JPH08298219A - Inductor and transformer - Google Patents

Abstract

PURPOSE: To obtain an inductor and a transformer in which the cost can be reduced by partially sharing the path. CONSTITUTION: A core member 1 is constituted to form two symmetric magnetic loops M1, M2. A winding LM is wound around the common part of a core member 1 and windings L1, L2 are wound around the branch part of the core member 1. The windings L1, L2 are connected in series so that the flux is added. Since the voltages induced in the windings L1, L2 by the flux BM generated from the winding LM are offset, the windings L1, L2 are insensitive to the flux BM. On the other hand, the flux B1 generated from the winding L1 and the flux B2 generated from the winding L2 are offset at the common path part and the winding LM is insensitive to the flux B1, B2. With such structure, the winding LM can be formed independently from the winding LS comprising the windings L1, L2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor and a transformer for use in general circuits, switching power supply circuits, resonance type power supply circuits and the like.

[0002]

2. Description of the Related Art Conventional inductors and transformers are composed of one or a set of windings, and each winding has a core member made of a ferromagnetic material or the like in order to increase the internal magnetic flux density and increase mutual inductance. Has been inserted. Usually, different core members are used to generate different magnetic fluxes. Therefore, the inductor and the transformer are treated as individual units, and separately configured in the same circuit.

[0003]

However, in the above-described conventional inductor and transformer, there is a problem that it is costly because they are separately configured in the same circuit and are individually incorporated as a single unit.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an inductor and a transformer which can be reduced in cost by sharing a part thereof.

[0005]

A first inductor according to the present invention is wound around a first winding and two branches of a magnetic loop generated by the first winding, and , A second winding and a third winding connected in series so that the magnetic fluxes generated by them are added to each other, and the magnetic flux generated by the first winding is the second winding. The first and the first winding so that the magnetic flux generated in the second winding and the third winding cancel each other in the wire and the third winding, and the magnetic fluxes generated in the second winding and the third winding cancel each other in the first winding. The second and third windings are arranged.

Further, the second inductor according to the present invention has a core member having two symmetrical magnetic loops formed therein, and a first inductor wound around a common path portion of the two magnetic loops of the core member. And a second winding and a third winding that are wound around each branch path portion of the two magnetic loops of the core member and are connected in series so that the magnetic fluxes generated by the respective windings are added to each other. And a winding.

In a third inductor according to the present invention, the core member is formed by joining two E-shaped core members facing each other, and is fitted into a central protrusion of the two E-shaped core members. A first bobbin that has a tubular portion that is wound around the tubular portion, and that is attached to at least one of the two E-shaped core members, and both sides of the central protrusion. A second bobbin around which the second winding and the third winding are wound in a position.

In a fourth inductor according to the present invention, the first bobbin is provided with a support member that supports a plurality of lead pins on one end side of the tubular portion, and the second bobbin is mounted on the E-shaped inductor. The central protrusion of the core member is fitted from one end side of the tubular portion, and the first to third windings are connected to the lead pin.

In the transformer according to the present invention, at least one of the first winding and the second and third windings of the inductor serves as a primary winding, and is coupled to the primary winding.
The feature is that a secondary winding is added.

[0010]

According to the first inductor of the present invention, the magnetic flux generated in the first winding is canceled inside the second winding and the third winding. By winding each of the three windings, the second winding and the third winding can be made insensitive to the magnetic flux generated in the first winding, while the second winding By arranging the second winding and the third winding so that the magnetic fluxes generated in the first winding and the third winding cancel each other inside the first winding. The winding can be made insensitive to the magnetic flux generated in the second winding and the third winding. Therefore, while sharing a part of the magnetic loop, the first winding, the second winding, and the third winding
It is possible to make the winding independent of the configuration.

According to the second inductor of the present invention, the first winding is wound around the common path portion of the two symmetrical magnetic loops formed in the core member, and the second and second branch paths are respectively provided. A third winding is wound, and the second and third windings are connected in series so that the generated magnetic fluxes are added, whereby the first winding and the second and third windings are connected. The line and the line can be operated independently so that the generated magnetic fluxes are not sensitive to each other.

According to the third inductor of the present invention, the central protrusions of the two E-shaped core members are fitted to the first bobbin around which the first winding is wound, and the two are opposed to each other. In addition to the conventional configuration, a second bobbin is attached to at least one E-shaped core member in advance, and second and third windings are wound around the second bobbin. The function of two inductors can be provided only by adding the and steps. Therefore, it is possible to obtain an inductor having a double function without significantly changing the conventional structure and manufacturing process, and to reduce the installation area on the printed board.

According to the fourth inductor of the present invention, a plurality of lead pins are arranged on one end side of the tubular member of the first bobbin, and the central protrusion of the E-shaped core member on which the second bobbin is mounted. The second bobbin is arranged in the vicinity of the plurality of lead pins by fitting the coil from one end side of the tubular portion, so that the first to third windings can be easily connected to the lead pins. The first bobbin and the second
The lead pin can be shared with the bobbin.

Further, according to the transformer of the present invention, at least one of the first winding and the second and third windings is a primary winding, and the secondary winding coupled to the primary winding is used. By adding the winding, it is possible to configure a transformer that is independent of other inductors or transformers while sharing a part of the magnetic loop, thus achieving cost reduction.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a structure of an inductor according to an embodiment of the present invention.

The core member 1 made of a ferromagnetic material such as ferrite or permalloy has two symmetrical magnetic loops M1 and M.
2 is formed by combining an I-shaped core member 1a and an E-shaped core member 1b. This core member 1
A first winding LM is wound around the common path portion of the magnetic loops M1 and M2 formed in 1. On the other hand, a second winding L1 and a third winding L2 are wound around the respective branch portions of the two magnetic loops M1 and M2. The second and third windings L1 and L2 are connected in series so that the magnetic fluxes generated by them are added to each other. Winding L
If the cross-sectional areas of the core member 1b on which 1 and L2 are wound are equal, the numbers of turns N1 and N2 of the windings L1 and L2 are also set to be equal.

Next, the function of the thus constructed inductor will be described. When a current IM is passed from the terminal A of the winding LM to the terminal B, a magnetic flux BM along two symmetrical magnetic loops is generated as shown in the figure. This magnetic flux BM is generated by winding L1,
Although passing through L2 as well, the magnetic flux BM passing through the winding L1 and the magnetic flux BM passing through the winding L2 are in opposite directions and have the same amount, so that the voltages generated in the windings L1 and L2 cancel each other, and
1 and L2 are insensitive to the magnetic flux BM generated by the winding LM. On the other hand, when the current IS is passed from the terminal C of the windings L1 and L2 to the terminal D, the magnetic flux B1 is generated by the winding L1 as shown in the figure.
Further, the magnetic flux B2 is generated by the winding L2. Since the magnetic fluxes B1 and B2 are generated in the same direction by the same amount,
The two magnetic loops M1 and M2 are added to each other in the branch path portion and cancel each other out in the common path portion. For this reason,
The winding LM is insensitive to the magnetic fluxes B1 and B2 generated by the windings L1 and L2. Accordingly, the winding LM and the winding LS including the windings L1 and L2 can be configured independently.

FIG. 2 is a diagram showing an equivalent circuit of the inductor. Since the winding LM and the winding LS including the windings L1 and L2 form an independent inductor in the shared core member 1, at least one of the windings LM and LS is connected to the primary winding LM1, LS1 and by adding secondary windings LM2 and LS2 respectively coupled to these primary windings, while sharing a part of the core member 1,
It is possible to obtain two substantially independent transformers TM and TS. As a preferred method of using the present invention, it is conceivable to use a transformer TM whose number of turns can be relatively increased as a main winding for a power transformer and a transformer TS as a sub winding for a signal transmission transformer or a filter.

Next, an application example of the transformer configured as described above will be described. FIG. 3 is a circuit diagram showing an example in which the secondary coil of the sub-transformer TS of the transformer T is applied as a filter coil. Diode 11 and capacitor 12 configured on the secondary side of the main transformer TM
Forms a rectifying / smoothing circuit 13. Then, a ripple filter 15 is formed by the secondary winding LS2 of the sub transformer TS and the capacitor 14, and the pulsating current output from the rectifying / smoothing circuit 13 is suppressed and a DC component is allowed to pass.

FIG. 4 is a circuit diagram showing an example in which the transformer T is applied to an output voltage stabilizing insulation feedback system of a switching power supply. The power supply terminals E and F are, for example, terminals connected to a commercial AC power supply, and a rectifying / smoothing circuit 23 including a diode 21 and a capacitor 22 is formed between the terminals E and F. The power supply voltage rectified and smoothed by the rectification smoothing circuit 23 is switched by a PWM (Pulse Width Modulation) switch 24 and applied to the primary winding LM1 of the main transformer TM. On the other hand, trance TM
The secondary side voltage is supplied to the PWM modulator 25 via the rectifying / smoothing circuit 13 similar to the above. PWM modulator 25
Based on the magnitude of the output voltage of the rectifying / smoothing circuit 13,
The M pulse is generated and fed back to the PWM switch 24 via the primary side winding LS1 and the secondary side winding LS2 of the sub transformer TS. PWM switch 24
Adjusts the switching time based on this PWM pulse.

FIG. 5 is a circuit diagram showing an example in which the transformer T is applied to a current resonance type switching power supply. A rectifying / smoothing circuit 2 which is supplied through the power supply terminals E and F and is similar to the above.
The power supply voltage rectified and smoothed by 3 is switched by the switch 31, and the primary side winding LM of the main transformer TM is switched.
1 is applied. Between the rectifying and smoothing circuit 23 and the primary winding LM1 of the main transformer TM, the sub transformer T
An LC parallel circuit 33 including an inductor and a capacitor 32 using a winding LS1 on the primary side of S is inserted. Due to the resonance action of this LC parallel circuit 33, the waveform on the secondary side of the transformer TM is made sinusoidal to prevent the generation of high frequency noise and to reduce the loss.

The case where the core member composed of the I-type core member and the E-type core member is inserted into the winding has been described above. The inserted core member is a combination of two E-type core members. You can

FIG. 6 is an exploded view showing a more specific structural example of a transformer in which two E-shaped core members are combined. FIG. 6 (a) is a front view and FIG. 6 (b) is a right side view. is there. This transformer has a tubular portion 41 around which the first winding LM is wound.
The first bobbin 41 having a has a structure in which two E-shaped core members 1a and 1c are fitted from above and below in the drawing, and the two are opposed to each other. A second bobbin 51 is mounted on the core member 1c, and second and third windings LS1 and LS2 are wound around both sides of the central protrusion.

The first bobbin 41, as shown in FIG.
The rectangular tubular portion 41a, the upper support plate 41b provided at the upper end of the tubular portion 41a in the figure, and the lower support member 41c provided at the lower end of the tubular portion 41a in the figure are made of, for example, plastic. In addition to being integrally molded, a plurality of lead pins 42 are provided on the lower surface of the lower support member 41c by, for example, insert molding so as to project. Upper support plate 4
In 1b, the portion corresponding to the upper end opening of the tubular portion 41a has an E
An opening 43 into which the central projection of the core member 1a of the mold can be fitted is formed, and two ribs 44a, 44 extending in the lateral direction that define the storage position of the core member 1a are formed in front of and behind the opening 43.
b is formed.

The lower support member 41c is also formed with an opening (not shown) into which the central projection of the E-shaped core member 1c can be fitted, at the portion corresponding to the lower end opening of the cylindrical portion 41a on the lower surface thereof. . Notches 45 that can be fitted to both end protrusions of the core member 1c are formed at both ends of the lower support member 41a. Further, a plurality of guide grooves 46 for guiding the end portion of the first winding LM to the lead pin 42 are formed on the front and rear end surfaces of the lower support member 41c. Lead pin 4
2 is a DIP (Dual In-li) on the lower surface of the lower support member 41c.
They are arranged in two rows to form a ne Pin) type. A plate-like leg portion 47 for supporting the first bobbin 41 on the printed circuit board is formed slightly inside the lead pin 42. The end of the first winding LM is lapped and connected to each lead pin 42 via the guide groove 46. In this example, the first winding LM has a transformer structure having an intermediate tap on the secondary side, for example.

The second bobbin 51 has a structure as shown in FIG.
It is composed of two bobbin members 51a and 51b. The bobbin member 51a includes two side plates 52a, which are arranged in parallel at a distance corresponding to the thickness of the E-shaped core member 1c.
52b and winding support portions 53a, 53b connecting the side plates 52a, 52b at two locations on one side, and fitted to the central protrusion of the core member 1c between the winding support portions 53a, 53b. And the winding support 5
Notches 55a and 55b are formed on the sides of the openings 3a and 53b opposite to the openings 54, which are fitted to the projections at both ends of the core member 1c. In addition, the opening 54 and the notch 55a,
The second and third windings LS1 and LS are provided on the periphery of 55b.
A guide 56 for guiding 2 is provided. The bobbin member 51b is the bobbin member 5 from the back side of the E-shaped core member 1c.
1a is attached to the open side of the side plates 52a and 52b. Second
And the third windings LS1 and LS2 are the E-shaped core member 1c.
Each winding supporting portion 53a of the second bobbin 51 mounted on the
It is wound around the portion 53b in the same direction and connected in series via a guide 57. The second and third windings LS1,
The end portion of the LS2 has a lower support member 41c after the central protrusion of the core member 1c is fitted into the lower opening of the first bobbin.
It is lapped and connected to the lead pin 42 via a guide 48 formed on the leg portion 47 of the.

FIG. 9 (a) is a plan view showing the assembled state of the transformer in the embodiment, FIG. 9 (b) is a front view,
The figure (c) is a right side view and the figure (d) is a bottom view. In the transformer of this embodiment, the second bobbin 51 is mounted on the core member 1c in advance, and the second and third windings LS1 and LS2 are wound around the second bobbin 51. It can be assembled by the same process as the manufacturing process of the transformer using the two conventional E-shaped core members 1a and 1c. That is, the core member 1c and the core member 1a are joined to the first bobbin 41 while facing each other in the upper and lower directions, and fixed by the tape 61 as shown in FIG. 9C. With the same structure as one conventional transformer, it is possible to have two functions of a transformer and an inductor. As a result, the layout area on the printed circuit board can be reduced.

Further, by fitting the central protrusion of the core member 1c, to which the second bobbin 51 is mounted, from the lower opening of the first bobbin 41, the second bobbin 51 is placed inside the lead pin 42. Since they are arranged, the ends of the windings LS1 and LS2 of the second bobbin 51 can be easily connected to the lead pins 42. Thereby, the first bobbin 41
Since the lead pin 42 can be shared by the second bobbin 51 and the second bobbin 51, the cost of parts can be reduced. Furthermore,
By fitting the central protrusion of the core member 1c on which the second bobbin 51 is mounted from the opening on the lower side of the first bobbin 41, the wiring portion is concentrated on the lower side of the lower support member 41c. Therefore, there is an effect that the wiring portion can be protected.

In the above embodiment, the second bobbin 41
Shows an example of an inductor having two terminals.
It is also possible to configure the third winding LS1 and the third winding LS2 with a primary winding and a secondary winding, respectively, and use them as a transformer. At this time, the cost can be further reduced because the two transformers are configured by one set of core members.

Further, in the above-mentioned embodiment, two sets of independent inductors or transformers are formed in one core member, but by further expanding the structure of the previous embodiment, three sets or more are set in one core member. It is also possible to configure an inductor or a transformer of

FIG. 10 is a view showing an example in which one core member 1 is configured with three independent inductors. The core member 1 is formed by symmetrically arranging the E-shaped core members 1a and 1b on both sides of the above-mentioned I-shaped core member 1b so as to have a generally U shape. Windings LMa and LMb are wound around the central cores of the E-shaped core members 1a and 1c, respectively. These windings LMa and LMb are wound in opposite directions and connected in series to form a main winding LM. The windings LMa, LMb generate two magnetic loops M1, M2 and M3, M4, respectively. The windings L1 and L2 forming the sub winding LS are wound in the same manner as described above. Further, in this embodiment, the windings L3 and L4 are respectively wound around the branch paths of the two magnetic loops M5 and M6 generated by the sub winding LS so that they form the magnetic flux BS 'in the same direction. Are connected in series.

Magnetic flux BM generated by the main winding LM
Passes through the windings L1 and L2, but since these are in opposite directions and have the same amount, the sub winding LS is the main winding LM.
It is not sensitive to the magnetic flux BM. On the other hand, the magnetic flux BM also passes through the windings L3 and L4, but since these are in opposite directions and have the same amount, the sub winding LS 'is also insensitive to the magnetic flux BM due to the main winding LM.

The magnetic fluxes BS generated by the windings L1 and L2 forming the sub winding LS are opposite to each other and have the same amount inside the main winding LM, and therefore do not occur inside the main winding LM. Therefore, the main winding LM is
Not sensitive to magnetic flux BS due to S. On the other hand, the magnetic flux BS generated by the sub winding LS also passes through the sub winding LS ',
These are offset in the opposite directions because they have the same amount. Therefore, the sub winding LS 'also has a magnetic flux BS due to the sub winding LS.
Not sensitive to.

The magnetic flux BS 'generated in the sub winding LS' also passes through the windings LMa and LMb of the main winding LM in the same direction, but the windings LMa and LMb are wound in opposite directions to each other. , Offset. Therefore, the main winding LM is
It is not sensitive to the magnetic flux BS 'of the sub winding LS'. On the other hand, the magnetic flux BS 'generated in the sub winding LS' does not occur inside the sub winding LS because the magnetic fluxes BS 'in the sub winding LS have opposite directions and the same amount. Therefore, the sub winding LS is insensitive to the magnetic flux BS 'of the sub winding LS'.

In this embodiment, the winding LMa or the winding LM
When b is the first winding, the windings L1 and L2 are the second and third windings, respectively, and when the sub-winding LS is the first winding, the windings L3 and L4 are the second and third windings, respectively. It becomes the third winding.

[0036]

As described above, according to the inductor of the present invention, the magnetic flux generated in the first winding is canceled in the second winding and the third winding.
By winding the winding and the third winding respectively,
The second winding and the third winding can be made insensitive to the magnetic flux generated in the first winding,
The second magnetic flux is generated by the second winding and the third winding so that the magnetic fluxes cancel each other out inside the first winding.
By arranging the first winding and the third winding,
Can be made insensitive to the magnetic flux generated by the second winding and the third winding, so that the first winding and the first winding can be shared while sharing a part of the magnetic loop. The second winding and the third winding can be independently configured.

Further, according to the transformer of the present invention, at least one of the first winding and the second and third windings is a primary winding, and the secondary winding coupled to the primary winding is used. By adding the winding, it is possible to configure a transformer that is independent of other inductors or transformers while sharing a part of the magnetic loop, thus achieving cost reduction.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an inductor according to an embodiment of the present invention.

FIG. 2 is a diagram showing an equivalent circuit of the inductor.

FIG. 3 is a circuit diagram showing an example in which a secondary coil of a sub-transformer of the transformer in the embodiment is applied as a filter coil.

FIG. 4 is a circuit diagram showing an example in which the transformer is applied to an output voltage stabilizing insulation feedback system of a switching power supply.

FIG. 5 is a circuit diagram showing an example in which the transformer is applied to a current resonance type switching power supply.

FIG. 6 is a diagram showing a configuration of a transformer according to another embodiment of the present invention.

FIG. 7 is a perspective view for explaining the structure of the first bobbin in the example.

FIG. 8 is a perspective view for explaining the structure of a second bobbin in the same embodiment.

FIG. 9 is a diagram showing a structure of a transformer in the example.

FIG. 10 is a diagram showing a structure of an inductor according to still another embodiment of the present invention.

[Explanation of symbols]

1, 1a to 1c ... Core member 11, 21, ... Diode,
12, 14, 22, 32 ... Capacitor, 13, 23 ... Rectifying / smoothing circuit, 15 ... Ripple filter, 24 ... PWM switch, 25 ... PWM modulator, 31 ... Switch, 33 ...
LC parallel circuit, 41 ... First bobbin, 41a ... Cylindrical part, 41b ... Upper support plate, 41c ... Lower support member, 42
... lead pins, 43, 54 ... openings, 44a, 44b ...
Ribs, 45, 55a, 55b ... Notches, 46 ... Guide grooves,
47 ... Legs, 48, 56, 57 ... Guide, 51 ... Second bobbin, 51a, 51b ... Bobbin member, 53a, 53b
... Winding support portion, 61 ... Tape, M1 to M6 ... Magnetic loop, LM, LM1, LM2, LMa, LMb, L1 to L
4, LS, LS ', LS1, LS2 ... Winding, N1, N2
... Number of turns, A to H ... Terminal, IM, IS, IS '... Current, B
M, BS, BS ', B1, B2 ... Magnetic flux, T, TM, TS
…Trance.

Claims (5)

[Claims] 1. A first winding and two windings of a magnetic loop generated by the first winding are respectively wound in series, and magnetic fluxes generated by the windings are connected in series so as to be added to each other. Second connected to
And a third winding, wherein the magnetic flux generated in the first winding cancels out inside the second winding and the third winding, and the second winding And the first, second and third windings are arranged so that the magnetic fluxes generated in the third winding cancel each other out inside the first winding. 2. A core member having two symmetrical magnetic loops formed therein, a first winding wound around a common path portion of the two magnetic loops of the core member, and 2 of the core member. And a second winding and a third winding that are wound around each branch portion of one magnetic loop and that are connected in series so that the magnetic fluxes generated by each branch may be added to each other. Inductor. 3. The core member is configured by joining two E-shaped core members facing each other, and has a cylindrical portion fitted to a central protrusion of the two E-shaped core members. A first bobbin around which the first winding is wound around the tubular portion and at least one of the two E-shaped core members are mounted, and the second winding is provided at positions on both sides of the central protrusion. And a second bobbin around which the third winding is wound, the inductor according to claim 2. 4. The first bobbin includes a support member that supports a plurality of lead pins on one end side of a tubular portion, and a central protrusion of an E-shaped core member to which the second bobbin is mounted is The inductor according to claim 3, wherein the first to third windings are fitted to each other from one end side of the tubular portion, and are connected to the lead pins. 5. The first winding according to claim 1 and at least one of the second and third windings is a primary winding, and is coupled to the primary winding. A transformer characterized in that a secondary winding is added.