Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2011-0100899, filed on Oct. 4, 2011, the contents of which is incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This specification relates to an apparatus for integrally fixing (fastening) a power semiconductor to a heat sink when fabricating the power semiconductor, such as an inverter and a charger, as core components of an electric vehicle, integrally with a booth bar or the like, and particularly, to an apparatus for fastening a power semiconductor using an integral springy (elastic) clip, capable of fixing a power semiconductor, such as a diode and a MOSFET, using elasticity of a U-shaped clip by integrally molding the clip onto a housing of a plastic module. 
     2. Background of the Invention 
     In general, a power semiconductor module is utilized as a core semiconductor device for power conversion which converts a Direct-Current (DC) or Alternating-Current (AC) voltage or current into an appropriate form and size required by a system. The power semiconductor module is often applied to an industrial application field, such as an inverter, an uninterruptible power supply, a welder, an elevator and the like, and a vehicle field. 
     To overcome problems of heat sinks which are used by being fixed to the power semiconductor devices, the power semiconductor devices such as transistors and MOSFETs are fixed to the heat sinks by directly forming screw insertion holes at the heat sinks or shielding the semiconductor devices by aluminum bars, which are cut by each length, and fixing the aluminum bars to the heat sinks by screws. However, this causes a problem of forming unnecessary screw insertion holes at the heat sinks. 
     The related art employs a scheme in which the power semiconductor is assembled onto a Printed Circuit Board (PCB) in a soldering manner, and coupled to a heat sink for cooling in a bolting manner. For ensuring assembly efficiency in the scheme, holes are additionally formed at the PCB when the semiconductor is located outside or inside the PCB. 
     A fixing structure for a power semiconductor according to the related art will be described with reference to  FIG. 1 , which shows a configuration that the semiconductor is located outside the PCB. 
     Each of power semiconductor devices  100  is installed on a semiconductor installation portion  19  of a heat sink  18  in a contact state, and bridges  110  is connected to one side of a PCB  20  in a soldering manner. The PCB  20  is inserted into a PCB fixing recess  24  of the heat sink  10 . A clip type fixing device  10 , as shown in  FIG. 1 , is separately coupled to each power semiconductor device  100  in a pressing manner to be appropriate for a specific structure of the heat sink. 
     Referring to  FIG. 2 , even when a bridge module is employed to connect the power semiconductor to an electronic circuit via a housing, the power semiconductor  100  located below the housing has to be fixed at the outside by a separate fixing clip  60 . Here, screws are inserted into fixing openings  133  formed through a semiconductor fixing piece  130  to fix the power semiconductor, and pressing pieces  65  of the fixing clip  60  which is a steel clip elastically fix the power semiconductor. Also, screws inserted into clip fixing openings  67  may be separately used to fix the fixing clip  60 . 
     Here, for a semiconductor with a small capacity, plastic screws are used. However, this has a disadvantage of being vulnerable to heat-resistance. Also, the fixing clip  60  completely covers the semiconductor, which additionally requires a hole for allowing a tool such as a driver to be inserted. This may result in a limitation of a circuit design. 
     In the related art as shown in  FIGS. 1 and 2 , the semiconductor is located outside the PCB to couple screws for fixing the semiconductor. Or, if such structure is impossible, a hole for allowing a tool such as a driver or the like to be inserted is required. This lowers a degree of freedom in view of designing patterns of the PCB due to the position limit. In addition, bolts are required for fixing the clip, thereby increasing the number of components. 
     Furthermore, as aforementioned, the plastic screws are used for fixing the small semiconductor. Accordingly, such screws may be deformed due to heat generation of the semiconductor and thereby a fixing force may be weakened or lost. 
     SUMMARY OF THE INVENTION 
     Therefore, to overcome the drawbacks of the related art, an aspect of the detailed description is to provide an integral clip type module for fixing a power semiconductor, capable of improving assembly efficiency and reducing a limit on a PCB pattern design by integrally mounting an elastic (springy) clip onto a lower surface of a housing of a plastic module to fix a semiconductor such as a diode and a MOSFET using elasticity of the clip. 
     Another aspect of the detailed description is to solve problems, such as deformation, lowered fixing force and loss of screws due to heat generation of a semiconductor, by reduction of the number of required components, such as separate screws and bolts for fixing a fixing clip, and without use of a plastic screw. 
     To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a an apparatus for fixing (fastening) a power semiconductor to a heat sink including a power semiconductor used for an inverter and a charger for an electric vehicle, a housing fixed onto a heat sink together with the power semiconductor and having a Printed Circuit Board (PCB), which is disposed on the housing, has electronic circuits thereon, such as the inverter, the charger and the like, and is connected to a bridge of the power semiconductor, which is located below the housing, via a through hole, and an elastic clip integrally mounted onto the lower surface of the housing to elastically press the lower power semiconductor so as to be fixed onto the heat sink. 
     In accordance with another exemplary embodiment, the elastic clip may include a plurality of U-shaped concave portions, which extends in a widthwise direction of a steel plate so as to form a plurality of pressing pieces, and a flat portion of the steel plate may form a molding portion integrally molded onto the housing. 
     As described above, the present disclosure may have the following effects in the aspects of the best mode, configuration and assembling to be explained later and an operational relation. 
     The present disclosure may not need a separate screw for fixing a semiconductor but integrally mount an elastic clip onto a lower surface of a housing of a plastic module so as to fixe the semiconductor, such as a diode and a MOSFET using elasticity of the clip, which may result in improvement of assembling efficiency and reduction of a limit on a pattern design of a printed circuit board. 
     Also, the number of required components, such as screws and bolts for fixing the clip may be reduced, thereby obtaining economical efficiency. 
     In addition, without use of screws made of plastic, concerns about deformation, lowered fixing force and loss of screws due to heat generation of the semiconductor may be avoided, an assembling operation may be facilitated, and a degree of freedom for an installation position of the semiconductor may be enhanced. 
     Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a view showing an apparatus for fixing a power semiconductor to a heat sink according to the related art; 
         FIG. 2  is a view showing a fixing manner of a power semiconductor onto a bridge module according to the related art; 
         FIG. 3  is a view showing a fixing manner of a power semiconductor onto a bridge module in accordance with the present disclosure; 
         FIG. 4  is a view showing an operation of fixing a power semiconductor device using an elastic (springy) clip in accordance with the present disclosure; 
         FIG. 5  is a view showing a molded relation between a housing and the elastic clip; and 
         FIG. 6  is a view showing that the elastic clip fixes the power semiconductor with pressing the power semiconductor in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Description will now be given in detail of an integral clip type module for fixing a power semiconductor according to the exemplary embodiments, with reference to the accompanying drawings. 
     Technical terms used in this specification are used to merely illustrate specific embodiments, and should be understood that they are not intended to limit the present disclosure. As far as not being defined differently, all terms used herein including technical or scientific terms may have the same meaning as those generally understood by an ordinary person skilled in the art to which the present disclosure belongs, and should not be construed in an excessively comprehensive meaning or an excessively restricted meaning. 
     The preferred exemplary embodiments for the configurations described in the detailed description and the figures are merely illustrative without entirely representing the technical scope of the present disclosure. Therefore, it should be understood that there are various equivalents and variations to replace them at the time of filing this application. 
     Hereinafter, the configuration of the present disclosure and the preferred exemplary embodiment will be described in detail with reference to  FIGS. 3 to 6 . 
     An apparatus for fixing (fastening) a power semiconductor onto a heat sink may include a power semiconductor  100  used for an inverter and a charger for an electric vehicle, a housing  200  fixed onto a heat sink together with the power semiconductor  100  and having a Printed Circuit Board (PCB), which is disposed on the housing, has electronic circuits thereon, such as the inverter, the charger and the like, and is connected to a bridge  110  of the power semiconductor  100 , which is located below the housing  200 , via a through hole  230 , and an elastic clip  300  integrally mounted onto the lower surface of the housing  200  to elastically press the lower power semiconductor so as to be fixed onto the heat sink. 
     Referring to  FIG. 3 , the power semiconductor  100  is located below the housing  200  and a heat sink (not shown) may be located below the power semiconductor  100 . The power semiconductor bridge  110  may upwardly protrude through the housing  200  via the through hole  230 , which is formed through the housing  200 . The bridge  110  may connect the power semiconductor  100  to a PCB (not shown) included in the inverter, the charger or the like, located thereon. 
     A scheme for connecting such type of full bridge module to the heat sink is employed from a typical connecting method for the inverter and the charger. Thus, detailed description of the scheme will be omitted. 
     The fixing method of the power semiconductor using the elastic clip may be applied to a molding package, such as a Power Factor Corrector (PFC) module and a full bridge module. 
     Still referring to  FIG. 3 , the fixing method using the power semiconductor fixing apparatus may be implemented such that the power semiconductor  100  located below the housing  200  is fixed onto the heat sink located therebelow in a contact state. Accordingly, the power semiconductor  100  may include a fixing element  130  protruding to one side thereof to be fixed onto the heat sink, and be integrally fixed onto the lower heat sink via a fixing opening  133  of the fixing element  130 . 
     The housing  200 , which fixes the power semiconductor  100  with downwardly pressing it, may include a housing fixing opening  210  by which the housing  200  is fixed onto the heat sink. 
     Referring to  FIGS. 3 and 4 , the apparatus according to the present invention may include the elastic clip  300  for fixing the power semiconductor  100  onto the heat sink with elastically pressing the power semiconductor  100 . The elastic clip  100  may be located between the housing  200  and the power semiconductor  100  and integrally attached onto the lower surface of the housing  200 . 
     With the elastic clip  300  integrally attached onto the lower surface of the housing  200 , a separate clip may not need to fix the power semiconductor  100  at the outside, as shown in the related art with reference to  FIG. 2 . Therefore, the fixing device  130  of the power semiconductor  100  may not be obscured. This allows for ensuring a sufficient working space and facilitates adjustment of a position of the semiconductor, resulting in enhancement of working efficiency. 
       FIG. 4  is a view showing an operation of fixing the lower power semiconductor  100  by pressing it with the elastic clip  300  formed on the lower surface of the housing  200 . And,  FIG. 5  shows a shape of the elastic clip  300  and coupling of the elastic clip  300  onto the lower surface of the housing  200 . 
     Referring to  FIGS. 4 and 5 , the elastic clip  300  may be formed of a steel plate having concave portions curved downwardly. Such elastic clip  300  may be integrally coupled to the lower surface of the housing  200 . 
     Although not shown, as another example, the elastic clip  300  may be formed of a steel plate or a plastic panel, which has wavy convex-concave shapes in a widthwise direction. Here, convex portions may be integrally coupled onto the housing  200  by an adhesive agent or molded onto the housing  200 . The concave portions may form pressing pieces  330  for fixedly pressing the lower power semiconductor  100 . 
     Referring to  FIG. 5 , the elastic clip  300  may have concave portions concaved in a widthwise direction on a steel plate or plastic panel which has a flat surface. The concave portion may implement the pressing piece  330 . The flat portion may form a molding portion  350  integrally coupled onto the lower surface of the housing  200 . 
     The pressing pieces  330  of the elastic clip  300  are a plurality of U-shaped concave portions extending in the widthwise direction of the steel plate and may be installed on a plurality of positions, especially, on positions corresponding to positions of the power semiconductors  100  fixed onto the lower surface of the elastic clip  300 . The flat portion of the steel plate may be formed as the molding portion  350 , which is integrally molded onto the housing or integrally coupled onto the housing by means of an adhesive agent. 
     Still referring to  FIG. 5 , the elastic clip  300  may be preferably integrally installed onto the lower surface of the plastic housing  200  in a molding manner. Alternatively, the elastic clip  300  may be integrally installed by use of the adhesive agent. 
       FIG. 6  is an elevation view showing that the pressing piece  330  of the elastic clip  300  fixes the power semiconductor  100  by downwardly pressing the power semiconductor  100 . Here, when the housing  200  is fixed onto the heat sink via the fixing opening  210 , a force P is downwardly applied onto the housing  200 . The pressing piece  330  of the elastic clip  300  is then closely adhered onto the power semiconductor  100  such that the power semiconductor  100  is fixed onto the heat sink. This may allow for designing a package type full bridge module even without a separate power semiconductor fixing apparatus. 
     That is, upon assembling the full bridge module onto the heat sink, the power semiconductor  100  is closely adhered onto the heat sink with being pressed by the elastic clip  300  located on the power semiconductor  100 . This structure may allow the power semiconductor device to be assembled onto the heat sink in the closely adhered state without a separate coupling element such as screws or the like. Accordingly, the number of components such as bolts or the like may be reduced so as to reduce a fabricating cost and the assembling operation may be facilitated. In addition, when plastic coupling bolts are used, deformation of the bolts or a loss of fixing force may be caused due to heat generation by the semiconductor. However, such problems can be overcome. 
     Also, enhancement of the degree of freedom for the installation position of the semiconductor may result in overcoming a position limit, thereby enhancing a degree of freedom for a pattern design for the PCB. 
     The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. 
     As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.

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