CN1774152A - Lamp tube current equalizing method and applied circuit - Google Patents

Abstract

A method for providing equalized current on lamp tube includes connecting one side winding of multiple transformers to multiple lamp tubes, connecting another side winding in series to form a closed loop, making current flowing on one side winding be equal to let lamp tube connected on another side winding generate the same operation current by utilizing magnetic-inductive property of transformer and closed loop formed on one side winding of transformer.

Description

Lamp tube current equalizing method and application circuit

Technical field

The present invention is a kind of lamp tube current equalizing method and application circuit, refers to a kind of annexation of utilizing a plurality of transformers and a plurality of fluorescent tubes especially, in order to lamp tube current equalizing method and the application circuit of regulating current balance type between a plurality of fluorescent tubes.

Background technology

Because technological progress and consumer demand, the LCD panel size constantly increases, and makes single fluorescent tube can't satisfy its illumination, thereby needs to use two or more a plurality of fluorescent tube.Brightness in order to ensure the LCD panel is even, must regulate each lamp tube current at any time, and each lamp tube current amount of flowing through is equated.But because cold cathode fluorescent lamp pipe (CCFL) is highly unstable and have various reasons such as negative resistance character, make tube impedance be difficult to keep unanimity, cause each tube impedance to change and that electric current can't be reached is equal.Electric current is unequal between each fluorescent tube, and except meeting made brightness irregularities, the fluorescent tube that electric current is too big also can shorten the life-span, makes that the rate of ageing (Aging Rate) between each fluorescent tube is inconsistent.

Please refer to Fig. 1, use differential ballast in the ball bearing made using schematic diagram of regulating two lamp currents for existing.Comprising there being transformer 12, the first coils 121 one ends with first coil 121 and second coil 122 to be connected to an AC power 10, the other end is connected to one first fluorescent tube 141, and the other end of first fluorescent tube 141 is connected to a reference potential G.And one second coil 122, the one end is connected to this AC power 10, and the other end is connected to one second fluorescent tube 142, and the other end of this second fluorescent tube 142 is connected to a reference potential G.As described above, first coil 121 and second coil 122 that this AC power 10 sees through transformer 12 form differential ballast, in order to stable electric current I to be provided respectively ₁, I ₂Use for first fluorescent tube 141 and second fluorescent tube 142, make the electric current that flows through first fluorescent tube 142 and second fluorescent tube 142 reach the effect of balance.

Cooperate Fig. 1, please refer to Fig. 2, be the transformer 12 equivalent magnetic loop schematic diagrames of Fig. 1.As shown in Figure 2, wherein magnetic core 120 includes two lateral column A1 and A2, and two shoulder post A3 and A4.Work as electric current I ₁, I ₂When identical, the electric current that flows through first coil 121 and second coil 122 also equates, and electric current I ₁Magnetomotive force and electric current I in 121 generations of first coil ₂The magnetomotive force that produces at second coil 122 equates that also promptly, the magnetomotive force among magnetomotive force among the lateral column A1 and the lateral column A2 is repealed by implication, and therefore takes among post A3 and the shoulder post A4 and there is no the magnetic flux intercommunication.Simultaneously, the loop is finished in the air gap outside the magnetic flux Φ 1 among lateral column A1 and the lateral column A2, Φ 2 can respectively hang oneself, but because therefore the magnetic resistance of air gap very high, the inductive effect that this loop caused generally can be ignored.

Cooperate Fig. 1, please refer to Fig. 3, connect the schematic diagram of fluorescent tube for Fig. 1 equivalence magnetic loop.Electric current I when first fluorescent tube 141 ₁Electric current I with second fluorescent tube 142 ₂When inequality, electric current I then ₁The magnetomotive force and the electric current I that on first coil 121, are produced ₂The magnetomotive force that is produced on second coil 122 is also inequality, be that magnetomotive force among lateral column A1 and the lateral column A2 is unequal, the difference of the two puts on the low-resistance loop that is made of lateral column A1, lateral column A2, shoulder post A3 and shoulder post A4 to produce a large amount of magnetic flux Φ, this magnetic flux Φ cuts first coil 121 and second coil 122, and can between its end points, respond to one of generation and revise voltage Δ V, this correction voltage Δ V can force the electric current I of first fluorescent tube 141 ₁Electric current I with second fluorescent tube 142 ₂Answer balance equalization.

Please refer to Fig. 4, use differential ballast in the ball bearing made using schematic diagram of regulating a plurality of lamp currents for existing, include a plurality of transformers 12 in the ball bearing made using shown in Figure 4 with first coil 121 and second coil 122, those first coil, 121 one ends are connected to a reference potential G, the other end is connected with one first fluorescent tube 141 respectively, and the other end of those first fluorescent tubes 141 is connected to an AC power 10.And those second coils 122, the one end is connected to this reference potential G, and the other end is connected with one second fluorescent tube 142 respectively, and the other end of those second fluorescent tubes 142 is connected to this AC power 10.As described above, first coil 121 and second coil 122 that this AC power 10 sees through those transformers 12 form differential ballast, in order to stable electric current I to be provided respectively ₁, I ₂Use for those first fluorescent tubes 141 and those second fluorescent tubes 142, make the electric current that flows through first fluorescent tube 141 and second fluorescent tube 142 reach the effect of balance, only limit between two fluorescent tubes also can't and other fluorescent tube between the effect of current balance type is arranged.

Please refer to Fig. 5, be the existing ball bearing made using schematic diagram that uses differential ballast to regulate lamp current of another kind.Shown in Figure 5, with two fluorescent tubes be example wherein two fluorescent tubes 31,32 one-tenth be connected in parallel, the high-pressure side of two fluorescent tubes 31,32 sees through a differential ballast element 39 and is connected to an AC power 10.This differential ballast element 39 can produce one and revise voltage, this a correction voltage and a lamp current I ₃₁, I ₃₂Between do not match proportional, and stackable to a common driving voltage.Therefore, through the driving voltage of revising, can suitably adjust lamp tube current I ₃₁, I ₃₂, make its mean allocation.Though this kind circuit can guarantee two lamp tube current and reach equal, its structure generally comprises the magnetic core and the bobbin of given shape, and the non-general general standard items of these magnetic cores and bobbin, thus in material arrangement and cost control, all constitute inconvenient.

Please refer to Fig. 6, be the existing ball bearing made using schematic diagram that uses differential ballast to regulate a plurality of lamp currents of another kind.Shown in Figure 6, a plurality of differential ballast elements T 1, T2, T3, T4, T5, T6, T7 are connected to an AC power 10 with tree-shaped connected mode, utilize the layering shunting principle that electric current is diverted to a plurality of fluorescent tube L1, L2, L3, L4, L5, L6, L7, L8 to reach current balance type, it is described that its operating principle is same as Fig. 5, do not add to give unnecessary details at this.

Existing adjusting lamp current circuit in the above-mentioned explanation, one common shortcoming is arranged, be when circuit application in many fluorescent tubes following times, can only be applied on two balances between the fluorescent tube, and can not be applied on the odd number fluorescent tube, and with Fig. 6 be inductance value on its coils at different levels of example neither with and can only be applied on the fluorescent tube number of two power.

Summary of the invention

A kind of lamp tube current equalizing method of the present invention and application circuit, its main purpose are to be to utilize a side winding of a plurality of transformers to be connected to a plurality of fluorescent tubes, and the opposite side winding of those a plurality of transformers, and serial connection forms a loop.Utilize transformer electromagnetic induction characteristic, and be connected in series formed loop, make the electric current that flows through a side winding equate, allow those fluorescent tubes that are connected in the opposite side winding produce identical operating current through those transformer one side windings.

Tube flow equalizing application circuit embodiment used in the present invention is to utilize an end of a plurality of fluorescent tubes to be connected respectively to an electric power source; And the other end of those fluorescent tubes connects a side winding of a plurality of transformers, and the opposite side winding serial connection of transformer forms a loop, and thus, this electric power source can provide identical operating current to those fluorescent tubes.

Another embodiment of tube flow equalizing application circuit used in the present invention is that the end with a plurality of fluorescent tubes links together, and utilizes the other end of those fluorescent tubes to be connected respectively to an end of a plurality of transformer one side windings, and the other end of winding then is connected to an electric power source.Simultaneously, the opposite side winding of those transformers serial connection forms a loop, and thus, this electric power source provides identical operating current to arrive those fluorescent tubes.

Tube flow equalizing application circuit used in the present invention is an embodiment more, it is the end that a end with a plurality of fluorescent tubes is connected respectively to those transformer one side windings in one first many transformer group, the other end of one side winding then is connected to one first electric power source, and the opposite side winding serial connection of those transformers forms a loop in this more than first transformer group.Simultaneously, the other end of those fluorescent tubes is connected to an end of those transformer one side windings in one second many transformer group, the other end of one side winding then is connected to one second electric power source, and the opposite side winding serial connection of those transformers forms a loop in this more than second transformer group.Thus, this first electric power source and this second electric power source can provide identical operating current to those fluorescent tubes.

The present invention utilizes transformer electromagnetic induction characteristic, is connected in series formed loop by those transformer one side windings, makes the electric current that flows through this side winding equate, uses to the fluorescent tube that those are connected on the opposite side winding so that identical operating current to be provided.The present invention simultaneously can be applied on odd number or the even number fluorescent tube, and reaches equal mobile equilibrium when making lamp works, and then improves available circuit.With shown in Figure 6, can on coils at different levels, the different induction amount will be arranged, and can not be applied on the odd number fluorescent tube, can only be applied to the shortcoming on the fluorescent tube number of two power.

Description of drawings

Fig. 1 uses differential ballast in the ball bearing made using schematic diagram of regulating two lamp currents for existing;

Fig. 2 is the transformer equivalence magnetic loop schematic diagram of Fig. 1;

Fig. 3 is the schematic diagram that the existing equivalent magnetic loop of Fig. 1 connects fluorescent tube;

Fig. 4 uses differential ballast in the ball bearing made using schematic diagram of regulating a plurality of lamp currents for existing;

Fig. 5 is the another kind of existing ball bearing made using schematic diagram that uses differential ballast to regulate lamp current;

Fig. 6 is the another kind of existing ball bearing made using schematic diagram that uses differential ballast to regulate a plurality of lamp currents;

Fig. 7 is the present invention's two tube flow equalizing application circuit schematic diagrames;

Fig. 8 is the present invention's three tube flow equalizing application circuit schematic diagrames;

Fig. 9 is another two tube flow equalizing application circuits schematic diagram of the present invention;

Figure 10 is another three tube flow equalizing application circuits schematic diagram of the present invention;

Figure 11 is more more than one tube flow equalizing application circuit schematic diagram of the present invention; And

Figure 12 is a lamp tube current equalizing method steps flow chart schematic diagram of the present invention.

The figure number explanation

Prior art

10 AC power, 12 transformers, 120 magnetic cores

121 first coils, 122 second coils, 141 first fluorescent tubes

142 second fluorescent tube G reference potential I1, I2 electric current

A1, A2 lateral column A3, A4 shoulder post Φ, Φ 1, Φ 2 magnetic fluxs

Δ V revises voltage 31,32 fluorescent tubes 39 differential ballast elements

I31, I32 lamp current

T1, T2, T3, T4, T5, T6, the differential ballast element of T7

L1, L2, L3, L4, L5, L6, L7, L8 fluorescent tube

The present invention:

L1, L2, L3 fluorescent tube V _SECElectric power source

V _SEC1 first electric power source V _SEC2 second electric power source

T1, T2, T3, T4, T5, T6 transformer

L1 _P, L2 _P, L3 _P, L1 _S, L2 _S, L3 _S, L4 _S, L5 _S, L6 _SWinding

Ix, ix1, ix2 electric current

I1, i2, i3 operating current

M1, M2, M3 mutual inductance value

Specific implementation method

Please refer to Fig. 7, be the present invention's two lamp tube current equalizings and application schematic diagram.Circuit shown in Figure 7 is an example with two fluorescent tubes, and comprising two fluorescent tube L1, L2 are arranged, this two fluorescent tube L1, L2 one end are connected respectively to an electric power source V _Sec, the other end then is connected respectively to the side winding L 1 of transformer T1, T2 _P, L2 _P, the opposite side winding L 1 of transformer T1, T2 _S, L2 _SBe that serial connection forms a loop.By transformer T1, T2 electromagnetic induction characteristic, and see through those transformers T1, T2 one side winding L 1 _S, L2 _SBe connected in series formed loop, make and flow through a side winding L 1 _S, L2 _SCurrent i x equate, thus, this electric power source V _SecIdentical operating current i is provided ₁, i ₂To this two fluorescent tube L1, L2.In the above-mentioned explanation, its both sides umber of turn of those transformers T1, T2 is for equal, and the balancing transformer for equating.Simultaneously, this two fluorescent tube L1, L2 can be cold-cathode tube (CCFL) or outer electrode cold-cathode tube (EEFL).

Please refer to Fig. 7, wherein transformer T1, T2 are the transformer of two balances, and therefore, the both sides umber of turn of transformer T1 equates (N1 _P=N1 _S); The both sides umber of turn of transformer T2 equates (N2 _P=N2 _S), can learn that so the equivalent electric sensibility reciprocal on the winding of transformer both sides also can equate, shown in following formula (1):

L1 _P＝L1 _S；L2 _P＝L2 _S (1)

In the top formula (1), L1 _PAnd L1 _SEquivalent inductance value on the winding of indication transformer T1 both sides, L2 _PAnd L2 _SEquivalent inductance value on the winding of indication transformer T2 both sides.If under transformer T1 and the situation that its number of turn of transformer T2 also equates, then formula (1) can be write as shown in the following formula (2):

L1 _P＝L1 _S＝L2 _P＝L2 _S (2)

Simultaneously, because transformer T1 equates with equivalent inductance value on the transformer T2 winding, so the mutual inductance value M1, the M2 that are produced between transformer T1, T2 both sides winding also can approximately equals, shown in following formula (3):

M1＝M2 (3)

In the top formula (3), M1 is the mutual inductance value between the winding of transformer T1 both sides, and M2 is the mutual inductance value between the winding of transformer T2 both sides.

Please, in figure, can learn electric power source V again with reference to figure 7 _SecIts value can be by internal resistance value Z1, Z2 and the operating current i of two fluorescent tube L1, L2 ₁, i ₂Equivalent inductance value L1 on transformer T1, the T2 winding _P, L2 _PThe mutual inductance value M1, the M2 that are produced between transformer T1, T2 both sides winding; And flow through transformer T1, T2 one side winding L 1 _S, L2 _SCurrent i x calculate and get, shown in following formula (4), (5):

V _sec＝(Z1+jωL1 _P)·i ₁-ix(jωM1) (4)

V _sec＝(Z2+jωL2 _P)·i ₂-ix(jωM2) (5)

In top formula (4), (5), ω is expressed as electric power source V _SecThe operating frequency value, j represents the equivalent inductance value L1 on the winding _P, L2 _PBe inductance characteristic.

Formula (6) below top formula (4), (5) can be learnt, as follows:

(Z1+jωL1 _P)·i ₁-ix(jωM1)＝(Z2+jωL2 _P)·i ₂-ix(jωM2)(6)

Formula (6) through arrangement after, can obtain following formula (7), in order to learning operating current i1 value, as follows:

$i_1=\frac{(\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="A20041008893000142.png"\; state="\{\{state\}\}">Z</figure-callout>}2+\mathrm{j\&omega;L}{2}_P)}{\mathrm{<figure-callout\; id="1"\; label="Z"\; filenames="A20041008893000142.png,A20041008893000151.png"\; state="\{\{state\}\}">Z</figure-callout>}1+{\mathrm{j\&omega;L}1}_P}\&CenterDot;i_2-\frac{(\mathrm{ix}\left(\mathrm{j\&omega;M}2\right)-\mathrm{ix}\left(\mathrm{j\&omega;M}1\right))}{\mathrm{<figure-callout\; id="1"\; label="Z"\; filenames="A20041008893000142.png,A20041008893000151.png"\; state="\{\{state\}\}">Z</figure-callout>}1+j{\mathrm{\&omega;L}1}_P}---\left(7\right)$

With reference to formula (7), owing to the mutual inductance value M1 that is produced between transformer T1, T2 both sides winding, its value of M2 are equal (M1=M2), therefore, the operating current i shown in the formula (7) ₁Value, can be write as shown in following formula (8):

$i_1=\frac{(\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="A20041008893000142.png"\; state="\{\{state\}\}">Z</figure-callout>}2+{\mathrm{j\&omega;L}2}_P)}{\mathrm{<figure-callout\; id="1"\; label="Z"\; filenames="A20041008893000142.png,A20041008893000151.png"\; state="\{\{state\}\}">Z</figure-callout>}1+{\mathrm{j\&omega;L}1}_P}\&CenterDot;i_2---\left(8\right)$

Reach (8) also with after it arrangement with reference to formula (2), can learn shown in the following formula (9):

$\frac{i_1}{i_2}=\frac{(\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="A20041008893000142.png"\; state="\{\{state\}\}">Z</figure-callout>}2+{\mathrm{j\&omega;L}1}_P)}{(\mathrm{<figure-callout\; id="1"\; label="Z"\; filenames="A20041008893000142.png,A20041008893000151.png"\; state="\{\{state\}\}">Z</figure-callout>}1+{\mathrm{j\&omega;L}1}_P)}---\left(9\right)$

Can learn by top formula (9), when the internal resistance value (Z1, Z2) of two fluorescent tube L1, L2 less than electric power source V _SecOperating frequency value ω and equivalent inductance value L1 _PThe time, the operating current i of fluorescent tube L1 then ₁Can be equal to the operating current i of fluorescent tube L2 ₂(i ₁=i ₂).If when the internal resistance value of two fluorescent tube L1, L2 is unequal (Z1Z2), the operating current i2 (i1=i2) that the operating current of fluorescent tube L1 is equal to fluorescent tube L2 equally sets up.

By learning in the top formula, the present invention utilizes transformer electromagnetic induction characteristic, is connected in series formed loop by transformer T1, T2 one side winding, makes the current i x that flows through this side winding equate, so that identical operating current i to be provided ₁, i ₂Use to those fluorescent tube L1, L2 that are connected on the opposite side winding, allow the operating current i of fluorescent tube L1, L2 ₁, i ₂Reach equal mobile equilibrium, and then improve available circuit and can on coils at different levels, produce the different induction amount, and can not be applied to be applied to the common drawback of even number fluorescent tube on the odd number fluorescent tube.

Please refer to Fig. 8, be the present invention's three tube flow equalizing application circuit schematic diagrames.Circuit shown in Figure 8 is an example with three fluorescent tubes, and comprising three fluorescent tube L1, L2, L3 are arranged, this three fluorescent tube L1, L2, L3 one end are connected respectively to an electric power source V _Sec, the other end then is connected respectively to the side winding L 1 of transformer T1, T2, T3 _P, L2 _P, L3 _P, the opposite side winding L 1 of transformer T1, T2, T3 _S, L2 _S, L3 _SSerial connection forms a loop.By transformer T1, T2, T3 electromagnetic induction characteristic, and see through those transformers T1, T2, T3 one side winding L 1 _S, L2 _S, L3 _SBe connected in series formed loop, make and flow through transformer T1, T2, T3 one side winding L 1 _S, L2 _S, L3 _SCurrent i x equate, thus, this electric power source V _SecIdentical operating current i is provided ₁, i ₂To this two fluorescent tube L1, L2.In the above-mentioned explanation, those transformers T1, its both sides umber of turn of T2, T3 are for equal, and the balancing transformer for equating.Simultaneously, this two fluorescent tube L1, L2, L3 can be cold-cathode tube (CCFL) or outer electrode cold-cathode tube (EEFL).

Multiple with reference to figure 8, three tube flow equalizing application circuits shown in Figure 8 and two tube flow equalizing application circuits shown in Figure 7, the derivation of its operating principle and formula is identical, does not therefore add at this and gives unnecessary details.So, the present invention can be applied on odd number or a plurality of fluorescent tubes of even number, and reaches equal mobile equilibrium when making lamp works, and then improves available circuit can produce the different induction amount on coils at different levels, and can not be applied to be applied to the common drawback of even number fluorescent tube on the odd number fluorescent tube.

Please refer to Fig. 9, be another two tube flow equalizing application circuits schematic diagram of the present invention.Circuit shown in Figure 9 is an example with two fluorescent tubes, and comprising two fluorescent tube L1, L2 are arranged, this two fluorescent tube L1, L2 one end are connected respectively to a reference edge G, and the other end then sees through the side winding L 1 of transformer T1, T2 respectively _P, L2 _PBe connected to an electric power source V _Sec, the opposite side winding L 1 of transformer T1, T2 _S, L2 _SSerial connection forms a loop.By transformer T1, T2 electromagnetic induction characteristic, reach those transformers T1, T2 one side winding L 1 _S, L2 _SBe connected in series formed loop, make and flow through transformer T1, T2 one side winding L 1 _S, L2 _SCurrent i x equate, thus, this electric power source V _SecIdentical operating current i is provided ₁, i ₂To this two fluorescent tube L1, L2.In the above-mentioned explanation, its both sides umber of turn of those transformers T1, T2 is for equal, and the balancing transformer for equating.Simultaneously, this two fluorescent tube L1, L2 can be cold-cathode tube (CCFL) or outer electrode cold-cathode tube (EEFL).

Please refer to Figure 10, be another three tube flow equalizing application circuits schematic diagram of the present invention.Circuit shown in Figure 10 is an example with three fluorescent tubes, and comprising three fluorescent tube L1, L2, L3 are arranged, this three fluorescent tube L1, L2, L3 one end are connected respectively to a reference edge G, and the other end then sees through the side winding L 1 of transformer T1, T2, T3 respectively _P, L2 _P, L3 _PBe connected to an electric power source V _Sec, the opposite side winding L 1 of transformer T1, T2, T3 _S, L2 _S, L3 _SSerial connection forms a loop.By transformer T1, T2, T3 electromagnetic induction characteristic, reach those transformers T1, T2, T3 one side winding L 1 _S, L2 _S, L3 _SBe connected in series formed loop, make and flow through transformer T1, T2, T3 one side winding L 1 _S, L2 _S, L3 _SCurrent i x equate, thus, this electric power source V _SecIdentical operating current i is provided ₁, i ₂, i ₃To this three fluorescent tube L1, L2, L3.In the above-mentioned explanation, those transformers T1, its both sides umber of turn of T2, T3 are for equal, and the balancing transformer for equating.Simultaneously, this two fluorescent tube L1, L2, L3 can be cold-cathode tube (CCFL) or outer electrode cold-cathode tube (EEFL).

Multiple with reference to figure 9 and Figure 10, as Fig. 9 and tube flow equalizing application circuit shown in Figure 10, the derivation of its operating principle and formula and Fig. 7, tube flow equalizing application circuit shown in Figure 8 are identical, so do not add at this and to give unnecessary details.So, the present invention can be applied on odd number or a plurality of fluorescent tubes of even number, and reaches equal mobile equilibrium when making lamp works, and then improves available circuit can produce the different induction amount on coils at different levels, and can not be applied to be applied to the common drawback of even number fluorescent tube on the odd number fluorescent tube.

Please refer to Figure 11, be the present invention's more than one tube flow equalizing application circuit schematic diagram more.Circuit shown in Figure 11 is imported reverse position voltage with the operating principle of a Floating circuit from the terminal at two ends, the fluorescent tube left and right sides lights a lamp fluorescent tube, is example at this with three fluorescent tubes.Three fluorescent tube L1, L2, L3 have two ends respectively in the circuit, and the side winding that the end of this three fluorescent tube L1, L2, L3 sees through transformer T1, T2, T3 respectively is connected to one first electric power source V _Sec1, and the opposite side winding of those transformers serial connection forms a loop.Simultaneously, the other end of this three fluorescent tube L1, L2, L3 is connected to one second electric power source V through the side winding of transformer T4, T5, T6 respectively _Sec2, and the opposite side winding of those transformers serial connection forms a loop.In the above-mentioned explanation, transformer T1, T2, T3 form one first many transformer group, and transformer T4, T5, T6 form one second many transformer group.

By transformer T1, T2, T3, T4, T5, T6 electromagnetic induction characteristic, reach those transformers T1, T2, T3, T4, T5, T6 one side winding L 1 _S, L2 _S, L3 _S, L4 _S, L5 _S, L6 _SBe connected in series formed loop, make and flow through transformer T1, T2, T3, T4, T5, T6 one side winding L 1 _S, L2 _S, L3 _S, L4 _S, L5 _S, L6 _SCurrent i x1 and ix2 equate.Thus, this first electric power source V _SEC1And the second electric power source V _Sec2 see through the opposite side winding L1 of transformer _P, L2 _P, L3 _P, L4 _P, L5 _P, L6 _PIdentical operating current i is provided ₁, i ₂, i ₃To this three fluorescent tube L1, L2, L3.Those transformers T1, T2, T3, T4, T5, its both sides umber of turn of T6 are for equal, and the balancing transformer for equating.Simultaneously, this two fluorescent tube L1, L2, L3 can be cold-cathode tube (CCFL) or outer electrode cold-cathode tube (EEFL).

In the above-mentioned explanation, be example explanation with two fluorescent tubes and three fluorescent tubes, if when therefore being applied to other a plurality of fluorescent tube, its circuit connecting method can increase or reduces fluorescent tube according to above-mentioned connected mode, and its operating principle is identical with above-mentioned explanation.

Multiple with reference to Figure 11, tube flow equalizing application circuit as shown in figure 11, the derivation of its operating principle and formula and Fig. 7, tube flow equalizing application circuit shown in Figure 8 are identical, so do not add at this and to give unnecessary details.So, the present invention can be applied on odd number or a plurality of fluorescent tubes of even number, and reaches equal mobile equilibrium when making lamp works, and then improves available circuit can produce the different induction amount on coils at different levels, and can not be applied to be applied to the common drawback of even number fluorescent tube on the odd number fluorescent tube.

Please refer to Figure 12, be lamp tube current equalizing method steps flow chart schematic diagram of the present invention.Its lamp tube current equalizing step of the present invention is as described below: at first, a side winding that connects a plurality of transformers respectively is to a plurality of fluorescent tube S100; Then, be connected in series the opposite side winding of those a plurality of transformers, form a loop; Then, add electric power in a side winding and those fluorescent tubes of those transformers, to carry out the S104 that lights a lamp of those fluorescent tubes; Produce identical operating current at last in those fluorescent tubes S106.

Lamp tube current equalizing method used in the present invention utilizes transformer electromagnetic induction characteristic, be connected in series formed loop by those transformer one side windings, make the electric current that flows through this side winding equate, use to the fluorescent tube that those are connected on the opposite side winding so that identical operating current to be provided.The present invention simultaneously can be applied on odd number or the even number fluorescent tube, and reach equal mobile equilibrium when making lamp works, and then improve available circuit and can on coils at different levels, produce the different induction amount, and can not be applied to be applied to the common drawback of even number fluorescent tube on the odd number fluorescent tube.

Claims (15)

1, a kind of lamp tube current equalizing method can allow a plurality of fluorescent tube circulations that the operating current of identical size is arranged, and step includes:

A side winding that connects a plurality of transformers respectively is to those fluorescent tubes;

Be connected in series the opposite side winding of those a plurality of transformers, form a loop;

Add electric power in a side winding and those fluorescent tubes of those transformers, to carry out lighting a lamp of those fluorescent tubes; And

Produce identical operating current in those fluorescent tubes.

2, lamp tube current equalizing method as claimed in claim 1 is characterized in that, those fluorescent tubes can be even number fluorescent tube or odd number fluorescent tube.

3, lamp tube current equalizing method as claimed in claim 1 is characterized in that, those transformers have equal umber of turn.

4, a kind of tube flow equalizing application circuit is characterized in that, includes:

A plurality of fluorescent tubes, the one end is connected respectively to an electric power source;

A plurality of transformers, one side winding is connected respectively to the other end of those fluorescent tubes, and opposite side winding serial connection forms a loop;

Thus, this electric power source provides identical operating current to arrive those fluorescent tubes.

5, tube flow equalizing application circuit as claimed in claim 4 is characterized in that, those fluorescent tubes can be even number fluorescent tube or odd number fluorescent tube.

6, tube flow equalizing application circuit as claimed in claim 4 is characterized in that, a plurality of fluorescent tubes can be cold-cathode tube or outer electrode cold-cathode tube.

7, tube flow equalizing application circuit as claimed in claim 4 is characterized in that, those transformers have equal umber of turn.

8, a kind of tube flow equalizing application circuit is characterized in that, includes:

A plurality of fluorescent tubes, the one end connects respectively;

A plurality of transformers, an end of one side winding is connected respectively to the other end of those fluorescent tubes, and the other end then is connected to an electric power source, and its opposite side winding serial connection forms a loop;

Thus, this electric power source provides identical operating current to arrive those fluorescent tubes.

9, tube flow equalizing application circuit as claimed in claim 8 is characterized in that, those fluorescent tubes can be even number fluorescent tube or odd number fluorescent tube.

10, tube flow equalizing application circuit as claimed in claim 8 is characterized in that, a plurality of fluorescent tubes can be cold-cathode tube or outer electrode cold-cathode tube.

11, tube flow equalizing application circuit as claimed in claim 8 is characterized in that, those transformers have equal umber of turn.

12, a kind of tube flow equalizing application circuit is characterized in that, includes:

A plurality of fluorescent tubes have two ends respectively;

More than first transformer group, have a plurality of transformers, one end of one side winding of those transformers is connected respectively to an end of those fluorescent tubes, and the other end of a side winding then is connected to one first electric power source, and the opposite side winding of those transformers serial connection forms a loop;

More than second transformer group, have a plurality of transformers, one end of one side winding of those transformers is connected respectively to the other end of those fluorescent tubes, and the other end of a side winding then is connected to one second electric power source, and the opposite side winding of those transformers serial connection forms a loop;

Thus, this first electric power source and this second electric power source provide identical operating current to those fluorescent tubes.

13, tube flow equalizing application circuit as claimed in claim 12 is characterized in that, those fluorescent tubes can be even number fluorescent tube or odd number fluorescent tube.

14, tube flow equalizing application circuit as claimed in claim 12 is characterized in that, a plurality of fluorescent tubes can be cold-cathode tube or outer electrode cold-cathode tube.

15, tube flow equalizing application circuit as claimed in claim 12 is characterized in that, those transformers have equal umber of turn.

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