JP3116586B2 - Flyback transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flyback transformer used for a television receiver or the like.

[0002]

2. Description of the Related Art The structure of a conventional flyback transformer will be described below with reference to FIG.

FIG. 3 shows the internal structure of a conventional flyback transformer. Here, 1 is a switching transistor, 2 is a damper diode, 3 is a resonance capacitor, 4 is a primary winding, 5 is a ferrite core, 6 is a secondary winding, 7 to 8 are high-voltage capacitors, 9 to 10 are high-voltage diodes, 11 is a DC power supply.

The DC voltage of the DC power supply 11 is switched by the switching transistor 1, and the correct AC voltage is boosted by the primary winding 4, the ferrite core 5, and the secondary winding 6, and
Transmit to the next side. On the secondary side, the high voltage capacitors 7 to 8 and the high voltage diodes 9 to 10 constitute the voltage doubler rectifier circuit 10 to generate a high voltage.

[0005]

In such a conventional flyback transformer, a high voltage component such as a high voltage capacitor is required in order to form a voltage doubler rectifier circuit, the mounting mechanism becomes complicated, and a high voltage cannot be supplied. There was a problem that the shape became large for insulation.

An object of the present invention is to solve the above-mentioned problem, and to provide an FBT which can reduce the number of components, especially high voltage capacitors, and can make the secondary side of the FBT generating a high voltage compact and simple. .

[0007]

In order to solve the above-mentioned problems, a flyback transformer according to the present invention has a structure in which a secondary winding is divided into a plurality of layers and laminated and wound, and each layer is insulated by an insulating film. And a voltage doubler circuit using stray capacitance generated between the layers as a high-voltage capacitor.

[0008]

According to the present invention, a high-voltage capacitor is eliminated from the secondary side voltage doubler circuit by the above configuration, and a small and simple voltage doubler circuit can be constructed at a low cost.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 12 denotes a flyback transformer of the present embodiment. 13, 14 and 15 are secondary windings of the flyback transformer 12, and the secondary windings are arranged and wound in a plurality of layers. An insulating film is interposed between the windings of each layer, and the windings of each layer are insulated by the insulating film. Reference numerals 16 and 17 denote diodes for rectification, respectively.

The winding start side 13a of the secondary winding 13 is connected to the ground, and the winding end side 13b is not connected anywhere. The winding start side 14a of the secondary winding 14 is not connected anywhere, and the winding end side 14b is connected to the cathode side of a diode 16, and the anode side of the diode 16 is connected to ground.

The anode side of the diode 17 is connected to the winding end side 14b of the secondary winding 14, and the cathode side of the diode 17 is connected to the winding end side 15b of the secondary winding 15. The winding start side 15a of the secondary winding 15 is not connected anywhere. The cathode side of the diode 17, ie, 2
A high voltage output is taken from the winding end side 15b of the next winding 15.

The secondary windings 13, 14, and 15 have a laminated winding structure in which an insulating film is interposed between the secondary windings 13, 14, and 15, and float between the secondary windings 13 and 14. Capacity 1
8, and a stray capacitance 19 also exists between the secondary winding 15 and the ground side. The stray capacitances 18 and 19 and the diodes 16 and 17 form a voltage doubler rectifier circuit.

FIG. 2 is a circuit diagram showing in detail the secondary winding and the rectifier circuit of the flyback transformer of this embodiment.

Next, the operation of the flyback transformer configured as described above will be described. The DC voltage of the DC power supply 11 is switched by the switching element 1. The AC voltage generated by this switching is applied to the primary winding 4. Therefore, an AC voltage having a high peak value is generated in the secondary windings 13, 14, 15.

At this time, on the secondary side, the floating capacitance 18 is charged through the diode 16 in the first half cycle. Assuming that the peak value of the AC voltage generated in the secondary windings 13, 14, 15 is V, the voltage of the stray capacitance 18 is a voltage V equal to this peak value.

In the next half cycle, the floating capacitance 19 is charged through the floating capacitance 18 and the diode 17. That is, the voltage 2V, which is the sum of the voltage V generated in the secondary winding and the voltage V of the floating capacitance 18, is applied to the floating capacitance 19, and the floating capacitance 19 is charged to a voltage of 2V. Thus, the voltage doubler rectification operation is performed. At this time, the stray capacitance 19 is, for example, CRT
If the secondary winding 15 can be used instead, the secondary winding 15 can be omitted.

[0018]

As described above, according to the present invention, the secondary winding is divided into a plurality of parts, laminated and wound, and each layer is insulated by an insulating film. Since the circuit is configured using the capacitance, the secondary side voltage doubler rectifier circuit can be simply and inexpensively configured, and can be realized in a small size and inexpensively.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a flyback transformer according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing in detail a secondary winding and a rectifier circuit of a flyback transformer in one embodiment of the present invention.

FIG. 3 is a circuit diagram of a conventional flyback transformer.

[Explanation of symbols]

 12 Flyback transformer 13, 14, 15 Secondary winding 16, 17 Diode 18, 19 Stray capacitance

Claims (1)

(57) [Claims] 1. A flyback transformer having a primary winding and a secondary winding, wherein the secondary winding is formed by a plurality of secondary windings aligned and wound in the same direction. The wire is formed in a laminated structure, the beginning of the first winding of this secondary winding is connected to the ground, and the end of the first winding is not connected anywhere, and the second layer of the secondary winding is Nothing is connected at the beginning of the winding, the cathode side of the first diode is connected at the end of the winding, the anode side of this diode is connected to the ground, and the anode side of the other second diode is connected to the secondary side. The winding is connected to the connection point on the cathode side of the first diode, and the end of the secondary winding of the third layer is connected to the cathode side of the second diode. Is not connected, and the output from the cathode side of the second diode is Flyback transformer, characterized in that issue.