JPH0548606B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a transformer that steps up or steps down an arbitrary voltage value to a desired voltage value, and is particularly suitable for circuits or devices that require large current supply and miniaturization, such as DC-DC converter circuits for photographic strobe devices. This is about a transformer. Conventional Structures and Their Problems Conventionally, transformers for voltage conversion have been used in various devices, and the DC-DC converter circuit of a photographic strobe device is one of the typical devices. Figure 1 shows the DC of the photographic strobe device mentioned above.
- It is a circuit diagram showing a general example of a DC converter circuit A, in which a transformer 1 has a primary winding 2 to which energy supply from a power source E is interrupted via an oscillation transistor Tr, as is well known. A secondary winding 3 that is electromagnetically coupled to induce a boosted voltage for charging the main capacitor C _M , an auxiliary winding 4 that controls the oscillation operation of the oscillation transistor T _r , and a magnetic core 5 around which these windings are wound. It is composed of In the figure, 6 is a power switch that controls the supply of power E, 7 is a starting resistor for the oscillation transistor T _r ,
It goes without saying that 8 represents a diode that rectifies the AC high voltage induced in the secondary winding 3, and the operation of the above-mentioned DC-DC converter circuit A including such a configuration is well known in the art. Therefore, it is omitted. Although not shown, it goes without saying that a flash discharge tube and a trigger circuit for this flash discharge tube are connected to both ends of the main capacitor _CM . Now, if we consider the desired performance of the above-mentioned transformer, it is strongly required that it be able to supply more energy than the secondary winding 3 and be compact. In other words, as is well known, the above-mentioned strobe device has a large amount of light emitted and the main capacitor C _M
There is a strong demand for a small capacitor with a short charging time, and therefore it is necessary to use the main capacitor as a transformer.
There is a demand for a compact device that can supply a large amount of energy so that the _CM can be charged in a short time. On the other hand, looking at the configuration of the conventional transformer 1 used in the DC-DC converter circuit A as described above, it has the three types of windings described above,
These windings are constructed by winding one copper wire around the magnetic core 5 from positions S ₁ , S ₂ and S ₃ as shown in FIG. Therefore, when the capacitance of the main capacitor _CM is set to a large value to increase the guide number of the strobe device, the charging time has traditionally been considered in order to increase the energy supplied to the main capacitor _CM . This is accomplished by increasing the thickness of the conductor wire, for example, the copper wire, used as the primary winding 2 of each of the aforementioned windings. In other words, in response to the increase in the capacity of the main capacitor C _M , the primary winding 2
By increasing the thickness of the primary winding 2, the current flowing through the primary winding 2 is increased, and the current supplied to the main capacitor C _M via the secondary winding 3 is also increased. In other words, they were trying to prevent this from happening. An example is shown in Table 1, and as the capacitance of the main capacitor _CM increases, the diameter of the copper wire of the primary winding 2 is set to be thicker as described above.

[Table] However, if we consider increasing the wire diameter of the primary winding 2 mentioned above from the perspective of the shape of the transformer, it goes without saying that the volume of the winding will increase, and of course the shape will also change. However, this results in an increase in size, which goes against the desire for miniaturization of conventional transformers. In addition, considering the manufacture of transformers, as the wire diameter increases, the strength against bending increases, making it difficult to wind the wire around the magnetic core 5. In other words, if the magnetic core is too small, it becomes impossible to wind the wire. A larger magnetic core must be used depending on the diameter, and this also makes the shape of the transformer larger. Furthermore, when considering the cost of the transformer, it is clear that the cost will increase as the volume of the winding increases and the size of the magnetic core increases. Therefore, in today's world where various devices in all fields are required to be smaller, lighter, and lower in cost, the current state of transformers as described above is not desirable, and improvements have been strongly desired. OBJECTS OF THE INVENTION The present invention provides a transformer that is small in size, low in cost, and capable of supplying a large amount of energy. Another object of the present invention is to provide a transformer in which at least the co-primary winding of the windings wound around the magnetic core is formed by parallel winding of a plurality of conductor wires. Configuration of the Invention The transformer according to the present invention is configured such that among the windings wound around the magnetic core, at least the co-primary windings are formed by parallel connections of a plurality of conductor wires. DESCRIPTION OF THE EMBODIMENTS FIG. 3 is a wiring diagram showing an embodiment of the transformer according to the present invention, and the same numbers as those in FIG. 1 indicate the same functional members. As is clear from the drawing, the embodiment shown in FIG. 3 corresponds to the transformer used in the DC-DC converter circuit shown in FIG. Each winding of wire 2, secondary winding 3, and auxiliary winding 4 is made of copper wires 2 ₁ , 2 ₂ , 3 ₁ , 3 ₂ , 4 ₁ , which are two conductor wires, respectively.
It is constructed by connecting 4 ₂ in parallel. Therefore, when considering the resistance value of each winding to DC in the transformer according to the present invention,
When using the same copper wire, compared to a conventional transformer in which each winding consists of a single winding, the volume of the windings is doubled if the number of turns is the same, but the resistance value is connected in parallel. When the volume of each winding is reduced to about 1/2 and the volume of the windings is kept the same, that is, in the illustrated embodiment, since two copper wires are used, the number of turns of each winding is reduced to 1/2. In this case, the resistance value will be reduced to about 1/4. That is, in the case of the illustrated transformer according to the present invention, the cross-sectional area of the copper wire through which current flows is twice that of a conventional transformer because two copper wires are used, so the resistance value to direct current as described above is This means that the characteristics can be obtained. Now, if the DC resistance decreases, it means that the current value that can be passed with the same voltage can be increased.Simply put, it means that even with the same magnitude, a large current can be passed. So it becomes. On the other hand, in the case of the transformer according to the present invention, if the same level of current as the conventional transformer is to flow, the volume of the winding can be significantly reduced by reducing the number of turns of the winding. That is,
If you want the same current to flow, you just have to make the cross-sectional areas the same.When constructing the illustrated transformer according to the present invention, it is possible to use copper wire with a smaller diameter, so the work of winding the copper wire can be simplified. This makes winding work possible even if the magnetic core is made smaller, which means that the volume of the transformer can be significantly reduced. In other words, even in conventional transformers, if you only want to reduce the volume, you can reduce the number of turns of the winding, but in the case of a single copper wire, it is necessary to reduce the number of turns of the winding. If you try to do this, the diameter will inevitably become thicker, making the winding work extremely difficult as mentioned at the beginning, and since you cannot use a small magnetic core, simply reducing the number of turns will not counteract the reduction in transformer volume. This means that the influence of both was not very large. Here, a transformer according to an embodiment of the present invention as shown in FIG. 3 was manufactured using the magnetic core of a conventionally used transformer, and a transformer as shown in FIG.
When applied to a DC-DC converter circuit, we have measured the time it takes to reach approximately 270V when a 1000μF main capacitor C _M is charged to 350V, which is generally known as the state in which a strobe device can emit light. Table 2 shows the specifications of each winding.

[Table] As is clear from Table 2 above, when the winding volumes are approximately equal, the charging time of the main capacitor is much shorter in the transformer according to the present invention. On the other hand, if we focus on the charging time, the conventional type A and the B type of the present invention have almost the same charging time, but when we compare the diameters of each winding, the B type is thinner, so , the volume of the transformer is significantly smaller than that of the B type of the present invention. That is, if the B-type transformer of the present invention is used in place of the conventional A-type transformer, the charging characteristics will deteriorate slightly;
This means that we can expect the effect of significantly reducing the volume. Now, if we take the above results even further, we can see that the DC resistance of a copper wire is determined by its cross-sectional area and length, so the wire diameter and number of turns should be set appropriately. This means that a more efficient transformer according to the present invention can be formed. For example, when a transformer with the specifications shown in Table 3 is manufactured and applied to the DC-DC converter circuit described above, the charging time under the above conditions is 3.2 seconds.
It was hot.

[Table] In other words, a transformer with a shorter charging time than the conventional A-type transformer shown in Table 2 was obtained by using a copper wire with a thin wire diameter. Therefore, the C type of the transformer according to the present invention is
Since the wire diameter is as small as 0.5φ, it is possible to use a small magnetic core, which would be extremely difficult to wind with a 0.65φ copper wire, and the volume of the transformer can be significantly reduced. The specific comparison results between the conventional A type and the C type of the present invention are shown in numerical terms.The charging time is approximately 20%.
The volume ratio decreased by approximately 56%, and the cost decreased by approximately 35%. This means that a small, low-cost transformer that can supply the large amount of energy conventionally required has been obtained. In addition, from the above results, A in the present invention
It is easy to see that if this type of transformer is used in place of the conventional transformer that uses 1φ thick copper wire as shown in Table 1, favorable results in terms of charging time and transformer volume will be obtained. There's no need to go into detail about what you can imagine. Further, in the embodiment shown in FIG. 3, two copper wires are connected in parallel in each winding, but it goes without saying that a larger number of copper wires may be connected in parallel. On the other hand, according to the inventor's experiments, it has become clear that the type of winding using multiple copper wires is more effective than the conventional transformer, as long as there are multiple co-primary windings. . That is, in the transformer of the present invention shown in Table 2, when each winding was changed from two copper wires to one wire as appropriate and the charging time was measured under the same conditions,
If only the auxiliary winding is made of a single copper wire, there is almost no effect other than that the charging time tends to be slightly longer, and even if the secondary winding is made of a single copper wire, the charging time will be slightly longer. The charging time will be about 0.5 seconds longer,
Although there was no major effect, if the primary winding was made into one, the charging time would be almost the same as that of a conventional transformer.Of course, since the wire diameter would be thicker, the magnetic core could not be made smaller. Therefore, as mentioned above, at least a plurality of co-primary windings must be constructed. Effects of the Invention In the transformer according to the present invention, since the co-primary winding is composed of a plurality of parallel conductor wires, a large amount of energy can be taken out from the output end, and the shape can be made extremely small. It has extremely practical effects that can reduce costs.

[Brief explanation of the drawing]

Fig. 1 is a circuit example diagram of a conventionally known DC-DC converter circuit, Fig. 2 is a winding connection diagram of a conventional transformer, and Fig. 3 is a winding connection diagram of an embodiment of a transformer according to the present invention. ing. 1...Transformer, 2...Primary winding, 3...Secondary winding, 4...Auxiliary winding, 5...Magnetic core.

Claims (1)

[Scope of Claims] 1. A transformer that converts voltage by having at least a primary winding and a secondary winding wound around a magnetic core, wherein the primary winding is composed of a plurality of windings having the same wire diameter and the same number of turns. A transformer composed of a first parallel connection formed of conductor wires. 2. The transformer according to claim 1, wherein the secondary winding is constituted by a second parallel connection formed of a plurality of conductor wires having the same wire diameter and the same number of turns. 3. The transformer according to claim 1, wherein the first parallel connection body is two copper wires.