CN1949417B - Transformer, lamp tube driving device and method for adjusting lamp brightness - Google Patents

Abstract

A transformer comprises an insulating shell, a first winding frame, a primary side winding, a second winding frame, a secondary side winding, a first magnetic core and a second magnetic core. The insulating shell is provided with a first cavity and a second cavity which are respectively opened on two opposite side walls of the insulating shell, and the first cavity is not communicated with the second cavity. The first bobbin has a first through hole disposed in the first chamber. The primary winding is wound on the first winding frame. The second winding frame is provided with a second through hole and is arranged in the second cavity. The secondary winding is wound on the second winding frame. The first magnetic core is embedded into the first through hole and the second through hole. The second magnetic core is coupled with the first magnetic core and forms a magnetic loop with the first magnetic core.

Description

The method of transformer, lamp tube driver and adjustment lighting tube brightness thereof

Technical field

The invention relates to a kind of lamp tube driver, and particularly about a kind of transformer of lamp tube driver.

Background technology

Along with the arriving of multimedia era, (Liquid Crystal Display, application LCD) will enlarge as the monitor of computer, LCD screen TV etc. LCD gradually.Generally speaking, LCD is used the light and handy lamp source that reaches dynamical discharge lamp as backlight module, therefore has thin thickness, the steady and audible characteristics of image quality.

Backlight module in the LCD is mainly by as cold-cathode tube (Cold Cathode FluorescentLamp, discharge lamp CCFL), and form in order to the transformer that drives cold-cathode tube.Please refer to Fig. 1, it illustrates the decomposing schematic representation of traditional transformer.Transformer 10 has drum stand 11, first magnetic core 13, second magnetic core 15, primary side coiling group 17 and secondary side coiling group 19.Behind transformer 10 logical upward electric currents, magnetic flux flow to the second end 15b along the first end 15a of second magnetic core 15.And flow into by the second end 15b magnetic flux and to get back to second magnetic core 15 by an end of first magnetic core 13.

Yet,, cause most probably forming arcing between coil on primary side coiling group and the secondary side coiling group and magnetic core because the voltage difference between primary side coiling group and secondary side coiling group is very high.Moreover at present regular meeting produces stray-capacity effect between the casing of cold-cathode tube and LCD, and this stray-capacity effect can cause in the LCD difference of electric current between different cold-cathode tubes, and then influences the stability of electric current.When the size of current that flows through each cold-cathode tube not simultaneously, each cold-cathode tube will produce different brightness, and make brightness of backlight module inhomogeneous.And will reduce the useful life of bright excessively cold-cathode tube.And in order to obtain the stability of electric current, manufacturer need respectively dispose a high-voltage capacitance and survey between the coiling group in each cold-cathode tube and secondary, to reduce the influence of stray capacitance, reduces the difference of electric current between different cold-cathode tubes.Yet it is quite high using the required cost of a plurality of high-voltage capacitances.

Summary of the invention

In view of this, purpose of the present invention is providing a kind of transformer exactly, increases safe insulation distance between primary side coiling group and the secondary side coiling group, improves the arcing problem.And outside magnetic conduction subassembly is set to be increased total magnetic flux, reduces electromagnetic interference, but and sense of equilibrium's induced current and then adjustment lighting tube brightness.

According to purpose of the present invention, propose a kind of transformer and comprise insulation shell, first drum stand, primary side coiling, second drum stand, secondary side coiling, first magnetic core and second magnetic core.Insulation shell has first chamber and second chamber, be opened on relative two sidewalls of insulation shell respectively, and first chamber is not communicated with second chamber.First drum stand has one first perforation and is arranged at first chamber.The primary side coiling is wound on first drum stand.Second drum stand has one second perforation, is arranged at second chamber.The secondary side coiling is wound on second drum stand.First magnetic core embeds first perforation and second perforation.Second magnetic core couples first magnetic core, and constitutes a magnetic loop with first magnetic core.

According to purpose of the present invention, reintroduce a kind of lamp tube driver and comprise drive circuit, first fluorescent tube and transformer.Drive circuit is in order to output AC voltage.Transformer is in order to receive alternating voltage and to drive first fluorescent tube according to this, and transformer comprises insulation shell, first drum stand, primary side coiling, second drum stand, secondary side coiling, first magnetic core and second magnetic core.Insulation shell has one first chamber and one second chamber, be opened on relative two sidewalls of insulation shell respectively, and first chamber is not communicated with second chamber.First drum stand has first perforation, is arranged at first chamber.Second drum stand has second perforation, is arranged at second chamber.First magnetic core embeds first perforation and second perforation.Second magnetic core couples first magnetic core, and constitutes a magnetic loop with first magnetic core.The primary side coiling is wound on first drum stand, and is coupled to drive circuit to receive alternating voltage.The secondary side coiling is wound on second drum stand, and is coupled to first fluorescent tube to drive first fluorescent tube.

According to purpose of the present invention, a kind of method of adjusting lighting tube brightness is proposed again, comprise step: transformer, first fluorescent tube and second fluorescent tube (a) are provided, and transformer comprises insulation shell, first drum stand, primary side coiling, second drum stand, secondary side coiling, first magnetic core and second magnetic core.Insulation shell has one first chamber and one second chamber, be opened on relative two sidewalls of insulation shell respectively, and first chamber is not communicated with second chamber.First drum stand has first perforation, is arranged at first chamber.Second drum stand has second perforation, is arranged at second chamber.First magnetic core embeds first perforation and second perforation.Second magnetic core couples first magnetic core, and constitutes a magnetic loop with first magnetic core.The primary side coiling is wound on first drum stand.The coiling of first secondary side is wound on second drum stand, and is coupled to first fluorescent tube.Second secondary side coiling is wound on second drum stand, and with the first secondary side winding department every a both set a distance, and be coupled to second fluorescent tube.The first outside magnetic conduction subassembly and first drum stand are arranged side by side.The second outside magnetic conduction subassembly system and second drum stand are arranged side by side; (b) provide one drive circuit, wind the line, and drive first fluorescent tube and second fluorescent tube according to this in order to export an alternating voltage to primary side; And the position of (c) adjusting the second outside magnetic conduction subassembly, and adjust the brightness of first fluorescent tube and second fluorescent tube according to this.

For above-mentioned purpose of the present invention, feature and advantage can be become apparent, a preferred embodiment cited below particularly, and conjunction with figs. are described in detail below:

Description of drawings

Fig. 1 illustrates the decomposing schematic representation of traditional transformer.

Fig. 2 illustrates the three-dimensional exploded view according to the transformer of embodiments of the invention one.

Fig. 3 illustrates the upward view of insulation shell, first drum stand and second drum stand according to Fig. 2.

Fig. 4 A illustrates the three-dimensional combination figure of looking up according to the transformer of Fig. 2.

Fig. 4 B illustrates the transformer magnetic line of force schematic diagram among Fig. 4 A.

Fig. 5 illustrates the profile according to the transformer among Fig. 2.

Fig. 6 illustrates the schematic diagram of the transformer application of Fig. 2 in lamp tube driver.

Fig. 7 illustrates the perspective view according to the transformer of embodiments of the invention two.

The primary clustering symbol description

10: transformer

11: drum stand

13: the first magnetic cores

15: the second magnetic cores

15a: first end of second magnetic core

15b: second end of second magnetic core

17: primary side coiling group

19: secondary side coiling group

100: transformer

110: insulation shell

112: the first chambers

114: the second chambers

116: perforate

118: dividing plate

119: the three chambers

120: the first drum stands

122: the primary side coiling

126: the first perforations

128: the first groups of stitch

130: the second drum stands

132,134: the secondary side coiling

136: the second perforations

138: the second groups of stitch

140: the first magnetic cores

142: the second magnetic cores

144: the first outside magnetic conduction subassemblies

146: the second outside magnetic conduction subassemblies

152: elastic parts

154: adjust assembly

200: lamp tube driver

210: drive circuit

L1: first fluorescent tube

L2: second fluorescent tube

300: transformer

310: insulation shell

312: the first chambers

314: the second chambers

318: dividing plate

328: the first groups of stitch

338: the second groups of stitch

Embodiment

The present invention proposes a kind of transformer, and the insulation shell of coiling is loaded in redesign, makes transformer under identical volume, and the safe insulation distance between the stitch of increase primary side coiling and the stitch of secondary side coiling is improved the arcing problem.Below elaborate, yet following narration and diagram only are the usefulness of explanation that desire protection range of the present invention is still defined with claims for several groups of embodiment.

Embodiment one

Please refer to Fig. 2, it illustrates the three-dimensional exploded view according to the transformer of embodiments of the invention one.The transformer 100 of present embodiment comprises insulation shell 110, first drum stand 120, primary side coiling 122, second drum stand 130, secondary side coiling 132, first magnetic core 140 and second magnetic core 142.First drum stand 120 has first perforation 126, and primary side coiling 122 is wound on first drum stand 120.Second drum stand 130 has second perforation 136, and secondary side coiling 132 is wound on second drum stand 130.

Fig. 3 illustrates the upward view of insulation shell, first drum stand and second drum stand according to Fig. 2.Please be simultaneously with reference to Fig. 2 and Fig. 3, insulation shell 110 have first chamber 112 and second chamber (as Fig. 3 114), be opened on relative two sidewalls of insulation shell 110 respectively, for example be end face and the bottom surface that lays respectively at insulation shell, and first chamber 112 and second chamber (as Fig. 3 114) be not communicated with.Please refer to Fig. 3, insulation shell 110 preferably also comprises dividing plate 118, the insulation shell 110 that dividing plate 118 extends between first chamber 112 and second chamber 114.On the other hand, first chamber 112 preferably has perforate 116, is positioned at the same side of insulation shell 110 with the opening of second chamber 114, for example be the bottom surface that is positioned at insulation shell, and perforate 116 is away from dividing plate 118.

Moreover transformer 100 also comprises first group of stitch 128 and second group of stitch 138.First group of stitch 128 extends two ends from primary side coiling 122, and extends two ends from secondary side coiling 132 corresponding to 116, the second groups of stitch of perforate 138.

When combination, first drum stand 120 is arranged at first chamber, 112, the second drum stands and is arranged at second chamber 114.First magnetic core 140 embeds first perforation 126 and second perforation 136.Second magnetic core 142 couples first magnetic core 140, and constitutes magnetic loop with first magnetic core 140.Please refer to Fig. 4 A, it illustrates the three-dimensional combination figure of looking up according to the transformer of Fig. 2.At this moment, first group of stitch 128 protrudes in the opening that 116, the second groups of stitch 138 of perforate protrude in second chamber 114 accordingly accordingly, as shown in Figure 4.Thus, the creepage distance between first group of stitch and second group of stitch comprises the distance X of perforate 116 to dividing plate 118, and the height Y of dividing plate.Primary side coiling and secondary side coiling are wound in and make on the same drum stand under the minimum situation of the creepage distance of two groups of stitch in the traditional transformer, the creepage distance that first group of stitch 128 of the primary side of present embodiment coiling 122 and secondary side wind the line between second group of stitch 138 of 132 is X+Y, can increase considerably the safe insulation distance of first group of stitch 128 and second group of stitch 138.

Please refer to Fig. 2, transformer 100 also comprises the first outside magnetic conduction subassembly 144 and the second outside magnetic conduction subassembly 146.Please refer to Fig. 4 A, transformer 100 is when combination, and the first outside magnetic conduction subassembly 144 and first drum stand 120 are arranged side by side, preferably are placed in the 4th chamber 117.The second outside magnetic conduction subassembly 146 and second drum stand 130 are arranged side by side, preferably are placed in the 3rd chamber 119.Please refer to Fig. 4 B, it illustrates the transformer magnetic line of force schematic diagram among Fig. 4 A.Wind the line 122 the time when electric current flows into primary side, secondary side coiling group 132 produces an induced current.Primary side coiling group 122 can produce magnetic flux on the path that electric current is flowed through simultaneously, and the magnetic line of force that magnetic flux constituted as shown in Figure 2.The magnetic line of force extends to secondary side coiling group 132 by primary side coiling group 122, and through first magnetic core 140 and second magnetic core 142 to constitute the first magnetic circuit A1.And this magnetic flux is primary side coiling group 122 and 132 main magnetic fluxs (magnetic flux A1) partly that produce of secondary side coiling group.In Fig. 4 B, except the first magnetic circuit A1 also comprises the second magnetic circuit B1 and the 3rd magnetic circuit C1.The second magnetic circuit B1 is the part magnetic flux (magnetic flux B1) of primary side coiling group 122, and the 3rd magnetic circuit C1 refers to the part magnetic flux (magnetic flux C1) that secondary side coiling group 132 produces.Therefore, total magnetic flux is A1+B1+C1.Hence one can see that, places magnetic conduction subassembly at first drum stand and second drum stand outside, the leakage field bundle in the coil outside can be guided, and not only can reduce electromagnetic interference problem, more can form extra magnetic loop, to increase total magnetic flux.

Be noted that transformer 100 can also comprise another secondary side coiling 134, as shown in Figure 2.Another secondary side coiling 134 is wound on second drum stand 130, and with secondary side coiling 132 a both set a distance at interval.Fig. 5 illustrates the profile according to the transformer among Fig. 2.Please refer to Fig. 5, insulation shell 110 comprises that also the 3rd chamber 119 and the 4th chamber 117, the three chambers 119 and second chamber 114 are set up in parallel, and the 4th chamber 117 and second chamber 114 are set up in parallel.Transformer 100 also comprises elastic parts 152 and adjusts assembly 154.Elastic parts 152 is arranged on the insulation shell 110, in order to push an end of the second outside magnetic conduction subassembly 146.Adjust assembly 154 and be arranged on the insulation shell 110, and be positioned at the other end of the second outside magnetic conduction subassembly 146.Wherein, elastic parts 152 with adjust assembly 154 in order to adjust the relative position of the second outside magnetic conduction subassembly 146 and secondary side coiling 132 and another secondary side coiling 134.

The transformer of present embodiment can be applicable in the lamp tube driver.Please refer to Fig. 6, it illustrates the schematic diagram of the transformer application of Fig. 2 in lamp tube driver.Lamp tube driver 200 comprises drive circuit 210, the first fluorescent tube L1 and above-mentioned transformer 100.Drive circuit 210 is in order to output AC voltage.Transformer 100 is in order to receive alternating voltage and to drive the first fluorescent tube L1 according to this; The primary side coiling 122 of transformer 100 is to be wound on first drum stand 120, and be coupled to drive circuit 210 to receive alternating voltage, the secondary side coiling 132 of transformer 100 is wound on second drum stand 130, and is coupled to the first fluorescent tube L1 to drive the first fluorescent tube L1.

Preferably, lamp tube driver 200 also comprises the second fluorescent tube L2 and another secondary side coiling 134.Another secondary side coiling 134 is to be wound on second drum stand 130, with secondary side coiling 132 intervals one both set a distance, and is coupled to the second fluorescent tube L2 to drive the second fluorescent tube L2.Whereby, lamp tube driver can drive the fluorescent tube more than simultaneously.

Say that further the transformer application of present embodiment can provide the function of adjusting lighting tube brightness in lamp tube driver.Below propose a kind of method of adjusting lighting tube brightness, its step-by-step procedures is as follows.At first, transformer 100, the first fluorescent tube L1 and the second fluorescent tube L2 are provided, first secondary side coiling 132 of transformer is to be wound on second drum stand 130, and be coupled to the first fluorescent tube L1, second secondary side coiling 134 of transformer, system is wound on second drum stand 130, and with first secondary side coiling 132 a both set a distance at interval, and be coupled to the second fluorescent tube L2.Then, provide drive circuit 210, in order to exporting an alternating voltage, and drive the first fluorescent tube L1 and the second fluorescent tube L2 according to this.At last, adjust the position of the second outside magnetic conduction subassembly 146, and adjust the brightness of the first fluorescent tube L1 and the second fluorescent tube L2 according to this.Please refer to Fig. 5, when the brightness of the first fluorescent tube L1 during greater than the brightness of the second fluorescent tube L2, the direction of the second outside magnetic conduction subassembly 146 towards second secondary side coiling 134 moved, for example be that adjustment assembly 154 is unscrewed, then elastic parts 152 promotes the second outside magnetic conduction subassembly 146, makes the second outside magnetic conduction subassembly 146 move towards second secondary side coiling 134.Because the second outside magnetic conduction subassembly 146 is near second secondary side coiling 134, can increase the inductance value and the leakage inductance amount of second secondary side coiling 134, and the magnetic flux that strengthens can make the induced current by second secondary side coiling 134 increase, further the brightness of the blast second fluorescent tube L2 weakens the brightness of the first fluorescent tube L1.Similarly, when the brightness of the first fluorescent tube L1 during less than the brightness of the second fluorescent tube L2, the direction of the second outside magnetic conduction subassembly 146 towards first secondary side coiling 132 moved, for example be that adjustment assembly 154 is screwed, promote the second outside magnetic conduction subassembly 146 towards extruding elastic parts 152, make the second outside magnetic conduction subassembly 146 move towards first secondary side coiling 132.Because the second outside magnetic conduction subassembly 146 is near first secondary side coiling 132, can increase the inductance value and the leakage inductance amount of first secondary side coiling 132, and the magnetic flux that strengthens can make the induced current by first secondary side coiling 132 increase, further the brightness of the blast first fluorescent tube L1 weakens the brightness of the second fluorescent tube L2.The output current that utilizes such principle control fluorescent tube to be to reach good balance, the brightness of two fluorescent tubes of unification whereby.When lamp tube driver when driving the cold-cathode tube of LCD, can homogenizing source backlight, improve display quality.Further, adjusted balanced balanced current is in order to driving fluorescent tube, useful life that can prolonging lamp tube.

Embodiment two

The transformer difference of present embodiment and the foregoing description only is the opening of insulation shell, the material of the first outside magnetic conduction subassembly and the second outside magnetic conduction subassembly and first group of stitch and second group of stitch the position is set, remaining component is all identical, and label also continues to continue to use, and repeats no more in this.

Please refer to Fig. 7, it illustrates the perspective view according to the transformer of embodiments of the invention two.The insulation shell 310 of the transformer 300 of present embodiment is covered on first drum stand 320 and second drum stand 330 fully, yet at the end face of this not shown insulation shell 310, in order to reader's reference.In the transformer 300 of present embodiment, the spacing of first chamber 312 and second chamber 314 has dividing plate 318, and be opened on respectively insulation shell 310 about two sidewalls.First group of stitch 328 extends two ends from primary side coiling 122, and protrudes in the opening of first chamber 112.Second group of stitch 338 extends two ends from secondary side coiling 132, and protrudes in the opening of second chamber 114.Therefore, the creepage distance of first group of stitch 328 and second group of stitch 338 approximates the width of transformer 300, and the safe insulation distance more increases.

Moreover, the transformer of present embodiment also can comprise the first outside magnetic conduction subassembly and the second outside magnetic conduction subassembly (not shown in figure), be set up in parallel with first drum stand and second drum stand, and preferably MnZn material or nickel zinc material, when using nickel zinc material, have preferred resistance (greater than 1M ohm), can avoid the high voltage flash problem.

The transformer of the disclosed lamp tube driver of the above embodiment of the present invention, with the chamber opening of ccontaining drum stand in the opposite side of insulation shell, for example be the disclosed end face of embodiment and bottom surface, left side and right side, maximize the safe insulation distance of the stitch of coiling whereby, improve the safe in utilization of transformer, and enlarge the scope of application of transformer.In addition, transformer comprises that also outside magnetic conduction subassembly can be more guide the leakage number in the coiling outside return, and not only can reduce electromagnetic interference problem, more can increase total magnetic flux.Moreover when transformer application of the present invention during in lamp tube driver, its outside magnetic conduction subassembly can be used for adjusting lighting tube brightness.Especially when transformer drives two fluorescent tubes, the brightness that outside magnetic conduction subassembly can unification two fluorescent tubes makes brightness even, improves fluorescent tube useful life.

In sum; though the present invention with a preferred embodiment openly as above; right its is not in order to limit the present invention; any insider; without departing from the spirit and scope of the present invention; when can being used for a variety of modifications and variations, so protection scope of the present invention is as the criterion when looking claims person of defining.

Claims (20)

1. A transformer comprising: An insulating housing having a first chamber and a second chamber respectively opening on two opposite side walls of the insulating housing, and the first chamber is not communicated with the second chamber; a first bobbin, having a first through hole, disposed in the first chamber; One primary side winding, wound on the first winding frame; a second bobbin, having a second through hole, disposed in the second chamber; a secondary side winding, wound on the second winding frame; a first magnetic core embedded in the first through hole and the second through hole; and A second magnetic core is coupled to the first magnetic core and forms a magnetic circuit with the first magnetic core. 2 . The transformer according to claim 1 , wherein the first chamber has an opening, and the opening of the second chamber is located on the same side of the insulating case. 3 . 3. The transformer according to claim 2, further comprising: a first set of stitches extending from two ends of the primary winding and protruding from the opening; and A second group of stitches extends from two ends of the secondary winding and protrudes from the opening of the second chamber. 4. The transformer according to claim 2, wherein the insulating casing further comprises: A partition extends from the insulating housing between the first chamber and the second chamber. 5. The transformer according to claim 4, wherein the opening is far away from the separator. 6. The transformer according to claim 1, further comprising: a first set of stitches extending from two ends of the primary winding and protruding from the opening of the first cavity; and A second group of stitches extends from two ends of the secondary winding and protrudes from the opening of the second chamber. 7. The transformer according to claim 1, further comprising: Another secondary side winding is wound on the second winding frame and is separated from the secondary side winding by a predetermined distance. 8. The transformer according to claim 7, further comprising: a first external magnetically permeable component juxtaposed with the first bobbin; and A second external magnetic conduction component is paralleled with the second bobbin. the 9. The transformer according to claim 8, wherein the insulating housing further comprises a third chamber, the third chamber is arranged side by side with the second chamber, wherein the transformer further comprises: an elastic component, disposed on the insulating shell, is used to push one end of the second external magnetic conductive component; and an adjustment component, arranged on the insulating shell, and located at the other end of the second external magnetic conduction component; Wherein, the elastic component and the adjusting component are used to adjust the relative positions of the second external magnetic permeable component, the secondary winding and the other secondary winding. 10. A lamp driving device, comprising: a drive circuit for outputting an AC voltage; a first light tube; and A transformer is used to receive the AC voltage and drive the first lamp according to it, the transformer includes: An insulating housing having a first chamber and a second chamber respectively opening on two opposite side walls of the insulating housing, and the first chamber is not communicated with the second chamber; a first bobbin, having a first through hole, disposed in the first chamber; a second bobbin, having a second through hole, disposed in the second chamber; a first magnetic core embedded in the first through hole and the second through hole; a second magnetic core coupled to the first magnetic core and forming a magnetic circuit with the first magnetic core; a primary winding wire wound on the first winding frame and coupled to the drive circuit to receive the AC voltage; and A secondary winding wire is wound on the second winding frame and coupled to the first light tube to drive the first light tube. 11. The lamp driving device according to claim 10, wherein the second chamber has an opening, and the opening of the first chamber is located at the same side of the insulating housing. 12. The lamp driving device according to claim 11, further comprising: a first set of stitches extending from two ends of the primary winding and protruding from the opening of the first chamber; and A second group of stitches extends from two ends of the secondary winding and protrudes from the opening. 13. The lamp driving device according to claim 11, wherein the insulating housing further comprises: A partition extends from the insulating housing between the first chamber and the second chamber. the 14. The lamp driving device according to claim 13, wherein the opening is far away from the partition. 15. The lamp driving device according to claim 10, further comprising: a first set of stitches extending from two ends of the primary winding and protruding from the opening of the first cavity; and A second group of stitches extends from two ends of the secondary winding and protrudes from the opening of the first chamber. 16. The lamp driving device according to claim 10, further comprising: a second light tube; and Another secondary side winding is wound on the second winding frame, spaced a predetermined distance away from the secondary side winding, and coupled to the second light tube to drive the second light tube. ; 17. The lamp driving device according to claim 16, further comprising: a first external magnetically permeable component juxtaposed with the first bobbin; and A second external magnetic conduction component is paralleled with the second bobbin. 18. The lamp driving device according to claim 17, wherein the insulating housing further comprises a third chamber arranged in parallel with the second chamber, wherein the transformer further comprises: an elastic component, disposed on the insulating shell, is used to push one end of the second external magnetic conductive component; and an adjustment component, arranged on the insulating shell, and located at the other end of the second external magnetic conduction component; Wherein, the elastic component and the adjusting component are used to adjust the relative positions of the second external magnetic permeable component, the secondary winding and the other secondary winding. 19. A method for adjusting the brightness of a lamp tube, comprising the following steps: Provide a transformer, a first lamp tube and a second lamp tube, the transformer includes: An insulating housing has a first chamber and a second chamber, the first chamber and the second chamber are respectively opened on two opposite side walls of the insulating housing, and the first chamber and the second chamber are The two chambers are not connected; a first bobbin, having a first through hole, disposed in the first chamber; a second bobbin, having a second through hole, disposed in the second chamber; a first magnetic core embedded in the first through hole and the second through hole; a second magnetic core coupled to the first magnetic core and forming a magnetic circuit with the first magnetic core; One primary side winding, wound on the first winding frame; a first secondary winding, wound on the second winding frame, and coupled to the first lamp tube; A second secondary side winding, wound on the second winding frame, spaced a predetermined distance from the first secondary side winding, and coupled to the second lamp tube; a first external magnetically permeable component juxtaposed with the first bobbin; and A second external magnetically conductive component, juxtaposed with the second winding frame; providing a driving circuit for outputting an AC voltage to the primary winding to drive the first lamp and the second lamp; and Adjust the position of the second external magnetic conduction component, and accordingly adjust the brightness of the first lamp tube and the second lamp tube. 20. The method for adjusting the brightness of the lamp tube according to claim 19, wherein the method for adjusting the brightness of the first lamp tube and the second lamp tube comprises: When the brightness of the first lamp tube is greater than the brightness of the second lamp tube, moving the second external magnetic conductive component toward the direction of the second secondary side winding; and When the brightness of the first lamp tube is lower than the brightness of the second lamp tube, the second external magnetic conduction component is moved toward the direction of the first secondary side winding. the

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