CN100489606C - Tube driving circuit - Google Patents
Tube driving circuit Download PDFInfo
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- CN100489606C CN100489606C CNB2005100912959A CN200510091295A CN100489606C CN 100489606 C CN100489606 C CN 100489606C CN B2005100912959 A CNB2005100912959 A CN B2005100912959A CN 200510091295 A CN200510091295 A CN 200510091295A CN 100489606 C CN100489606 C CN 100489606C
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Abstract
This invention relates to tube driven circuit, which is used to drive multiple lamp tube, wherein, the multi-lamp tube is used to aphototropism parts; the aphotoropism parts are to provide LCD to display the needed light source; the tube is connected to one coil with same coils number and magnetic circuit to allow these tube achieve balance.
Description
Technical field
The relevant a kind of LCD of the present invention, and particularly relevant a kind of lamp tube drive circuit that allows lamp tube current balance.
Background technology
The normal framework that uses one group of driving circuit 100 to drive a fluorescent tube of LCD.This fluorescent tube is used for the backlight liquid crystal display assembly, required light source when the liquid crystal display displays image to be provided.As shown in Figure 1, it is the synoptic diagram of traditional tube driving circuit.One group of driving circuit 100 comprises direct supply DC, change-over switch 102 and transformer 104.Change-over switch 102 switches to alternating voltage to transformer 104 in order to the DC voltage that direct supply DC is exported, and drives the required alternating voltage position standard of fluorescent tube 106 so that transformer 104 produces according to this.
But along with the size of LCD constantly increases, for example large-sized LCD TV, the required brightness that provides of its backlight assembly also must increase thereupon, just can keep the image quality of picture.So in order to improve the luminosity of backlight assembly, except the fluorescent tube that uses longer dimension, just also must be by using many fluorescent tubes can reach required brightness.
Therefore drive the many costs that fluorescent tube is required in order to reduce, traditional practice often is to allow above-mentioned one group of driving circuit 100 drive the mode of many fluorescent tubes.For example shown in Figure 2, it is another routine synoptic diagram of traditional tube driving circuit.By allowing many fluorescent tubes 106 (1)～106 (N) electrically connect in parallel each other reducing the usage quantity of transformer 104 and change-over switch 102, and then reach the purpose that reduces cost, N is a positive integer.
Yet, though the above-mentioned practice can reduce cost, being subject to the characteristic of fluorescent tube 106 itself, i.e. every fluorescent tube 106 impedance to each other is all inequality, and the electric current that makes every fluorescent tube 106 be flow through is all inequality.Such result will cause the luminosity of every fluorescent tube 106 inequality, and then cause the brightness irregularities of backlight assembly and allow the shown image quality of LCD reduce.So how to solve when driving many fluorescent tubes, the problem of carrying cost and current imbalance is the problem that industry is badly in need of solution.
Summary of the invention
In view of this, the objective of the invention is is providing a kind of lamp tube drive circuit, in order to drive many fluorescent tubes and to allow these lamp tube current of flowing through reach balance.So, it is more even to make that backlight assembly offers the light source of display panels, and fluorescent tube electric current is to each other reached balance and more will be made the longer service life of fluorescent tube.
According to purpose of the present invention, a kind of lamp tube drive circuit is proposed, in order to drive one first fluorescent tube and one second fluorescent tube.This lamp tube drive circuit comprises power supply circuit and at least one balancing circuitry.Power supply circuit provides an alternating voltage.Balancing circuitry is in order to receive alternating voltage and to drive first fluorescent tube and second fluorescent tube.Balancing circuitry comprises first winding and second winding at least.One end of first winding is in order to receive alternating voltage.The other end of first winding is exported first electric current to the first fluorescent tube.One end of second winding is in order to receive alternating voltage, and the other end of second winding is exported second electric current to the second fluorescent tube.The cross-pressure of first winding corresponds to the cross-pressure of second winding.
For the present invention's above-mentioned purpose, characteristics and advantage can be become apparent, a preferred embodiment cited below particularly, and cooperate institute's accompanying drawing to be elaborated:
Description of drawings
Fig. 1 is the synoptic diagram of traditional tube driving circuit.
Fig. 2 is another routine synoptic diagram of traditional tube driving circuit.
Fig. 3 is the synoptic diagram of LCD.
Fig. 4 A is the synoptic diagram of an example of the lamp tube drive circuit of first embodiment of the invention.
Fig. 4 B is another routine synoptic diagram of the lamp tube drive circuit of first embodiment of the invention.
Fig. 5 is the synoptic diagram of an example of balancing circuitry.
Fig. 6 is the synoptic diagram of second example of balancing circuitry.
Fig. 7 is the synoptic diagram of the 3rd example of balancing circuitry.
Fig. 8 is the synoptic diagram of the 4th example of balancing circuitry.
Fig. 9 is the synoptic diagram of the 5th example of balancing circuitry.
Figure 10 is the synoptic diagram of the 6th example of balancing circuitry.
Figure 11 is disposed at the synoptic diagram of an example of lamp tube drive circuit for feedback circuit.
Figure 12 is the synoptic diagram of the lamp tube drive circuit of second embodiment of the invention.
Figure 13 is the synoptic diagram of an example of balancing circuitry.
Figure 14 is the synoptic diagram of second example of balancing circuitry.
Figure 15 is the synoptic diagram of the 3rd example of balancing circuitry.
Figure 16 is the synoptic diagram of the 4th example of balancing circuitry.
Figure 17 is the synoptic diagram of the 5th example of balancing circuitry.
Figure 18 is the synoptic diagram of the 6th example of balancing circuitry.
Figure 19 is the synoptic diagram of the 7th example of balancing circuitry.
Figure 20 is the synoptic diagram of the 8th example of balancing circuitry.
Figure 21 is the synoptic diagram of the 9th example of balancing circuitry.
Figure 22 is the synoptic diagram of the tenth example of balancing circuitry.
Figure 23 is disposed at the synoptic diagram of an example of lamp tube drive circuit for feedback circuit.
Embodiment
The invention provides a kind of lamp tube drive circuit, in order to drive many fluorescent tubes.Many fluorescent tubes are used for backlight assembly.Backlight assembly required light source when the liquid crystal display displays image to be provided.By allowing these fluorescent tubes electrically connect with a coil (coil) respectively, these coils have identical coiling number each other and have identical magnetic circuit, to allow these lamp tube current of flowing through reach balance.So, it is more even to make that backlight assembly offers the light source of display panels, and fluorescent tube electric current is to each other reached balance and more will be made more prolong the serviceable life of fluorescent tube.
Please refer to Fig. 3, it is the synoptic diagram of LCD.LCD 200 comprises lamp tube drive circuit 202 and backlight assembly 204.Lamp tube drive circuit 202 is in order to drive many fluorescent tubes 206 (1)～206 (N), and N is a positive integer.Many fluorescent tubes 206 (1)～206 (N) are used for backlight assembly 204, use so that backlight assembly 204 provides LCD 200 show images required light source.Lamp tube drive circuit 202 for example comprises power supply circuit 208 and balancing circuitry 210.Power supply circuit 208 is in order to provide an alternating voltage AC.Balancing circuitry 210 is in order to receiving this alternating voltage AC and drive many fluorescent tubes 206 (1)～206 (N) according to this, and allows the flow through electric current of these fluorescent tubes 206 (1)～206 (N) keep balance.Below be that the present invention is described further with two embodiment.
First embodiment
To drive two fluorescent tubes, promptly first fluorescent tube 206 (1) is done explanation with 206 (2) and balancing circuitrys 210 of second fluorescent tube for example.Please refer to Fig. 4 A, it is the synoptic diagram of an example of the lamp tube drive circuit 202 of first embodiment of the invention.Power supply circuit 208 for example comprises transformer TS, direct supply DC and change-over switch 212.Transformer TS has a first siding ring P and a second siding ring S.The alternating voltage AC1 that is provided from LCD 200 for example is provided first siding ring P.Change-over switch 212 switches to alternating voltage AC1 to transformer TS in order to the DC voltage that direct supply DC is exported, so that producing according to this, transformer TS drives first fluorescent tube 206 (1) the alternating voltage position standard required, i.e. alternating voltage AC2 with second fluorescent tube 206 (2).Wherein, the alternating voltage AC1 that transformer TS is received also can be directly by civil power except can producing by above-mentioned direct supply DC and change-over switch 212, and for example AC110 converts required alternating voltage AC1 to through energy converter provides.Why do not drive first fluorescent tube 206 (1) the alternating voltage position standard (alternating voltage AC2) required in the received alternating voltage AC1 of limiting transformer TS source in present embodiment with second fluorescent tube 206 (2) as long as can produce according to this.
Please refer to Fig. 5, it is the synoptic diagram of an example of balancing circuitry 210.With the framework shown in Fig. 4 A is example.Balancing circuitry 210 comprises the first winding coil (1) and the second winding coil (2).The end of the first winding coil (1) is in order to receive alternating voltage AC2, and its other end is exported first electric current I, 1 to first fluorescent tube 206 (1).The end of the second winding coil (2) is in order to receive alternating voltage AC2, and its other end is exported second electric current I, 2 to second fluorescent tubes 206 (2).The first winding coil (1) and the second winding coil (2) curl up jointly on same core unshakable in one's determination (1), and the first winding coil (1) has identical in fact coiling number with the second winding coil (2).So the cross-pressure of the first winding coil (1) corresponds to the cross-pressure of the second winding coil (2), promptly allow drive current I1 and I2 much at one by the first winding coil (1) the magnetic circuit mode identical with the second winding coil (2) induction.So, the luminosity that can make first fluorescent tube 206 (1) and second fluorescent tube 206 (2) finally allows the luminosity of backlight assembly more even much at one.And electric current I 1 reaches balance with I2 more will make more prolong the serviceable life of fluorescent tube 206 (1) and 206 (2).
In addition, the first winding coil (1) and the second winding coil (2) also can relend the mode that helps impedance matching and reach better counterbalance effect.Please refer to Fig. 6, it is the synoptic diagram of second example of balancing circuitry 210.Balancing circuitry 210 also comprises coupling inductance L, first capacitor C 1 and second capacitor C 2.The other end of the first winding coil (1) couples an end of inductance L via the first capacitor C l.The other end of the second winding coil (2) couples the other end of inductance L via second capacitor C 2.That is to say that balancing circuitry 210 also can be by the resistance value of selecting suitable inductance L and capacitor C 1, C2, to reach better current balance type effect.
Please refer to Fig. 7, it is the synoptic diagram of the 3rd example of balancing circuitry 210.Similarly, be to be example with the framework shown in Fig. 4 A.Balancing circuitry 210 also comprises second core unshakable in one's determination (2), tertiary winding coil (3) and the 4th winding coil (4).The first winding coil (1), the second winding coil (2), tertiary winding coil (3) are all identical with the coil turn of the 4th winding coil (4).The tertiary winding coil (3) and the first winding coil (1) are around on first core unshakable in one's determination (1) together.And tertiary winding coil (3) forms a loop with the 4th winding coil (4).The 4th winding coil (4) and the second winding coil (2) are around on second core unshakable in one's determination (2) together.By being total to magnetic circuit, promptly the first winding coil (1) and the second winding coil (1) make the first winding coil (1) sense identical voltage with tertiary winding coil (3) by being total to magnetic circuit equally.And tertiary winding coil (3) forms same loop and has identical coil turn with the 4th winding coil (4), so tertiary winding coil (3) has identical cross-pressure with the 4th winding coil (4).The second last winding coil (2) and the 4th winding coil (4) also by being total to magnetic circuit, make the second winding coil (2) sense identical voltage with the 4th winding coil (4).Finally, first electric current I 1 and second electric current I 2 will be reached balance automatically.
In like manner, please refer to Fig. 8 again, it is the synoptic diagram of the 4th example of balancing circuitry 210.Change with a balancing circuitry 210 and drive three fluorescent tubes.Balancing circuitry 210 also comprises second core unshakable in one's determination (2), the 3rd core unshakable in one's determination (3), tertiary winding coil (3), the 4th winding coil (4), the 5th winding coil (5) and the 6th winding coil (6).Tertiary winding coil (3), the 4th winding coil (4), the 5th winding coil (5) are all identical with the coil turn of the 6th winding coil (6).The tertiary winding coil (3) and the first winding coil (1) are around on first core unshakable in one's determination (1) together.The 4th winding coil (4) and the 5th winding coil (5) are around on second core unshakable in one's determination (2) together.The second winding coil (2) and the 6th winding coil (6) are around on the 3rd core unshakable in one's determination (3) together.Tertiary winding coil (3), the 5th winding coil (5) and the 6th winding coil (6) form a loop.The end of the first winding coil (1), the second winding coil (2) and the 4th winding coil (1) is all in order to receive the second alternating voltage AC2, and its other end is exported first electric current I 1, second electric current I 2 and the 3rd electric current I 3 respectively.As the described principle to Fig. 7, first electric current I 1, second electric current I 2 and the 3rd electric current I 3 will be reached balance automatically.So far, in sum under the capacity permission of transformer TS, balancing circuitry 210 can drive the fluorescent tube 206 more than three, that is to say, by allowing corresponding with the one separately winding coil of every fluorescent tube 206 (for example first winding coil (1) among Fig. 8, the second winding coil (2) and the 4th winding coil (4)) connect.And these corresponding winding coil (1), coil (2) and coil (4) all curl up in same core unshakable in one's determination with a corresponding winding coil (for example tertiary winding coil (3) among Fig. 8, the 5th winding coil (5) and the 6th winding coil (6)) separately and go up and allow these windings coil (3), coil (5) and coil (6) form a loop, finally allow the flow through electric current of these fluorescent tubes 206 reach balance.
And between the output terminal of balancing circuitry 210, but cross-over connection one electric capacity more, to reach better current balance type effect.As shown in Figure 9, it is the synoptic diagram of the 5th example of balancing circuitry 210.Fig. 9 system is an example with framework shown in Figure 7, and balancing circuitry 210 also comprises the 3rd capacitor C 3.3 cross-over connections of the 3rd capacitor C are in the output terminal of balancing circuitry 210.Perhaps, please refer to Figure 10, it is the synoptic diagram of the 6th example of balancing circuitry 210.Figure 10 is to be example with framework shown in Figure 8, and balancing circuitry 210 also comprises the 4th capacitor C 4 and the 5th capacitor C 5.4 cross-over connections of the 4th capacitor C are between the input end of fluorescent tube 206 (1) and 206 (2).5 cross-over connections of the 5th capacitor C are between the input end of fluorescent tube 206 (2) and 206 (3).In addition, above-mentioned capacitor C 3, C4 and C5 all can be divided into two electric capacity separately, and for example the 3rd capacitor C 3 is divided into capacitor C 3 (1) and C3 (2).And capacitor C 4 (1), C4 (2), C5 (1) couple corresponding output terminal respectively with the end of C5 (2), and its other end is coupled to ground voltage respectively.
Then, in the feedback aspect.Above-mentioned lamp tube drive circuit 202 also comprises a feedback circuit 214.Feedback circuit 214 is in order to according to driving the required electric signal of fluorescent tube 206 to export a feedback signal (FeedbackSignal) FSi.Lamp tube drive circuit 202 is according to the work period of this feedback signal FSi adjustment change-over switch 212, so that fluorescent tube 206 reaches desired brightness and keeps stable.Please refer to Figure 11, it is the synoptic diagram of an example that is disposed at lamp tube drive circuit of feedback circuit.Because in the above-mentioned balancing circuitry 210, partly winding coil forms a loop, for example from then on the disclosed structure of Fig. 7 and Fig. 8 obtains required electric signal to be converted to feedback signal FSi in the loop.For example feedback circuit 214 can be from tertiary winding coil (3) and the formed loop of the 4th winding coil (4), obtain required electric signal, be the voltage difference between tertiary winding coil (3) and the 4th winding coil (4), to export corresponding feedback signal FSi to reach above-mentioned purpose.Feedback circuit 214 comprises a complete/half-wave rectifying circuit 216 and a wave filter 218.Entirely/half-wave rectifying circuit 216 is in order to will exporting wave filter 218 to after the above-mentioned voltage difference rectification, so that wave filter 218 according to this behind the filtering noise, is thought feedback signal FSi.
Then, please refer to Fig. 4 B, it is another routine synoptic diagram of the lamp tube drive circuit 202 of first embodiment of the invention.It is that example is done explanation that an above-mentioned homogeneous balancing circuitry 210 drives many fluorescent tubes.So, lamp tube drive circuit 202 also comprises another balancing circuitry, i.e. first balancing circuitry 210 (1) and one second balancing circuitry 210 (2) originally.First balancing circuitry 210 (1) all can be the structure shown in above-mentioned Fig. 5～10 with second balancing circuitry 210 (2).The fluorescent tube quantity of each balancing circuitry 210 each self-driven correspondence, Fig. 4 B is to be example with balancing circuitry shown in Figure 8 210 frameworks.One set drive, promptly lamp tube drive circuit 202, just can once drive the problem that six roots of sensation fluorescent tube 206 (1)～206 (N) also solves current imbalance simultaneously, drive the many costs that fluorescent tube is required to reach to reduce.
Wherein, what need pay special attention to is, in winding impedance aspect.There is certain corresponding relation to exist between each winding coil and tube impedance.When learning the winding impedance much larger than tube impedance from experiment, its counterbalance effect is good more.But consider that the winding impedance is big more, its empty wasted work rate of institute is also just big more.So the winding impedance is greater than 1/5 of tube impedance at least, just can reach certain current balance type effect.
Second embodiment
Be different from first embodiment, the framework of balancing circuitry changes the both-end input in second embodiment, promptly has two input ends, the first input end IN (1) and the second input end IN (2).Please refer to Figure 12, it is the synoptic diagram of the lamp tube drive circuit 202 ' of second embodiment of the invention.LCD 200 ' is as above-mentioned lamp tube drive circuit 202 ' and the backlight assembly 204 ' of comprising.Lamp tube drive circuit 202 ' has also comprised power supply circuit 208 ' and balancing circuitry 210 '.What need pay special attention to is, power supply circuit 208 ' comprises two first siding ring P1 and P2 and two second siding ring S1 and S2.Two first siding ring P1 and P2 all receive the first alternating voltage AC1 '.The first alternating voltage AC1 ' is as first embodiment, and producing or directly convert required alternating voltage by civil power AC110 volt to through energy converter by direct supply and change-over switch provides.Direct supply and change-over switch just no longer are illustrated on the figure in this.Two second siding ring S1 are connected with the serial connection pattern with S2, its common contact place can receive ground voltage (GND) or suspension joint (floating), the common contact place of second siding ring S1 for example shown in Figure 12 and S2 is coupled to ground voltage, uses so that the voltage same polarity of the first input end IN (1) and the second input end IN (2).Second siding ring S1 is in parallel with a capacitor C T1, CT2 respectively with the two ends of S2, and promptly the two ends of second siding ring S1 are in parallel with capacitor C T1, and the two ends of second siding ring S2 are in parallel with capacitor C T2.Two second siding ring S1 and S2 export the second alternating voltage AC2 ' (1) and AC2 ' (2) the two input end IN (1) and IN (2) to balancing circuitry 210 ' respectively.Balancing circuitry 210 ' is in order to receiving the second alternating voltage AC2 ' (1) and AC2 ' (2) and drive many fluorescent tubes 206 (1)～206 (N) according to this, and allows the flow through electric current of these fluorescent tubes 206 (1)～206 (N) keep balance, and N is positive integer.
At first, earlier to drive two fluorescent tubes, promptly first fluorescent tube 206 (1) is done explanation with the situation of second fluorescent tube 206 (2).Please refer to Figure 13, it is the synoptic diagram of an example of balancing circuitry 210 '.Balancing circuitry 210 ' comprises the first winding coil ' (1) and the second winding coil ' (2).The end of the first winding coil ' (1) (first input end IN (1)) is in order to receive alternating voltage AC2 ' (1), and its other end is exported first electric current I 1 ' to first fluorescent tube 206 (1).The end of the second winding coil ' (2) (first input end IN (2)) is in order to receive alternating voltage AC2 ' (2), and its other end is exported second electric current I 2 ' to second fluorescent tube 206 (2).The first winding coil ' (1) and the second winding coil ' (2) curl up jointly on core ' unshakable in one's determination (1), and the first winding coil ' (1) has identical coiling number with the second winding coil ' (2).As above-mentioned equilibrium principle, the luminosity that can make win fluorescent tube 206 (1) and second fluorescent tube 206 (2) finally allows the luminosity of backlight assembly more even much at one.And electric current I 1 ' and I2 ' reach balance more will make more prolong the serviceable life of the win fluorescent tube 206 (1) and second fluorescent tube 206 (2).
Wherein, but cross-over connection one capacitor C 3 ' also between two output terminals of balancing circuitry 210 ' shown in Figure 13, to reach better current balance type effect.Please refer to Figure 14, it is the synoptic diagram of second example of balancing circuitry 210 '.Perhaps, please refer to Figure 15, it is the synoptic diagram of the 3rd example of balancing circuitry 210 '.Capacitor C 3 ' between two output terminals of balancing circuitry 210 ' also can be divided into two electric capacity, for example capacitor C 3 ' (1) and capacitor C 3 ' (2), capacitor C 3 ' (1) is coupled to corresponding output terminal respectively with an end of capacitor C 3 ' (2), and its other end all is coupled to ground voltage.
In addition, as first embodiment, the first winding coil ' (1) also can relend the mode that helps impedance matching with the second winding coil ' (2) and reach better current balance type effect.Please refer to Figure 16, it is the synoptic diagram of the 4th example of balancing circuitry 210 '.Balancing circuitry 210 ' also comprises inductance L ', first capacitor C 1 ' and second capacitor C 2 '.The other end of the first winding coil ' (1) couples inductance L via first capacitor C 1 ' ' an end.The other end of the second winding coil ' (2) couples inductance L via second capacitor C 2 ' ' the other end.Balancing circuitry 210 ' is in inductance L ' two ends export first electric current I 1 and second electric current I 2 respectively.
Please refer to Figure 17, it is the synoptic diagram of the 5th example of balancing circuitry 210 '.Similarly, be example with the framework that drives two fluorescent tubes.Balancing circuitry 210 ' also comprises second core ' unshakable in one's determination (2), tertiary winding coil ' (3) and the 4th winding coil ' (4).The first winding coil ' (1), the second winding coil ' (2), tertiary winding coil ' (3) are all identical with the coil turn of the 4th winding coil ' (4).The tertiary winding coil ' (3) and the first winding coil ' (1) are around on first core ' unshakable in one's determination (1) together.And tertiary winding coil ' (3) forms a loop with the 4th winding coil ' (4).The 4th winding coil ' (4) and the second winding coil ' (2) are around on second core unshakable in one's determination (2) together.By being total to magnetic circuit, promptly the first winding coil ' (1) and the second winding coil ' (1) make the first winding coil ' (1) sense identical voltage with tertiary winding coil ' (3) by being total to magnetic circuit equally.And tertiary winding coil ' (3) forms same loop and has identical coil turn with the 4th winding coil ' (4), so tertiary winding coil ' (3) has identical cross-pressure with the 4th winding coil ' (4).The second last winding coil ' (2) and the 4th winding coil ' (4) also by being total to magnetic circuit, make the second winding coil ' (2) sense identical voltage with the 4th winding coil ' (4).Finally, make the first winding coil ' (1) export first electric current I 1 ' of first fluorescent tube 206 (1) to and second electric current I 2 that the second winding coil ' (2) exports first fluorescent tube 206 (2) to will be reached balance automatically.
Under framework shown in Figure 17, the output terminal of balancing circuitry 210 ' also can be as above-mentioned cross-over connection one capacitor C 3 ' ', as shown in figure 18, it is the synoptic diagram of the 6th example of balancing circuitry 210 '.Balancing circuitry 210 ' also comprises a capacitor C 3 ' '.Perhaps, capacitor C 3 ' ' also can be divided into two capacitor C 3 ' ' (1) and C3 ' ' (2), as shown in figure 19, it is the synoptic diagram of the 7th example of balancing circuitry 210 '.These two capacitor C 3 ' ' (1) is coupled to corresponding output terminal respectively with the end of C3 ' ' (2), and its other end all is coupled to ground voltage.
Then, again to drive four fluorescent tubes, promptly first fluorescent tube 206 (1), second fluorescent tube 206 (2), the 3rd fluorescent tube 206 (3) are done explanation with the situation of the 4th fluorescent tube 206 (4).Please refer to Figure 20, it is the synoptic diagram of the 8th example of balancing circuitry 210 '.Balancing circuitry 210 ' also comprises 4 core ' unshakable in one's determination and 8 winding coil '.4 core ' unshakable in one's determination are respectively: the first above-mentioned core ' unshakable in one's determination (1), second core ' unshakable in one's determination (2), the 3rd core ' unshakable in one's determination (3) and four-limbed core ' (4).8 winding coil ' are respectively: the first above-mentioned winding coil ' (1) and the second winding coil ' (2), and tertiary winding coil ' (3), the 4th winding coil ' (4), the 5th winding coil ' (5), the 6th winding coil ' (6), the 7th winding coil ' (7) and the 8th winding coil ' (8).The coil turn of winding coil ' (1)～winding coil ' (8) is all identical.And, the first winding coil ' (1) and tertiary winding coil ' (3) are around on first core ' unshakable in one's determination (1) together, the 4th winding coil ' (4) and the 5th winding coil ' (5) are around on second core ' unshakable in one's determination (2) together, the 6th winding coil ' (6) and the second winding coil ' (2) are around on the 3rd core ' unshakable in one's determination (3) together, and the 7th winding coil ' (7) and the 8th winding coil ' (8) are around on the four-limbed core ' (4) together.The first winding coil ' (1) and the 8th winding coil ' (8) form a loop.The 5th winding coil ' (5) and the 6th winding coil ' (6) form another loop.
The first winding coil ' (1) receives the second alternating voltage AC2 (1) with the termination of the 4th winding coil ' (4), and its other end is exported first electric current I 1 ' and the 3rd electric current I 3 ' respectively.First electric current I 1 ' is in order to drive first fluorescent tube 206 (1).The 3rd electric current I 3 ' is in order to drive the 3rd fluorescent tube 206 (3).The second winding coil ' (2) receives the second alternating voltage AC2 (2) with the termination of the 7th winding coil ' (7), and its other end is exported second electric current I 2 ' and the 4th electric current I 4 ' respectively.Second electric current I 2 is in order to drive second fluorescent tube 206 (2).The 4th electric current I 4 ' is in order to drive the 4th fluorescent tube 206 (4).By above-mentioned framework, but with the electric current I 1～I4 of four fluorescent tubes 206 of balance.
Wherein, also can distinguish cross-over connection one electric capacity between the output terminal of balancing circuitry 210 '.For example shown in Figure 21, it is the synoptic diagram of the 9th example of balancing circuitry 210 '.Be cross-over connection one capacitor C 4 ' between two output terminals of balancing circuitry 210 ' output current I1 ' and I3 ', and two another capacitor C 5 ' of output terminal cross-over connection of balancing circuitry 210 ' output current I2 ' and I4 '.Perhaps, as shown in figure 22, it is the synoptic diagram of the tenth example of balancing circuitry 210 '.Capacitor C 4 ' and C5 ' are respectively to being divided into two electric capacity.For example capacitor C 4 ' is divided into two capacitor C 4 ' (1) and C4 ' (2), and capacitor C 4 ' (1) is coupled to corresponding output terminal respectively with the end of C4 ' (2), and its other end all is coupled to ground voltage.In like manner, capacitor C 5 ' also can be taked this way.By cross-over connection one electric capacity between the output terminal of balancing circuitry 210 ', can reach better current balance type effect.
Then, in the feedback aspect of circuit.Please refer to Figure 23, it is the synoptic diagram of an example that is disposed at lamp tube drive circuit 202 ' of feedback circuit.Lamp tube drive circuit 202 ' also comprises a feedback circuit 214 '.As above-mentioned, feedback circuit 214 ' is in order to according to driving the required electric signal of fluorescent tube 206 to export a feedback signal (Feedback Signal) FSi '.Lamp tube drive circuit 202 ' is according to the work period of this feedback signal FSi adjustment change-over switch 212, so that fluorescent tube 206 reaches desired brightness and keeps stable.Because in the above-mentioned balancing circuitry 210 ', partly winding coil ' forms a loop, for example all forms at least one loop in the disclosed structure of Figure 17 to Figure 20.From these loops, obtain required electric signal to be converted to feedback signal FSi '.For example shown in Figure 23, feedback circuit 214 ' can be from the tertiary winding coil ' (3) and the formed loop of the 4th winding coil ' (4) of Figure 17, obtain required electric signal, be the voltage difference between tertiary winding coil ' (3) and the 4th winding coil ' (4), to export corresponding feedback signal FSi ' to reach above-mentioned purpose.
Wherein, what need pay special attention to is, described as the first embodiment final stage.In winding impedance aspect.There is certain corresponding relation to exist between each winding coil and tube impedance.When learning the winding impedance much larger than tube impedance from experiment, its counterbalance effect is good more.But consider that the winding impedance is big more, its empty wasted work rate of institute is also just big more.So the winding impedance is greater than 1/5 of tube impedance at least, just can reach certain current balance type effect.
The disclosed lamp tube drive circuit of the above embodiment of the present invention, no matter balancing circuitry is single-ended or both-end input or be which kind of pattern in order to the transformer of lifting/voltage reducing transformer, for example transformer can or form a transformer by a plurality of transformers connected in parallel equivalences for one, electrically connect (series connection) with a coil (coil) respectively by a plurality of fluorescent tubes that allow desire drive, and these coils has identical coiling number and has identical magnetic circuit to allow these lamp tube current of flowing through reach balance.So, it is more even to make that backlight assembly offers the light source of display panels, and fluorescent tube electric current is to each other reached balance and more will be made the longer service life of fluorescent tube.
In sum; though the present invention discloses as above with many preferred embodiments; yet it is not in order to limit the present invention; any person skilled in the art person; without departing from the spirit and scope of the present invention; when the variation that can do various equivalences or replacement, so protection scope of the present invention is when looking accompanying being as the criterion that the application's claim scope defined.
Claims (31)
1. lamp tube drive circuit, in order to drive one first fluorescent tube and one second fluorescent tube, this lamp tube drive circuit comprises:
One power supply circuit is in order to provide an alternating voltage; And
At least one balancing circuitry, in order to receive this alternating voltage and to drive this first fluorescent tube and this second fluorescent tube according to this, this balancing circuitry comprises at least:
One first winding, an end of this first winding is in order to receive this alternating voltage, and the other end of this first winding is exported one first electric current to this first fluorescent tube; And
One second winding, an end of this second winding is in order to receive this alternating voltage, and the other end of this second winding is exported one second electric current to this second fluorescent tube;
Wherein, the cross-pressure of this first winding corresponds to the cross-pressure of this second winding.
2. lamp tube drive circuit as claimed in claim 1 is characterized in that, this balancing circuitry also comprises:
One iron core, this first winding and this second winding all are around on this iron core, and the coil turn of this first winding equals the coil turn of this second winding.
3. lamp tube drive circuit as claimed in claim 2 is characterized in that, the impedance of this first winding is corresponding to the impedance of this first fluorescent tube, and the impedance of this second winding is corresponding to the impedance of this second fluorescent tube.
4. lamp tube drive circuit as claimed in claim 2 is characterized in that, this balancing circuitry also comprises:
One first inductance;
One first electric capacity, the other end of this first winding couple an end of this first inductance via this first electric capacity; And
One second electric capacity, the other end of this second winding couple the other end of this first inductance via this second electric capacity.
5. lamp tube drive circuit as claimed in claim 1 is characterized in that the coil turn of this first winding equals the coil turn of this second winding, and this balancing circuitry also comprises:
One first iron core;
One second iron core;
One tertiary winding, the coil turn of this tertiary winding equals the coil turn of this first winding, and this tertiary winding and this first winding are with being around on this first iron core; And
One the 4th winding, this tertiary winding and the 4th winding form a loop, and the coil turn of the 4th winding equals the coil turn of this first winding, and the 4th winding and this second winding are with being around on this second iron core.
6. lamp tube drive circuit as claimed in claim 5 is characterized in that, this balancing circuitry also comprises:
One electric capacity is coupled between the other end of the other end of this first winding and this second winding.
7. lamp tube drive circuit as claimed in claim 5 is characterized in that, this balancing circuitry also comprises:
One first electric capacity, the other end of this first winding is coupled to a fixed voltage via this first electric capacity; And
One second electric capacity, the other end of this second winding is coupled to this fixed voltage via this second electric capacity.
8. lamp tube drive circuit as claimed in claim 5 is characterized in that also comprising:
One feedback circuit is exported a feedback signal according to the voltage difference between an end of end of this tertiary winding and the 4th winding;
Wherein, this power supply circuit is exported this alternating voltage according to this feedback signal.
9. lamp tube drive circuit as claimed in claim 8 is characterized in that, this feedback circuit comprises:
One full-wave rectifying circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
10. lamp tube drive circuit as claimed in claim 8 is characterized in that, this feedback circuit comprises:
One half-wave rectification circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
11. lamp tube drive circuit as claimed in claim 1 is characterized in that also in order to drive one the 3rd fluorescent tube, this balancing circuitry also comprises:
One first iron core;
One second iron core;
One the 3rd iron core;
One tertiary winding, the coil turn of this tertiary winding equals the coil turn of this first winding, and this tertiary winding and this first winding are with being around on this first iron core;
One the 4th winding, an end of the 4th winding is in order to receive this alternating voltage, and the other end of the 4th winding is exported one the 3rd electric current to the 3rd fluorescent tube, and the coil turn of the 4th winding equals the coil turn of this first winding;
One the 5th winding, the coil turn of the 5th winding equals the coil turn of the 4th winding, and the 5th winding and the 4th winding are with being around on this second iron core; And
One the 6th winding, the coil turn of the 6th winding equals the coil turn of this second winding, and the 6th winding and this second winding are with being around in this three-iron in the heart;
Wherein, this tertiary winding, the 5th winding and the 6th winding form a loop, and the coil turn of this first winding equals the coil turn of this second winding in fact.
12. lamp tube drive circuit as claimed in claim 11 is characterized in that, this balancing circuitry also comprises:
One first electric capacity is coupled to the other end of this first winding and the other end of the 4th winding; And
One second electric capacity is coupled to the other end of the 4th winding and the other end of this second winding.
13. lamp tube drive circuit as claimed in claim 11 also comprises:
One feedback circuit is exported a feedback signal according to the voltage difference between an end of end of this tertiary winding and the 6th winding;
Wherein, this power supply circuit is exported this alternating voltage according to this feedback signal.
14. lamp tube drive circuit as claimed in claim 13 is characterized in that, this feedback circuit comprises:
One full-wave rectifying circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
15. lamp tube drive circuit as claimed in claim 13 is characterized in that, this feedback circuit comprises:
One half-wave rectification circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
16. lamp tube drive circuit as claimed in claim 1, it is characterized in that, this alternating voltage also comprises one first alternating voltage and one second alternating voltage, one end of this first winding is in order to receive this first alternating voltage, to export this first electric current in the other end of this first winding to this first fluorescent tube, one end of this second winding is in order to receive this second alternating voltage, to export this second electric current in the other end of this second winding to this second fluorescent tube.
17. lamp tube drive circuit as claimed in claim 16 is characterized in that, this balancing circuitry also comprises: an iron core, and this first winding and this second winding are around in on this iron core, and the coil turn of this first winding equals the coil turn of this second winding.
18. lamp tube drive circuit as claimed in claim 17 is characterized in that, the impedance of this first winding is corresponding to the impedance of this first fluorescent tube, and the impedance of this second winding is corresponding to the impedance of this second fluorescent tube.
19. lamp tube drive circuit as claimed in claim 17 is characterized in that, this balancing circuitry also comprises:
One first inductance;
One first electric capacity, the other end of this first winding couple an end of this first inductance via this first electric capacity; And
One second electric capacity, the other end of this second winding couple the other end of this first inductance via this second electric capacity.
20. lamp tube drive circuit as claimed in claim 16 is characterized in that, this balancing circuitry also comprises:
One first iron core;
One second iron core;
One tertiary winding, the coil turn of this tertiary winding equals the coil turn of this first winding, and this tertiary winding and this first winding are with being around on this first iron core; And
One the 4th winding, this tertiary winding and the 4th winding system forms a loop, and the coil turn of the 4th winding equals the coil turn of this first winding, and the 4th winding is around on this second iron core with this second winding is same.
Wherein, the coil turn of this first winding equals the coil turn of this second winding.
21. lamp tube drive circuit as claimed in claim 20 is characterized in that, this balancing circuitry also comprises:
One electric capacity is coupled to the other end of this first winding and the other end of this second winding.
22. lamp tube drive circuit as claimed in claim 20 is characterized in that, this balancing circuitry also comprises:
One first electric capacity, the other end of this first winding is coupled to a fixed voltage via this first electric capacity; And
One second electric capacity, the other end of this second winding is coupled to this fixed voltage via this second electric capacity.
23. lamp tube drive circuit as claimed in claim 20 is characterized in that, also comprises:
One feedback circuit is exported a feedback signal according to the voltage difference between an end of end of this tertiary winding and the 4th winding.
24. lamp tube drive circuit as claimed in claim 23 is characterized in that, this feedback circuit comprises:
One full-wave rectifying circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
25. lamp tube drive circuit as claimed in claim 23 is characterized in that, this feedback circuit comprises:
One half-wave rectification circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
26. lamp tube drive circuit as claimed in claim 16 is characterized in that, also in order to drive one the 3rd fluorescent tube and one the 4th fluorescent tube, this balancing circuitry also comprises:
One first iron core;
One second iron core;
One the 3rd iron core;
One four-limbed;
One tertiary winding, the coil turn of this tertiary winding equals the coil turn of this first winding, and this tertiary winding and this first winding are with being around on this first iron core;
One the 4th winding, an end of the 4th winding is in order to receive this first alternating voltage, and the other end of the 4th winding is exported one the 3rd electric current to the 3rd fluorescent tube, and the coil turn of the 4th winding equals the coil turn of this first winding;
One the 5th winding, the coil turn of the 5th winding equals the coil turn of the 4th winding, and the 5th winding and the 4th winding are with being around on this second iron core;
One the 6th winding, the 6th winding and the 5th winding system forms a loop, and the coil turn of the 6th winding equals the coil turn of the 5th winding, and the 6th winding is around in this three-iron in the heart with this second winding is same;
One the 7th winding, an end of the 7th winding is in order to receive this second alternating voltage, and the other end of the 7th winding is exported one the 4th electric current to the 4th fluorescent tube, and the coil turn of the 7th winding equals the coil turn of this second winding; And
One the 8th winding, the 8th winding and this tertiary winding system forms a loop, and the coil turn of the 8th winding equals the coil turn of the 7th winding, and the 8th winding is around in this four-limbed with the 7th winding is same;
Wherein, the coil turn of this first winding equals the coil turn of this second winding.
27. lamp tube drive circuit as claimed in claim 26 is characterized in that, this balancing circuitry also comprises:
One first electric capacity is coupled to the other end of this first winding and the other end of the 4th winding; And
One second electric capacity is coupled to the other end of this second winding and the other end of the 7th winding.
28. lamp tube drive circuit as claimed in claim 26 is characterized in that, also comprises:
One feedback circuit is exported a feedback signal according to the voltage difference between an end of end of this tertiary winding and the 8th winding.
29. lamp tube drive circuit as claimed in claim 28 is characterized in that, this feedback circuit comprises:
One full-wave rectifying circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
30. lamp tube drive circuit as claimed in claim 28 is characterized in that, this feedback circuit comprises:
One half-wave rectification circuit is in order to exporting after this voltage difference rectification; And
One wave filter in order to behind this voltage difference filtering noise after the rectification, is thought this feedback signal.
31. lamp tube drive circuit as claimed in claim 1 is characterized in that, this power supply circuit comprises:
At least one transformer is in order to export this alternating voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100912959A CN100489606C (en) | 2005-08-23 | 2005-08-23 | Tube driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100912959A CN100489606C (en) | 2005-08-23 | 2005-08-23 | Tube driving circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1737651A CN1737651A (en) | 2006-02-22 |
| CN100489606C true CN100489606C (en) | 2009-05-20 |
Family
ID=36080492
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100912959A Expired - Fee Related CN100489606C (en) | 2005-08-23 | 2005-08-23 | Tube driving circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100489606C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100849795B1 (en) * | 2007-03-26 | 2008-07-31 | 삼성전기주식회사 | Current balancing circuit which can be easy electrical connecting |
| TWI408636B (en) | 2008-02-14 | 2013-09-11 | Au Optronics Corp | Light driving circuit device and backlight device |
| CN105792492B (en) * | 2014-12-23 | 2019-07-05 | 通用电气公司 | Lamp tube current balance system |
-
2005
- 2005-08-23 CN CNB2005100912959A patent/CN100489606C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1737651A (en) | 2006-02-22 |
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Granted publication date: 20090520 |