Patent Publication Number: US-8988179-B2

Title: Transformer

Description:
BACKGROUND 
     The embodiment relates to a transformer and a method of manufacturing the same. 
     In recent years, a power supply device using a switching mode power supply (SMPS) is attracting attention. The SMPS stably provides power using a switching device, such as a metal oxide semiconductor field effect transistor (MOS FET) or a bipolar junction transistor (BJT), and a transformer. 
     Meanwhile, as household appliances have tended toward the light and slim structure with a small size, there is a need to implement the SMPS having the slim structure. In this regard, research has been continuously performed to reduce a volume of a transformer having a large volume among circuit components constituting the SMPS. 
     SUMMARY 
     According to a transformer and a method of manufacturing the same of an embodiment, the transformer can be manufactured in a slim structure so that a power supply device including the transformer may have a slim structure. 
     Further, according to a transformer and a method of manufacturing the same of an embodiment, a manufacturing cost of the transformer can be reduced and the efficiency of the transformer can be improved. 
     According to the embodiment, there is provided a transformer including a core inducing a magnetic field and including an upper core and a lower core; a first insulating part in an inner side of the core; a secondary winding part in an upper portion of the insulating part, a part of the secondary winding part being exposed out of the core; a second insulating part in an upper portion of the secondary winding part to insulate the second winding part; a primary winding part in an upper portion of the second insulating part; and a film between the upper core and the lower core. 
     According to the transformer and the method of manufacturing the same of an embodiment, the transformer can be manufactured in a slim structure so that a power supply device including the transformer may have a slim structure. 
     Further, according to the transformer and the method of manufacturing the same of an embodiment, a manufacturing cost of the transformer can be reduced and the efficiency of the transformer can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view illustrating a transformer according to an embodiment. 
         FIG. 2  is an exploded view illustrating an exploded transformer according to an embodiment. 
         FIG. 3  is a flowchart sequentially illustrating a method of manufacturing a transformer according to an embodiment. 
         FIGS. 4 to 11  are views sequentially illustrating a method of manufacturing a transformer according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, an exemplary embodiment of the disclosure will be described with reference to accompanying drawings. The details of other embodiments are contained in the following detailed description and accompanying drawings. The advantages and features of the disclosure, and the method of accomplishing the advantages and features of the disclosure will be apparent through the following description together with accompanying drawings. The same reference numerals will be assigned to the same elements. 
       FIG. 1  is a side view illustrating a transformer according to an embodiment, and  FIG. 2  is an exploded view illustrating an exploded transformer according to an embodiment. 
     Referring to  FIGS. 1 and 2 , the transformer  100  according to the embodiment includes a core  120 , a first insulating part  104 , a secondary winding part  106 , a second insulating part  108 , a primary winding part  110 , a power signal supply part  112 , and a power signal output part  114 . 
     The core  120  is provided to induce the magnetic field. The first insulating part  104  is provided in an inner side of the core to insulate the secondary winding part  106 . 
     In this case, the core  120  may include a lower core  120   a  and an upper core  120   b , and the first insulating part  104  may be provided as an insulating sheet. 
     The core  120  includes the lower core  120   a  and the upper core  120   b . The lower core  120   a  and the upper core  120   b  may have an “E” shape. In detail, the lower core  120   a  includes a central part  122 , a first side part  121 , and a second side part  123 . An end of the first side part  121 , an end of the second side part  123 , and an end of the central part  122  are connected with each other. An opposite side of the first side part  121 , an opposite side of the second side part  123 , and an opposite side of the central part  122  are separated from each other. The first and second side parts  121  and  123  are disposed in both ends of the lower core  120   a , respectively. The central part  122  is spaced apart from the first and second side parts  121  and  123  and is disposed in the center of the first and second side parts  121  and  123 . A thickness of the central part  122  may be thinner than a thickness of each of the first and second side parts  121  and  123 . However, the embodiment is not limited thereto. A structure of the upper core  120   b  has a structure having first and second side parts  124  and  126  and a central part  125 , and the upper core  120   b  has the same shape as the shape of the lower core  120   a , so a detailed description of the upper core  120   b  will be omitted. 
     The upper core  120   b  may be coupled with the lower core  120   a  in correspondence with the lower core  120   a . That is, the upper core  120   b  may be coupled with the lower core  120   a  while facing the lower core  120   a.    
     In general, in the transformer, a ratio of magnetizing inductance of the primary side measured in an open state of the secondary side of the transformer to leakage inductance measured in a short state of the transformer is ideally set to 7:1 to 5:1, and the transformer having a ratio of 5:1 has been produced because of productivity. To this end, gaps are respectively formed in the central part  122  of the lower core  120   a  and in the central part  125  of the upper core  120   b  and silicon is bonded in the gaps. However, due to the silicon, a volume of the core  120  in the transformer is increased and a winding thickness becomes larger, so that a manufacturing cost is increased. In addition, since the volume of the core  120  is increased, a PCB area is enlarged. 
     For this reason, for example, a film  130  is formed between the first side part  121  of the lower core  120   a  and the first side part  124  of the upper core  120   b  to determine a ratio of magnetizing inductance to leakage inductance as a ratio approximate to 7:1. 
     The film  130  may include an insulating material, for example, a plastic material such as polyester. However, the embodiment is not limited thereto. 
     The film  130  may have a thickness corresponding to a volume of the core  120 . For example, when a transverse length of the core  120  is 38 mm, and a longitudinal length of the core  120  including the first and second side parts  121  and  123  and the central part  122  is 35 mm, the film  130  may have a thickness of 0.05 to 0.06 mm. 
     The film  130  may be formed on at least one of the first and second side parts  121  and  123  or the central part  122 . When a plurality of films  130  are formed on the first and second side parts  121  and  123  or the central part  122 , the films  130  may be increased or reduced in thickness. 
     When the film  130  is formed on at least one of the first and second side parts  121  and  123  or the central part  122 , only the film  130  is inserted without polishing a core of a formed port, so that productivity can be improved. 
     Because the ratio of the magnetizing inductance to the leakage inductance may be set approximately to 7:1 due to the film  130 , an electric current flowing through the primary side and the secondary side is reduced so that a thickness of a coil and heat loss are reduced. 
     The secondary winding part  106  is provided in an upper portion of the first insulating part  140  and a part of which is exposed out of the lower core  120   a  of the core  120 . 
     The secondary winding part  106  may be provided in the form of a metallic pattern layer having inductance. 
     The metallic pattern layer may be formed by a metallic material having high conductivity to efficiently and easily output a transformed power signal. 
     The second insulating part  108  is provided in an upper portion of the secondary winding part  106  a part of which is exposed out of the lower core  120   a  of the cores  120 , thereby insulating the secondary winding part  106 . 
     The second insulating part  108  may be provided as an insulating sheet. 
     The primary winding part  110  is provided in an upper portion of the second insulating part  108  to be insulated from the second insulating part  108  a part of which is exposed out of the upper core  120   b  of the cores  120 . 
     The primary winding part  110  exposed out of the upper core  120   b  of the cores  120  and the secondary winding part  106  exposed out of the lower core  120   a  of the core  120  may be provided in different directions. 
     The primary winding part  110  may be provided as a printed circuit board  110   a  including a metal pattern P 1  having inductance. 
     The metal pattern P 1  having the inductance is provided by a metallic material having high conductivity to efficiently and easily supply a power signal from a power signal supply part  112  to be described below. 
     The power signal supply part  112  is electrically connected to the primary winding part  110  exposed out of the upper core  120   b  of the core  120  and supplies a power signal. 
     The power signal supply part  112  may be electrically connected to an end of the primary winding part  110  exposed out of the upper core  120   b  of the core  120 . 
     The power signal supply part  112  may be provided by a metallic material having high conductivity to efficiently and easily supply a power signal to the primary winding part  110 . 
     In this case, the power signal supply part  112  may be provided as a terminal to be coupled with a first via hole  110   b  formed in the printed circuit board  110   a.    
     A power signal output part  114  may be electrically connected to the secondary winding part  106  exposed out of the lower core  120   a  of the core  120  to output a power signal transformed by the secondary winding part  106 . 
     In this case, the power signal output part  114  may be electrically connected to an end of the secondary winding part  106  exposed out of the lower core  120   a  of the core  120 . 
     The power signal output part  114  may be made from a metallic material having high conductivity to efficiently and easily output a power signal transformed by the secondary winding part  106 . 
     In this case, the power signal output part  114  may be provided as a terminal to be locked in a second via hole  108   a  formed in the second insulating part  108 . 
     Hereinafter, a method of sequentially manufacturing the transformer  100  according to the embodiment will be described with reference to  FIGS. 3 to 11 . 
       FIG. 3  is a flowchart sequentially illustrating a method of manufacturing a transformer according to an embodiment, and  FIGS. 4 to 11  are views sequentially illustrating a method of manufacturing a transformer according to an embodiment. 
     Referring to  FIG. 3 , the method  600  of manufacturing the transformer includes the steps of: preparing a lower core (S 601 ), providing a first insulating part (S 603 ), providing a secondary winding part (S 605 ), providing a second insulating part (S 607 ), providing a primary winding part (S 609 ), providing an upper core (S 611 ), providing a power signal supply part (S 613 ), and providing a power signal output part (S 615 ). 
     First, in the preparing of the lower core (S 601 ), the lower core  120   a  is prepared to induce a magnetic field as illustrated in  FIG. 4 . In the providing of the first insulating part (S 603 ), the first insulating part  104  is provided in an inner side of the lower core  120   a  as illustrated in  FIG. 5 . 
     In this case, the providing of the first insulating part (S 603 ) may be a step of providing the first insulating part  104  in the form of an insulating sheet. 
     After that, in the providing of the secondary winding part (S 605 ), the secondary winding part  106  is provided in an upper portion of the first insulating part  104 , a part of which is exposed out of the lower core  120   a  as illustrated in  FIG. 6 . 
     The providing of the secondary winding part (S 605 ) may include a step of providing the secondary winding part  106  in the form of a metal pattern layer having inductance. 
     In this case, the providing of the secondary winding part (S 605 ) may include a step of forming the metal pattern layer having the inductance through at least one of a photo-lithography process using a photo mask and etching solution or an injection molding process using a compression press. 
     The providing of the secondary winding part (S 605 ) may include a step of efficiently and easily outputting a transformed power signal by forming a metal pattern layer  106   a  having inductance using a metallic material having conductivity. 
     After that, as shown in  FIG. 7 , in the providing of the second insulating part (S 607 ), the second insulating part is provided in an upper portion of the secondary winding part  106  to insulate the secondary winding part  106  by providing the second insulating part  108  in an upper portion of the secondary winding part  106  such that an end of the second insulating part is exposed out of the lower core  102   a.    
     The providing of the second insulating part (S 607 ) may include a step of providing the second insulating part  108  by an insulating sheet. 
     After that, as illustrated in  FIG. 8 , in the providing of the primary winding part (S 609 ), the primary winding part  110  is provided in an upper portion of the second insulating part  108  to insulate the second insulating part  108  such that a part of the primary winding part  110  is exposed out of the lower core  120   a.    
     In this case, the providing of the primary winding part (S 609 ) may include a step of providing the primary winding part  110  exposed out of the upper core  120   b  and the secondary winding part  106  exposed out of the lower core  120   a  in different directions. 
     After that, the forming of the film  130  (S 610 ) is performed. The film  130  may be formed in the first side part  121  of the lower core  120   a.    
     After that, as shown in  FIG. 9 , in the providing of the upper core (S 611 ), the upper core  120   b  is provided to fix the primary winding part  110  such that the upper core  120   b  can be coupled with the lower core  120   a.    
     After that, as shown in  FIG. 10 , in the providing a power signal supply part (S 613 ), the power signal supply part  112  is provided such that the power signal supply part  112  can be electrically connected to the first primary winding part  110  exposed out of the lower core  120   b , thereby supplying a power signal. 
     In this case, the providing a power signal supply part (S 613 ) may include a step of electrically connecting the power signal supply part  112  to an end of the primary winding part  110  exposed out of the upper core  120   b.    
     The providing of the power signal supply part (S 613 ) may include a step of efficiently and easily supplying a power signal to the primary winding part  110  by providing the power signal supply part  112  using a metallic material having high conductivity. 
     In this case, the providing a power signal supply part (S 613 ) may include a step of providing the power signal supply part  112  as a terminal to be coupled with a first via hole  110   b  formed in the printed circuit board  110   a.    
     Finally, as illustrated in  FIG. 11 , in the providing of the power signal output part (S 615 ), the power signal output part  114  is provided such that the power signal output part  114  can be electrically connected to the secondary winding part  106  exposed out of the lower core  120   a  to output a power signal transformed by the secondary winding part  106 . 
     In this case, the providing of the power signal output part (S 615 ) may include a step of electrically connecting the power signal output part  114  to an end of the secondary winding part  106  exposed out of the lower core  120   a.    
     The providing of the power signal output part (S 615 ) may include a step of efficiently and easily outputting a power signal transformed by the secondary winding part  106  by providing the power signal output part  114  using a metallic material having high conductivity. 
     In this case, the providing of the power signal output part (S 615 ) may include a step of providing the power signal output part  114  as a terminal to be coupled with a second via hole  108   a  formed in the second insulating part  108 . 
     In the transformer according the embodiment, when the film  130  is formed on at least one of the first and second side parts  121  and  123  or the central part  122 , the film  130  may be simply inserted without polishing a portion of the core where the film  130  is formed, so that productivity can be improved and a volume of the core  120  is decreased up to 30% than before. 
     Since the ratio of the magnetizing inductance to the leakage inductance may be set approximately to 7:1 to 5:1 due to the film  130 , an electric current flowing through the primary side and the secondary side is reduced so that a thickness of a coil and heat loss are reduced, thereby improving efficiency of the transformer. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effects such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.