Abstract:
A transformer ( 10 ), coupled to a circuit board ( 20 ) defining a receiving hole ( 210 ), includes a base ( 110 ) having a first end portion ( 110   a ) and an oppositely disposed second end portion ( 110   b ), a bobbin assembly ( 120 ) disposed between the first end portion and the second end portion, and a post ( 140 ) disposed on the base. The post is received in the receiving hole for positioning the transformer on the circuit board.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention pertains to electronic devices, and particularly to an electronic device with a transformer having a plurality of positioning posts. 
       DESCRIPTION OF RELATED ART 
       [0002]    Recently, with the development of electronic technology, electronic devices are getting more and more complicated with a large number of electronic components. In order to assemble the electronic components onto a circuit board of the electronic device, one common technique involved is called surface mounting technology (SMT). In the SMT process, much attention must be taken to correctly locate the electronic components on the circuit board so that leads of each component are correctly aligned with corresponding pads of the circuit board. 
         [0003]    Commonly, in the SMT process, the leads of the small electronic components, such as SMT resistors, capacitors, chips and so on, can be easily aligned with the corresponding pads of the circuit board. However, difficulties may be encountered when aligning the leads of larger electronic components, such as transformers, connectors, CPU sockets and so on, since these components are heavy enough and difficult to keep positioned on the circuit board when soldering in a reflow oven. Consequently, the larger components may shift during soldering. When this happens, connections of the leads of the components with the pads of the circuit board may be faulty, thus causing the electronic device to fail in operation. 
         [0004]    Therefore, a heretofore unaddressed need exists in the industry to overcome the aforementioned deficiencies and inadequacies. 
       SUMMARY OF THE INVENTION 
       [0005]    One aspect of the invention provides a transformer. The transformer, coupled to a circuit board defining a receiving hole, includes a base having a first end portion and a second end portion opposite to the first end portion, a bobbin assembly disposed between the first end portion and the second end portion, and at least one post disposed on the base. Wherein the at least one post is received in the receiving hole for positioning the transformer on the circuit board. 
         [0006]    Another aspect of the invention provides an electronic device. The electronic device includes a circuit board defining a receiving hole, and a transformer coupled to the circuit board. The transformer includes a base having a first end portion and a second end portion opposite to the first end portion, a bobbin assembly disposed between the first end portion and the second end portion, and at least one post disposed on the base. Wherein the at least one post is received in the receiving hole for positioning the transformer on the circuit board. 
         [0007]    Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an exploded, isometric view of an electronic device of an exemplary embodiment of the present invention, the electronic device including a transformer and a circuit board; 
           [0009]      FIG. 2  is an isometric view of a transformer of another exemplary embodiment of the present invention; 
           [0010]      FIG. 3  is an isometric view of a transformer of a further exemplary embodiment of the present invention; and 
           [0011]      FIG. 4  is an isometric view of a transformer of a still further exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]      FIG. 1  shows an electronic device  60  of an exemplary embodiment of the present invention. The electronic device  60 , such as an inverter, a converter, and the like, comprises a circuit part like a circuit board  20  and an electronic component like a transformer  10  coupled to the circuit board  20 . 
         [0013]    The transformer  10  comprises a base  110  mounted on the circuit board  20 , a bobbin assembly  120 , a core module  130 , and two positioning means like two positioning posts  140 . The base  110  comprises a first end portion  110   a  and a second end portion  110   b  opposite to the first end portion  110   a . Both of them are able to electrically connectable to the circuit board  20 . The bobbin assembly  120  is disposed between the first end portion  110   a  and the second end portion  110   b . The bobbin assembly  120  comprises a first bobbin  121  having a primary winding wound thereon, and a second bobbin  122  having a secondary winding wound thereon. The second bobbin  122  is connected to the first bobbin  121 . The first bobbin  121  is adjacent to the first end portion  110   a , while the second bobbin  122  is adjacent to the second end portion  110   b . The positioning posts  140  are disposed on opposite ends of the first end portion  110   a.    
         [0014]    The first bobbin  121  is disposed collinear with the second bobbin  122 . The bobbin assembly  120  defines a hollow portion  123  extending therethrough. The core module  130  has a first core portion  130   a  and an opposite second core portion  130   b , both of which are inserted in the hollow portion  123  from opposite ends of the bobbin assembly  120  to form a closed magnetic loop. Each of the core portions  130   a  and  130   b  has an E-shaped cross-section. 
         [0015]    The circuit board  20  comprises two receiving holes  210  corresponding to the positioning posts  140 . When the transformer  10  is coupled to the circuit board  20 , the positioning posts  140  are received in the receiving holes  210 . Thereby the transformer  10  is accurately positioned on the circuit board  20 , facilitating soldering in a reflow oven. 
         [0016]    In another exemplary embodiment of the invention, referring to  FIG. 2 , the positioning posts  140  are disposed on the second end portion  110   b  of the base  110 . 
         [0017]    In a further exemplary embodiment of the invention, referring to  FIG. 3 , one of the positioning posts  140  is disposed on the first end portion  110   a  of the base  110 , while the other is disposed on the second end portion  110   b  of the base  110 . 
         [0018]    In a still further exemplary embodiment of the invention, referring to  FIG. 4 , a transformer  30  is shown. The transformer  30  comprises a base  310  having a first end portion  310   a  and a second end portion  310   b  opposite to the first end portion  310   a , a bobbin assembly  320  having a first bobbin  321  and a second bobbin  322  parallel to the first bobbin  321 , and two positioning posts  340 . The bobbin assembly  320  is disposed between the first end portion  310   a  and the second end portion  310   b . The first bobbin  321  defines a first hollow portion  324 , while the second bobbin  322  defines a second hollow portion  323 . The transformer  30  further comprises a core module  330  having a first core portion  330   a  and a second core portion  330   b  received in the hollow portions  324  and  323  respectively. Each of the core portions  330   a  and  330   b  has a U-shaped cross-section. The positioning posts  340  have a similar positioning means to that of the aforementioned exemplary embodiments of the present invention. When the transformer  30  is coupled to the circuit board  20  of  FIG. 1 , the positioning posts  340  are received in the receiving holes  210 . As a result, the transformer  30  is accurately positioned on the circuit board  20 , facilitating soldering in the reflow oven. 
         [0019]    While exemplary embodiments have been described above, it should be understood that they have been presented by way of example only and not by way of limitation. Thus the breadth and scope of the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.