JPH08222460A - Fly-back transformer - Google Patents

Abstract

PURPOSE: To lessen a fly-back transformer in load variation and load variation size by a method wherein the ends of a first split coil of split coils which form a high voltage coil are positioned inside those of a second split coil, and the first split coil is specified in winding width and wire diameter. CONSTITUTION: A pressure coil is composed of split coils K1, K2, K3... and Kn, wherein the first split coil K1 is set 0.7 to 0.9 times as wide as the second split coil K2 in winding width. When the first split coil K1 is wound on the peripheral surface of a high-voltage bobbin, the ends T1 and T2 of the first split coil K1 are positioned between the ends T3 and T4 of the second split coil K2. Moreover, the first split coil K1 and the second split coil K2 are usually set equal in number of turns. Furthermore, the first split coil K1 is set thinner than the second split coil K2 in wire diameter.

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 in a display device of variable operating frequency type.

[0002]

2. Description of the Related Art A high voltage coil on the output side of a flyback transformer is magnetically coupled to a low voltage coil on the power source side via a core. FIG. 4 shows a cross-sectional view of the upper half portion of the high voltage coil of the laminated winding flyback transformer. The high-voltage coil is composed of a first layer, a second layer, which is formed by winding an electric wire having the same wire diameter on the outer peripheral surface of a high-voltage bobbin (not shown) in a uniform width and in layers.
,,, n-th layer split coils K1, K2, ..., Kn,
, Kn, and the diodes D1, D2, ..., Dn. The winding start end of the split coil K1 is grounded,
The cathode end of the diode D1 is connected to the winding end.
Further, the anodic end of the diode D1 is connected to the winding start end of the split coil K2. Similarly, split coil K
, ..., Kn are connected via diodes D2 and Dn-1. At the end of winding of the split coil Kn, there is a die diode Dn.
The cathode end of this is connected, and the anode of this diode Dn is connected.
The output voltage is supplied to the cathode ray tube (CRT) from the terminal. This is shown in an equivalent circuit as shown in FIG. In this case, the split coils K1, K2, ..., Kn are represented by the series connection of the resistance r and the inductance L.

Further, in order to boost the voltage generated in the low voltage coil by the high voltage coil, a design is made to maintain a high-order tuning state between the low voltage coil and the high voltage coil. The load voltage of the output voltage of the flyback transformer varies due to this higher order tuning state. That is, in the ideal high-order tuning state, a pulse voltage having a shape close to a rectangular wave is obtained, whereas when the high-order tuning state becomes poor, a pulse voltage having a shape close to a rectangular wave changes to a unimodal shape. Therefore, the load fluctuation of the output voltage after rectifying the pulse voltage was large. Therefore, in the flyback transformer used in a conventional television device or the like that is used at a constant operating frequency, the split coils K1, K2, ...
The winding position of Kn is changed, or the winding ratio is selected to set the high-order tuning state in which the load fluctuation is minimal.

However, in a display device or the like which is used by being connected to a computer in recent years, since it is used by being connected to various computers, for example, 30 to 90 k is used.
It is required to be able to cover the entire operating frequency range of Hz. Therefore, for the flyback transformer used in such a display device, it is necessary to set the high-order tuning state in which the load fluctuation is small over the entire range of the operating frequency. Therefore, as shown in FIG. 6, a resistor 2 is provided between the winding coil end and the ground of the split coil K1 that constitutes the high voltage coil of a normal flyback transformer.
Further, the width of the load fluctuation is narrowed by connecting the damping circuit 4 in which the capacitor 3 is connected in series. That is, as shown in FIG. 7, when the operating frequency is plotted on the horizontal axis and the load fluctuation of the ordinary flyback transformer is plotted on the vertical axis, the load fluctuation curve 5 is a curve in which alternating-current components are superimposed as shown by the solid line. Become. When the damping circuit 4 is connected, the load fluctuation curve 5 is smoothed and the width of the load fluctuation is narrowed, and is corrected to the corrected load fluctuation curve 6 indicated by the alternate long and short dash line.

[0005]

However, the corrected load fluctuation curve 6 of the flyback transformer is smoothed near the lower limit position of the load fluctuation curve 5 like the corrected load fluctuation curve 7, and the width of the load fluctuation is further reduced. It is ideal to be narrow, but in reality, smoothing is performed in the vicinity of the upper limit position of the load fluctuation curve 5, so that the value of the load fluctuation is large, and the width of the load fluctuation is wider than the required characteristics. It was

Therefore, an object of the present invention is to provide a flyback transformer having a small value of load fluctuation and a narrow width of load fluctuation even when used over the entire operating frequency range.

[0007]

The present invention is configured as follows to achieve the above object. That is, in the laminated winding flyback transformer, both ends of the first layer of the split coil forming the high-voltage coil are located inside both ends of the second layer, and the winding width of the first layer is the second layer. The winding diameter is 0.7 to 0.9 times, and the diameter of the electric wire forming the first layer of the split coil is smaller than that of the split coil of the second layer.

[0008]

Both ends of the split coil of the first layer are located between both ends of the split coil of the second layer. Therefore, a capacitance is formed between the split coil of the first layer and the split coil portions of the second layer on both ends of the split coil of the first layer. As a result, a pulse voltage having a shape close to a rectangular wave can be obtained, so that the width of load fluctuation of the output voltage after rectifying the pulse voltage is narrowed.

Further, since the diameter of the electric wire used for winding the first layer split coil is smaller than the diameter of the electric wire used for winding the second layer split coil, The resistance value of the split coil becomes large, the same effect as when the damping circuit is connected to the split coil of the first layer is produced, and the value of the load fluctuation becomes small.

[0010]

EXAMPLE An example of the present invention will be described with reference to FIGS. The description of the same components as the conventional one is omitted and the same numbers are used.

As shown in FIG. 1, the winding width of the first-layer split coil K1 constituting the high-voltage coil is the same as that of the second-layer split coil K.
The length is set to be 0.7 to 0.9 times the length of the winding width of 2. When the split coil K1 is wound around the outer peripheral surface of the high-voltage bobbin (not shown), both ends T1 and T2 of the split coil K1 are positioned between the end portions T3 and T4 of the split coil K2. . The split coil K of the first layer
1 and the number of turns of the second layer split coil K2 are usually the same. To form a difference in winding width between the split coil K1 and the split coil K2, for example, assuming that the wire diameters used for the split coils K1 and K2 are φ1 and φ2, 0.025 mm φ ≦ φ
An electric wire of 1 <0.035 mmφ and 0.035 mmφ ≦ φ2 is used. The split coil K1 and the split coil K
If the winding width difference of 2 is made extremely large, the difference between the voltages generated between the layers of the split coil K1 and the split coil K2 becomes large. Therefore, a measure is taken to increase the electrical breakdown voltage between the split coil K1 and the split coil K2. There must be. For this reason,
When the winding width of the split coil K1 is in the range of 0.7 to 0.9 times the winding width of the split coil K2, it is not necessary to take any countermeasure against electrical withstand voltage. Is.

By winding the split coil K1 and the split coil K2 under such conditions, the split coil K1, the coil portion between T3 and T1 of the split coil K2, and T4.
Capacitors 8 and 9 are formed between the coil portions between T2 and T2. This is shown in an equivalent circuit as shown in FIG. That is, the difference from the equivalent circuit shown in FIG.
1 is that the capacitors 8 and 9 are connected in series at both ends of the series connection including the resistor r1 and the inductance L1. The split coil K2 has a resistance r2 and an inductance L2 connected in series. Similarly, the split coil Kn has a resistance rn and an inductance Ln connected in series. The resistance value of the resistance r1 of the split coil K1 is
In order to use an electric wire thinner than the electric wire diameter used to wind the conventional split coil K1, the conventional split coil K1
It becomes larger than the resistance value of the resistance r.

Since the pulse voltage having a shape close to a rectangular wave is obtained by forming the capacitors 8 and 9, the fluctuation range of the load fluctuation curve of the output voltage after rectifying the pulse voltage becomes narrow.
Further, since the resistance value of the resistance r1 of the split coil K1 of the present invention is larger than the resistance value r of the conventional split coil K1, the value of the load fluctuation is damped and becomes smaller.

The split coil K1 and the split coil K2
If the winding state of No. 1 satisfies the above-mentioned winding condition, the winding width length of the split coils K3, ..., Kn may be the same as the winding width length of the split coil K1 as shown in FIG. You may wind it in width. In this case, the split coils K2, ..., K
The winding diameters of n may be the same or different, that is, the number of turns of the split coils K2, ..., Kn may not be the same.

[0015]

When winding the first layer and second layer split coils K1 and K2 constituting the high-voltage coil, the wire diameter of the first layer split coil K1 is equal to that of the second layer split coil K2. Split coils K1 and K are used because they are thinner than the diameter.
Even if the number of windings of 2 is the same, the winding can be performed such that both ends of the split coil K1 are located inside both ends of the split coil K2. As a result, the load fluctuation can be improved, and it is not necessary to connect the damping circuit in parallel to the first layer split coil of the high voltage coil. Further, since the number of parts can be reduced, the flyback transformer can be downsized and can be manufactured at low cost.

In a flyback transformer used at a high frequency, even if the present invention is used, the high voltage load fluctuation becomes relatively large. Therefore, the value of the load fluctuation can be improved by using the present invention in combination with the damping circuit. In this case, since it is possible to reduce the damping resistance and the like that form the damping circuit, it is possible to reduce heat generation, and it is possible to incorporate the damping circuit in the flyback transformer used at high frequencies.

[Brief description of drawings]

FIG. 1 is a sectional view of an upper half portion of a high voltage coil according to the present invention.

FIG. 2 is an equivalent circuit of a high-voltage coil according to the present invention.

FIG. 3 is a sectional view of an upper half portion of another high-voltage coil according to the present invention.

FIG. 4 is a cross-sectional view of an upper half portion of a conventional high voltage coil.

FIG. 5 is an equivalent circuit of a conventional high voltage coil.

FIG. 6 is a diagram showing a load variation with respect to an operating frequency of a conventional flyback transformer.

[Explanation of symbols]

 Kn split coil r, r1, r2, r3, ... rn resistance L, L1, L2, L3, ... Ln inductance D1, D2, D3, ... Dn diode T1, T2 split coil K1 Both ends of T3, T4 Both ends of split coil K2 1 Insulator 4 Damping circuit 5, 6, 7 Load fluctuation curve 8, 9 Capacitance

[Procedure amendment]

[Submission date] June 19, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a sectional view of an upper half portion of a high voltage coil according to the present invention.

FIG. 2 is an equivalent circuit of a high-voltage coil according to the present invention.

FIG. 3 is a sectional view of an upper half portion of another high-voltage coil according to the present invention.

FIG. 4 is a cross-sectional view of an upper half portion of a conventional high voltage coil.

FIG. 5 is an equivalent circuit of a conventional high voltage coil.

FIG. 6 is an equivalent circuit in the case where a damping circuit is connected between the ground and the winding end of the divided coil of the first layer of the conventional high voltage coil.

FIG. 7 is a diagram showing a load variation with respect to an operating frequency of a conventional flyback transformer.

Claims (1)

[Claims] 1. In a laminated winding flyback transformer, both ends of a first layer of a split coil constituting a high-voltage coil are positioned inside both ends of a second layer, and a winding width length of the first layer is the above-mentioned. It is in the range of 0.7 to 0.9 times the winding width of the second layer, and the diameter of the wire forming the first layer of the split coil is smaller than the wire diameter of the split coil of the second layer. Flyback transformer to do.