Patent Publication Number: US-7724115-B2

Title: Circuit carrier and transformer assembly

Description:
FIELD OF THE INVENTION 
   The present invention relates to a circuit carrier and transformer assembly, and more particularly to a circuit carrier and transformer assembly with reduced height by partially receiving the transformer in multiple receiving holes of the circuit carrier. 
   BACKGROUND OF THE INVENTION 
   Generally, a circuit carrier (e.g. a printed circuit board) and a transformer are included in an electronic device such as a LCD television. The transformer is mounted on the circuit carrier to form a circuit carrier and transformer assembly. The transformer has become an essential electronic component for voltage regulation into required voltages for the electronic device. 
     FIG. 1  is a schematic exploded view illustrating a transformer and a circuit carrier according to prior art. As shown in  FIG. 1 , the transformer  1  is mounted on the circuit carrier  11 . As shown in  FIG. 1 , the transformer  10  principally comprises a magnetic core assembly  12 , a bobbin  13 , a primary winding coil  14  and a secondary winding coil  15 . The primary winding coil  14  and the secondary winding coil  15  are wound around a first winding part  131  and a second winding part  132  of the bobbin  13 , respectively. In addition, a first side plate  131   a  and a second side plate  131   b  are arranged on opposite sides of the first winding part  131  of the bobbin  13 . A third side plate  132   a  and a fourth side plate  132   b  are arranged on opposite sides of the second winding part  132  of the bobbin  13 . The second side plate  131   b  of the first winding part  131  is separated from the third side plate  132   a  of the second winding part  132  by a gap d. Due to the gap d, a desired creepage distance is maintained between the primary winding coil  14  and the secondary winding coil  15 . Moreover, two bobbin bases  16  are externally and vertically extended from the first side plate  131   a  of the first winding part  131  and the fourth side plate  132   b  of the second winding part  132 , respectively. A plurality of pins  17  are disposed on the bobbin bases  16  and inserted into corresponding perforations (not shown) of the circuit carrier  11 , so that the transformer  10  is fixed on the circuit carrier  11 . 
     FIG. 2  is a schematic cross-sectional view illustrating a circuit carrier and transformer assembly shown in  FIG. 1 . Please refer to  FIGS. 1 and 2 . The circuit carrier and transformer assembly, however, still has some drawbacks. For example, after the pins  17  of the transformer  10  are inserted into corresponding perforations of the circuit carrier  11 , the bobbin bases  16  of the transformer  10  are sustained against the surface of the circuit carrier  11 . Since the bobbin bases  16  have inherent volume, the bobbin bases  16  occupy extra space above the circuit carrier  11 . In other word, the circuit carrier and transformer assembly is detrimental to minimization and slimness of the electronic device. Moreover, since the gap d between the second side plate  131   b  of the first winding part  131  and the third side plate  132   a  of the second winding part  132  maintains the desired creepage distance between the primary winding coil  14  and the secondary winding coil  15 , the second side plate  131   b  and the third side plate  132   a  are very close to the circuit carrier  11  after the transformer  10  is mounted on the circuit carrier  11 . If the distance between the second side plate  131   b  (or the third side plate  132   a ) and the circuit carrier  11  is smaller than 1 mm, the creepage distance between the primary winding coil  14  and the secondary winding coil  15  is shortened and thus the electrical safety is reduced. 
   There is a need of providing a circuit carrier and transformer assembly to obviate the drawbacks encountered from the prior art. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a circuit carrier and transformer assembly so as to achieve minimization and slimness of the electronic device. 
   Another object of the present invention provides a circuit carrier and transformer assembly so as to increase electrical safety. 
   In accordance with an aspect of the present invention, there is provided a circuit carrier and transformer assembly. The circuit carrier and transformer assembly includes a circuit carrier and a transformer. The transformer includes a bobbin with multiple bobbin bases. The circuit carrier includes multiple receiving holes corresponding to respective bobbin bases of the bobbin. The bobbin bases are received in respective bobbin bases when the transformer is mounted on the circuit carrier. 
   The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic exploded view illustrating a transformer and a circuit carrier according to prior art; 
       FIG. 2  is a schematic cross-sectional view illustrating a circuit carrier and transformer assembly shown in  FIG. 1 ; 
       FIG. 3  is a schematic exploded view illustrating a transformer and a circuit carrier according to a preferred embodiment of the present invention; 
       FIG. 4  is a schematic assembled view illustrating a circuit carrier and transformer assembly shown in  FIG. 3 ; 
       FIG. 5  is an upside-down view of the circuit carrier and transformer assembly shown in  FIG. 4 ; and 
       FIG. 6  is a schematic cross-sectional view illustrating a circuit carrier and transformer assembly shown in  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
     FIG. 3  is a schematic exploded view illustrating a transformer and a circuit carrier according to a preferred embodiment of the present invention.  FIG. 4  is a schematic assembled view illustrating a circuit carrier and transformer assembly shown in  FIG. 3 .  FIG. 5  is an upside-down view of the circuit carrier and transformer assembly shown in  FIG. 4 . The transformer  30  and the circuit carrier  34  are included in an electronic device such as a LCD television. 
   Please refer to  FIGS. 3 ,  4  and  5 . The transformer  30  is mounted on the circuit carrier  34 , and principally comprises a magnetic core assembly  31 , a bobbin  32  and a plurality of shielding members  33 . The magnetic core assembly  31  includes two magnetic parts, which are cooperatively formed as for example an EE-type core assembly. Each magnetic part has a middle portion  310  and two leg portions  311 . The leg portions  311  are arranged on bilateral sides of the middle portion  310 . 
   The bobbin  32  includes a winding section  320  and a first channel  321 . The first channel  321  passes through the inner portion of the winding section  320 . The middle portions  310  of the magnetic core assembly  31  are embedded into the first channel  321  of the bobbin  32 . The winding section  320  includes a first winding part  322  and a second winding part  323 . A primary winding coil (not shown) and a secondary winding coil (not shown) are wound around the first winding part  322  and the second winding part  323 , respectively. The primary winding coil and the secondary winding coil interact with the magnetic core assembly  31  to achieve the purpose of voltage regulation. 
   In some embodiments, a first side plate  322   a  and a second side plate  322   b  are arranged on opposite sides of the first winding part  322  of the bobbin  32 . A third side plate  323   a  and a fourth side plate  323   b  are arranged on opposite sides of the second winding part  323  of the bobbin  32 . The second side plate  322   b  of the first winding part  322  has two concave portions  322   c  at bilateral upper corners thereof. Corresponding to the concave portions  322   c , the third side plate  323   a  of the second winding part  323  has two concave portions  323   c  at bilateral upper corners thereof. The concave portions  322   c  and  323   c  may enhance the creepage distance between the primary winding coil and the secondary winding coil. 
   Furthermore, the second side plate  322   b  of the first winding part  322  is separated from the third side plate  323   a  of the second winding part  323  by a gap d′. The gap d′ may also enhance the creepage distance between the primary winding coil and the secondary winding coil. In some embodiments, the second winding part  323  further includes a partition plate  323   d  between the third side plate  323   a  and the fourth side plate  323   b . By the partition plate  323   d , the secondary winding coil is wound around the second winding part  323  in two portions so as to enhance the heat-dissipating efficiency of the secondary winding coil. 
   In some embodiments, the bobbin  32  has a plurality of bobbin bases  325  and a plurality of pins  324 . For example, two bobbin bases  325  are externally and vertically extended from the first side plate  322   a  of the first winding part  322  and the fourth side plate  323   b  of the second winding part  323 , respectively. The pins  324  are for example L-shaped. The pins  324  have respective first ends fixed in the bobbin bases  325  and respective second ends inserted into corresponding perforations (not shown) of the circuit carrier  34 . 
   In some embodiments, the shielding members  33  are separated from each other for shielding the bobbin  32 . Each shielding members  33  includes a receiving part  331 , a bottom plate  333 , a first extension plates  334  and a second extension plate  335 . The first extension plate  334  is downwardly and vertically extended from bilateral sides of the bottom plate  333 . At least one ventilation hole  336  is formed in the first extension plate  334  for enhancing convection and heat-dissipation. 
   Please refer to  FIGS. 3 ,  4  and  5  again. The receiving part  331  has a hollow portion disposed in the center thereof and defined by four sidewalls. The receiving part  331  has a first opening  331   a  and a second opening  331   b , which are formed in two opposite sidewalls of the receiving part  331 . For example, the first opening  331   a  is formed in the first sidewall of the receiving part  331 . After the first winding part  322  and the second winding part  323  of the bobbin  32  are inserted into the receiving parts  331  through the first openings  331   a , the first winding part  322  and the second winding part  323  are received in the receiving parts  331 . Meanwhile, the first sidewall  331   c  of the receiving part  331  is arranged between the second side plate  322   b  of the first winding part  322  and the third side plate  323   a  of the second winding part  323  in order to further enhance the creepage distance between the primary winding coil and the secondary winding coil. Moreover, the hollow upper side of the receiving part  331  may maintain the creepage distance between the primary winding coil and the secondary winding coil so as to increase electrical safety of the transformer  30 . 
   Please refer to  FIGS. 3 ,  4  and  5  again. After the first winding part  322  and the second winding part  323  of the bobbin  32  are inserted into the receiving parts  331  through the first openings  331   a , the second openings  331   b  of the receiving part  331  are communicated with the first channel  321  of the bobbin  32  such that the middle portions  310  of the magnetic core assembly  31  may be embedded into the first channel  321  of the bobbin  32  through the second openings  331   b . Furthermore, the second extension plates  335  are externally and vertically extended from the upper sides of the receiving parts  331 . For each shielding member  33 , two recesses  338  are defined between the second extension plate  335 , the bottom plate  333  and the external surfaces of two sidewalls of the receiving part  331 . When the middle portions  310  of the magnetic core assembly  31  are embedded into the first channel  321  of the bobbin  32  through the second openings  331   b  of the shielding members  33 , the leg portions  311  of the magnetic core assembly  31  are received in corresponding recesses  338 . After the magnetic core assembly  31 , the bobbin  32  and the shielding member  33  are assembled as the transformer  30  shown in  FIGS. 4 and 5 , an insulation tape (not shown) is wound around the outer surface of the transformer  30  so as to securely combine the magnetic core assembly  31 , the bobbin  32  and the shielding member  33  together. 
   Please refer to  FIGS. 3 ,  4  and  5  again. The circuit carrier  34  (e.g. a printed circuit board) is used for supporting the transformer  30 . The circuit carrier  34  has several perforations  341  and several receiving holes  342 . The locations of the perforations  341  are aligned with corresponding pins  324  of the bobbin  32  of the transformer  30 . After the pins  324  of the bobbin  32  are inserted into the perforations  341  of the circuit carrier  34 , the transformer  30  is fixed on the circuit carrier  34 . The locations of the receiving holes  342  are aligned with corresponding bobbin bases  325  of the transformer  30 . The dimension of each receiving hole  342  is substantially equal to that of a corresponding bobbin base  325 . When the pins  324  of the bobbin  32  are inserted into the perforations  341  of the circuit carrier  34 , the bobbin bases  325  of the transformer  30  are received in corresponding receiving holes  342 . As a consequence, the overall height of the transformer  30  with respect to the circuit carrier  34  is reduced. 
   In some embodiment, the circuit carrier  34  has a slot  343  between the receiving holes  342  and corresponding to the range of from the second side plate  322   b  of the first winding part  322  to the third side plate  323   a  of the second winding part  323 . That is, the dimension of the slot  343  is substantially equal to the shadow area from the second side plate  322   b  of the first winding part  322  to the third side plate  323   a  of the second winding part  323 . After the transformer  30  is mounted on the circuit carrier  34 , the second side plate  322   b  of the first winding part  322  and the third side plate  323   a  of the second winding part  323  are disposed above the slot  343 . The slot  343  may increase the minimum distance between the second side plate  322   b  of the first winding part  322  (or the third side plate  323   a  of the second winding part  323 ) and the circuit carrier  34  so as to increase electrical safety of the transformer  30 . 
     FIG. 6  is a schematic cross-sectional view illustrating a circuit carrier and transformer assembly shown in  FIG. 4 . Hereinafter, a process of fabricating the circuit carrier and transformer assembly according to the present invention will be illustrated with reference to  FIGS. 3 ,  4 ,  5  and  6 . First of all, the bobbin  32  is shielded by the shielding members  33  such that the first winding part  322  and the second winding part  323  are received in the receiving parts  331  of respective shielding members  33  and the first channel  321  of the bobbin  32  is communicated with the second openings  331   a  of the shielding members  33 . Meanwhile, the first sidewall  331   c  of the receiving part  331  is arranged between the second side plate  322   b  of the first winding part  322  and the third side plate  323   a  of the second winding part  323 . Next, the middle portions  310  of the magnetic core assembly  31  are embedded into the first channel  321  of the bobbin  32  through the second openings  331   b  of the shielding members  33  and the leg portions  311  of the magnetic core assembly  31  are received in corresponding recesses  338 . After the magnetic core assembly  31 , the bobbin  32  and the shielding member  33  are assembled as the transformer  30 , an insulation tape (not shown) is wound around the outer surface of the transformer  30 . Next, the pins  324  of the bobbin  32  of the transformer  30  are aligned with corresponding perforations  341  of the circuit carrier  34  and the bobbin bases  325  of the transformer  30  are aligned with corresponding receiving holes  342  of the circuit carrier  34 . Afterwards, the pins  324  are inserted into corresponding perforations  341  and the bobbin bases  325  are received in corresponding receiving holes  342  such that the transformer  30  is mounted on the circuit carrier  34 . Under this circumstance, the second side plate  322   b  of the first winding part  322  and the third side plate  323   a  of the second winding part  323  are disposed above the slot  343 . Since the bobbin bases  325  are partially received in corresponding receiving holes  342  of the circuit carrier  34 , the overall height of the circuit carrier and transformer assembly is reduced. 
   Moreover, for facilitating fixing the transformer  30  on the circuit carrier  34  and preventing deformation of the pins  324 , the transformer  30  further includes one or more sustaining elements  326  as shown in  FIG. 5 . The sustaining elements  326  are disposed beside the bobbin bases  325 . When the bobbin bases  325  are partially received in corresponding receiving holes  342  of the circuit carrier  34 , the sustaining elements  326  are sustained against the surface of the circuit carrier  34  and adjacent to the receiving holes  342  so as to assist the pins in supporting the transformer  30 . 
   From the above description, the circuit carrier and transformer assembly according to the present invention has reduced height by partially receiving the bobbin bases of the transformer in corresponding receiving holes of the circuit carrier. As a consequence, the electronic device with the circuit carrier and transformer assembly can meet the requirements of minimization and slimness. Moreover, since the slot of the circuit carrier may increase the minimum distance between the second side plate of the first winding part (or the third side plate of the second winding part) and the circuit carrier, the creepage distance between the primary winding coil and the secondary winding coil is enhanced so as to increase the electrical safety of the electronic device. 
   While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.