JP2006114717A - Multi-output inverter transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a mounting area of an inverter transformer is large and, when a plurality of discharge lamps are lit on, a discharge lamp light-on circuit is large-sized. <P>SOLUTION: The inverter transformer comprises a first bobbin 10 and a second bobbin 20 to which terminals 15, 25 are attached respectively, a pair of cores 50, 60, a first-order coil 30 wound on the groove 14 of the first bobbin 10, and a second-order coil 40 wound on the groove 24 of the second bobbin 20. At least four grooves 24 of the second bobbin 20 are formed, and a plurality of coils 26 composed of the adjacent two grooves 24 are provided in the second bobbin 20. The second-order coil 40 is wound on the one groove 24 of each of the coils 26, and the lead wire of the second-order coil 40 is passed through the other groove 24, so that the terminal is connected to the terminal 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inverter for lighting a discharge lamp, and more particularly to a multi-output inverter transformer capable of taking out a plurality of outputs.

With the increase in the size of liquid crystal display screens, about 10 to 20 discharge lamps for illuminating the back surface have been used. For this reason, the number of inverter transformers used in discharge lamp lighting circuits is increasing.
An example of a conventional multi-output type inverter transformer is disclosed in Patent Document 1. As shown in FIG. 11 and FIG. 12, the transformer includes two secondary bobbins 2 that face one primary bobbin 1. A primary winding 3 is wound around the bobbin 1, and a secondary winding 4 is wound around each of the two bobbins 2. The lead wire of the secondary winding 4 is pulled out along the lower surface of the bobbin 2 through a slit 2 a provided in the bobbin 2 and then connected to the terminal 5. Reference numerals 7 and 8 denote a pair of cores that electromagnetically couple the primary winding 3 and the two secondary windings 4.
JP 2001-126937 A

  The lead wire of the high-voltage secondary winding 4 drawn out below the bobbin 2 is covered with an adhesive applied to the lower surface of the bobbin 2 so as to enhance the withstand voltage characteristic. For this reason, there exists a fault which assembly workability | operativity and mass productivity fall. In addition, there is a variation in the application state of the adhesive, and when the transformer is mounted on the printed circuit board, a dielectric breakdown voltage defect between the lead wire and the printed circuit board may occur.

  When such a two-output type transformer is used, the mounting area on the printed circuit board can be made smaller than when two single-output type transformers are used. However, the transformer of FIG. 10 still has a large mounting area because the two bobbins 2 on the secondary winding side are arranged in the horizontal direction. In particular, when a large number of discharge lamps are lit, a large number of transformers are required, and the inverter transformer occupies a wide space on the printed circuit board, resulting in a problem that the discharge lamp lighting circuit portion is enlarged.

  The inverter transformer according to the present invention has a cylindrical winding shaft with a through hole, a groove is formed around the winding shaft, and a first bobbin 10 and a second bobbin to which a plurality of terminals 15 and 25 are attached. 20 and a pair of first legs 51 inserted into the through holes of the first bobbin 10 and second legs 52 inserted into the through holes 21 of the second bobbin 20 to form a closed magnetic circuit Cores 50 and 60, a primary winding 30 wound around the groove 14 of the first bobbin 10, and a secondary winding 40 wound around the groove 24 of the second bobbin 20 and electromagnetically coupled to the primary winding 30 And at least four grooves 24 of the second bobbin 20 are formed, and a plurality of winding portions 26 composed of two adjacent grooves 24 are provided on the second bobbin 20, and each winding is provided. The secondary winding 40 is wound around one groove 24 of the portion 26, and the other groove 24 is connected to the terminal 25 through the lead wire of the secondary winding 40.

  According to the present invention, not only can a plurality of discharge lamps be simultaneously turned on by a single inverter transformer, but also a plurality of secondary windings are arranged in the vertical direction. Can be greatly reduced. This is particularly useful when many transformers are mounted on the same substrate. In addition, since a bobbin ridge is interposed between the lead wire of the secondary winding and the conductor pattern of the printed circuit board, there is an effect that a stable withstand voltage characteristic can be obtained.

  1 to 3 show an embodiment of an inverter transformer according to the present invention, which is a configuration example in the case of a 4-output type. Reference numeral 10 denotes a bobbin having a cylindrical winding shaft with a through-hole 11 (FIG. 3), a groove 14 formed around the winding shaft, and a plurality of terminals 15 attached thereto. A low-voltage-side primary winding 30 is wound around the groove 14, and the lead wire is connected to the terminal 15. The transformer of the present embodiment includes two secondary bobbins 20 next to the primary bobbin 10. The two bobbins 20 are equidistant from the bobbin 10.

  The bobbin 20 has a cylindrical winding shaft 22 with a through-hole 21 as shown in an enlarged view in FIG. 4, and includes four grooves 24 partitioned by five ridges 23 around the winding shaft 22. Yes. A plurality of terminals 25 are attached to the central collar 23c. The bobbin 20 is formed with two winding portions 26 composed of two adjacent grooves 24. The two winding portions 26 are symmetrically arranged in the vertical direction around the center flange 23c. In each winding portion 26, a secondary winding 40 on the high voltage side is wound around a groove 24a far from the center flange 23c. The lead wire of the secondary winding 40 is led to the other groove 24b through the slit 27 provided in the flanges 23b and 23d, and then connected to the terminal 25 through this groove 24b.

  The terminal 25 attached to the bobbin 20 is embedded in the flange 23c with both ends protruding outward. FIG. 5 is a plan view of the bobbin 20 with a part of the upper flange 23e cut out. As is apparent from FIGS. 5 and 4, one end of the terminal 25 is a short terminal 25a protruding in the lateral direction of the bobbin 20, and the other end is a long terminal 25b bent downward. The longer terminal 25b is for connecting the printed circuit board, and the short terminal 25a is for connecting the lead wire of the secondary winding 40. As shown in FIG. 6, only the lead wire connection terminals 25a may be collected on one side surface of the bobbin 20, and the printed circuit board connection terminals 25b may be pulled out from the other side surface.

50 and 60 are a pair of cores made of a magnetic material. As shown in FIG. 3, the lower core 50 is formed with a substantially square leg 51 projecting upward, columnar legs 52a and 52b, and an elongated protrusion 54. The leg 51 is inserted into the through hole 11 of the winding shaft of the primary bobbin 10, and the legs 52a and 52b are inserted into the through holes 21 of the winding shaft 22 of the different secondary bobbins 20, respectively.
A flat core 60 is abutted against the core 50 at the portions of the legs 51, 52a, 52b to form a closed magnetic circuit. Note that the protrusion 54 is not necessarily formed. The legs 52a and 52b may be provided on the upper core 60 side, or may be provided on both the cores 50 and 60.

  The bobbin 10 and the two bobbins 20 are sandwiched between the core 50 and the core 60 and fixed by the cores 50 and 60 bonded to each other. The protrusion 54 is located between the four secondary windings 40 and the primary winding 30 and acts to weaken electromagnetic coupling between the primary winding 30 and the secondary winding 40. The four secondary windings 40 have the same number of turns and are electromagnetically coupled to the primary winding 30 with the same degree of coupling. Therefore, when this inverter transformer is incorporated in an inverter, four output voltages having the same value can be obtained.

  In the above-described embodiment, as is apparent from FIG. 4, the winding portions 26 are arranged symmetrically in the vertical direction around the central flange 23c, and all the terminals 25 are attached to the central flange 23c. However, as shown in FIG. 7, the terminals 25 for the two secondary windings 40a and 40b wound around one bobbin 20 may be provided separately in a central flange 23c and a lower flange 23a. At this time, the lead wires 41a and 41b of the respective secondary windings 40a and 40b are passed through the grooves 24 just above the flanges 23a and 23c to which the terminals 25 are attached.

FIG. 8 shows a configuration example of a two-output transformer by using one bobbin 20 as shown in FIG. 4 on the secondary side. Thus, even when a two-output transformer similar to the conventional example of FIG. 12 is used, there is an advantage that the planar projection area can be made more compact than the conventional one.
9 to 11 show embodiments of different multi-output transformers configured by using one primary bobbin 10 and a plurality of secondary bobbins 20. The bobbin 20 uses the same bobbin as in the previous embodiment. FIG. 9 shows a four-output transformer in which secondary bobbins 20 are symmetrically arranged around the primary bobbin 10, FIG. 10 shows a six-output transformer using three secondary bobbins 20, and FIG. 8 output transformers used.

Each of the above embodiments has been described with respect to the example of the bobbin 20 including the two winding portions 26. However, the configuration in which the number of the grooves 24 is increased and three or more winding portions 26 are provided on one bobbin 20 is described. It is good.
Although the inverter transformer of the present invention is configured to allow multiple outputs, instead of taking out one output for each secondary winding 40, as shown in FIG. It may be used in a circuit configuration in which two secondary windings 40 are connected to an electric lamp and lighted at a double voltage. In other words, one end of each of the two secondary windings 40 is grounded, and the other end that is not grounded is connected to both ends of a single discharge lamp so as to be lit at twice the voltage.

The front view which shows 1st Example of the inverter transformer of this invention Top view of the transformer A plan view of the transformer excluding the upper core Partial cross-sectional front view showing the secondary bobbin in an enlarged manner Partial cutaway plan view of secondary bobbin Plan view of the secondary bobbin showing a modification of the terminal Front sectional view of a wound state showing another embodiment of the secondary bobbin The top view which shows 2nd Example of the transformer of this invention The top view which shows 3rd Example of the transformer of this invention The top view which shows 4th Example of the transformer of this invention The top view which shows 5th Example of the trans | transformer of this invention Plan view showing a conventional inverter transformer AA line sectional view of FIG.

Explanation of symbols

10 First bobbin
20 Second bobbin
24 groove
26 Winding part
30 Primary winding
40 Secondary winding

Claims (5)

First and second bobbins each having a cylindrical winding shaft with a through hole, a groove formed around the winding shaft, and a plurality of terminals attached thereto;
A pair of cores having a first leg inserted into the through hole of the first bobbin and a second leg inserted into the through hole of the second bobbin, and forming a closed magnetic circuit;
A primary winding wound in the groove of the first bobbin;
In an inverter transformer comprising a secondary winding wound around the groove of the second bobbin and electromagnetically coupled to the primary winding,
Forming at least four grooves in the second bobbin;
A plurality of winding portions composed of two adjacent grooves are provided on the second bobbin,
A multi-output inverter transformer, wherein a secondary winding is wound in one groove of each winding portion, and a lead wire of the secondary winding is connected to a terminal through the other groove.   The multi-output inverter transformer according to claim 1, wherein a plurality of second bobbins are provided, and the same number of second legs as the second bobbins are formed in the core.   The multi-output inverter transformer according to claim 1, wherein a plurality of second legs equidistant from the first leg are formed in the core, and a plurality of second bobbins equidistant from the first bobbin are provided.   The four grooves partitioned by five scissors are provided in the second bobbin, the winding portions are arranged symmetrically in the vertical direction around the central scissors, and the terminals are attached to the central scissors. Multi-output inverter transformer.   Four grooves partitioned by five scissors are provided in the second bobbin, terminals are attached to the center scissors and bottom scissors, and the lead wire of the secondary winding is passed through the grooves directly above these scissors. Item 1. Multi-output inverter transformer.

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