JPH088155B2 - Fluorescent tube drive circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a two-stone resonance type fluorescent tube driving circuit.

SUMMARY OF THE INVENTION The present invention provides a two-stone resonance type fluorescent tube drive circuit,
Conventionally, the parts of the resonance capacitor and the transformer, which are separately provided, are alternately laminated with a plurality of conductor films and dielectric films to form an integrated structure with a transformer part wound around a magnetic core. This is to reduce the size and the number of parts without complicating the line structure.

[Conventional technology]

As a conventional fluorescent tube drive circuit, a type called a two-stone resonance type is known. In this fluorescent tube drive circuit, two transistors whose emitters are commonly connected are alternately oscillated to perform a push-pull operation, and a parallel resonance circuit including a transformer and a resonance capacitor connected between the collectors of the respective transistors. The output of the fluorescent lamp is turned on.

[Problems to be solved by the invention]

However, in the conventional two-stone resonance type fluorescent tube driving circuit, the resonance capacitor and the transformer are separately configured. Therefore, there is a limit to the reduction of the number of partial points, and it is difficult to reduce the size. Further, it is possible to wind the resonance capacitor around the transformer as a method for downsizing, but in this case, there is a drawback that the winding structure becomes complicated because each conductor is separate.

By the way, a plurality of pairs of conductive layers and insulating layers are alternately laminated and wound by the applicant of the present application to form a circuit including a coil and a capacitor, a capacitor,
A multifunctional reactance device (Japanese Patent Application No. 60-77253) has been proposed, which can selectively obtain either a transformer or a transformer having a capacitor, and a fluorescent tube drive circuit using this reactance device. It is conceivable to downsize.

Therefore, it is an object of the present invention to provide a fluorescent tube drive circuit which has a reduced number of parts and a reduced size without complicating the winding structure of a transformer.

[Means for solving problems]

The present invention relates to a first transformer 1 which is formed by winding first and second conductive films 13 and 15 and first and second dielectric films 14 and 16 alternately around a magnetic core 11. One end 13a of the second conductive film 13 and the second conductive film 15
The other end 15b of the first and second conductive films 13,
Direct current voltage is supplied to the common connection point (17) of 15 through the choke coil 4 and driven in reverse phase between the other end 13b of the first conductor film 13 and the one end 15a of the second conductor film 15. The fluorescent tube driving circuit is characterized in that the two switching elements 5 and 6 are connected to a series circuit of the fluorescent tube 9 and the ballast element 8.

[Action]

The conductor films 13 and 15 and the dielectric films 14 and 16 are sequentially laminated, and the laminated body is wound around the magnetic core 11, and the starting end 13a of the conductor film 13 and the conductor film 15 are formed.
Is connected to the end 15a. Therefore, the conductor film 1
A capacitor 21 is equivalently formed between 3 and 15, and the transformer unit 1 is a multi-function one having a transformer and a capacitor for parallel resonance even though it is a single unit. Used in a fluorescent tube drive circuit.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention.
The broken line portion indicated by 1 in FIG. 1 is the transformer portion. Three terminals 17, 18 and 19 are derived from the transformer unit 1.

One end of the choke coil 4 is connected to the rectifier circuit 3 to which the AC voltage source 2 is connected, and the other end of the choke coil 4 is connected to the terminal 17 of the transformer section 1. Base drive circuit 7
, The bases of NPN type transistors 5 and 6 are connected to each other, and the emitters of the transistors 5 and 6 are commonly connected to
This common connection point is connected to the rectifier circuit 3. The collector of the transistor 5 is connected to the terminal 19 of the transformer unit 1, and the collector of the transistor 6 is connected to the terminal 18 of the transformer unit 1. Further, one end of the ballast coil 8 is connected to the terminal 19 of the transformer section 1, the other end of the coil 8 is connected to one end of the fluorescent tube, and the other end of the fluorescent tube is connected to the terminal 18 of the transformer section 1. To be done.

FIG. 2 is a cross-sectional view of the transformer portion in one embodiment of the present invention, and 13 and 15 in FIG. 2 are conductor films such as copper foil and aluminum foil. Also,
In FIG. 2, 14 and 16 are dielectric films such as polyester film and polypropylene film.

The conductor films 13 and 15 and the dielectric films 14 and 16 are sequentially laminated, and the laminated body (strip-shaped laminated body) is formed with the insulator 12 interposed therebetween. It is wound as shown in the figure. The number of windings in this case is arbitrary.

As shown in FIG. 2, the starting ends of the conductor films 13 and 15 at which winding starts are 13a and 15a.
When the end of the winding end of is 13b and 15b,
Connections are made as shown in FIG. That is, the start end 13a of the conductor film 13 and the end 15b of the conductor film 15 are connected, the terminal 17 is derived from this connection point, the terminal 18 is derived from the start end 15a of the conductor film 15, the conductor film The terminal 19 is led out from the terminal end 13b of 13 to form the transformer unit 1.

Therefore, between the conductor films 13 and 15, the facing area of the conductor films 13 and 15 to be electrodes and the dielectric film 14,
A coil having equivalently formed capacitor 21 having a capacitance defined by the thickness and dielectric constant of 16 and having an inductance defined by the number of turns and the magnetic permeability of magnetic core 11.
Parallel resonance circuits 21 and 22 with 20 are formed, and the transformer section 1 has the same characteristics as the equivalent circuit shown in FIG.

The transformer unit 1 thus configured is connected to each unit as shown in FIG. 1, and the DC voltage from the rectifier circuit 3 is supplied to the terminal 17 through the choke coil 4. Also,
The transistors 5 and 6 are alternately turned on by a reverse-phase drive pulse from the base drive circuit 7 to perform push-pull operation, and collector currents are alternately generated at the terminals 18 and 19. The parallel resonant circuits 21 and 22 resonate, the resonant capacitor 21 repeats charging and discharging, and the sine wave output output from the parallel resonant circuits 21 and 22 is applied to both ends of the fluorescent tube 9 via the ballast coil 8. Then, the fluorescent tube 9 lights up.

〔The invention's effect〕

In this invention, two conductor films and two dielectric films are sequentially laminated, the laminate is wound around the magnetic core, and the end portions of the conductor films are connected in a predetermined relationship. It Therefore, a capacitor is equivalently formed between the conductor films, and the transformer section is a multi-functional one having a transformer and a resonance capacitor. This transformer section is a two-stone resonance type fluorescent tube drive circuit. Used for.

Therefore, according to the present invention, since the conductive film of the transformer also serves as the capacitor for resonance, the number of components can be reduced without complicating the winding structure of the transformer, and the size can be reduced. Thus, it is possible to provide a low-cost two-stone resonance type fluorescent tube driving circuit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a connection diagram of an embodiment of the present invention, FIG. 2 is a sectional view used for explaining a transformer section in the embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a connection diagram used for explaining the transformer section in the example, and FIG. 4 is a connection diagram showing an equivalent circuit of the transformer section in one embodiment of the present invention. Description of main symbols in the drawings 1: Transformer part, 4: Choke coil, 5,6: NPN transistor, 8: Ballast coil, 9: Fluorescent tube, 11: Magnetic core, 13, 15: Conductor Films, 14,16:
Dielectric film.

Claims (1)

[Claims] 1. One end of the first conductive film of a transformer formed by winding first and second conductive films and first and second dielectric films alternately on a magnetic core. And the other end of the second conductor film are connected to each other, and a DC voltage is supplied to a common connection point of the first and second conductor films via a choke coil. Fluorescent tube driving, characterized in that two switching elements driven in reverse phase and a series circuit of a fluorescent tube and a ballast element are connected between an end and one end of the second conductive film. circuit.