Patent Publication Number: US-2022223335-A1

Title: Transformer

Description:
RELATED APPLICATION 
     This application claims priority to China Application Serial Number 202110028651.1, filed Jan. 11, 2021, which is herein incorporated by reference in its entirety. 
     BACKGROUND 
     Field of Invention 
     The present disclosure relates to a transformer. 
     Description of Related Art 
     In general, there are two types of transformers with a primary inductance and a leakage inductance. The first type of the transformer is the combination of primary transformer with a resonant inductance to generate and adjust the leakage inductance by the resonant inductance. However, this type of transformer requires two components, which are the primary transformer and the resonant inductance, so the space for the first type of the transformer needs to be large, which is disadvantageous for miniaturization. The second type of the transformers is a split-tank transformer. The split-tank transformer has two coils to generate a primary induction magnetic path and a leakage induction magnetic path. The coils are separated by air, and a leakage inductance value is controlled by a number of turns of the coils, so no additional components are required. A space for the second type of the transformers is small, but the number of turns of the coils must be defined during the manufacturing process, so the leakage inductance value cannot be further adjusted after the manufacturing process is completed, which results in low commonality. 
     SUMMARY 
     An aspect of the present disclosure is related to a transformer. 
     According to an embodiment of the present disclosure, the transformer includes a core group, a first coil and a second coil. The core group includes two external portions and a middle portion. The middle portion is located between the two external portions. The middle portion has an upper section, a middle section and a lower section. Each of the upper section and the lower section has a first gap between one of the two external portions. The middle section has a second gap between one of the two external portions. The first gap is different from the second gap. The second coil surrounds the upper section of the middle portion. 
     In an embodiment of the present disclosure, each of the upper section and the lower section of the middle portion has a protruding portion extending in a first direction, and the first direction faces toward the external portion. 
     In an embodiment of the present disclosure, the middle section of the middle portion has a protruding portion extending in the first direction. 
     In an embodiment of the present disclosure, a width of the middle section of the middle portion is the same as a width of the upper section and a width of the lower section in a first direction, and the first direction faces toward the external portion. 
     In an embodiment of the present disclosure, the upper section of the middle portion has a protruding portion extending in a third direction, the third direction is vertical to a first direction, the first direction faces toward the external portion, and a width of the protruding portion in the first direction is the same as a width of the middle section and a width of the lower section in the first direction. 
     In an embodiment of the present disclosure, the second gap is bigger than the first gap. 
     In an embodiment of the present disclosure, the second gap is an air gap. 
     In an embodiment of the present disclosure, the transformer further comprises a positionally adhesive layer. The positionally adhesive layer is located in the first gap and contacts one of the upper section and the lower section and one of the two external portions. 
     In an embodiment of the present disclosure, a portion of the first coil and a portion of the second coil are accommodated in the two external portions of the core group. 
     In an embodiment of the present disclosure, a number of the first coil is different from a number of the second coil. 
     In an embodiment of the present disclosure, the number of the first coil is more than the number of the second coil. 
     In an embodiment of the present disclosure, a distance between a top surface of the upper section and the middle section is different from a distance between a bottom surface of the lower section and the middle section. 
     In an embodiment of the present disclosure, the distance between the top surface of the upper section and the middle section is smaller than the distance between the bottom surface of the lower section and the middle section. 
     In an embodiment of the present disclosure, a width of the upper section, a width of the middle section and a width of the lower section are smaller than a distance between two opposite edges of the first coil in a first direction, and the first direction faces toward the external portion. 
     In an embodiment of the present disclosure, a width of the upper section, a width of the middle section and a width of the lower section are smaller than a distance between two opposite edges of the second coil in a first direction, and the first direction faces toward the external portion. 
     In an embodiment of the present disclosure, a thickness of the middle section of the middle portion is smaller than a thickness of the upper section and a thickness of the lower section in a second direction, the second direction is vertical to a first direction, and the first direction faces toward the external portion. 
     In an embodiment of the present disclosure, each of the two external portions has a first side pillar, a middle pillar, a second side pillar and a body, and the first side pillar, the middle pillar, and the second side pillar extend outward from the body. 
     In an embodiment of the present disclosure, the first gap is different from the second gap. 
     In the embodiments of the present disclosure, due to the first coil of the transformer surrounds on the lower section of the middle portion and the second coil surrounds on the upper section of the middle portion, a primary inductance and a leakage inductance may be generated. In addition, a primary induction magnetic path passes through the first gap between the middle portion and the external portions of the core group, and a leakage induction magnetic path passes through the second gap between the middle portion and the external portions of the core group. In this way, a primary inductance value may be adjusted by adjusting a size of the first gap, and a leakage inductance value may be adjusted by adjusting a size of the second gap, such that the transformer with high commonality and small space is achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG. 1  illustrates a stereoscopic view of a transformer according to one embodiment of the present disclosure. 
         FIG. 2  illustrates a cross-sectional view along section  2 - 2  of the transformer in  FIG. 1 , in which the first coil and the second coil are omitted. 
         FIG. 3  illustrates a cross-sectional view of the transformer in  FIG. 1  while the transformer is operated. 
         FIG. 4  illustrates a cross-sectional view of a core group according to another embodiment of the present disclosure, in which a cross-sectional position in the  FIG. 4  is the same as it in the  FIG. 2 . 
         FIG. 5  illustrates a cross-sectional view of a core group according to another embodiment of the present disclosure, in which a cross-sectional position in the  FIG. 5  is the same as it in the  FIG. 2 . 
         FIG. 6  illustrates a stereoscopic view of a core group according to yet another embodiment of the present disclosure. 
         FIG. 7  illustrates a stereoscopic view of a core group according to yet another embodiment of the present disclosure. 
         FIG. 8  illustrates a stereoscopic view of a core group according to yet another embodiment of the present disclosure. 
         FIG. 9  illustrates a stereoscopic view of a core group according to yet another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” “front,” “back” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. 
       FIG. 1  illustrates a stereoscopic view of a transformer  100  according to one embodiment of the present disclosure.  FIG. 2  illustrates a cross-sectional view along section  2 - 2  of the transformer  100  in the  FIG. 1 , in which the first coil  120  and the second coil  130  are omitted. Referring to the  FIG. 1  and the  FIG. 2  together, in this embodiment, the transformer  100  includes a core group  110 , a first coil  120  and a second coil  130 . The core group  110  includes two external portions  111  and a middle portion  112 . The middle portion  112  of the core group  110  is located between the two external portions  111  of the core group  110 . The middle portion  112  of the core group  110  has an upper section  112   a , a middle section  112   b  and a lower section  112   c . In this disclosure, the upper section  112   a  of the middle portion  112  means a part above the middle section  112   b , and the lower section  112   c  of the middle portion  112  means a part below the middle section  112   b . As shown in  FIG. 2 , in a second direction D 2 , a thickness t 1  of the upper section  112   a  of the middle portion  112  and a thickness t 3  of the lower section  112   c  of the middle portion  112  are bigger than a thickness t 2  of the middle section  112   b , and the upper section  112   a  includes a surrounding area where the second coil  130  surrounds, and the lower section  112   c  includes a surrounding area where the first coil  120  surrounds. 
     Two sides of the upper section  112   a  of the middle portion  112  have a first gap G 1  between two external portions  111 , respectively, and two sides of the lower section  112   c  of the middle portion  112  also have a first gap G 1  between two external portions  111 , respectively. In addition, two sides of the middle section  112   b  of the middle portion  112  have a second gap G 2  between two external portions  111 , respectively. In other words, there are four first gaps G 1  and two second gaps G 2  between the middle portion  112  and the two external portions  111 . The first gap G 1  is different from the second gap G 2 . For example, the first gap G 1  is smaller than the second gap G 2 . The first coil  120  surrounds the lower section  112   c  of the middle portion  112  of the core group  110 , and the second coil  130  surrounds the upper section  112   a  of the middle portion  112  of the core group  110 , so that a primary inductance and a leakage inductance may be generated during power-on operation. The first gap G 1  is located on a magnetic path of the primary inductance (will be described in detail in  FIG. 3 ), and the second gap G 2  is located on a magnetic path of the leakage inductance, and the primary inductance magnetic path is different from the leakage inductance magnetic path. 
     For example, when the first gap G 1  is bigger, a primary inductance value is lower. Similarly, when the second gap G 2  is bigger, a leakage inductance value is lower. In some embodiments, the middle portion  112  and the two external portions  111  of the core group  110  may be made up of a material that includes iron cores, but it is not limited in this regard. In addition, the coil thickness of the second coil  130  is larger than the coil thickness of the first coil  120 . The number of turns of the first coil  120  is different from the number of turns of the second coil  130 . For example, the number of turns of the first coil  120  is more than the number of the turn of the second coil  130 . In some embodiments, a portion (such as an external portion) of the first coil  120  and a portion (such as an external portion) of the second coil  130  are accommodated in the two external portions  111  of the core group  110 . 
     The  FIG. 3  illustrates a cross-sectional view of the transformer  100  in the  FIG. 1  while the transformer  100  is operated. Referring to the  FIG. 2  and the  FIG. 3  together, the first coil  120  of the transformer  100  surrounds the lower section  112   c  of the middle portion  112  of the core group  110 , and the second coil  130  surrounds the upper section  112   a  of the middle portion  112  of the core group  110 , so the primary inductance and the leakage inductance may be generated. Also, the primary inductance magnetic path P 1  passes through the first gaps G 1  between the middle portion  112  and the two external portions  111  of the core group  110 , and the leakage inductance magnetic path P 2  passes through the second gap G 2  between the middle portion  112  and the two external portions  111  of the core group  110 . Therefore, the primary inductance value may be adjusted by the first gap G 1 , and the leakage inductance value may be adjusted by the second gap G 2 . In this embodiment, the first gap G 1  and the second gap G 2  may be air gaps. A middle pillar  117  of the external portions  111  may be performed by a grinding process during manufacturing, such that the second gap G 2  may be bigger than the first gap G 1  after the core group  110  is assembled. 
     In this way, the primary inductance value may be adjusted by adjusting a size of the first gap G 1 , and the leakage inductance value may be adjusted by adjusting a size of the second gap G 2 , such that the transformer  100  with high commonality and small space is achieved. 
     In some embodiments, the upper section  112   a  of the middle portion  112  of the core group  110 , the middle section  112   b  of the middle portion  112  of the core group  110  and the lower section  112   c  of the middle portion  112  of the core group  110  each have a protruding portion  114   a ,  114   b , and  114   c  extending in a first direction D 1 , the first direction D 1  faces toward the external portion  111 , and the first direction D 1  and a second direction D 2  are vertical to each other. That is, the protruding portion  114   a  of the upper section  112   a  of the middle portion  112 , the protruding section  114   b  of the middle section  112   b  of the middle portion  112  and the protruding section  114   c  of the lower section  112   c  of the middle portion  112  may form the middle portion  112  into a shape shown in the  FIG. 2 . The middle portion  112  and the two external portions  111  shown in the  FIG. 2  has four first gaps G 1  and two second gaps G 2  therebetween. 
     In this embodiment, the two external portions  111  each have a first side pillar  115 , a middle pillar  117 , a second side pillar  119  and a body  113 . The first side pillar  115 , the middle pillar  117  and the second side pillar  119  extend from the body  113 . The middle pillar  117  of the external portion  111  is located between the first side pillar  115  and the second side pillar  119  of the external portion  111 . There is a first gap G 1  between the protruding portion  114   a  of the upper section  112   a  of the middle portion  112  and the first side pillar  115  of the external portion  111 . There is a first gap G 1  between the protruding portion  114   c  of the lower section  112   c  of the middle portion  112  and the second side pillar  119  of the external portion  111 . There is a second gap G 2  between the protruding portion  114   b  of the middle section  112   b  of the middle portion  112  and the middle pillar  117  of the external portion  111 . 
     For example, a length of the middle pillar  117  of the external portion  111  extending from the body  113  is smaller than a length of the first side pillar  115  of the external portion  111  extending from the body  113  and smaller than a length of the second side pillar  119  of the external portion  111  extending from the body  113 , so the second gap G 2  is different from the first gap G 1 . In details, the second gap G 2  is bigger than the first gap G 1 . 
     In addition, a width W 1  of the protruding portion  114   a  of the upper section  112   a  of the middle portion  112 , a width W 2  of the protruding portion  114   b  of the middle section  112   b  and a width W 3  of the protruding portion  114   c  of the lower section  112   c  are smaller than a distance d 1  between two opposite edges  124  and  126  of the first coil  120 . Moreover, the width W 1  of the protruding portion  114   a  of the upper section  112   a , the width W 2  of the protruding portion  114   b  of the middle section  112   b  and the width W 3  of the protruding portion  114   c  of the lower section  112   c  are smaller than a distance d 2  between two opposite edges  134  and  136  of the second coil  130 . In other words, the two opposite edges  124  and  126  of the first coil  120  and the two opposite edges  134  and  136  of the second coil  130  extend into the two external portions  111 . 
     It is to be noted that the connection relationship of the aforementioned elements will not be repeated. In the following description, other types of core groups will be described. 
       FIG. 4  illustrates a cross-sectional view of a core group  110   a  according to another embodiment of the present disclosure, in which a cross-sectional position in the  FIG. 4  is the same as it in the  FIG. 2 . The difference from the embodiment in the  FIG. 2  is that a transformer  100   a  further includes a positionally adhesive layer  140  filled in the first gap G 1 . The positionally adhesive layer  140  has a positioning effect. The positionally adhesive layer  140  may be located in the first gap G 1  between the middle portion  112  and the two external portions  111 . The positionally adhesive layer  140  may contact the protruding portion  114   a  of the upper section  112   a  of the middle portion  112  and the first side pillar  115  of the external portion  111 . The positionally adhesive layer  140  may also contact the protruding portion  114   c  of the lower section  112   c  of the middle portion  112  and the second side pillar  119  of the external portion  111 . For example, the positionally adhesive layer  140  may be a tape, an adhesive or a glass bead tape, but it is not limited in this regard. The positionally adhesive layer  140  may provide the viscosity necessary to position the positional relationship between the middle portion  112  and the two external portions  111 . In addition, the glass bead tape has glass beads with different sizes, so the glass beads with different sizes may be selected to adjust the size of the first gap G 1  and to provide viscosity between the middle portion  112  and the two external portions  111  to produce positioning effect. 
       FIG. 5  illustrates a cross-sectional view of a core group  110   b  according to another embodiment of the present disclosure, in which a cross-sectional position in the  FIG. 5  is the same as it in the  FIG. 2 . The difference from the embodiment in the  FIG. 2  is that a distance d 3  between a top surface  116  of the middle portion  112  of the core group  110   b  and the middle section  112   b  of the middle portion  112  is different from a distance d 4  between a bottom surface  118  of the middle portion  112  of the core group  110   b  and the middle section  112   b  of the middle portion  112 . For example, the distance d 3  is smaller than the distance d 4 . 
       FIG. 6  illustrates a stereoscopic view of a core group  110   c  according to yet another embodiment of the present disclosure. The difference from the embodiment in the  FIG. 2  is that the upper section  112   a  and the lower section  112   c  of the middle section  112  of the core group  110   c  each have a protruding section  114   a  and  114   c  extending in the first direction D 1 , but the middle section  112   b  does not have the protruding portion  114   b  shown in the  FIG. 2 . That is, the protruding portion  114   a  of the upper section  112   a  of the middle portion  112  and the protruding portion  114   c  of the lower section  112   c  of the middle portion  112  form the middle portion  112  into a shape shown in the  FIG. 6 . The middle portion  112  and the two external portions  111  shown in the  FIG. 6  has four first gaps G 1  and two second gaps G 2  therebetween. Also, the second gap G 2  is bigger than the first gap G 1 . 
       FIG. 7  illustrates a stereoscopic view of a core group  110   d  according to yet another embodiment of the present disclosure. The difference from the embodiment in the  FIG. 2  is that the upper section  112   a  of the middle portion  112  of the core group  110   d  and the lower section  112   c  of the middle portion  112  each have a protruding portion  114   a  and  114   c  extending in the first direction D 1 , but the middle section  112   b  does not have the protruding portion  114   b  shown in the  FIG. 2 . The middle portion  112  of the core group  110   d  and the two external portions  111  has four first gaps G 1  and two second gaps G 2  therebetween. Also, the second gap G 2  is bigger than the first gap G 1 . 
       FIG. 8  illustrates a stereoscopic view of a core group  110   e  according to yet another embodiment of the present disclosure. The difference from the embodiment shown in the  FIG. 2  is that the middle portion  112  of the core group  110   e  does not have the protruding portions  114   a ,  114   b , and  114   c  shown in the  FIG. 2 . In other words, the width W 2  of the middle section  112   b  of the middle portion  112  of the core group  110   e  is the same as the width W 1  of the upper section  112   a  and the width W 3  of the lower section  112   c . That is, the upper section  112   a , the middle section  112   b , and the lower section  112   c  with the same width may form the middle portion  112  into a cuboid. The cuboid middle portion  112  and the two external portions  111  has four first gaps G 1  and two second gaps G 2  therebetween. Also, the second gap G 2  is bigger than the first gap G 1 . 
       FIG. 9  illustrates a stereoscopic view of a core group  110   f  according to yet another embodiment of the present disclosure. The difference from the embodiment in the  FIG. 2  is that the upper section  112   a  of the middle portion  112  of the core group  110   f  has a protruding portion  114   d  extending in a third direction D 3 , the third direction D 3 , the first direction D 1  and the second direction D 2  are vertical to each other, and a width W 4  of the protruding portion  114   d  of the upper section  112   a  in the first direction D 1  is the same as the width W 2  of the middle section  112   b  in the first direction D 1  and the width W 3  of the lower section  112   c  in the first direction D 1 . The middle portion  112  of the core group  110   f  and the two external portions  111  has four first gaps G 1  and two second gaps G 2  therebetween. Also, the second gap G 2  is bigger than the first gap G 1 . 
     The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.