 using bolts or the like. For example, the left mounting portion 32 of the pair of mounting portions 32 is attached to the case-side attachment portion 23 via a display member 5. The display member 5 is a metal disc with graduations engraved thereon.

[0061] (3) Modification The above embodiment is just one of various embodiments of the present disclosure. The above embodiment can be variously modified according to design and the like as long as the object of the present disclosure can be achieved.

[0062] Hereinafter, modification examples of the embodiment will be listed. Hereinafter, the above embodiment may also be referred to as a "basic example". The above basic example and the modification examples described below can be applied in appropriate combinations.

[0063] (3.1) Modification Example 1 As shown in FIG. 5, the shielding structure S1 may be a covering member 9 that covers the power circuit board B1. The covering member 9 contains a synthetic resin such as polyurethane. Note that the synthetic resin used as the covering member 9 is not limited to polyurethane.

[0064] The covering member 9 which is a synthetic resin is filled, for example, in a case 24 in which the power circuit board B1 is housed. The covering member 9 is filled in the case 24 at least up to behind the switching element Q1.

[0065] (3.2) Modification Example 2 As shown in FIG. 6, the power supply device 2 may have a case 24a that seals the power circuit board B1 in a state of being shielded from the outside air. In this case, the shielding structure S1 is realized by the case 24a. In other words, the shielding structure S1 includes a case 24a that seals the power circuit board B1 in a state of being shielded from the outside air.

[0066] The case 24a has a case body 241 with one side (rear surface) open, a case lid 242 that closes the opening surface of the case body 241, and a sealing material 243 that seals the gap between the opening surface of the case body 241 and the case lid 242.

[0067] The case lid 242 is placed over the opening surface of the case body 241 that houses the power circuit board B1, and is fixed to the case body 241 with a plurality of screws or the like. Thereby, an internal space Sp2 surrounded by the case body 241 and the case lid 242 is formed. The power circuit board B1 is housed in the internal space Sp2. At this time, since the gap between the opening surface of the case body 241 and the case lid 242 is sealed by the sealing material 243, the case 24a can seal the power circuit board B1 in a state of being shielded from the outside air.

[0068] The sealing material 243 is formed of, for example, silicone rubber. Note that the sealing material 243 is not limited to silicone rubber and may be a metal such as indium.

[0069] Also, in this case, the power supply device 2 may further include a moisture absorbent H1 such as silica gel disposed in the internal space Sp2 of the case 24a. The moisture absorbent H1 disposed in the internal space Sp2 absorbs moisture contained in the outside air that has passed through the sealing material 243 and entered the internal space Sp2. That is, the shielding structure S1 further includes a moisture absorbent H1 disposed in the case 24a. Thereby, it is possible to more reliably suppress the guard ring portion G1 of the semiconductor chip 7 included in the switching element Q1 from being corroded by moisture contained in the outside air.

[0070] (3.3) Modification Example 3 As shown in FIG. 7, the power supply device 2 may have a housing 20a that houses the case 24 and seals the power circuit board B1 in a state of being shielded from the outside air. In this case, the shielding structure S1 is realized by the housing 20a. In other words, the shielding structure S1 includes a housing 20a that houses the case 24 and seals the power circuit board B1 in a state of being shielded from the outside air.

[0071] The housing 20a includes a box-shaped case body 21a with one side (the rear side) open, a case lid 22a that closes the opening surface (the rear side) of the case body 21a, and a sealing material 26 that seals the gap between the opening surface of the case body 21a and the case lid 22a. The case lid 22a is placed over the opening surface of the case body 21a so as to overlap with the rear end surface of the case body 21a and is screwed to the case body 21a with a plurality of screws. Thereby, an internal space Sp3 surrounded by the case body 21a and the case lid 22a is formed. The case 24 in which the power circuit board B1 is housed is housed in the internal space Sp3. At this time, since the gap between the opening surface of the case body 21a and the case lid 22a is sealed by the sealing material 26, the housing 20a can seal the power circuit board B1 in a state shielded from the outside air.

[0072] The sealing material 26 is formed of, for example, silicone rubber. Note that the sealing material 26 is not limited to silicone rubber and may be a metal such as indium.

[0073] Also, in this case, the power supply device 2 may further include a moisture absorbent H2 such as silica gel disposed in the internal space Sp3 of the housing 20a. The moisture absorbent H2 disposed in the internal space Sp3 absorbs moisture contained in the outside air that has passed through the sealing material 26 and entered the internal space Sp3. That is, the shielding structure S1 further includes a moisture absorbent H2 disposed in the housing 20a. Thereby, it is possible to more reliably prevent the guard ring portion G1 of the semiconductor chip 7 provided in the switching element Q1 from being corroded by moisture contained in the outside air.

[0074] (4) Summary The power supply device (2) according to the first aspect of the present disclosure includes a switching element (Q1) that uses a semiconductor containing silicon carbide as a material and performs a high-frequency switching operation, and a shielding structure (S1) that shields the switching element (Q1) from the outside air. The switching element (Q1) has a conduction part (C1), a guard ring part (G1), and a protective film (73). A current flows through the conduction part (C1) according to the switching operation of the switching element (Q1). The guard ring part (G1) is provided around the conduction part (C1). The protective film (73) is made of polyimide and covers at least the guard ring part (G1).

[0075] According to this aspect, it is possible to suppress moisture contained in the outside air from permeating through the protective film (73) and reaching the guard ring part (G1), and to prevent the guard ring part (G1) from corroding. Thereby, the reliability of the power supply device (2) can be improved.

[0076] In the power supply device (2) according to the second aspect, in the first aspect, the shielding structure (S1) has a covering member (8) that covers the switching element (Q1). The covering member (8) contains a synthetic resin.

[0077] According to this aspect, it is possible to suppress the guard ring part (G1) from corroding with a simple configuration.

[0078] The power supply device (2) according to the third aspect further includes a substrate (B1) on which the switching element (Q1) is mounted in the first aspect. The shielding structure (S1) has a covering member (9) that covers the substrate (B1). The covering member (9) contains a synthetic resin.

[0079] According to this aspect, it is possible to more reliably suppress the guard ring part (G1) from corroding.

[0080] The power supply device (2) according to the fourth aspect further includes a container (24) in which the substrate (B1) is housed in the third aspect. The synthetic resin contained in the covering member (9) is filled in the container (24).

[0081] According to this aspect, it is possible to more reliably suppress the corrosion of the guard ring portion (G1).

[0082] The power supply device (2) according to the fifth aspect further includes a substrate (B1) on which the switching element (Q1) is mounted in any one of the first to fourth aspects. The shielding structure (S1) includes a container (24a) that seals the substrate (B1) in a state of being shielded from the outside air.

[0083] According to this aspect, by suppressing the intrusion of outside air into the container (24a), it is possible to suppress the corrosion of the guard ring portion (G1).

[0084] In the power supply device (2) according to the sixth aspect, in the fifth aspect, the shielding structure (S1) further includes a moisture absorbent material (H1) disposed inside the container (24a).

[0085] According to this aspect, by the moisture absorbent material (H1) absorbing the moisture contained in the outside air that has entered the container (24a), it is possible to suppress the corrosion of the guard ring portion (G1).

[0086] The power supply device (2) according to the seventh aspect further includes a substrate (B1) on which the switching element (Q1) is mounted and a first container (24) that houses the substrate (B1) in any one of the first to sixth aspects. The shielding structure (S1) includes a second container (20a) that houses the first container (24) and seals the substrate (B1) in a state of being shielded from the outside air.

[0087] According to this aspect, by suppressing the intrusion of outside air into the second container (20a), it is possible to suppress the corrosion of the guard ring portion (G1).

[0088] In the power supply device (2) according to the eighth aspect, in the seventh aspect, the shielding structure (S1) further includes a moisture absorbent material (H2) disposed inside the second container (20a).

[0089] According to this aspect, the moisture absorbent (H2) absorbs the moisture contained in the outside air that has entered the second container (20a), thereby suppressing corrosion of the guard ring portion (G1).

[0090] The lighting fixture (A1) of the ninth aspect includes the power supply device (2) of any one of the first to eighth aspects and a light source module (10) to which power is supplied from the power supply device (2).

[0091] According to this aspect, it is possible to suppress the moisture contained in the outside air from permeating through the protective film (73) and reaching the guard ring portion (G1), thereby suppressing corrosion of the guard ring portion (G1). As a result, the reliability of the lighting fixture (A1) can be improved.

[0092] Note that the second to eighth aspects are not essential configurations of the power supply device (2) and can be omitted as appropriate.

Explanation of Reference Numerals

[0093] 2 Power supply device 8 Coating member 9 Coating member 10 Light source module 20 Container 20a Second container 24 Container, first container 24a Container 73 Protective film A1 Lighting fixture B1 Power supply circuit board (board) C1 Conductive portion G1 Guard ring portion H1 Moisture absorbent H2 Moisture absorbent Q1 Switching element S1 Shielding structure

Claims

1. A switching element that uses a semiconductor containing silicon carbide as a material and performs a high-frequency switching operation, and a shielding structure that shields the switching element from the outside air. The switching element has: a conduction part through which current flows according to the high-frequency switching operation; a guard ring part provided around the conduction part; and a protective film made of polyimide that covers at least the guard ring part. A power supply device.

2. The shielding structure has a covering member that covers the switching element, and the covering member contains a synthetic resin. The power supply device according to claim 1.

3. The power supply device further includes a substrate on which the switching element is mounted. The shielding structure has a covering member that covers the substrate, and the covering member contains a synthetic resin. The power supply device according to claim 1.

4. The power supply device further includes a container that houses the substrate, and the synthetic resin is filled in the container. The power supply device according to claim 3.

5. The power supply device further includes a substrate on which the switching element is mounted. The shielding structure includes a container that seals the substrate in a state shielded from the outside air. The power supply device according to claim 1.

6. The shielding structure further includes a moisture absorbent disposed in the container. The power supply device according to claim 5.

7. The power supply device further includes a substrate on which the switching element is mounted and a first container that houses the substrate. The shielding structure includes a second container that houses the first container and seals the substrate in a state shielded from the outside air. The power supply device according to claim 1.

8. The shielding structure further includes a moisture absorbent disposed in the second container. The power supply device according to claim 7.

9. An illumination device including the power supply device according to any one of claims 1 to 8 and a light source module supplied with power from the power supply device. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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