CN1469695A - Current transformer driving several discharge lamp tubes - Google Patents
Current transformer driving several discharge lamp tubes Download PDFInfo
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- CN1469695A CN1469695A CNA021261075A CN02126107A CN1469695A CN 1469695 A CN1469695 A CN 1469695A CN A021261075 A CNA021261075 A CN A021261075A CN 02126107 A CN02126107 A CN 02126107A CN 1469695 A CN1469695 A CN 1469695A
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Abstract
The current transformer driving several discharge lamp tubes includes one transformer, one first current balancing circuit, one second current balancing circuit and one comparator circuit. The transformer is used to drive the first and the second discharge lamp tubes; the two current balancing circuits are connected serially to the two discharge lamp tubes separately to regulate their current separately based on a comparison signal; and the comparator circuit compares the first detection signal from the first current balancing circuit and the second detection signal from the second current balancing circuit to control the first current balancing circuit and the second current balancing circuit and to balance the current in the first lamp tube and that in the second one.
Description
Technical field
The present invention refers in particular to the current transformer (inverter) of a kind of driving several discharge lamp tubes (discharge lamp) relevant for (backlight) backlight module of display unit.
Background technology
Generally speaking the display unit of liquid crystal display (LCD) type all has a backlight module with display message, and the requirement that must approach and must meet efficient of this backlight module thickness.Comprise discharge lamp more than one in the employed backlight module of LCD panel to be used as the light source of show image, (Cold-Cathode Fluorescent Lamp CCFL) can satisfy the demand of LCD backlight module with cathode fluorescent tube in the at present all types of discharge lamps.
For adapting to the more and more big development trend of LCD display size, backlight module need drive many CCFL to provide the large-scale LCD panel enough illuminations, and in order to reduce the complexity of cost and reduction circuit, preferable mode is to drive many CCFL but not the current transformers of group more than taking with one group of converter device, with the two lamp LCD panels of Fig. 1 is example, the shell 10 of LCD display is coating LCD panel 20 and is being positioned at the fluorescent tube LP10 of panel both sides, LP12, wherein capacitor C 10, fluorescent tube LP10 and capacitor C 12, fluorescent tube LP12 is connected in parallel in the second siding ring of the transformer T10 in the converter device.The benefit of the parallel-connection structure shown in Fig. 1 is that cost is low and circuit is simple, yet, because the coupling of circuit component and the factor of configuration, be difficult to make the flow through electric current of fluorescent tube LP10, LP12 to equate, and cause the problem of brightness disproportionation, and, fluorescent tube characteristic changing (causing as aging institute) shortens lamp tube service life because of causing current imbalance to will speed up wearing out of fluorescent tube.In view of this, the present invention proposes a kind of current transformer that can drive many CCFL simultaneously, to overcome the restriction of known technology.
Summary of the invention
The purpose of this invention is to provide a kind of current transformer that drives several discharge lamp tubes, can the balance lamp current with life-span of prolonging lamp tube.
Another object of the present invention provides a kind of current transformer that drives several discharge lamp tubes, has current balance circuit, can economic, simple circuit drives the many tubes in the LCD backlight module.
For reaching described purpose, the invention provides a kind of current transformer that drives several discharge lamp tubes, comprise a transformer, one first current balance circuit, one second current balance circuit and a comparison circuit.Transformer is used for driving one first discharge lamp and one second discharge lamp, first current balance circuit then connects first discharge lamp with series system, first lamp current that can detect first discharge lamp of flowing through is to produce one first detection signal, and according to a comparison signal to adjust first lamp current, similarly, second current balance circuit connects second discharge lamp with series system, second lamp current that then can detect second discharge lamp of flowing through to be to produce one second detection signal, also according to aforesaid comparison signal to adjust second lamp current.Comparison circuit receives first detection signal and second detection signal, and the generation comparison signal equates first lamp current and second lamp current to control first current balance circuit and second current balance circuit after comparing first detection signal and second detection signal.Wherein, first current balance circuit, second current balance circuit comprise the first transistor circuit and transistor seconds circuit respectively.When comparison signal was first state, the first transistor circuit response comparison signal was to reduce by first lamp current, and the transistor seconds circuit then responds comparison signal to increase by second lamp current; When comparison signal was second state, the first transistor circuit response comparison signal was to increase by first lamp current, and the transistor seconds circuit then responds comparison signal to reduce by second lamp current.
In addition, current transformer of the present invention also comprises a resonance push-pull type change-over circuit and a lamp tube drive circuit.Comprise aforesaid transformer in the resonance push-pull type change-over circuit, it has first siding ring and second siding ring, and resonance push-pull type change-over circuit provides an alternating voltage to drive first discharge lamp and second discharge lamp that is connected in the parallel connection on the transformer secondary lateral coil with the resonance push pull mode.The input of lamp tube drive circuit partly receives a direct current power supply, its output partly then couples the transformer first siding ring in the resonance push-pull type change-over circuit, and lamp tube drive circuit is adjusted alternating voltage according to first detection signal from first current balance circuit with control resonance push-pull type change-over circuit.
According to another embodiment of the present invention, drive the current transformer of several discharge lamp tubes, comprise a transformer, a comparison circuit and organize current balance circuit more.Transformer is used for driving several discharge lamps, many group current balance circuits then connect corresponding discharge lamp with series system respectively, the lamp current that these current balance circuits can detect the corresponding discharge lamp of flowing through separately to be producing several detection signals, and according to one group of comparison signal with the flow through lamp current of these discharge lamps of each self-adjusting.Comparison circuit receives and compares these detection signals, controls these current balance circuits to produce this group comparison signal, and the lamp current of these discharge lamps is equated.Comprise a transistor circuit in these current balance circuits separately, if aforesaid one group of comparison signal shows in these discharge lamps that wherein the lamp current of a tubes is for maximum, this corresponding transistor circuit responds this group comparison signal to reduce corresponding lamp current, and the transistor circuit in remaining current balance circuit then responds this group comparison signal to increase the lamp current of all the other discharge lamps.
Description of drawings
For described 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 as follows:
Fig. 1 is the perspective diagram of two fluorescent tube LCD display;
Fig. 2 is the circuit diagram of the preferred embodiment according to the present invention;
Fig. 3 A is the block schematic diagram of another embodiment of the present invention; And
Fig. 3 B is the logic diagram of comparison circuit among Fig. 3 A.
Label declaration
10: display casing; The 20:LCD panel; 210: lamp tube drive circuit; 212: the input of lamp tube drive circuit partly; 214: the output of lamp tube drive circuit partly; 220: resonance push-pull type change-over circuit; 230,230 ': current balance circuit; 232,232 ': rectification circuit; 234,234 ': testing circuit; 236,236 ': transistor circuit; 240: comparison circuit; 320: resonance push-pull type change-over circuit; 330,330 ', 330 ": current balance circuit; 340: comparison circuit; 341a-c: the input of comparison circuit 340; 343a-c: comparator; 345a-c: not gate; 347a-c: with door; 349a-c: the output of comparison circuit 340;
T10, T20: transformer; W
P: first siding ring; W
s: second siding ring; D1, D2, D3, D4, D5, D6, D1 ', D2 ', D3 ', D4 ', D5 ', D6 ': diode; LP10, LP12, LP20, LP22, LP30, LP32, LP34: discharge lamp; Q1, Q2, Q1 ', Q2 ': transistor; C1, C1 ', C10, C12, C20, C22, C30, C32, C34: electric capacity; R1, R2, R3, R4, R1 ', R2 ', R3,, R4 ': resistance; PC, PC ', PC ": coupling device.
Embodiment
Fig. 2 is the current transformer according to two discharge lamps of driving of the present invention, and as shown in the figure, the input of lamp tube drive circuit 210 partly 212 receives a direct current power supply V
DC, in resonance push-pull type (resonantpush-pull) change-over circuit 220, the first siding ring W of transformer T20
PHave output that center tap end (center tap) is coupled to lamp tube drive circuit 210 partly 214, resonance push-pull type change-over circuit 220 provides an alternating voltage with the resonance push pull mode, drives and is connected in transformer secondary lateral coil W
SOn discharge lamp LP20, the LP22 of parallel connection, capacitor C 20, C22 then are connected on second siding ring W respectively
SAnd stable to be used as (ballast) electric capacity between fluorescent tube LP20, the LP22, via lamp tube drive circuit 210 and resonance push-pull type change-over circuit 220, DC power supply V
DCThe low dc voltage that is provided will convert quite high alternating voltage to light fluorescent tube LP20, LP22.According to the present invention, resonance push-pull type change-over circuit 220 is preferable with Royer formula change-over circuit.
As shown in Figure 2, current balance circuit 230 comprises rectification circuit 232, testing circuit 234 and transistor circuit 236, and current balance circuit 230 ' comprises rectification circuit 232 ', testing circuit 234 ' and transistor circuit 236 ' equally.Rectification circuit 232,232 ' by diode D1-D4 and full wave bridge rectifier that D1 '-D4 ' formed, is used the Dc bias that provides transistor circuit 236 and transistor circuit 236 ' required for respectively.The input X of rectification circuit 232 input ports is connected in fluorescent tube LP20, another input Y is connected in the input A of testing circuit 234, the two ends WZ of rectification circuit 232 output ports also follows transistor circuit 236, similarly, the input X ' of rectification circuit 232 ' input port is connected in fluorescent tube LP22, another input Y ' is connected in the input A ' of testing circuit 234 ', and the two ends W ' Z ' of rectification circuit 232 ' output port then also follows transistor circuit 236 '.The output B of testing circuit 234 and the output B ' of testing circuit 234 ' be connected to the normal phase input end of comparison circuit 240+with inverting input-, as shown in the figure, testing circuit 234 is made of resistance R 1-R2, diode D5-D6 and capacitor C 1, and testing circuit 234 ' is made of resistance R 1 '-R2 ', diode D5 '-D6 ' and capacitor C 1 ' equally, so, testing circuit 234,234 ' can detect lamp current I
L1And I
L2To produce signal FV and signal FV '.
Continuation is with reference to figure 2, current balance circuit 230 and current balance circuit 230 ' comprise coupling device PC and coupling device PC ' separately, to isolate the noise that comparison circuit 240 is produced, coupling device PC is coupled between comparison circuit 240 and the transistor circuit 236, and coupling device PC ' then is coupled between comparison circuit 240 and the transistor circuit 236 '.According to the present invention, coupling device can be the isolation coupling device of the optical coupler (photocoupler) or the class of relay (relay), and being the present invention, bipolar junction transistor (BJT), junction field effect transistor (JFET) or metal oxide semiconductcor field effect transistor (MOSFET) consider the transistor types implemented, the coupling device of present embodiment is an optical coupler, and transistor then is representative with the bipolar junction transistor.In transistor circuit 236, the collector electrode of transistor Q1, emitter are connected to the output port two ends of rectification circuit 232, the collector electrode of transistor Q2, emitter are connected to base stage, the emitter of transistor Q1, the two ends of resistance R 3 are connected in collector electrode, the base stage of transistor Q1, and the two ends of resistance R 4 then are connected in base stage, the emitter of transistor Q2.The output PC of optical coupler PC
3Be connected in the base stage of transistor Q2, its another output PC
4Then be connected in the collector electrode of transistor Q1, the input PC of optical coupler PC
1Receive comparison signal COMP, its another input PC
2Then couple reference voltage V
RefTransistor circuit 236 ' is made of resistance R 3 ', R4 ' and transistor Q1 ', Q2 ' in a similar fashion, the collector electrode of transistor Q1 ', emitter are connected to the output port two ends of rectification circuit 232 ', the collector electrode of transistor Q2 ', emitter are connected to base stage, the emitter of transistor Q ' 1, the two ends of resistance R 3 ' are connected in collector electrode, the base stage of transistor Q1 ', and the two ends of resistance R 4 ' then are connected in base stage, the emitter of transistor Q2 '.The output PC of optical coupler PC '
3' be connected in the base stage of transistor Q2 ', its another output PC
4' then be connected in the collector electrode of transistor Q1 ', the input PC of optical coupler PC '
2' reception comparison signal COMP, its another input PC
1' then couple reference voltage V
RefReference voltage V
RefBe chosen to be half of system voltage Vcc (not shown), make optical coupler PC, the PC ' can operate as normal.In fact, current balance circuit 230,230 ' and included rectification circuit, testing circuit and transistor circuit preferably dispose identical circuit.
If comparison signal COMP is a logic high, the indication lamp current I
L1Greater than lamp current I
L2Conducting between the optical coupler PC output at this moment, make transistor Q2 be operated in saturation region (saturationregion) and cause the base current of transistor Q1 practically negligible, owing to this moment transistor Q1 collector electrode, emitter both end voltage allow transistor Q1 be operated in breakdown region (breakdown region) quite greatly, so limited lamp current I
L1Simultaneously, the comparison signal COMP of logic high makes to form between the optical coupler PC ' output and opens circuit, cause transistor Q2 ' to turn-off and make transistor Q1 ' be operated in active zone (active region), so the resistance decreasing between transistor Q1 ' collector electrode, emitter, make lamp current I
L2Increase.If comparison signal COMP is a logic low, the indication lamp current I
L1Less than lamp current I
L2, forms between the optical coupler PC output this moment and open circuit, cause transistor Q2 shutoff and make transistor Q1 be operated in active zone, so the resistance decreasing between transistor Q1 collector electrode, emitter, make lamp current I
L1Increase; On the other hand, the comparison signal COMP of logic low makes conducting between the optical coupler PC ' output, make transistor Q2 ' be operated in the saturation region and cause the base current of transistor Q1 ' practically negligible, owing to transistor Q1 ' collector electrode, emitter both end voltage allow transistor Q1 ' be operated in the breakdown region quite greatly, will therefore make lamp current I
L2Reduce, reach the state of lamp tube current balance at last.
3A, 3B figure explanation the present invention is applied in the embodiment of several discharge lamp tubes, represent with identical label with assembly identical or approximate among Fig. 2, be example only with three discharge lamps herein, be for convenience of description for the purpose of and be not to be used for limiting the present invention.As shown in the figure, the input of lamp tube drive circuit 210 partly 212 receives DC power supply V
DC, in resonance push-pull type change-over circuit 320, transformer T20 first siding ring W
POn the output partly 214 that is coupled to lamp tube drive circuit 210 of center tap end, resonance push-pull type change-over circuit 320 provides alternating voltage to drive with the resonance push pull mode and is connected in transformer secondary lateral coil W
SOn three discharge lamp LP30, LP32 and the LP34 of parallel connection, capacitor C 30, C32 and C34 then are connected on second siding ring W respectively
SAnd between fluorescent tube LP30, LP32 and the LP34.Current balance circuit 330,330 ' and 330 " be connected corresponding discharge lamp LP30, LP32 and LP34, current balance circuit 330,330 ' and 330 with series system respectively " can detect the lamp current I of flow through discharge lamp LP30, LP32 and LP34 separately
L1, I
L2And I
L3To produce detection signal FV, FV ' and FV respectively "; comparison circuit 340 receives and compares these detection signals to produce one group of comparison signal COMP1-COMP3, current balance circuit 330,330 ' and 330 " organize the lamp current I that comparison signal is adjusted flow through discharge lamp LP30, LP32 and LP34 respectively according to this
L1, I
L2And I
L3, make these lamp currents reach balance.Wherein current balance circuit 330 feeds back to lamp tube drive circuit 210 with detected detection signal FV, adjusts alternating voltage with control resonance push-pull type change-over circuit 320.
Current balance circuit 330,330 ' and 330 " have identical substantially configuration, comprised rectification circuit 232, testing circuit 234, transistor circuit 236 and optical coupler PC in each current balance circuit respectively.With current balance circuit 330 is example, the input X of rectification circuit 232 input ports is connected in fluorescent tube LP30, another input Y is connected in the input A of testing circuit 234, the two ends WZ of rectification circuit 232 output ports then also follows transistor circuit 236, and the output B of testing circuit 234 then provides detection signal FV to comparison circuit 340.In transistor circuit 236, the collector electrode of transistor Q1, emitter are connected to the output port two ends WZ of rectification circuit 232, the collector electrode of transistor Q2, emitter are connected to base stage, the emitter of transistor Q1, the two ends of resistance R 3 are connected in collector electrode, the base stage of transistor Q1, and the two ends of resistance R 4 then are connected in base stage, the emitter of transistor Q2.The output PC of optical coupler PC
3Be connected in the base stage of transistor Q2, its another output PC
4Then be connected in the collector electrode of transistor Q1, the input PC of optical coupler PC
1Couple an output 349a of comparison circuit 340, another input PC
2Then couple ground reference.
Shown in Fig. 3 B, comparison circuit 340 is by comparator 343a-c, formed with door (AND gate) 347a-c NAND gate (NOT gate) 345a-c, wherein not gate 345a-c with door 347a-c formation combinational logic circuit.The input 341a-c of comparison circuit 340 receives detection signal FV, FV ' and FV respectively ", and one group of comparison signal COMP1-COMP3 offered optical coupler PC, PC ' and PC by the output 349a-c of comparison circuit 340 ".If detection signal FV is greater than detection signal FV ', FV ", the signal COMP1 that comparison circuit 240 produces is a logic high, and signal COMP2, COMP3 are logic low, that is comparison signal COMP1-COMP3 shows the lamp current I of discharge lamp LP30
L1Be maximum, conducting between this moment optical coupler PC output and optical coupler PC ', PC " forms between the output and open circuit, so as previously described, the transistor circuit 236 of current balance circuit 330 will reduce lamp current I
L1, remaining current balance circuit 330 ', 330 " 236 of transistor circuits increase the lamp current I of discharge lamp LP32, LP34
L2, I
L3If detection signal FV ' is greater than detection signal FV, FV ", the signal COMP2 that comparison circuit 240 produces is a logic high, and signal COMP1, COMP3 are logic low, show the lamp current I of discharge lamp LP32
L2Be maximum, make the transistor circuit 236 of current balance circuit 330 ' reduce lamp current I
L2, current balance circuit 330,330 " 236 of transistor circuits increase the lamp current I of discharge lamp LP30, LP34
L1, I
L3In like manner, if lamp current I
L3Greater than lamp current I
L1, I
L2, the signal COMP3 that comparison circuit 240 produces is a logic high, and signal COMP1, COMP2 are logic low, makes current balance circuit 330 " transistor circuit 236 reduce lamp current I
L3, current balance circuit 330,236 increases of transistor circuit discharge lamp LP30 of 330 ', the lamp current I of LP32
L1, I
L2In this way, can reach the state of lamp tube current balance at last.
Comprehensive the above, the present invention discloses a kind of current transformer that drives several discharge lamp tubes, can reach the life-span of the purpose of balance lamp current with prolonging lamp tube, according to the present invention, because the cause of current balance circuit, circuit is unrestricted and be easier to layout, the many tubes in can economic drives LCD backlight module.
Though the present invention with a specific embodiment openly as above; so it is only in order to be easy to illustrate technology contents of the present invention; and be not with narrow sense of the present invention be defined in this embodiment; any those skilled in the art; under the situation that does not break away from the spirit and scope of the present invention; can change and improvement, so protection scope of the present invention is as the criterion with the claim restricted portion that is proposed.
Claims (24)
1. current transformer that drives several discharge lamp tubes comprises:
One transformer is to drive one first discharge lamp and one second discharge lamp;
One first current balance circuit, connect this first discharge lamp with series system, this first current balance circuit detects one first lamp current of this first discharge lamp of flowing through, producing one first detection signal, and according to a comparison signal to adjust this first lamp current;
One second current balance circuit, connect this second discharge lamp with series system, this second current balance circuit detects one second lamp current of this second discharge lamp of flowing through, producing one second detection signal, and according to this comparison signal to adjust this second lamp current; And
One comparison circuit, receive this first detection signal and this second detection signal, and relatively this first detection signal and this second detection signal, control this first current balance circuit and this second current balance circuit to produce this comparison signal, this first lamp current and this second lamp current are equated.
2. current transformer as claimed in claim 1, wherein said comparison circuit is at described first detection signal during greater than described second detection signal, the described comparison signal that produces is one first state, during less than described second detection signal, the described comparison signal of generation is one second state at described first detection signal.
3. current transformer as claimed in claim 2, wherein said first current balance circuit comprises a first transistor circuit, when described comparison signal is described first state, this the first transistor circuit responds described comparison signal to reduce described first lamp current, when described comparison signal was described second state, this first transistor circuit responded described comparison signal to increase described first lamp current.
4. current transformer as claimed in claim 2, wherein said second current balance circuit comprises a transistor seconds circuit, when described comparison signal is described first state, this transistor seconds circuit responds described comparison signal to increase described second lamp current, when described comparison signal was described second state, this transistor seconds circuit responded described comparison signal to reduce described second lamp current.
5. current transformer as claimed in claim 3, wherein said first current balance circuit also comprises one first coupling device, is coupled between described comparison circuit and the described the first transistor circuit, to isolate the noise that described comparison circuit is produced.
6. current transformer as claimed in claim 4, wherein said second current balance circuit also comprises one second coupling device, is coupled between described comparison circuit and the described transistor seconds circuit, to isolate the noise that described comparison circuit is produced.
7. current transformer as claimed in claim 3, wherein said first current balance circuit also comprises one first rectification circuit, one first input end of the input port of this first rectification circuit is connected in described first discharge lamp, and the two ends of the output port of this first rectification circuit also connect described the first transistor circuit.
8. current transformer as claimed in claim 4, wherein said second current balance circuit also comprises one second rectification circuit, one first input end of the input port of this second rectification circuit is connected in described second discharge lamp, and the two ends of the output port of this second rectification circuit also connect described transistor seconds circuit.
9. current transformer as claimed in claim 7, wherein said first current balance circuit also comprises one first testing circuit, the input of this first testing circuit is connected in one second input of the input port of described first rectification circuit, the output of this first testing circuit is connected in a first input end of described comparison circuit, this first testing circuit detects described first lamp current of described first discharge lamp of flowing through, so that described first detection signal to be provided.
10. current transformer as claimed in claim 8, wherein said second current balance circuit also comprises one second testing circuit, the input of this second testing circuit is connected in one second input of the input port of described second rectification circuit, the output of this second testing circuit is connected in one second input of described comparison circuit, this second testing circuit detects described second lamp current of described second discharge lamp of flowing through, so that described second detection signal to be provided.
11. current transformer as claimed in claim 1 also comprises:
One resonance push-pull type change-over circuit, comprise described transformer, and described transformer has one lateral coils and a second siding ring, this resonance push-pull type change-over circuit provides an alternating voltage with the resonance push pull mode, drives described first discharge lamp and described second discharge lamp that are connected in the parallel connection on this transformer secondary lateral coil; And
One lamp tube drive circuit, the input of this lamp tube drive circuit partly receives a direct current power supply, the output of this lamp tube drive circuit partly couples this transformer first siding ring in this resonance push-pull type change-over circuit, with according to described first detection signal, control this resonance push-pull type change-over circuit and adjust this alternating voltage from described first current balance circuit.
12. a current transformer that drives several discharge lamp tubes comprises:
One resonance push-pull type change-over circuit, comprise that one has the transformer of one lateral coils and a second siding ring, this resonance push-pull type change-over circuit provides an alternating voltage with the resonance push pull mode, drives one first discharge lamp and one second discharge lamp that are connected in the parallel connection on this transformer secondary lateral coil;
One first current balance circuit, connect this first discharge lamp with series system, this first current balance circuit detects one first lamp current of this first discharge lamp of flowing through, producing one first detection signal, and according to a comparison signal to adjust this first lamp current;
One second current balance circuit, connect this second discharge lamp with series system, this second current balance circuit detects one second lamp current of this second discharge lamp of flowing through, producing one second detection signal, and according to this comparison signal to adjust this second lamp current;
One comparison circuit, receive this first detection signal and this second detection signal, and relatively this first detection signal and this second detection signal, control this first current balance circuit and this second current balance circuit to produce this comparison signal, this first lamp current and this second lamp current are equated; And
One lamp tube drive circuit, the input of this lamp tube drive circuit partly receives a direct current power supply, the output of this lamp tube drive circuit partly couples this transformer first siding ring in this resonance push-pull type change-over circuit, adjusts this alternating voltage to control this resonance push-pull type change-over circuit according to this first detection signal.
13. current transformer as claimed in claim 12, wherein said comparison circuit is at described first detection signal during greater than described second detection signal, the described comparison signal that produces is one first state, during less than described second detection signal, the described comparison signal of generation is one second state at described first detection signal.
14. current transformer as claimed in claim 13, wherein said first current balance circuit comprises that a first transistor circuit and described second current balance circuit comprise a transistor seconds circuit, when described comparison signal is described first state, this the first transistor circuit responds described comparison signal to reduce described first lamp current, this transistor seconds circuit then responds described comparison signal to increase described second lamp current, when described comparison signal is described second state, this the first transistor circuit responds described comparison signal to increase described first lamp current, and this transistor seconds circuit then responds described comparison signal to reduce described second lamp current.
15. current transformer as claimed in claim 14, wherein said first current balance circuit and described second current balance circuit also comprise one first coupling device and one second coupling device separately, to isolate the noise that described comparison circuit is produced, this first coupling device is coupled between described comparison circuit and the described the first transistor circuit, and this second coupling device then is coupled between described comparison circuit and the described transistor seconds circuit.
16. current transformer as claimed in claim 14, wherein said first current balance circuit and described second current balance circuit also comprise one first rectification circuit and one second rectification circuit separately, one first input end of the input port of this first rectification circuit is connected in described first discharge lamp, the two ends of the output port of this first rectification circuit also connect described the first transistor circuit, and a first input end of the input port of this second rectification circuit is connected in described second discharge lamp, and the two ends of the output port of this second rectification circuit also connect described transistor seconds circuit.
17. current transformer as claimed in claim 16, wherein said first current balance circuit also comprises one first testing circuit, the input of this first testing circuit is connected in one second input of the input port of described first rectification circuit, the output of this first testing circuit is connected in a first input end of described comparison circuit, this first testing circuit detects described first lamp current of described first discharge lamp of flowing through, so that described first detection signal to be provided.
18. current transformer as claimed in claim 16, wherein said second current balance circuit also comprises one second testing circuit, the input of this second testing circuit is connected in one second input of the input port of described second rectification circuit, the output of this second testing circuit is connected in one second input of described comparison circuit, this second testing circuit detects described second lamp current of described second discharge lamp of flowing through, so that described second detection signal to be provided.
19. a current transformer that drives several discharge lamp tubes comprises:
One transformer is to drive several discharge lamp tubes;
Many group current balance circuits, connect corresponding described discharge lamp with series system respectively, the lamp current that described current balance circuit detects the corresponding discharge lamp of flowing through separately to be producing a plurality of detection signals, and according to one group of comparison signal with the flow through lamp current of described discharge lamp of each self-adjusting; And
One comparison circuit receives described detection signal, and more described detection signal controls described current balance circuit to produce this group comparison signal, and the lamp current of described discharge lamp is equated.
20. current transformer as claimed in claim 19, wherein said many group current balance circuits comprise a transistor circuit separately, if described one group of comparison signal shows in the described several discharge lamp tubes that wherein a lamp current is for maximum, this corresponding transistor circuit responds this group comparison signal to reduce this corresponding lamp current, and the transistor circuit in all the other described many group current balance circuits then responds this group comparison signal to increase the lamp current of all the other described several discharge lamp tubes.
21. as the 20th described current transformer of claim, wherein said many group current balance circuits also comprise a coupling device separately, be respectively coupled between described comparison circuit and the described many group current balance circuits transistor circuit separately, to isolate the noise that described comparison circuit is produced.
22. current transformer as claimed in claim 21, wherein said many group current balance circuits also comprise a rectification circuit separately, one first input end of the input port of this rectification circuit is connected in discharge lamp corresponding in the described several discharge lamp tubes, and the two ends of the output port of this rectification circuit also connect described many group current balance circuits transistor circuit separately.
23. current transformer as claimed in claim 22, wherein said many group current balance circuits also comprise a testing circuit separately, the input of this testing circuit is connected in one second input of the input port of described many group current balance circuits rectification circuit separately, the output of described testing circuit is connected in the corresponding input of described comparison circuit, described many group current balance circuits testing circuit separately detects lamp current corresponding in the described several discharge lamp tubes of flowing through, so that described a plurality of detection signal to be provided.
24. current transformer as claimed in claim 19 also comprises:
One resonance push-pull type change-over circuit, comprise described transformer, and described transformer has one lateral coils and a second siding ring, this resonance push-pull type change-over circuit provides an alternating voltage with the resonance push pull mode, drives the described several discharge lamp tubes that is connected in the parallel connection on this transformer secondary lateral coil; And
One lamp tube drive circuit, the input of this lamp tube drive circuit partly receives a direct current power supply, the output of this lamp tube drive circuit partly couples this transformer first siding ring in this resonance push-pull type change-over circuit, with according to from one of them described detection signal in described many group current balance circuits, control this resonance push-pull type change-over circuit and adjust this alternating voltage.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021261075A CN100450326C (en) | 2002-07-16 | 2002-07-16 | Current transformer driving several discharge lamp tubes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021261075A CN100450326C (en) | 2002-07-16 | 2002-07-16 | Current transformer driving several discharge lamp tubes |
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| Publication Number | Publication Date |
|---|---|
| CN1469695A true CN1469695A (en) | 2004-01-21 |
| CN100450326C CN100450326C (en) | 2009-01-07 |
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|---|---|---|---|
| CNB021261075A Expired - Fee Related CN100450326C (en) | 2002-07-16 | 2002-07-16 | Current transformer driving several discharge lamp tubes |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1838851B (en) * | 2005-03-24 | 2010-12-22 | 电灯专利信托有限公司 | Circuit device operating at least first and second lamp capable of being inserted to circuit device |
| CN101959344A (en) * | 2009-07-13 | 2011-01-26 | 台达电子工业股份有限公司 | Current balanced power supply circuit of multiple groups of direct current (DC) loads |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6317347B1 (en) * | 2000-10-06 | 2001-11-13 | Philips Electronics North America Corporation | Voltage feed push-pull resonant inverter for LCD backlighting |
| CN1353568A (en) * | 2000-11-10 | 2002-06-12 | 联昌电子企业股份有限公司 | Current converter for regulated back lighting |
| US6356035B1 (en) * | 2000-11-27 | 2002-03-12 | Philips Electronics North America Corporation | Deep PWM dimmable voltage-fed resonant push-pull inverter circuit for LCD backlighting with a coupled inductor |
-
2002
- 2002-07-16 CN CNB021261075A patent/CN100450326C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1838851B (en) * | 2005-03-24 | 2010-12-22 | 电灯专利信托有限公司 | Circuit device operating at least first and second lamp capable of being inserted to circuit device |
| CN101959344A (en) * | 2009-07-13 | 2011-01-26 | 台达电子工业股份有限公司 | Current balanced power supply circuit of multiple groups of direct current (DC) loads |
| CN101959344B (en) * | 2009-07-13 | 2013-11-06 | 台达电子工业股份有限公司 | Current balanced power supply circuit of multiple groups of direct current (DC) loads |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100450326C (en) | 2009-01-07 |
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