CN2727923Y - Multi-tube differential ballast - Google Patents

Abstract

The utility model discloses multi-tube differential ballast which is formed by the inter coupling of a plurality of identical drum-shaped coils, and the coils are adjacent and juxtaposed to each other. The same phase ends of the coils are connected together, and the other ends are connected with a plurality of lamp tubes. The magnetic flux is inducted to flow across the connected coil magnetic cores, when the current in an individual lamp tube is inconsistent. The magnetic path, between the coils ends connected with the individual lamp tube, inducts a correction voltage which readjusts the unbalanced current in the individual amp tube.

Description

The differential ballast of many fluorescent tubes

Technical field

The utility model relates to the differential ballast of a kind of many fluorescent tubes, particularly relates to a kind ofly utilizing that the drum type coil is adjacent to be of coupled connections side by side, in order to regulate the differential ballast of current balance type between many fluorescent tubes.

Background technology

Cathode fluorescent tube (CCFL Cold Cathode Fluorescent Lamp) is known to be to use in display panels (LCD Panel) light source as module backlight (Backlight System).These cathode fluorescent tubes are driven by a drive circuit that is called converter (Inverter).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 fluorescent tubes.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 the cathode fluorescent tube height is 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, except meeting make lighting tube brightness inhomogeneous, 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.

In the known technology, making a plurality of cathode fluorescent tubes have the most direct mode of same brightness, is that each fluorescent tube is used independent drive circuit and feedback controller.All lamp tube current can be controlled at fixed value with a common control signal.Fig. 1 shows that known technology adopts the different driving circuit to drive the circuit framework of a plurality of cathode fluorescent tubes, and it is to be example with two fluorescent tubes. Fluorescent tube 11,12 is subjected to circuit 13,14 and transformer 15,16 to drive and control respectively, electric current I 11, the I12 of fluorescent tube 11,12 of flowing through feeds back to circuit 13,14 respectively, and electric current I 11, I12 all be controlled in a default fixed value, reaches the effect that electric current equates.Yet owing to need drive and control circuit for each fluorescent tube all is provided with one, this kind circuit relatively has higher element cost, and takies bigger space.

A kind of known technology that does not need to be provided with a plurality of drivings and control circuit is used ballast (ballast) element, and the current difference between each fluorescent tube is dwindled as much as possible.Fig. 2 shows that known technology adopts single drive circuit to drive the circuit framework figure of a plurality of cathode fluorescent tubes, and it is an example with two fluorescent tubes.As shown in the figure, two fluorescent tubes 21,22 one-tenth are connected in parallel, and are driven by a circuit 23 and a transformer 25.The high-pressure side of two fluorescent tubes 21,22 is connected in series an electric capacity 27,28 respectively as ballast element (Ballast).Two electric capacity 27,28 have identical impedance, and its resistance value is much larger than the impedance of fluorescent tube 21,22, are enough to make the flow through electric current I 21 of two fluorescent tubes 21,22, the size of I22 arranged by condensance.That is, even it is when the impedance of two fluorescent tubes 21,22 produces difference, very slight and can ignore to the difference ground influence of electric current I 21, I22.Therefore two fluorescent tubes 21,22 that driven by common high drive source can be adjusted to and have close current value.Yet, can be more accurate in order to make electric current distribution control, that is, the difference of electric current I 21, I22 is dwindled as far as possible, this circuit will use the ballast element of high impedance, so need unusual high driving voltage.The generation of high driving voltage expends cost with processing and is difficult to reach very much, so this kind mode is not widely used.

The another kind of known technology that can not need to be provided with a plurality of drivings and control circuit is used differential ballast element (Differential Ballast).Fig. 3 shows this kind circuit framework figure, and it is an example with two fluorescent tubes.As shown in the figure, two fluorescent tubes 31,32 one-tenth are connected in parallel, and are driven by a circuit 33 and a transformer 35.The high-pressure side of two fluorescent tubes 31,32 is connected to the secondary side of transformer 35 by a differential ballast element 39.Differential ballast element 39 can produce one and revise voltage, and not matching between this correction voltage and lamp current I31, the I32 is proportional, and stackable to a common driving voltage.Therefore,, can suitably regulate lamp tube current I31, I32, make its mean allocation through the driving voltage of revising.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.

Summary of the invention

Technical problem to be solved in the utility model provides the differential ballast of a kind of many fluorescent tubes, and what solve prior art is difficult to reach the problem of balance as a plurality of lamp tube current of back light.

For achieving the above object, the utility model provides a kind of many fluorescent tubes differential ballast, is connected in an AC power and at least two fluorescent tubes, and its characteristics are, comprise: at least two drum type magnetic cores, the hat cap magnetic core portion by a trunk magnetic core portion and these trunk magnetic core portion two ends forms respectively; At least one coil windings is wound in this each trunk magnetic core portion, and this each coil windings one end is connected to this AC power simultaneously, and the other end is connected respectively to described fluorescent tube; The hat cap magnetic core portion adjacent coupled of described each drum type magnetic core connects, and constitutes the flux circuit of each drum type magnetic core of circulation.

The above-mentioned differential ballast of many fluorescent tubes, its characteristics be, between the end points of described each fluorescent tube that this coil windings was connected to, the flux of magnetic induction that flows through described flux circuit goes out one and flows through the correction voltage of described lamp tube current in order to adjusting.

The above-mentioned differential ballast of many fluorescent tubes, its characteristics are that described each coil windings is identical with respect to the coiling direction of affiliated magnetic core.

The above-mentioned differential ballast of many fluorescent tubes, its characteristics are that the coiling number of turn of described each coil windings is identical.

Technique effect of the present utility model is:

The differential ballast of many fluorescent tubes that the utility model provides, its basic structure is to be wound with at least two that the drum type magnetic core of coil windings is adjacent to be of coupled connections side by side, and an end of those coil windings is connected in an AC power simultaneously, the other end is connected respectively to a fluorescent tube, so, those drum type magnetic cores, constitute a magnetic flux path, flow through the magnetic flux of this magnetic flux path, can be between the end points of those fluorescent tubes that those coil windings are connected to, voltage is revised in induction one, and this correction voltage flows through those lamp tube current in order to adjusting, can make to flow through the effect that those lamp tube current reach balance.

Further describe specific embodiment of the utility model below in conjunction with accompanying drawing.

Description of drawings

Fig. 1 drives the circuit diagram of a plurality of cathode fluorescent tubes for known technology adopts the different driving circuit;

Single drive circuit drives the circuit diagram of a plurality of cathode fluorescent tubes to Fig. 2 for known technology adopts;

Single drive circuit drives another circuit framework figure of a plurality of cathode fluorescent tubes to Fig. 3 for known technology adopts;

Fig. 4 is used to regulate the differential ballast schematic perspective view of two fluorescent tubes for the utility model;

Fig. 5 is used to regulate the ball bearing made using schematic diagram of two fluorescent tubes for the utility model;

Fig. 6 is the utility model equivalence magnetic loop schematic diagram;

Fig. 7 is the schematic diagram that the utility model equivalence magnetic loop connects fluorescent tube; And

Fig. 8 is used in the ball bearing made using schematic diagram of regulating three fluorescent tubes for the utility model.

Wherein, description of reference numerals is as follows:

Known;

11,12 fluorescent tubes

13,14 circuit

15,16 transformers

21,22 fluorescent tubes

23 circuit

25 transformers

27,28 ballast elements (electric capacity)

31,32 fluorescent tubes

33 circuit

35 transformers

39 differential ballast elements

The utility model:

4 differential ballasts

42 first drum type coils

420 first drum type magnetic cores

422 hat cap magnetic core portions

424 first trunk magnetic core portions

426 first coil windings

44 second drum type coils

440 second drum type magnetic cores

442 hat cap magnetic core portions

444 second trunk magnetic core portions

446 second coil windings

50 AC power

62 first fluorescent tubes

64 second fluorescent tubes

70 magnetic cores

80 drum type coils

82 fluorescent tubes

Φ, Φ 1, Φ 2 magnetic fluxs

A1, A2 lateral column

A3, A4 NAN take on post

I1, I2 electric current

Δ V revises voltage

The G reference potential

Embodiment

Please refer to Fig. 4, for the utility model is used to regulate two differential ballast schematic perspective views of fluorescent tube.The differential ballast 4 of the utility model includes the first drum type coil 42 and one second drum type coil 44, wherein the first drum type coil 42 is by one first drum type magnetic core 420 of one first trunk magnetic core portion 424 and two ends hat cap magnetic core portion 422 compositions thereof, and use one first coil windings 426, be wound in this first trunk magnetic core portion 424 and combine.Identical, the one second drum type magnetic core 440 that one second drum type coil 44 is formed by one second trunk magnetic core portion 444 and two ends hat cap magnetic core portion 442 thereof, and use one second coil windings 446, be wound in this second trunk magnetic core portion 444 and combine, utilize the first drum type coil 42 and the second drum type coil 44, be of coupled connections side by side by those hat cap magnetic core portions 422,442 are adjacent, to constitute a magnetic flux path.In the above-mentioned explanation, this first coil windings 426 is same direction with these second coil windings, 446 its coiling directions, and its coiling number of turn is identical.

Please refer to Fig. 5, be used to regulate the ball bearing made using schematic diagram of two fluorescent tubes for the utility model.Comprising there being one first drum type coil, 42 one ends to be connected to an AC power 50, the other end is connected to one first fluorescent tube 62, and the other end of first fluorescent tube 62 is connected to a reference potential G.And one second drum type coil 44, adjacent this first drum type coil 42 that is listed in, the one end is connected to this AC power 50, the other end is connected to one second fluorescent tube 64, and this second fluorescent tube 64 the other end be connected to a reference potential G.As described above, this AC power 50 is by the first drum type coil 42 and the differential ballast of the second drum type coil, 44 formed the utility model, provide stable electric current I 1, I2 to use respectively, make the electric current that flows through first fluorescent tube 62 and second fluorescent tube 64 reach the effect of balance to first fluorescent tube 62 and second fluorescent tube 64.

Cooperate Fig. 4, please refer to Fig. 6, be the utility model equivalence magnetic loop schematic diagram.The magnetic loop of the magnetic loop that is made of adjacent arranged side by side first drum type coil 42 and one second drum type coil 44 itself and general differential ballast is as good as.As shown in Figure 6, wherein magnetic core 70 includes two lateral column A1 and A2, and two shoulder post A3 and A4. lateral column A1 be the first trunk magnetic core portion 424 of the first drum type magnetic core 420 shown in Figure 4, and lateral column A2 is the second trunk magnetic core portion 444 of the second drum type magnetic core 440 shown in Figure 4.Two shoulder post A3 and A4 then are that the two ends of the first drum type magnetic core 420 and the second drum type magnetic core 440 are preced with cap magnetic core portion 422,442 and are of coupled connections and form.When electric current I 1, when I2 is identical, the electric current that then flows through first coil windings 426 and second coil windings 446 also equates, and, electric current I 1 also equates in the magnetomotive force that second coil windings 446 produces with electric current I 2 in the magnetomotive force that first coil windings 426 produces, promptly, magnetomotive force among magnetomotive force among the lateral column A1 and the lateral column A2 is cancelled out each other, 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 the magnetic resistance of air gap is very high so inductive effect that this loop caused generally can be ignored.

Cooperate Fig. 5, please refer to Fig. 7, connect the schematic diagram of fluorescent tube for the utility model equivalence magnetic loop.When the electric current I 2 of the electric current I 1 of first fluorescent tube 62 and second fluorescent tube 64 is inequality, then the magnetomotive force that produced on second coil windings 446 of the magnetomotive force that produced on first coil windings 426 of electric current I 1 and electric current I 2 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 by lateral column A1, lateral column A2, the low-resistance loop that shoulder post A3 and shoulder post A4 are constituted is to produce a large amount of magnetic flux Φ, this magnetic flux Φ cuts first coil windings 426 and second coil windings 446, 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 1 of first fluorescent tube 62 and the electric current I 2 of first fluorescent tube 64 to reply the balance equalizations.

Please refer to Fig. 8, be used to regulate the ball bearing made using schematic diagram of three fluorescent tubes for the utility model.Comprising there being three drum type coils, 80 one ends to be connected to an AC power 50, the other end is connected respectively to three fluorescent tubes 82, and the other end of those fluorescent tubes 82 is connected to a reference potential G.Its operation principle is identical with the above-mentioned differential ballast of regulating two fluorescent tubes that is used in, and does not add at this and gives unnecessary details.

In sum, the differential ballast of a kind of many fluorescent tubes of the present utility model, be a kind of simple and differential cheaply ballast, be of coupled connections side by side at least two drum type magnetic cores that have been wound with coil windings are adjacent, and an end of those coil windings is connected in an AC power simultaneously, the other end is connected respectively to a fluorescent tube, can make those lamp tube current of flowing through reach the effect of balance.

The above is preferred embodiment of the present utility model only, is not to be used for limiting practical range of the present utility model; Every equivalence of doing according to the utility model changes and revises, and is all contained by claim of the present utility model.

Claims (6)

1, the differential ballast of a kind of many fluorescent tubes is connected in an AC power and at least two fluorescent tubes, it is characterized in that, comprising:

At least two drum type magnetic cores, the hat cap magnetic core portion by a trunk magnetic core portion and these trunk magnetic core portion two ends forms respectively;

At least one coil windings is wound in this each trunk magnetic core portion, and this each coil windings one end is connected to this AC power simultaneously, and the other end is connected respectively to described fluorescent tube;

The hat cap magnetic core portion adjacent coupled of described each drum type magnetic core connects, and constitutes the flux circuit of each drum type magnetic core of circulation.

2, the differential ballast of many fluorescent tubes according to claim 1 is characterized in that, described each coil windings is identical with respect to the coiling direction of affiliated magnetic core.

3, the differential ballast of many fluorescent tubes according to claim 1 is characterized in that, the coiling number of turn of described each coil windings is identical.

4, the differential ballast of many fluorescent tubes according to claim 1 is characterized in that, between the end points of described each fluorescent tube that this coil windings was connected to, the flux of magnetic induction that flows through described flux circuit goes out one and flows through the correction voltage of described lamp tube current in order to adjusting.

5, the differential ballast of many fluorescent tubes according to claim 4 is characterized in that, described each coil windings is identical with respect to the coiling direction of affiliated magnetic core.

6, the differential ballast of many fluorescent tubes according to claim 4 is characterized in that, the coiling number of turn of described each coil windings is identical.

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