Patent Publication Number: US-9907200-B2

Title: Power supply device, light fixture, and vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority of Japanese Patent Application Number 2013-207583, filed Oct. 2, 2013, the entire content of which is hereby incorporated by reference. 
     TECHNICAL FIELD 
     The disclosure relates to a power-supply device, a light fixture including the same, and a vehicle including the light fixture. 
     BACKGROUND ART 
     A discharge lamp device such as a headlamp including a discharge lamp, like a high intensity discharge (HID) lamp, as a light source uses a power-supply device (lighting circuit module) to control lighting of a discharge lamp. 
     Such a power-supply device includes: a lighting circuit (power circuit) for lighting a discharge lamp; and a circuit case (housing) that houses the lighting circuit. The power-supply device is often fixed to the outside of a lamp housing in a discharge lamp device (see Japanese Unexamined Patent Application Publication No. 2009-170359, for instance). 
     In this case, to electrically connect the lighting circuit in the circuit case and the discharge lamp in the lamp housing, a through hole that communicates with both the lamp housing and the circuit case is formed in each of the lamp housing and the circuit case. Moreover, a connector terminal that projects toward the lamp housing to face the through hole is connected to a circuit board of the lighting circuit. Furthermore, an input/output cable line (harness) is led out from the lamp housing, and is interested in the through holes of the lamp housing and the circuit case and connected to the connector terminal of the circuit board. 
     SUMMARY 
     In a conventional power-supply device, since a connector terminal is provided to a lamp housing of a circuit board, even when the power-supply device is fixed to the outside of the lamp housing, there is an advantage that the connector terminal is unlikely to be obstructive. 
     However, since the conventional power-supply device is attached to the outside of the lamp housing, the conventional power-supply requires strength for the shock of a vehicle or the like. For this reason, it has been difficult to use, for a circuit case (casing), a press molded product formed by metal stamping, instead of aluminum die-cast having high stiffness. 
     In particular, when part of the circuit case is fit in part of the lamp housing, connection to an external connector line, the shock of the vehicle, or the like puts a load on a portion of the circuit case to which a connector terminal is provided. Accordingly, it is very difficult to use the press molded product for the circuit case in such a structure. 
     The disclosure has been conceived to solve such a problem, and an object of the disclosure is to provide a power-supply device or the like that makes it possible to make a casing thinner and ensure the strength of the casing. 
     In order to achieve the above object, a first power-supply device according to one aspect of the present invention includes: a casing formed by metal stamping and having a space therein; and a circuit board disposed inside the casing, wherein the casing includes a casing portion having an opening, and a cover portion disposed to cover the opening of the casing portion, the casing portion has a through hole formed at a position corresponding to a connector terminal connected to the circuit board, and a non-flat portion is provided to a region having a size greater than or equal to an outside diameter of a connector of an external connector line connected to the connector terminal in the casing portion. 
     Moreover, a second power-supply device according to another aspect of the present invention includes: a casing made of metal and having a thickness ranging from 0.3 to 3.0 mm and a space therein; and; and a circuit board disposed inside the casing, wherein the casing includes a casing portion having an opening, and a cover portion disposed to cover the opening of the casing portion, the casing portion has a through hole formed at a position corresponding to a connector terminal connected to the circuit board, and a non-flat portion is provided to a region having a size greater than or equal to an outside diameter of a connector of an external connector line connected to the connector terminal in the casing portion. 
     Furthermore, in the first and second power-supply devices in the foregoing aspects of the present invention, the cover portion may have a thickness ranging from 0.8 to 3.0 mm, and the casing portion may have a thickness ranging from 0.3 to 1.0 mm. 
     Moreover, in the first and second power-supply devices in the foregoing aspects of the present invention, the region having the size greater than or equal to the outside diameter of the connector may be defined by a circle having a diameter greater than or equal to φ15 mm. 
     Furthermore, in the first and second power-supply devices in the foregoing aspects of the present invention, the circuit board may be fixed to the cover portion. 
     Moreover, in the first and second power-supply devices in the foregoing aspects of the present invention, a groove may be formed in an inner face of the cover portion to surround the circuit board. 
     Furthermore, in the first and second power-supply devices in the foregoing aspects of the present invention, the casing portion may include a body portion and a protruding portion, the protruding portion being part of a top face of the body portion that protrudes outward, and the through hole may be provided to a top face of the protruding portion. 
     Moreover, in the first and second power-supply devices in the foregoing aspects of the present invention, the connector terminal may be fixed to a coupler base provided to the circuit board, and the coupler base may be provided to a portion where the protruding portion is formed. 
     A light fixture according to still another aspect of the present invention includes: a housing including a light extraction portion; a light source disposed inside the housing; and either one of the first power-supply device and the second power-supply device according to the foregoing aspects of the present invention that is disposed outside the housing and supplies power to the light source. 
     A vehicle according to yet another aspect of the present invention includes a vehicle body; and the light fixture according to still another aspect of the present invention. 
     According to the disclosure, it is possible to make the casing thinner and ensure the strength of the casing. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The figures depict one or more implementations in accordance with the present teaching, by way of examples only, not by way of limitations. In the figures, like reference numerals refer to the same or similar elements. 
         FIG. 1A  is a perspective view when a power-supply device according to Embodiment 1 is viewed obliquely from above. 
         FIG. 1B  is a perspective view when a power-supply device according to Embodiment 1 is viewed obliquely from below. 
         FIG. 2  is an exploded perspective view of a power-supply device according to Embodiment 1. 
         FIG. 3  is a diagram showing an outline of a power-supply device according to Embodiment 1, wherein (a) is a left lateral view, (b) is a top view, (c) is a front view, and (d) is a bottom view. 
         FIG. 4  is a diagram showing a state where an output harness and an input harness are connected to a power-supply device according to Embodiment 1. 
         FIG. 5A  is a cross-sectional view of a power-supply device according to Embodiment 1 at line A-A′ in  FIG. 3 . 
         FIG. 5B  is a cross-sectional view of a power-supply device according to Embodiment 1 at line B-B′ in  FIG. 3 . 
         FIG. 6  is a cross-sectional view of a light fixture according to Embodiment 2. 
         FIG. 7  is a block diagram showing a configuration of a light fixture according to Embodiment 2. 
         FIG. 8A  is a perspective view when an attachment portion between a power-supply device according to Embodiment 1 and a housing of a light fixture according to Embodiment 2 is viewed obliquely from above. 
         FIG. 8B  is a perspective view when an attachment portion between a power-supply device according to Embodiment 1 and a housing of a light fixture according to Embodiment 2 is viewed obliquely from below. 
         FIG. 9  is an exploded perspective view of a structure in an attachment portion between a power-supply device according to Embodiment 1 and a housing of a light fixture according to Embodiment 2. 
         FIG. 10  is a block diagram showing a schematic configuration of a vehicle according to Embodiment 3. 
         FIG. 11  is a diagram showing a state where another output harness and another input harness are connected to a power-supply device according to Embodiment 1. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the disclosure will be described with reference to the drawings. It is to be noted that each of the subsequently-described embodiments show a specific preferred example of the disclosure. Therefore, numerical values, shapes, materials, structural components, the arrangement and connection of the structural components, as well as steps and the sequence of the steps, etc. shown in the following exemplary embodiments are mere examples, and are not intended to limit the scope of the present invention. Furthermore, among the structural components in the following exemplary embodiment, components not recited in any one of the independent claims which indicate the broadest concepts of the present invention are described as arbitrary structural components. 
     It should be noted that the respective figures are schematic diagrams and are not necessarily precise illustrations. Furthermore, in the respective figures, substantially identical components are assigned the same reference signs, and overlapping description is omitted or simplified. 
     Embodiment 1 
       FIG. 1A  is a perspective view when a power-supply device  1  according to Embodiment 1 is viewed obliquely from above.  FIG. 1B  is a perspective view when the power-supply device  1  is viewed obliquely from below.  FIG. 2  is an exploded perspective view of the power-supply device  1 .  FIG. 3  is a diagram showing an outline of the power-supply device  1 , wherein (a) is a left lateral view, (b) is a top view, (c) is a front view, and (d) is a bottom view. 
     The power-supply device  1  is a lighting circuit module (ballast) for turning ON an HID lamp used as a light source in a discharge lamp device such as a vehicular headlamp for example, and includes, as shown in  FIG. 1A ,  FIG. 1B ,  FIG. 2 , and  FIG. 3 , a casing  100  having a space therein, a circuit board  200  disposed inside the casing  100 , an electronic component  210  provided to the circuit board  200 , and a coupler  300 . 
     In the power-supply device  1  according to this embodiment, a non-flat portion is provided to a region having a size greater than or equal to an outside diameter of a connector of an external connector line (output harness  10  and input harness  20 ) connected to the connector terminal  311  in the casing  100  (casing portion  110 ). 
     Here, a case where the output harness  10  and the input harness  20  are connected to the power-supply device  1  in this embodiment will be described using  FIG. 4 .  FIG. 4  is a diagram showing a state where the output harness  10  and the input harness  20  are connected to the power-supply device  1 . 
     The output harness  10  is an external connector line for supplying output power of the power-supply device  1  to the discharge lamp device, and includes a cable  11 , a first connector  12  provided at one end of the cable  11 , and a second connector  13  provided at the other end of the cable  11 , for instance. 
     The first connector  12  of the output harness  10  is an external connector connected to the power-supply device  1 , and is a connector with a waterproof rubber grommet in this embodiment. Moreover, although not shown, the second connector  13  of the output harness  10  is electrically connected to the HID lamp in the discharge lamp device. 
     When the output harness  10  is connected to the power-supply device  1 , the first connector  12  is connected to an output connector terminal  311   a  (internal connector) by being pushed into a coupler housing  320 . With this, the output harness  10  and the output connector terminal  311   a  are electrically connected. In this case, the first connector  12  is closely attached to the coupler housing  320  to cover a first through hole  321  of the coupler housing  320 . Accordingly, it is possible to ensure a waterproof property in the connection portion between the output harness  10  and the power-supply device  1 . 
     In contrast, the input harness  20  is an external connector line for supplying input power to the power-supply device  1 , and includes a cable  21  and a connector  22  provided at one end of the cable  21 , for instance. 
     The connector  22  of the input harness  20  is an external connector connected to the power-supply device  1 . Like the output harness  10 , when the input harness  20  is connected to the power-supply device  1 , the connector  22  is connected to an input connector terminal  311   b  (internal connector) by being pushed into the coupler housing  320 . Specifically, the connector  22  is inserted through a second through hole  322  of the coupler housing  320  and connected to the input connector terminal  311   b  corresponding to the second through hole  322 . With this, the input harness  20  and the input connector terminal  311   b  are electrically connected. 
     It is to be noted that although not shown, an other end of the input harness  20  is electrically connected to an external power source. 
     Hereinafter, the respective constituent components of the power-supply device  1  in this embodiment will be described in detail using  FIG. 5A  and  FIG. 5B  with reference to  FIG. 1A ,  FIG. 1B ,  FIG. 2 , and  FIG. 3 .  FIG. 5A  is a cross-sectional view of the power-supply device  1  at line A-A′ in  FIG. 3 .  FIG. 5B  is a cross-sectional view of the power-supply device  1  at line B-B′ in  FIG. 3 . 
     (Casing) 
     The casing  100  is a circuit case having a space therein, and is a press molded product formed by metal stamping. Here, the casing  100  has a thickness ranging from 0.3 to 3.0 mm. The casing  100  is formed to surround the circuit board  200 . 
     In this embodiment, the casing  100  includes a casing portion  110  having an opening  111 , and a cover portion (cover)  120  disposed to cover the opening  111  of the casing portion  110 . 
     The casing portion  111  is a cover formed to cover the circuit board  200 . The casing portion  110  is a metal cover, and is molded to have a space therein by performing metal stamping on a metal plate having a predetermined shape such as an aluminum plate and a stainless steel plate. In this embodiment, the casing portion  110  having a substantially box shape is molded by performing, for instance, press work on a metal plate having a thickness ranging from 0.3 to 3.0 mm. 
     It is to be noted that the metal plate used for the casing portion  110  is preferably thinner than the metal plate used for the cover portion  120 , and may have a thickness ranging from 0.3 to 1.0 mm, for example. It is possible to easily perform press work by making the metal plate used for the casing portion  110  thinner in the above manner. As a result, it is possible to produce the casing portion  110  having a desired shape with high accuracy. Moreover, a material of the casing portion  110  is not limited to metal, but may be resin or the like. 
     The casing portion  110  includes a body portion  110   a  for mainly storing the circuit board  200 , and an attaching portion  110   b  for mainly attaching the power-supply device  1  to an external device. 
     The body portion  110   a  is formed to cover the circuit board  200  entirely. The body portion  110   a  in this embodiment is substantially rectangular in planar view. With this, it is possible to reduce a waste of space in which the circuit board  200  is disposed. 
     The attaching portion  110   b  is a portion at which the power-supply device  1  is attached to a lamp housing (not shown) of the discharge lamp device, and is formed to protrude toward the lamp housing. Specifically, the attaching portion  110   b  is part of a top face of the body portion  110   a  that protrudes toward the lamp housing so that the part of the top face of the body portion  110   a  is fit in a hole of an attaching hole portion provided to the lamp housing. In other words, the attaching portion  110   b  is the part of the top face of the body portion  110   a  that protrudes outward. As stated above, by fitting the attaching portion  110   b  in the lamp housing, it is possible to increase a waterproof property in the connection portion between the casing portion  110  and the lamp housing. 
     In this embodiment, press work is performed on the attaching portion  110   b  so that the attaching portion  110   b  protrudes cylindrically, and a shape of the attaching portion  110   b  in planar view is substantially circular. With this, it is possible to further increase the waterproof property in the connection portion between the casing portion  110  and the lamp housing. 
     Moreover, since the attaching portion  110   b  is formed so that only the portion attached to the lamp housing protrudes in the casing portion  110 , it is possible to suppress an increase in overall height of the casing portion  110 . Accordingly, it can be intended to miniaturize the power-supply device  1 . 
     A through hole  112  is formed in the attaching portion  110   b . The through hole  112  is formed to penetrate a top face of the attaching portion  110   b . In other words, the through hole  112  is surrounded by a wall portion that is a side wall of the attaching portion  110   b.    
     Moreover, the through hole  112  is formed at a position corresponding to a connector terminal  311  connected to the circuit board  200 , and is formed at a position opposite to the connector terminal  311  in this embodiment. 
     More specifically, the through hole  112  includes a first through hole  112   a  and a second through hole  112   b . The first through hole  112   a  is opposite to the output connector terminal  311   a , and the second through hole  112   b  is opposite to the input connector terminal  311   b.    
     It is to be noted that a partition plate that partitions the first through hole  112   a  and the second through hole  112   b  is provided as part of the casing portion  110  to the top face of the attaching portion  110   b . This partition plate is used as a ground connection terminal for the output harness  10  and the input harness  20  connected to the connector terminal  311 . 
     Moreover, a groove  113  is formed in the attaching portion  110   b  of the casing portion  110  to surround the through hole  112 . A seal material such silicone resin is applied to the groove  113 . With this, the casing portion  110  and the coupler housing  320  are bonded together. In addition, the casing portion  110  and the coupler housing  320  can be sealed completely by circularly applying the seal material along the groove  113 . With this configuration, it is possible to ensure a superior waterproof property in the connection portion between the lamp housing and the power-supply device  1 . In addition, by forming the groove  113  in the attaching portion  110   b , it is also possible to increase the stiffness of the top face of the attaching portion  110   b.    
     Furthermore, in the casing portion  110 , a non-flat portion is provided to a region (first region) having a size greater than or equal to outside diameters of the first connector  12  of the output harness  10  and the connector  22  of the input harness  20  that are connected to the connector terminal  311 . In other words, in the region (first region) that is greater than or equal to the outside diameters of the first connector  12  of the output harness  10  and the connector  22  of the input harness  20  in the casing portion  110 , the entire region will not become flat. 
     In this embodiment, the first region is a region defined by a circle having a diameter greater than or equal to φ15 mm, for instance. To put it another way, a non-flat portion is in the circular region defined by the circle having the diameter greater than or equal to φ15 mm. In short, the entire circular region will not become flat. 
     Specifically, the non-flat portion is provided in the first region by providing a protruding portion or a recess portion to a top face (i.e. the top face of the body portion  110   a  and the top face of the attaching portion  110   b ) of the casing portion  110 . 
     More specifically, as shown in  FIG. 2  and (b) of  FIG. 3 , two ridge portions  114  are provided to the top face of the body portion  110   a . Moreover, two recess portions  115  are formed in the top face of the attaching portion  110   b  to surround part of the through hole  112 . As shown in  FIG. 5A  and  FIG. 5B , the ridge portions  114  and the recess portions  115  can be formed by performing press work or emboss on part of the metal plate included in the casing portion  110 . Providing the ridge portions  114  and the recess portions  115  prevents the entire first region in the top face of the body portion  110   a  and the top face of the attaching portion  110   b  from becoming flat. 
     As stated above, by providing the non-flat portions in the region having the size greater than or equal to the outside diameters of the first connector  12  of the output harness  10  and the connector  22  of the input harness  20  in the casing portion  110 , it is possible to increase the stiffness of the casing portion  110 . 
     With this, when the first connector  12  of the output harness  10  or the connector  22  of the input harness  20  is fit in the connector terminal  311  by being pushed into the coupler  300  (a coupler base  310  and the coupler housing  320 ), or when the first connector  12  of the output harness  10  or the connector  22  of the input harness  20  is detached (pulled) from the coupler  300  (the coupler base  310  and the coupler housing  320 ) to be released from the connector terminal  311 , it is possible to suppress exertion of stress (e.g. pressing force) per area on the flat portion of the casing portion  110 , which is commensurate with stress exerted on the first connector  12  of the output harness  10  or the connector  22  of the input harness  20 . Consequently, it is possible to suppress deformation of the casing portion  110  due to the stress exerted when the output harness  10  or the input harness  20  is attached to or detached from the power-supply device  1 . 
     In particular, since a rubber grommet (rubber cover) is provided to the first connector  12  of the output harness  10 , when the first connector  12  is attached to the coupler housing  320 , the rubber grommet is closely attached to the coupler housing  320  to cover the first through hole  321 . In this case, the first connector  12  is strongly pushed into the coupler housing  320 , and thus pressing force is strongly exerted on the top face of the attaching portion  110   b  of the casing portion  110 . In addition, since the rubber grommet is closely attached to the coupler housing  320 , when the first connector  12  is detached from the coupler housing  320 , pulling force is also exerted on the top face of the attaching portion  110   b.    
     In this embodiment, however, since the non-flat portion is provided in the first region of the casing portion  110 , the casing portion  110  has high stiffness. Accordingly, even when strong stress (pressing force or pulling force) is exerted on the top face of the attaching portion  110   b  of the casing portion  110 , the casing portion  110  will not be deformed. 
     It is to be noted that from a viewpoint of preventing deformation caused by stress exerted when the output harness  10  and the input harness  20  are attached or detached, a height of the ridge portions  114  and a depth of the recess portions  115  (i.e. a thickness of the non-flat portion) may be greater than or equal to a thickness of the metal plate included in the casing portion  110 . More preferably, for example, when the metal plate included in the casing portion  110  has a thickness ranging from 0.3 to 3.0 mm, the height of the ridge portions  114  and the depth of the recess portions  115  may be greater than or equal to 1 mm. 
     The cover portion  120  is a substantially plate-like metal case body formed to cover the opening  111  of the casing portion  110 . The cover portion  120  is molded into a predetermined shape by processing a metal plate such as an aluminum plate and a stainless steel plate. In this embodiment, the cover portion  120  having the predetermined shape is molded by performing press work on a metal plate having a thickness ranging from 0.3 to 3.0 mm. 
     It is to be noted that the metal plate used for the cover portion  120  is preferably thinner than the metal plate used for the casing portion  110 , and may have a thickness ranging from 0.8 to 3.0 mm, for example. With this, it is possible to decrease thermal resistance in the cover portion  120 , and thus it is possible to efficiently radiate heat given off from the electronic component  210 . In other words, since the exterior of the cover portion  120  is exposed to the air when the power-supply device  1  is attached to the lamp housing, decreasing the thermal resistance in the cover portion  120  makes it possible to effectively radiate the heat given off from the electronic component  210 . 
     The storage portion  121  for storing the electronic component  210  mounted on the circuit board  200  is provided to the cover portion  120 . The storage portion  121  may store the whole or part of the electronic component  210 . 
     The storage portion  121  is provided so that the storage portion  121  bulges outward from the casing  100 , and is provided to a corner portion of the cover portion  120 , for instance. As shown in  FIG. 5A  and  FIG. 5B , the storage portion  121  stores, for example, part of a transformer  210   a  as the electronic component  210  provided across the circuit board  200 . Specifically, the storage portion  121  stores a core of the transformer  210   a.    
     With this configuration, even when the high electronic component  210  such as a transformer is provided to the circuit board  200 , it is only necessary to heighten a portion of the cover portion  120  which corresponds to the storage portion  121 , and it is unnecessary to the heighten the casing portion  110 . In other words, since the cover portion  120  makes it possible to ensure a storage space for the high electronic component  210 , it is possible to reduce the height of the casing portion  110 . With this, it is possible to suppress the occurrence of the waste of space between the casing  100  and the electronic component  210 , and thus it can be intended to miniaturize the casing  100  as a whole. 
     It is to be noted that when the electronic component  210  is provided on another face (reverse face) of the circuit board  200  which faces the cover portion  120 , the storage portion  121  may store the electronic component provided to the reverse face of the circuit board  200 . 
     Moreover, when the cover portion  120  is seen in a planar view, the storage portion  121  is provided at a position where the storage portion  121  does not overlap the through hole  112 . Stated differently, when the cover portion  120  is seen in a planar view, the storage portion  121  and the through hole  112  do not overlap each other. 
     Since the through hole  112  is formed at the position corresponding to the connector terminal  311  connected to the circuit board  200 , when the cover portion  120  is seen in a planar view, preventing the storage portion  121  and the through hole  112  from overlapping each other makes it possible to avoid an increase in partial thickness of the casing  100  that is caused by thick portions of the cover portion  120  and the casing portion  110  overlapping each other. 
     Furthermore, when the cover portion  120  is seen in a planar view, the storage portion  121  is preferably provided at a position where the storage portion  121  does not overlap the attaching portion  110   b . Stated differently, when the cover portion  120  is seen in a planar view, the storage portion  121  and the side wall (wall portion) of the attaching portion  110   b  preferably do not overlap each other. 
     Since the storage portion  121  and the attaching portion  110   b  bulge outward in opposite directions, when the storage portion  121  and the side wall (wall portion) of the attaching portion  110   b  overlap each other, the casing  100  increases in thickness. In view of this, preventing the storage portion  121  and the side wall of the attaching portion  110   b  from overlapping each other makes it possible to make the casing  100  thinner. 
     Moreover, a groove (seal groove)  122  is formed inside the cover portion  120  (for the circuit board  200 ) to surround the circuit board  200 . The groove  122  is circularly formed along a periphery portion of the cover portion  120 . 
     A seal material such silicone resin is applied to the groove  122 . With this, the casing portion  110  and the cover portion  120  are bonded together. In this case, the casing portion  110  and the cover portion  120  can be sealed completely by circularly applying the seal material along the groove  122 . With this configuration, it is possible to ensure a superior waterproof property in the connection portion between the casing portion  110  and the cover portion  120 . 
     Moreover, forming the groove  122  makes it possible to increase the stiffness of the plate-like cover portion  120 . Accordingly, it is possible to suppress exertion of mechanical stress on the circuit board  200  fixed to the cover portion  120 . 
     Furthermore, the storage portion  121  may be provided at a position where the storage portion  121  is not connected to the groove  122 . In other words, a recess portion of the storage portion  121  and a recess portion of the groove  122  do not communicate with each other, and the storage portion  121  and the groove  122  should not be formed continuously. 
     Moreover, a first protruding portion  123 , a second protruding portion  124 , a third protruding portion  125 , and a through hole  126  are formed in the cover portion  120 . 
     The first protruding portion  123  is provided at a position opposite to the coupler base  310 . In this embodiment, the first protruding portion  123  is provided in three places around the central part of the cover portion  120  and opposite to protruding portions  314  of the coupler base  310 . 
     The second protruding portion  124  is provided in the periphery portion of the cover portion  120 . In this embodiment, the second protruding portion  124  is provided in three places in the periphery of and inside the groove  122 . 
     The third protruding portion  125  is provided in the periphery portion of the cover portion  120 . In this embodiment, the third protruding portion  125  is provided in one place in the periphery of a corner portion of and inside the groove  122 . The third protruding portion  125  is formed into a stepped protruding shape. A tip portion of the third protruding portion  125  is inserted into the first through hole  201  formed in the circuit board  200 , and a step face of the third protruding portion  125  abuts the reverse face of the circuit board  200  (the face facing the cover portion  120 ). 
     The first protruding portion  123 , the second protruding portion  124 , and the third protruding portion  125  support the circuit board  200 . The first protruding portion  123  and the second protruding portion  124  have their tips in contact with the reverse face of the circuit board  200 , and the third protruding portion  125  has its step face in contact with the reverse face of the circuit board  200  as stated above. Placing the circuit board  200  on the first protruding portion  123 , the second protruding portion  124 , and the third protruding portion  125  makes it possible to create a space between the circuit board  200  and the cover portion  120 . 
     In this embodiment, the first protruding portion  123  and the second protruding portion  124  are substantially circular in planar view, and can be formed by performing emboss on the metal plate included in the cover portion  120 , for instance. Moreover, the third protruding portion  125  that is stepped can be formed by processing the metal plate. A height of the first protruding portion  123  and the second protruding portion  124  and a first step height of the third protruding portion  125  are approximately 0.6 mm, for example. 
     The through hole  126  is formed at a position corresponding to the second through hole  202  of the circuit board  200  and a through hole  313  of the coupler base  310 . A rivet  410  is inserted through the through hole  126 . 
     Moreover, as shown in  FIG. 1A  and  FIG. 1B , brackets  127  for attaching the power-supply device  1  to the lamp housing (not shown) are provided to the cover portion  120 . A hole through which a bolt or a nut is inserted is provided to each of the brackets  127 . 
     Furthermore, two reinforcement ribs are formed on each bracket  127 . The ribs can be formed by performing emboss on the bracket  127 , for instance. In this case, when recess portions on the back sides of the ribs communicate with the recess portion of the groove  122 , there is a possibility that leakage of the seal material applied to the groove  122  to the ribs results in a space between the cover portion  120  and the casing portion  110 , which decreases a waterproof property. Thus, the ribs of the brackets  127  may be formed separately from the groove  122 . 
     (Circuit Board and Electronic Component) 
     As shown in  FIG. 2 , the circuit board  200  is a mounting board on which the electronic component  210  is mounted, and is, for instance, a PCB on which metal wiring having a predetermined pattern is formed. The circuit board  200  and the electronic component  210  constitute a circuit unit (electronic circuit). 
     The circuit board  200  is disposed in a space inside the casing  100 . In this embodiment, the circuit board  200  is fixed to the cover portion  120 . Specifically, the circuit board  200  is fixed to the cover portion  120  by being supported by protruding portions (the first protruding portion  123 , the second protruding portion  124 , and the third protruding portion  125 ) provided to the cover portion  120 . By being placed on the protruding portions in this manner, the circuit board  200  is disposed away from the cover portion  120  by a space. With this, it is possible to suppress a short circuit of a conductive portion (metal wiring and via) on the reverse face of the circuit board  200  and the cover portion  120 , and to ensure an insulation property between the circuit board  200  and the cover portion  120 . 
     It is to be noted that silicone resin may be partially applied to part, of the space between the circuit board  200  and the cover portion  120 , where heat of the circuit board  200  is great so that the part is in contact with the circuit board  200  and the cover portion  120 . 
     Moreover, the first through hole  201 , the second through hole  202 , and a third through hole  203  are formed in the circuit board  200 . The first through hole  201  is formed at a position corresponding to the third protruding portion  125  of the cover portion  120 . The second through hole  202  is formed at a position corresponding to the through hole  126  of the cover portion  120  and the through hole  313  of the coupler base  310 . The third through hole  203  is formed at positions corresponding to two of the three protruding portions  314  of the coupler base  310 . 
     It is to be noted that the tip portion of the third protruding portion  125  of the cover portion  120  is fit in the first through hole  201 . With this, it is possible to restrict the circuit board  200  to a horizontal movement. 
     The electronic component  210  mounted on the circuit board  200  is composed of circuit elements including the transformer  210   a . It is to be noted that although  FIG. 2  shows only the transformer  210   a  as the electronic component  210 , electronic components other than the transformer  210   a  are mounted on the circuit board  200 . Examples of the electronic components other than the transformer  210   a  include a resistor, a capacitor, a coil, a transistor, and a diode. These electronic components make up an electronic circuit such as a DC/DC converter and an inverter, for controlling lighting of an HID lamp. 
     It is to be noted that in this embodiment, although many of the electronic components are mounted on the face (surface) of the circuit board  200  which faces the casing portion  110 , any low electronic component among the electronic components may be mounted on the other face (reverse face) of the circuit board  200  which faces the cover portion  120 . 
     The transformer  210   a  in this embodiment is a sheet transformer, and includes, for instance, a winding pattern and a core (including E-shaped core and I-shaped core) formed in the circuit board  200 . As shown in  FIG. 2 ,  FIG. 5A , and  FIG. 5B , the transformer  210   a  is provided across the circuit board  200 . Specifically, the transformer  210   a  is formed so that cores included in the transformer  210   a  sandwich the circuit board  200 . In this embodiment, leg portions of the E-shaped core included in the transformer  210   a  are inserted through holes formed in the circuit board  200 . Stated differently, the transformer  210   a  is formed by the E-shaped core and the I-shaped core sandwiching the circuit board  200 . 
     It is to be noted that the core of the transformer  210   a  is not limited to a core of an EI type including the E-shaped core and the I-shaped core, but may be an EIR type core or a CI type core. Moreover, the E-shaped core and the I-shaped core of the transformer  210   a  may be fixed to each other with a plate spring or the like. Furthermore, a fixing spring may be inserted between the core and the circuit board  200  so that a wobble of the transformer  210   a  is suppressed and the transformer  210   a  is stably fixed to the circuit board  200 . 
     (Coupler) 
     As shown in  FIG. 2 , the coupler  300  includes: the coupler base  310  mainly having a conducting function; and the coupler housing  320  mainly having a mechanical stress holding function and a waterproofing function. In this manner, it is possible to reduce a mounting space by separating the coupler  300  into two components depending on functions, and it can be intended to miniaturize the power-supply device  1 . 
     The coupler base  310  and the coupler housing  320  are molded into a predetermined shape using a resin material. In this embodiment, the coupler base  310  is made of polyphenylene sulfide (PPS) resin, and the coupler housing  320  is made of polybutylene terephthalate (PBT) resin. A material having high heat resistance at a high melting point is preferably used as the material of the coupler base  310  so that the coupler base  310  resists heat generated at a time of reflow soldering. For this reason, in this embodiment, the material of the coupler base  310  is different from that of the coupler housing  320 . 
     The coupler base  310  is for bundling connector terminals  311 , and the connector terminals  311  are fixed to the coupler base  310 . Each of the connector terminals  311  includes output connector terminals  311   a  and input connector terminals  311   b . In other words, the output connector terminals  311   a  and the input connector terminal  311   b  are attached to the coupler base  310  all together. 
     The coupler base  310  is disposed on the face (surface) of the circuit board  200  which faces the casing portion  110 . Moreover, the coupler base  310  is provided to a portion where the attaching portion  110   b  of the casing portion  110  is formed. In this embodiment, the coupler base  310  is provided opposite to the attaching portion  110   b . With this, the connector terminals  311  attached to the coupler base  310  are provided to face the through hole  112  of the attaching portion  110   b  of the casing portion  110 . To put it another way, the connector terminals  311  are disposed to the lamp housing (not shown) to which the attaching portion  110   b  is attached. 
     Specifically, the output connector terminals  311   a  are disposed to the face (surface) of the circuit board  200  which faces the casing portion  110 , and are provided to protrude toward the first through hole  112   a . In addition, the input connector terminals  311   b  are disposed to the face (surface) of the circuit board  200  which faces the casing portion  110 , and are provided to protrude toward the second through hole  112   b . Stated differently, as shown in (b) of  FIG. 3 , the output connector terminals  311   a  and the input connector terminals  311   b  can be visually recognized through the first through hole  112   a  and the second through hole  112   b  when the power-supply device  1  is viewed from top (seen in a planar view). 
     Each connector terminal  311  (each output connector terminal  311   a  and each input connector terminal  311   b ) is a conductive pin made of a metal material. The output connector terminal  311   a  and the input connector terminal  311   b  have one ends electrically connected to the metal wiring of the circuit board  200 . In this embodiment, the one ends have a substantial L-shape formed by outwardly bending portions connected to the circuit board  200 . The output connector terminal  311   a  and the input connector terminal  311   b  have the other ends connected to the first connector  12  of the output harness  10  and the connector  22  of the input harness  20 , respectively. 
     The coupler base  310  in this embodiment includes a fixing portion  312  provided at a portion between the output connector terminal  311   a  and the input connector terminal  311   b . The fixing portion  312  is provided to fix the coupler base  310 , the circuit board  200 , and the cover portion  120  (casing  100 ). With this configuration, it is possible to reduce stress in a solder connected portion of the connector terminal  311 . 
     Specifically, a tip portion of the fixing portion  312  abuts the circuit board  200 , and as shown in  FIG. 2 , the through hole  313  through which the fixing rivet  410  is inserted is formed in the fixing portion  312 . The through hole  313  is formed to correspond to the second through hole  202  of the circuit board  200  and the through hole  126  of the cover portion  120 . 
     As shown in  FIG. 2 , the cover portion  120 , the circuit board  200 , and the coupler base  310  are fixed using the rivet  410 . Specifically, the rivet  410  is inserted through the through hole  126  of the cover portion  120 , the second through hole  202  of the circuit board  200 , and the through hole  313  of the coupler base  310 , from outside the cover portion  120  via a spring washer  420 . It is to be noted that using the spring washer  420  makes it possible to suppress an increase in conduction resistance caused by thinning of the circuit board  200 . The rivet  410  is a blind rivet, for instance. 
     A protruding portion  314  that protrudes toward the circuit board  200  is provided to the coupler base  310 . The protruding portion  314  is provided at a position opposite to the first protruding portion  123  of the cover portion  120 , to sandwich the circuit board  200 , and abuts the circuit board  200 . Since the protruding portion  314  and the first protruding portion  123  have a function to reduce stress exerted on the coupler base  310 , it is preferable that a plurality of the protruding portions  314  and a plurality of the first protruding portions  123  are provided. In this embodiment, three protruding portions  314  are provided. Moreover, it is preferable that the protruding portions  314  are provided in the periphery portion of the coupler base  310  to disperse stress. It is to be noted that the numbers of the protruding portions  314  and the first protruding portions  123  may be three to suppress a wobble of the circuit board  200 . 
     It is to be noted that in this embodiment, tip portions of two of the three protruding portions  314  are formed into a stepped protruding shape. The tip portions are inserted into the third through holes  203  formed in the circuit board  200 , and step faces of the two protruding portions  314  abut the surface of the circuit board  200  (face facing the casing portion  110 ). In addition, the remaining one protruding portion  314  has a tip portion that abuts the surface of the circuit board  200 . 
     The first through hole  321  into which the first connector  12  of the output harness  10  is inserted and the second through hole  322  into which the connector  22  of the input harness  20  is inserted are formed in the coupler housing  320 . The first through hole  321  and the second through hole  322  in the coupler housing  320  are inserted into the first through hole  112   a  and the second through hole  112   b  in the attaching portion  110   b  of the casing portion  110 , respectively. 
     A flange portion  323  is provided to the coupler housing  320  to surround the first through hole  321  and the second through hole  322 . The flange portion  323  is bonded to the groove  113  of the attaching portion  110   b  by a seal material. 
     Moreover, a seal component  330  is attached to the coupler housing  320 . The seal component  330  is a connector seal and has a shape matching an inside wall of the second through hole  322  of the coupler housing  320 . Specifically, the seal component  330  is a elastic body formed into a predetermined circular shape, and is attached to the inside wall of the second through hole  322 . The seal component  330  is a silicone rubber, for example. 
     By attaching the seal component  330  to the second through hole  322 , it is possible to completely seal the coupler housing  320  and the input harness  20  in the connection portion between the connector  22  of the input harness  20  and the input connector terminal  311   b . With this configuration, it is possible to ensure a superior waterproof property in the connection portion between the coupler housing  320  and the input harness  20 . 
     It is to be noted that as stated above, the waterproof property in the connection portion between the coupler housing  320  and the output harness  10  is ensured by the rubber grommet attached to the first connector  12 . 
     (Summary) 
     As described above, according to the power-supply device  1  in this embodiment, the non-flat portion is provided to the region having the size greater than or equal to the outer diameter of the connector (the first connector  12  of the output harness  10  and the connector  22  of the input harness  20 ) of the external connector line in the casing portion  110 . 
     With this configuration, even when the casing  100  is the press molded product formed by metal stamping or has a thin structural such as a metal item having a thickness ranging from 0.3 to 3.0 mm, it is possible to increase the strength of the casing portion  110 . Accordingly, when the output harness  10  or the input harness  20  is attached to or detached from the power-supply device  1 , it is possible to suppress the exertion of the stress (e.g. pressing force) per area on the flat portion of the casing portion  110 , which is commensurate with the stress exerted on the first connector  12  of the output harness  10  and the connector  22  of the input harness  20 . Therefore, when the external connector line is attached or the like, it is possible to suppress the deformation of the casing portion  110 . 
     As stated above, according to the power-supply device  1  in this embodiment, it is possible to make the casing  100  thinner and ensure the strength of the casing  100 , and thus it is possible to achieve a power-supply device having a casing (circuit case) that is small and has high stiffness. 
     Embodiment 2 
     Next, a light fixture  30  according to Embodiment 2 will be described using  FIG. 6  and  FIG. 7 .  FIG. 6  is a cross-sectional view of the light fixture  30  according to Embodiment 2.  FIG. 7  is a block diagram showing a configuration of the light fixture  30 . 
     The light fixture  30  according this embodiment is a headlight in a vehicle such as an automobile, and, as shown in  FIG. 6 , includes: a housing (lamp housing)  31  having a light extraction portion; an HID lamp  32  that is a light source housed inside the housing  31 ; an igniter  33  with integrated socket for attaching the HID lamp  32 ; and the power-supply device  1  for controlling lighting of the HID lamp  32 . The light extraction portion of the housing  31  is a translucent component that transmits and emits light from the HID lamp  32  to the outside, and is a translucent cover or a translucent panel, for example. 
     The power-supply device  1  thus configured is attached to the outside of the housing  31 . Specifically, the power-supply device  1  is attached to the bottom of the housing  31 . Though not shown, the power-supply device  1  and the igniter  33  are electrically connected via the output harness  10  or the like, and the power-supply device  1  supplies predetermined power to the HID lamp  32  via the igniter  33 . 
     As shown in  FIG. 7 , in the light fixture  30 , the power-supply device  1  includes, as a power supply circuit unit, an inverter  34 , a DC/DC converter  35 , and a control unit  36 , and is connected to a power source  37  (e.g. direct-current power source such as a battery) via the input harness  20 . Direct current power supplied from the power source  37  to the power-supply device  1  undergoes power conversion by the power-supply device  1 , and an output of the inverter  34  is supplied to the igniter  33  via the output harness  10 . 
     The igniter  33  generates a high voltage of several tens of kV for starting up the HID lamp  32 , and causes the HID lamp  32  to start up by applying the high voltage to the HID lamp  32 . 
     The inverter  34  is, for example, a full-bridge inverter that converts a direct current output voltage of the DC/DC converter  35  to a low-frequency square wave. Prior to the start up of the HID lamp  32 , the inverter  34  supplies the igniter  33  with a voltage that causes the generation of a starting pulse. 
     The DC/DC converter  35  is, for example, a flyback DC/DC converter that raises or lowers the direct current voltage from the power source  37  to the voltage required by the HID lamp, by changing the ON time, drive frequency, or the like, of a switching element. The DC/DC converter  35  includes the transformer  210   a  in Embodiment 1. 
     The control unit  36  controls the DC/DC converter  35  so that the output power of the power-supply device  1  is at target power. 
     As stated above, the small power-supply device  1  in Embodiment 1 can be used for a light fixture of a vehicle or the like. Accordingly, it is possible to suppress an increase in size of the light fixture, and to realize a lightweight light fixture. 
     Here, an attachment structure of the power-supply device  1  and the light fixture  30  will be described in detail using  FIG. 8A ,  FIG. 8B , and  FIG. 9 . Each of  FIG. 8A  and  FIG. 8B  is a diagram for illustrating a structure of an attachment portion between the power-supply device  1  and the housing  31  of the light fixture  30 .  FIG. 8A  is a perspective view when the attachment portion is viewed obliquely from above, and  FIG. 8B  is a perspective view when the attachment portion is viewed obliquely from below.  FIG. 9  is an exploded perspective view of a structure in the attachment portion between the power-supply device  1  and the housing  31  of the light fixture  30 . It is to be noted that  FIG. 8A ,  FIG. 8B , and  FIG. 9  show a portion of the bottom of the housing  31 . 
     As shown in  FIG. 8A ,  FIG. 8B , and  FIG. 9 , an attaching hole portion  31   a  for attaching the power-supply device  1  is provided to the bottom of the housing  31 . The attaching portion  110   b  of the casing  100  in the power-supply device  1  is attached to the attaching hole portion  31   a.    
     Moreover, three protruding portions  31   b  each having a hole into which a bolt  39  is inserted are formed at the bottom of the housing  31 . Furthermore, three brackets  123  each having a hole through which the bolt  39  is inserted are formed in the cover portion  120  of the power-supply device  1 . 
     When the power-supply device  1  is attached to the housing  31 , the attaching portion  110   b  of the power-supply device  1  is attached to the hole of the attaching hole portion  31   a . Specifically, the attaching portion  110   b  of the power-supply device  1  is fit in the hole of the attaching hole portion  31   a  via a resin O-ring  38 . In this state, the three bolts  39  are inserted through the holes of the brackets  127  of the power-supply device  1  and into the holes of the protruding portions  31   b  of the housing  31 , and the housing  31  and the power-supply device  1  are fastened and fixed with the bolts  39 . 
     As stated above, it is possible to eliminate a space between the attaching portion  110   b  and the attaching hole portion  31   a  by fitting the attaching portion  110   b  and the attaching hole portion  31   a  via the O-ring  38 . With this, it is possible to ensure a superior waterproof property in the connection portion between the power-supply device  1  and the housing  31 . 
     It is to be noted that the headlight is described as an exemplary discharge lamp device in this embodiment, the power-supply device  1  may be applied to a discharge lamp device other than the headlight. 
     Embodiment 3 
     Next, a vehicle  40  according to Embodiment 3 will be described using  FIG. 10 .  FIG. 10  is a block diagram showing a schematic configuration of the vehicle  40  according to Embodiment 3. 
     As shown in  FIG. 10 , the vehicle  40  according to this embodiment is, for example, a four-wheeled automobile, and includes a vehicle body  41  and headlights that are light fixtures  30  attached to the vehicle body  41 . 
     In recent years, engine room space is being reduced to secure more passenger room inside the automobile or for weight-reduction aimed at improving fuel consumption. Consequently, there is a demand for a smaller power-supply device. Since a light fixture using the power-supply device  1  in Embodiment 1 is small and lightweight, such a light fixture is useful for automobiles for which weight-reduction is required. 
     (Other Modifications, and so on) 
     Although the power-supply device, the light fixture, and the vehicle according to the disclosure have been described based on the embodiments, the present invention is not limited to the above-described embodiments. 
     For instance, although the output harness  10  of 90° type is used as shown in  FIG. 4  in the embodiments, an output harness  10 A of straight type may be used as shown in  FIG. 11 . 
     Moreover, although the cover portion  120 , the circuit board  200 , and the coupler base  310  are fixed using the rivet  410  in the embodiments, the cover portion  120 , the circuit board  200 , and the coupler base  310  may be fixed using a screw instead of the rivet  410 . In this case, an insertion direction of the screw may be a direction from outside to inside of the casing  100  or a direction from inside to outside of the casing  100 . 
     Furthermore, although the power-supply device  1  and the housing  31  are fixed using the bolts  39  in the embodiments, the power-supply device  1  and the housing  31  may be fixed using another fixing means. 
     Moreover, although the HID lamp is used as the light source in the embodiments, the light source is not limited to a discharge lamp, but may be a solid light emitting device such as a light emitting diode (LED) and an organic electro luminescence (EL) device. In other words, the power-supply device  1  may serve as a light source (load) to control lighting of a semiconductor light-emitting device such as an LED. 
     Forms obtained by various modifications to the exemplary embodiments and modifications that can be conceived by a person of skill in the art as well as forms realized by arbitrarily combining structural components and functions in the exemplary embodiments and modifications which are within the scope of the essence of the present invention are included in the present invention. 
     While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that they may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all modifications and variations that fall within the true scope of the present teachings.