JP2002064017A - Thin transformer and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching power supply thin transformer which is used for various electronic apparatuses, has high coupling, is small in power loss, high in efficiency, hardly produces noises, and is suitable for the high-frequency driving of a switching power supply, and to provide a method of manufacturing the same. SOLUTION: A primary and a secondary main windings are each split into, at least, three or more. The primary and secondary main windings have nearly the same winding width and are single-layered, this thin transformer has a structure in which a core is built in an alternately laminated coil from both above and below so that the folded opposed surfaces are not produced, and an increase in high-frequency resistance due to a proximity effect can be restrained. The transformer can be decreased in line capacity, and noises can be decreased. Furthermore, a distance between the primary and secondary main winding becomes minimum, the opposed surfaces of the primary and secondary winding can be kept maximum in area, and the primary and secondary winding can be decreased in leakage inductance, so that high coupling can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin transformer for a switching power supply mounted on a thin power supply used in electronic equipment, mainly a communication device, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, information communication infrastructure networks have been large, and with the progress thereof, an increase in power consumption has become a social problem. In particular, in order to respond to the demand for miniaturization and reduction in power consumption of communication equipment, the power supply system has shifted from centralized power supply to distributed power supply, and these power supply units now have many small and thin on-board power supplies. It is used. On the other hand, large currents and low voltage for power consumption reduction are rapidly progressing with high speed of LSIs, and on-board power supplies for driving these LSIs are also required to support low voltage / high current. I have. These thin on-board power supplies tend to drive the switching frequency at a higher frequency as a means for further miniaturization. In particular, for a transformer which is a main component of the power supply unit, a low-loss, low-noise, small-sized and inexpensive surface-mount thin transformer suitable for high-frequency driving is demanded. In order to meet the development needs of these power supplies, many thin transformers using laminated type coils using windings have been proposed.

A conventional thin transformer using a winding is disclosed in Japanese Utility Model Laid-Open No. 4-99818, Japanese Utility Model Laid-Open No. 6-70223.
And Japanese Patent Application Laid-Open No. 4-105523 (Utility Model Registration No. 25512537), in which a spiral coil is laminated on a coil base and molded. JP-A-5-95026 (utility model registration No. 2592905)
), A structure in which spiral coils are laminated on a coil base, a structure in which rectangular wire spiral coils are laminated as shown in JP-A-8-316054, and a method as described in JP-A-10-340819. There is a configuration in which a spiral coil formed by winding two layers of a flat rectangular conductor in a folded manner is laminated on a coil base.

With reference to these prior art examples, primary,
Divide the secondary winding into more than one, at least one of which is 3
FIGS. 10 to 1 show application examples in which a multi-layered structure is obtained by dividing into multiple layers.
3 is shown.

Hereinafter, a conventional application example will be described with reference to FIGS.

FIG. 10 is an exploded perspective view of a conventional thin transformer, FIG. 11 is a perspective view of a conventional thin transformer, and FIG. 12 is a conventional example 1 of JP-A-10-340819 and JP-A-4-105523. (Utility model registration 255123
FIG. 13 is a cross-sectional view showing an application example of a laminated coil in which the configuration of No. 7) is combined, and FIG.
It is sectional drawing which shows another application example of the laminated coil which combined the structure of Unexamined-Japanese-Patent No. 054 and the actual publication Hei 5-95026 (utility model registration No. 2592905). 10 to 13, 1 is a primary main winding, 1a is a primary auxiliary winding, 2 is a secondary main winding, 3 is insulating paper, 4 is a terminal, 5 is a connecting portion, 6 is a coil base, 7 Denotes an insulating resin, 8 denotes a molded coil, and 9 denotes a magnetic core.

In FIG. 12, two spiral coils each of which is formed by winding two layers of a rectangular conductor back and forth are used as a primary main winding 1.
One is prepared in advance as the next auxiliary winding 1a. Furthermore, by punching or etching a thin plate conductor
Four secondary main windings 2 are prepared and prepared. The secondary main winding 2, the primary main winding 1, and the secondary main winding 1 are interposed via an insulating paper 3 on a coil base 6 in which terminals 4 are implanted at both ends of each of the windings prepared in advance. Wire 2, primary auxiliary winding 1a,
The secondary main winding 2, the primary main winding 1, and the secondary main winding 2 are stacked in this order. Thereafter, the terminal 4 and each winding are connected at the connection portion 5 by a method such as soldering to complete a laminated coil. The molded coil 8 is completed by sealing with the insulating resin 7 so as to cover the connection portion 5 of the completed laminated coil. Next, as shown in FIG. 10, magnetic cores 9 are assembled from above and below the molded coil 8 to complete a thin transformer as shown in FIG.

FIG. 13 is basically similar to FIG.
Is the same as the conventional example, except that the number of divisions of the secondary main winding 2 formed of a thin plate-shaped conductor is set to three, and a rectangular wire is used as the primary main winding 1 and the primary auxiliary winding 1a. Using a spiral coil in which the primary windings 1 and 2 are wound in a single layer.
The difference is that a secondary main winding 2, a secondary main winding 2, a secondary main winding 2, a primary main winding 1, and a primary auxiliary winding 1a are used. Furthermore, resin molding is not performed.

[0009]

However, in the configuration shown in FIG. 12 showing the first conventional example, two primary main windings 1 are used.
Due to the layer winding, the stray capacitance between the windings increases, and noise such as noise terminal voltage increases. Also,
High-frequency resistance due to the proximity effect also increases. Further, the primary auxiliary winding 1a is disposed between the secondary main windings 2 and the primary main winding 1 and the secondary main winding 2 are not completely alternately laminated. There is a problem that the coupling is deteriorated, the leakage inductance increases, and the loss due to the leakage inductance increases.

In the configuration of FIG. 13 showing the second conventional example, since the secondary main winding 2 is continuously laminated in three layers,
High frequency resistance increases due to the proximity effect. Also in this case, since the primary main winding 1 and the secondary main winding 2 are not completely alternately laminated, the coupling between the windings is deteriorated and the leakage inductance is increased. As a result, there is a problem that the loss increases.

The present invention solves the above-mentioned problems and provides high coupling, low loss / high efficiency suitable for high-frequency driving of a switching power supply,
An object of the present invention is to provide a low-noise thin transformer and a method for manufacturing the same.

[0012]

In order to solve the above-mentioned problems, the present invention provides a laminated coil in which a primary and secondary main windings are divided into a plurality of, and at least one of them is divided into three or more. In which the primary main winding and the secondary main winding are
The laminated coil is laminated and alternately laminated, and a magnetic core is incorporated from above and below the laminated coil.

With the above configuration, the primary and secondary main windings are each formed of a single layer, so that there is no folded facing surface between the primary windings and the secondary windings. Can be reduced. In addition, the capacitance between the lines is reduced, and the noise can be reduced. Furthermore, since the primary and secondary main windings are formed to have substantially the same winding width, single-layer winding and complete alternate lamination, the distance between the primary and secondary main windings is minimized.
In addition, the opposing area can be maximized, and the primary,
Since the leakage inductance (Le) of the secondary main winding can be reduced, high coupling is achieved. As a result, high coupling, low loss / high efficiency suitable for high-frequency driving of switching power supplies,
A low-noise thin transformer can be provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, the primary and secondary main windings are divided into a plurality of coils, at least one of which is divided into three or more.
The secondary main winding and the secondary main winding are wound in a single layer with substantially the same winding width, and are alternately laminated. The magnetic core is incorporated from above and below the laminated coil. Since each of the next main windings has a single-layer winding, there is no folded facing surface between the primary windings and the secondary windings, so that an increase in high-frequency resistance due to a proximity effect or the like can be reduced. In addition, the capacitance between the lines is reduced, and the noise can be reduced. In addition, since the primary and secondary main windings have substantially the same winding width, single-layer winding and complete alternate lamination, the distance between the primary and secondary main windings is minimized, and the facing area is also maximized. Can be secured as much as possible.
Next, since the leakage inductance (Le) of the secondary main winding can be reduced, high coupling is achieved. As a result, a high-coupling, low-loss / high-efficiency, low-noise thin transformer suitable for high-frequency driving of a switching power supply can be provided.

The second aspect of the present invention is the first aspect.
In addition to the configuration described above, the auxiliary winding is arranged on the uppermost layer or the lowermost layer of the primary and secondary main windings, and no extra winding is arranged between the primary and secondary main windings. Therefore, the distance between the primary and secondary main windings is minimized and stable, so that the leakage inductance (Le) is minimized, the coupling between the windings can be maximized, and the variation in performance is small. You can do it.

According to a third aspect of the present invention, in addition to the constitutions of the first and second aspects, the entire laminated coil is sealed with an insulating resin. Since the coil portion can be soaked, the temperature rise can be reduced. Further, insulation between the windings and between the windings and the magnetic core can be enhanced.

The invention described in claim 4 of the present invention is claim 1.
In addition to the above configurations, the windings are laminated on a coil base. Since the coil base is used, the operation of laminating the windings is stable, and the quality is stable.

The invention described in claim 5 of the present invention is claim 1
In addition to the configurations of (1) to (3), the windings are stacked without using the coil base, and the number of components can be reduced because the coil base is not used. In addition, since no extra insulator is used, the space factor of the winding can be increased, and downsizing can be achieved.

The invention according to claim 6 of the present invention is the invention according to claim 3.
In addition to the structures of (1) to (5), this is sealed by casting with an insulating resin. Since the generation of stress in the process of encapsulating the resin and curing the resin is small, disconnection and the like can be prevented, and the coil design is free. The degree spreads.

The invention described in claim 7 of the present invention is claim 3.
In addition to the above-described configurations, the molding is performed by molding with an insulating resin and sealing is performed. Since the molding method is used, the sealing time can be greatly reduced as compared with casting, so that productivity is improved.

The invention described in claim 8 of the present invention is claim 1.
In addition to the configurations of (1) to (7), at least one of the primary and secondary main windings is an electric wire with an insulating coating, and the number of turns can be easily changed, so that the degree of freedom in design is expanded.

The ninth aspect of the present invention is the eighth aspect.
In addition to the configuration described above, the electric wire is a rectangular electric wire, and the space factor of the winding can be increased, so that the winding resistance can be reduced, that is, the loss can be reduced.

According to a tenth aspect of the present invention, in addition to the configuration of the eighth aspect, the electric wire is a round electric wire, so that the cost of the winding material can be reduced. Further, the speed of the winding can be increased, and the workability is improved.

According to an eleventh aspect of the present invention, in addition to the configuration of the eighth aspect, at least one of the primary and secondary windings is an electric wire with a three-layer insulating film, Sufficient insulation between primary and secondary can be maintained even for high voltage input. It also facilitates compliance with safety standards of each country.

According to a twelfth aspect of the present invention, in addition to the first to eleventh aspects, at least one of the primary and secondary main windings is formed of a thin plate conductor. In addition, even if the number of turns is small, a facing area between the primary and secondary windings can be ensured, so that high coupling can be achieved. In addition, since a cross-sectional area can be secured, it is easy to handle a large current.

According to a thirteenth aspect of the present invention, in addition to the constitution of the first to twelfth aspects, at least one of the primary and secondary auxiliary windings is a round electric wire with an insulating film. The primary and secondary main windings can adopt various winding configurations such as rectangular electric wire, round electric wire, electric wire with three-layer insulating film, thin plate conductor, etc. according to the current and the number of turns. Therefore, the specifications of the main winding ensure the optimum winding configuration for basic performance, while improving the degree of freedom in designing the auxiliary output winding.
Effects such as material reduction can be obtained.

According to a fourteenth aspect of the present invention, in addition to the first to twelfth aspects, at least one of the primary and secondary auxiliary windings is formed of a non-winding type substrate. Since the thickness of the laminated surface is stable, performance variations can be reduced.

According to a fifteenth aspect of the present invention, in addition to the structure of the fourteenth aspect, the non-winding type substrate is formed by a printed circuit board by an etching method, and has high versatility, so that the procurement is improved. Cost reduction can be achieved.

According to a sixteenth aspect of the present invention, in addition to the constitutions of the fourteenth and fifteenth aspects, an unwound coil having two or more wire loops is formed in the same layer, and the laminated thickness of the coil does not increase. , A large number of auxiliary outputs can be formed, and the degree of freedom in transformer design increases. In addition, since the relative position between the plurality of wire loops is also stabilized, the performance variation can be reduced.

According to a seventeenth aspect of the present invention, in addition to the constitutions of the eighth to eleventh and thirteenth aspects, each winding is provided with a fusion layer, and each winding is fixed in a wound state. Therefore, winding formation without a bobbin can be easily realized.

The invention according to an eighteenth aspect of the present invention is the one in which, in addition to the configuration of the seventeenth aspect, the fusion layer is an alcohol fusion type fusion layer. Since it can be fixed, it is easy to implement equipment.

According to a nineteenth aspect of the present invention, an insulated wire with a fusion layer is wound in a single-layer winding state and fixed, and each main winding is plural, and at least one of the main windings is three or more. A first step of preparing, and the primary main winding and 2
The manufacturing method has a second step of alternately stacking the next main windings and a third step of incorporating a magnetic core from above and below. Since each winding is fixed in a wound state, The shape can be maintained as a single unit, and even when the primary and secondary main windings are divided into a plurality of pieces, the alternately laminated coil can be easily manufactured. Further, since insulated wires are used, it is possible to easily cope with a variable number of windings only by changing the setting of the number of windings without largely changing the process, thereby enabling flexible production.

According to a twentieth aspect of the present invention, in addition to the configuration of the nineteenth aspect, in the first step, an alcohol coating device is attached to a winding machine by setting the fusion layer to an alcohol fusion type to perform a winding operation. At the same time, the manufacturing method is such that alcohol is welded, so that the winding and the fixing process can be integrated,
This eliminates the need for a heat-curing facility and a curing step as compared with heat fusion and the like, thereby simplifying the manufacturing process.

According to a twenty-first aspect of the present invention, in addition to the configuration of the nineteenth aspect, in the second step, the auxiliary windings having different winding widths and wire diameters are formed on the uppermost layer of the primary and secondary main windings. Since the manufacturing method is such that the primary main windings and the secondary main windings are alternately stacked on the lowermost layer, it is possible to reduce variations in the stacking thickness when the primary main windings and the secondary main windings are alternately stacked. Variation in coupling can be reduced. In addition, since auxiliary windings having different winding widths are stacked first or last, the efficiency of stacking the main windings is improved.

According to a twenty-second aspect of the present invention, in addition to the features of the nineteenth to twenty-first aspects, a manufacturing method in which the auxiliary winding is formed on a non-winding type substrate in the first step, Eliminating the winding work of the auxiliary winding, the wiring of the lead leads, the winding work, etc., can reduce the number of working steps.

According to a twenty-third aspect of the present invention, there is provided a manufacturing method according to the nineteenth aspect, further comprising a step of sealing the laminated coil with an insulating resin between the second step and the third step. Because the outer shape of the laminated coil is stable,
Incorporation of the magnetic core in a later step is also facilitated.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a sectional view of a laminated coil showing a first embodiment of a thin transformer according to the present invention. In FIG. 1, 1 is a primary main winding, 1a is a primary auxiliary winding, 2 is a secondary main winding, 3 is insulating paper, 4 is a terminal, 5 is a connection part, and 6 is a coil base.

FIG. 1 is basically similar to FIG. 13 showing the second conventional example, but differs greatly in that the stacking order is the secondary main winding 2, the primary main winding 1, and the secondary main winding 1. The difference is that the winding 2, the primary main winding 1, the secondary main winding 2, and the primary auxiliary winding 1a are used.

In summary, in FIG. 1, the primary main winding 1, the secondary primary winding 1, and the secondary main winding 2 are divided into three, and the primary main winding 1, the secondary secondary winding 2 are divided into three. The main winding 2 has a single-layer winding, the primary main winding 1 and the secondary main winding 2 are completely alternately stacked, and the primary auxiliary winding 1a is stacked on the uppermost layer. This is a point that is significantly different from Conventional Example 1 (FIG. 12) and Conventional Example 2 (FIG. 13).

As described above, according to the structure of FIG. 1 of the present invention, the primary main winding 1 is divided into two, and the secondary main winding 2 is divided into three. Since both the secondary main windings 2 are single-layer wound, there is no folded facing surface between the primary windings and the secondary windings, so that an increase in AC resistance in a high frequency region due to a proximity effect or the like can be suppressed. That is, since the high-frequency resistance can be reduced, the loss can be reduced. Also, the line capacitance of each main winding is reduced, and low noise can be achieved. Further, since the primary main winding 1 and the secondary main winding 2 are formed to have substantially the same winding width, single-layer winding and complete alternate lamination, the distance between the primary main winding 1 and the secondary main winding 2 is minimized. And the opposing area can be maximized.
Next, the leakage inductance (Le) of the secondary winding can be reduced. That is, high coupling between the windings is achieved. As a result, a high-coupling, low-loss / high-efficiency, low-noise thin transformer suitable for high-frequency driving of a switching power supply can be provided.

The primary auxiliary winding 1a is arranged on the uppermost layer so that no extra winding is arranged between the primary and secondary main windings. Since the distance is minimum and stable, the leakage inductance (Le) can be minimized, the coupling between windings can be maximized, and the variation in performance can be reduced.

The effect is the same even if the primary auxiliary winding 1a is arranged in the lowermost layer. Furthermore, the same effect can be obtained if the same arrangement is made even when the auxiliary winding is on the secondary side.

Table 1 shows the experimental results of the characteristic comparison based on these differences in the basic configuration.

[0046]

[Table 1]

Table 1 shows a comparison between the configuration in FIG. 1 showing the first embodiment of the present invention and the configurations in FIGS. 12 and 13 showing the conventional example. (1) Leakage inductance (Le) and leakage inductance ratio ( Le / Lp) is small, that is, high coupling of the windings can be achieved.

(2) Since the rate of increase in AC resistance at high frequencies (experimental example: 500 kHz) is small, the efficiency of the power supply is improved. That is, low loss can be achieved.

(3) Since the inter-winding capacitance is also small, the level of the noise terminal voltage is low, and low noise can be achieved. This was clearly confirmed by experiments.

Further, as shown in FIG. 1, the respective windings are stacked on the coil base 6, and since the coil base 6 is used, the work of stacking the windings is stable, and the quality is stable.

Further, since the primary main winding 1 and the secondary main winding 2 are electric wires with an insulating film, the number of windings can be easily changed, so that the degree of freedom in design is widened. In this case, if at least one of the primary and secondary main windings is formed as an electric wire with an insulating film, the degree of freedom of design is widened and the same effect can be obtained.

In this case, the wire is a rectangular wire, and the space factor of the winding can be increased, so that the winding resistance can be reduced.
That is, low loss can be achieved.

Further, each winding is configured so as to have a fusion layer on the surface of the insulating film, and the fusion layer can be fixed while each winding is wound, so that the winding can be formed easily without a bobbin. Can be realized.

Further, the fusion layer of these windings is a fusion layer of an alcohol fusion type, and the winding can be easily fixed only by applying the alcohol, thereby facilitating the equipment.

FIG. 1 showing the first embodiment of the present invention.
A first step in which an insulated electric wire with a fusion layer is wound in a single-layer winding state and fixed, and a plurality of main windings, at least one of which is at least three, are prepared. A second step of alternately laminating the primary main windings 1 and the secondary main windings 2 and a third step of incorporating a magnetic core from above and below. , The shape can be maintained by the winding alone,
Even when the secondary main winding is divided into a plurality of parts, an alternately laminated coil can be easily manufactured. Also, because insulated wires are used, the process is not significantly changed even if the number of turns is variable.
By simply changing the setting of the number of turns, it is possible to easily cope with the situation, and it becomes possible to flexibly cope with production.

Further, in the first step, since the fusion layer is an alcohol fusion type, an alcohol coating device is attached to the winding machine and the alcohol is fused simultaneously with the winding operation. Will be able to
This eliminates the need for a heat-curing facility and a curing step as compared with heat fusion and the like, thereby simplifying the manufacturing process.

In the second step, the auxiliary windings having different winding widths and wire diameters are laminated so as to be arranged on the uppermost layer or the lowermost layer of the primary and secondary main windings. When the wires 1 and the secondary main windings 2 are alternately stacked, variations in the lamination thickness can be reduced, and variations in the coupling between the primary and secondary main windings can be reduced. In addition, since auxiliary windings having different winding widths are stacked first or last, the efficiency of stacking the main windings is improved.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a sectional view of a laminated coil showing a second embodiment of the thin transformer of the present invention. In FIG. 2, reference numeral 7 denotes an insulating resin.

The basic configuration is the same as that of FIG. 1 showing the first embodiment of the present invention. The major difference is that the entire laminated coil is sealed with an insulating resin 7. That is, after the laminated coil is completed, the insulating resin 7 is poured by casting, and then heat-cured and sealed in a thermostat.

Table 2 shows an experimental result of characteristic comparison based on a difference between the basic configuration and the configuration of FIG. 2 showing the second embodiment of the present invention.

[0061]

[Table 2]

Table 2 shows that the configuration of FIG. 1 showing the first embodiment of the present invention is compared with the configurations of FIGS. 12 and 13 showing the conventional example. (1) High coupling, low loss, low noise As for the conversion, it can be improved as in FIG. 1 showing the first embodiment.

(2) Further, the temperature rise can be greatly reduced, and low heat generation can be achieved. You can see that.

As described above, according to the structure of FIG. 2 showing the second embodiment of the present invention, the insulating resin 7 is poured into the gap between the laminated coils, so that the coil portion can be made uniform so that the temperature rise is reduced. it can. Further, insulation between the windings and between the windings and the magnetic core can be enhanced.

Further, since the resin is cast and cured with the insulating resin 7, the occurrence of stress in the resin encapsulation and in the process of curing the resin is reduced, so that disconnection and the like can be prevented, and the degree of freedom in coil design can be reduced. Spreads.

Although the insulating resin 7 is cured by heating in this embodiment, the effect is not changed even if it is cured at room temperature.

As described above, the manufacturing method of FIG. 2 showing the second embodiment of the present invention is the same as that shown in FIG. 1 showing the first embodiment of the present invention. Resin 7
Since the step of sealing the laminated coil is provided, the outer shape of the laminated coil is stabilized, so that the magnetic core can be easily incorporated in a later step.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a sectional view of a laminated coil showing a third embodiment of the thin transformer of the present invention, FIG. 4 is an exploded perspective view of the thin transformer showing the third embodiment of the present invention, and FIG. It is a perspective view of a thin transformer showing a 3rd embodiment of the present invention. The basic configuration in FIG. 3 is the same as that in FIG. 2 showing the second embodiment of the present invention. The major differences are that each coil is laminated on a jig without using the coil base 6 in FIG. 2 and that the laminated coil is sealed by molding with an insulating resin 7 using a molding die. . As shown in FIG. 4, the magnetic core 9 is assembled from above and below the completed molded coil 8 in FIG. 3 to complete the thin transformer shown in FIG.

As described above, according to the configuration of FIG. 3 showing the third embodiment of the present invention, the number of components can be reduced because the coil base 6 is not used. Further, since no extra insulator is used, the space factor of the windings can be increased, and downsizing can be achieved.

Further, since the molding method is used, the sealing time can be greatly reduced as compared with the casting, so that the productivity is improved. A new effect is born.

(Embodiment 4) Next, a fourth embodiment of the thin transformer of the present invention will be described with reference to FIG.
FIG. 6 is a sectional view of a laminated coil showing a thin transformer according to a fourth embodiment of the present invention. The basic configuration in FIG. 6 is the same as that in FIG. 3 showing the third embodiment of the present invention.
The major difference is that the secondary auxiliary winding 2a is added.
The secondary main winding 1, the primary auxiliary winding 1a, and the secondary auxiliary winding 2a are round electric wires, so that a reduction in the cost of the winding material can be achieved. Further, the speed of the winding can be increased, and the workability is improved.

In FIG. 6, at least one of the primary and secondary windings is formed as an electric wire with a three-layer insulating film, so that even if a high voltage is input, the primary and secondary windings can be interposed. Sufficient insulation can be maintained. It also facilitates compliance with safety standards of each country.

(Fifth Embodiment) Next, a fifth embodiment of the thin transformer according to the present invention will be described with reference to FIG.
FIG. 7 is a sectional view of a laminated coil showing a thin transformer according to a fifth embodiment of the present invention. The basic configuration in FIG. 7 is the same as FIG. 6 showing the fourth embodiment of the present invention.
The major difference is that both the primary main winding 1 and the secondary main winding 2 in FIG. 6 are formed of a thin-plate conductor, and the facing area between the primary and secondary windings is small even if the number of turns is small. High coupling can be achieved. In addition, since a cross-sectional area can be secured, it is easy to handle a large current.

Although the description has been made with reference to FIG. 7, it is needless to say that these effects can be obtained by using at least one of the windings as a thin plate conductor.

Further, in FIG. 7, only the primary auxiliary winding 1a and the secondary auxiliary winding 2a use round electric wires as in FIG. 6, so that the degree of freedom in designing the auxiliary output winding and material reduction are reduced. An effect can be obtained. In other words, the primary main winding 1 and the secondary main winding 2 can adopt various winding configurations such as a rectangular electric wire, a round electric wire, an electric wire with a three-layer insulating film, and a thin plate-shaped conductor according to the current and the number of turns. Therefore, the specifications of the main winding ensure the optimum winding configuration for the basic performance, and at the same time, achieve the effect of improving the degree of freedom in designing the auxiliary output winding and reducing the material.

(Embodiment 6) Next, a sixth embodiment of the thin transformer of the present invention will be described with reference to FIGS. FIG. 8 is a cross-sectional view of a laminated coil showing a sixth embodiment of the present invention, and FIG. 9 is a cross-sectional view of another laminated coil showing a sixth embodiment of the present invention. FIGS. 8 and 9 are basically the same as FIGS. 6 and 7 showing the fourth embodiment of the present invention and FIG. 7 showing the fifth embodiment, respectively. The difference is that the auxiliary winding 2a is formed of a non-winding type substrate that does not require winding the winding,
Compared to a coil wound with a coil, the finished surface has less irregularities and the thickness of the laminated surface is stable, so that performance variations can be reduced.

A non-winding type substrate is generally a glass epoxy substrate or the like, but may be another substrate such as a ceramic substrate. Further, the method of forming the non-wound coil includes etching, printing, vapor deposition, etc., but it is not necessary to limit the method.

In particular, when a printed circuit board made of a glass epoxy substrate manufactured by etching is used, the versatility is high, so that the procurement can be improved and the cost can be reduced.

Further, if unwound coils having two or more wire loops are formed on the same layer on the substrate, a large number of auxiliary outputs can be formed without increasing the laminated thickness of the coils.
The degree of freedom in transformer design increases. In addition, since the relative position between the plurality of wire loops is also stabilized, the performance variation can be reduced.

As shown in FIGS. 8 and 9 showing the sixth embodiment of the present invention, the primary auxiliary winding 1a and the secondary auxiliary winding 2a are prepared in the first step of preparing the winding in advance. Is formed on a non-winding type substrate, and there is no need for winding work for auxiliary winding, wiring for lead leads, winding work, and the like, and the number of working steps can be reduced.

[0081]

As described above, according to the present invention, since there is no folded opposing surface between the windings, an increase in high-frequency resistance due to a proximity effect or the like can be reduced. In addition, the capacitance between the lines is reduced, and the noise can be reduced. Furthermore, the distance between the primary and secondary main windings is minimized, and the opposing area can be ensured to a maximum, and the leakage inductance (Le) of the primary and secondary main windings can be reduced. Is achieved.

As a result, the object of providing a high-coupling, low-loss / high-efficiency, low-noise thin transformer suitable for high-frequency driving of a switching power supply and a method of manufacturing the same can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a laminated coil showing a first embodiment of a thin transformer according to the present invention.

FIG. 2 is a sectional view of a laminated coil showing a second embodiment of the thin transformer of the present invention.

FIG. 3 is a sectional view of a laminated coil showing a third embodiment of the thin transformer of the present invention.

FIG. 4 is an exploded perspective view of a thin transformer showing a third embodiment of the present invention.

FIG. 5 is a perspective view of a thin transformer showing a third embodiment of the present invention.

FIG. 6 is a sectional view of a laminated coil showing a fourth embodiment of a thin transformer according to the present invention.

FIG. 7 is a sectional view of a laminated coil showing a fifth embodiment of the thin transformer of the present invention.

FIG. 8 is a sectional view of a laminated coil showing a thin transformer according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view of a laminated coil showing another example of the sixth embodiment of the thin transformer of the present invention.

FIG. 10 is an exploded perspective view of a conventional thin transformer.

FIG. 11 is a perspective view of a conventional thin transformer.

FIG. 12 is a sectional view showing an application example of a conventional laminated coil of a thin transformer.

FIG. 13 is a sectional view showing another application example of the laminated coil of the conventional thin transformer.

[Description of Signs] 1 Primary main winding 1a Primary auxiliary winding 2 Secondary main winding 2a Secondary auxiliary winding 3 Insulating paper 4 Terminal 5 Connection part 6 Coil base 7 Insulating resin 8 Mold coil 9 Magnetic core

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 31/00 J U (72) Inventor Katsunori Omura 1006 Kazuma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. F term (reference) 5E070 AA11 AB02 AB10 BA08 CA01 CA03 CA14 CB01 CB13 CB16 DA11 EA02 EB01

Claims (23)

[Claims] 1. The primary and secondary main windings are divided into a plurality of windings.
At least one of the laminated coils is divided into three or more, and the primary main winding and the secondary main winding are wound in a single layer with substantially the same winding width and alternately laminated. A thin transformer incorporating a magnetic core from above and below. 2. The thin transformer according to claim 1, wherein the auxiliary winding is arranged on an uppermost layer or a lowermost layer of the primary and secondary main windings. 3. The thin transformer according to claim 1, wherein the entire laminated coil is sealed with an insulating resin. 4. The thin transformer according to claim 1, wherein each winding is laminated on a coil base. 5. The thin transformer according to claim 1, wherein each winding is laminated without using a coil base. 6. The thin transformer according to claim 3, wherein the transformer is cast and sealed with an insulating resin. 7. The thin transformer according to claim 3, wherein the transformer is molded and sealed with an insulating resin. 8. An electric wire with an insulating coating on at least one of the primary and secondary main windings.
7. The thin transformer according to any one of 7. 9. The thin transformer according to claim 8, wherein the electric wire is a rectangular electric wire. 10. The thin transformer according to claim 8, wherein the electric wire is a round electric wire. 11. The thin transformer according to claim 8, wherein at least one of the primary and secondary windings is an electric wire with a three-layer insulating film. 12. The method according to claim 1, wherein at least one of the primary and secondary main windings is formed of a thin plate-shaped conductor.
12. The thin transformer according to any one of 11 above. 13. The thin transformer according to claim 1, wherein at least one of the primary and secondary auxiliary windings is a round electric wire with an insulating film. 14. The thin transformer according to claim 1, wherein at least one of the primary and secondary auxiliary windings is formed of a non-winding type substrate. 15. The thin transformer according to claim 14, wherein the non-winding type substrate is formed by a printed circuit board by an etching method. 16. The thin transformer according to claim 14, wherein an unwound coil having two or more wire loops is formed on the same layer on a substrate. 17. The method according to claim 8, wherein each winding is provided with a fusion layer.
14. The thin transformer according to any one of 11 or 13, 18. The thin transformer according to claim 17, wherein the fusion layer is an alcohol fusion type fusion layer. 19. A first step in which an insulated electric wire with a fusion layer is fixed in a state of being wound into a single-layer winding, and a plurality of main windings, at least one of which is three or more, are prepared. A second layer in which the prepared primary and secondary main windings are alternately stacked.
And a third step of incorporating a magnetic core from above and below. 20. The method according to claim 19, wherein in the first step, the fusion layer is of an alcohol fusion type, and an alcohol coating device is attached to the winding machine to perform the alcohol fusion simultaneously with the winding operation.
A method for producing the thin transformer as described above. 21. The thin transformer according to claim 19, wherein in the second step, auxiliary windings having different winding widths and wire diameters are stacked so as to be arranged on the uppermost layer or the lowermost layer of the primary and secondary main windings. Manufacturing method. 22. The method of manufacturing a thin transformer according to claim 19, wherein the auxiliary winding is formed on a non-winding type substrate in the first step. 23. The method for manufacturing a thin transformer according to claim 19, further comprising a step of sealing the laminated coil with an insulating resin between the second step and the third step.