JP2000082623A - Coil part for power source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil part for a power source for reducing a noise generated due to a magnetic flux leaking from the void of a core, and for preventing the generation of any adverse influence on the operation of a peripheral circuit and device. SOLUTION: A drum core 2 in which a coil 3 is wound around a coil winding part 2b is loaded on a terminal stand 3, and the drum core 2 is covered with a pot core 1 in this coil part. In this case, a shield coil 7 is arranged in the neighborhood of the pot core opening of the terminal stand 3. That is, a difference in level is formed on the face of a terminal stand 4 on which the core is loaded, and the shield coil 7 is wound around the vertical part of the difference in level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply winding component used as a transformer or a choke coil. Technology for reducing the impact on the environment.

[0002]

2. Description of the Related Art In a switching type power supply circuit, a circuit is generally constructed by combining a winding element such as a transformer or a choke coil with a switching element. Here, when a switching power supply having a relatively small power capacity is configured, a magnetic path structure in which a drum-type core and a pot-type core are combined with its winding parts, or a drum-type core and a ring-type core are combined Often used.
Such a drum pot type or drum ring type winding part having a magnetic path structure is inexpensive and has a wide variety of types as compared with the winding parts having other magnetic path structures. ,
It is used in various directions.

As an example of a winding part having a drum / pot type structure, there is one having a cross section at a predetermined position roughly as shown in FIG. The winding component shown in FIG. 6 has a structure in which a drum core 2 having a winding 3 wound around a winding winding portion 2 b is mounted on a terminal block 4, and the drum core 2 is further covered with a pot core 1. . Here, looking at the vicinity of the opening below the cylindrical portion 1 a of the pot core 1, a gap 6 exists between the lower flange 2 a of the drum core 2 and the inner surface of the cylindrical portion 1 a of the pot core 1. The gap 6 is provided for drawing out a winding lead 3 a of the winding 3 wound around the drum core 2. As a result, the winding lead 3a is drawn out from the inside of the pot core 1 through the gap 6, further drawn out below the terminal block 4 through the groove 4a provided on the side surface of the terminal block 4, and the terminal pin 5a protruding from the terminal block 4 is drawn. Will be tied up.

[0004]

Since the winding leads 3a are drawn out through the gap 6, the gaps 6 are formed at least with an interval larger than the wire diameter of the winding 3 (or the winding lead 3a). Certainly, the gap 6 is the winding lead 3a.
However, there is a problem that a magnetic path is cut off at that portion, and a large amount of magnetic flux leaks from the surface of each core near the air gap 6 to the surrounding space. Here, when a pulsed high-frequency current flows through the winding 3 as in a switching power supply, for example, a high-frequency magnetic flux is radiated from the air gap 6 to the surrounding space. The radiated magnetic flux generates high-frequency noise in circuits and devices installed in the vicinity, and may adversely affect the operation of the circuits and devices.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a power supply winding component that reduces noise caused by magnetic flux leaking from a gap between two cores and that is less likely to adversely affect the operation of peripheral circuits and devices.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a first core formed with a winding, a winding part on which the winding is wound, and a flange, and the first core is fitted with the first core. And a second core having a cylindrical portion formed so as to cover the periphery of the winding portion of the first core, wherein the opening of the cylindrical portion of the second core is provided. A shield winding or a loop-shaped conductor is arranged near the portion.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a first embodiment of the present invention, a drum core having windings wound around a winding winding portion is mounted on a terminal block, and a pot core is covered on the drum core. In the winding component, a shield winding is wound around the pot core opening of the terminal block. Here, a step is provided on the core mounting surface of the terminal block, and a shield winding is wound around a vertical portion of the step. Then, in use, a short circuit is made between the winding ends of the shield winding, or a functional circuit such as a filter circuit or a circuit element such as a resistor is connected between the winding ends to bring the circuit into a closed circuit state. As a second embodiment of the present invention, a drum core having a winding wound around a winding winding unit is mounted on a terminal block,
In a winding component having a structure in which a pot core is covered on a drum core, a closed-loop conductor is arranged near the pot core opening of the terminal block.

[0007]

1 and 2 show a first embodiment of a power supply winding component according to the present invention which can reduce noise caused by magnetic flux leakage and thereby reduce adverse effects on the operation of peripheral circuits and devices. As shown in FIG. FIG. 1 shows a cross section of the winding component at a predetermined position, and FIG. 2 shows an upper surface of the terminal block in a state where the core is not mounted. As shown in FIG. 1, a winding component according to the present invention includes a drum core 2 having a winding 3 wound around a winding winding portion 2b mounted on a terminal block 4, and a drum core 2 similar to the conventional one. With a pot core 1. And as a feature of the present invention, the pot core 1
The shield winding 7 is arranged near the opening at the lower end of the cylindrical portion 1a.

Specifically, a step is provided on the mounting surface of the drum core 2 of the terminal block 4 located near the opening of the pot core 1, and the shield winding 7 is wound around a vertical portion of the step. Then, a lead portion 7a, which is one end of the shield winding 7, is drawn out below the terminal block 4 through a groove 4d provided on the side surface of the terminal block, and wrapped around a terminal pin 5d protruding from the terminal block 4. . As can be seen from FIG. 2, the lead portion 7b, which is the other end of the shield winding 7, is drawn out below the terminal block 4 through the groove 4c and is tied to the terminal pin 5c. Although not shown in FIG. 2, the winding 3 wound around the drum core 2
As shown in FIG. 6, the winding lead of
Through the terminal block 4 and the terminal pins (5a
Other).

In the winding component having such a structure, magnetic fluxes other than the magnetic flux that tries to enter and exit the tip of the flange 2a and the inner surface of the cylindrical portion 1a near the gap 6, that is, from the core surface near the gap 6 to the surroundings Most of the leakage magnetic flux radiated into the space is linked with the shield winding 7. Here, the terminal pins 5c and 5d are mounted on the substrate on which the winding components are mounted.
If the circuit is short-circuited or a resistance element or the like is connected in the closed circuit state, a current flows in the shield winding 7 and a magnetic flux in the opposite direction to the leakage magnetic flux interlinked. Then, the leakage magnetic flux radiated from the gap 6 toward the surrounding space is weakened, and a part of the energy of the radiated magnetic flux is consumed in the shield winding 7 and a circuit element connected to the shield winding 7. . As a result, noise generated in the peripheral circuits and devices due to the leakage magnetic flux is reduced, and adverse effects on the operation caused by the noise are reduced.

FIG. 3 shows an example of a circuit when the present invention is applied to a transformer and the transformer is used by being incorporated in a power supply circuit. In the circuit shown in FIG. 3, the primary winding N1 of the transformer T and the current path between the collector and the emitter of the switching transistor Q1 are connected in series between the input terminal IT and the ground. Is connected to the capacitor C1. Secondary winding N2 of transformer T
Are connected to the output terminals O1 and O2, and the winding ends P1 and P2 of the shield winding N3 are short-circuited. The collector of the switching transistor Q1 is further connected to an output terminal O3 via a diode D1. A capacitor C2 is connected between the output terminal O3 and the ground, and a series circuit of resistors R1 and R2 is connected in parallel with the capacitor C2. The control circuit CON is connected to the base of the switching transistor Q1, and the connection point between the resistors R1 and R2 is connected to the control circuit CON.

In the circuit shown in FIG. 3, the primary winding N1 and the secondary winding N2 of the transformer T are connected to the winding 3 in FIG.
The shield winding N3 corresponds to the shield winding 7 in FIG. 1, and the winding ends P1 and P2 correspond to the terminal pins 5c and 5d in FIG. 1, respectively. In the winding component of the present invention shown in FIG. 3, it is assumed that the shield winding N3 is used in a short-circuited state. However, as shown in FIG. 4, the capacitor C3 and the resistor R3 are connected to the shield winding N3 via the terminal pins P1 and P2.
May be connected. In such a configuration, the inductance of the shield winding N3 and the capacitor C
A filter circuit is configured with the capacitance of 3. Then
Depending on the magnitude of the inductance and the capacitance, frequency selectivity can be imparted to the noise reduction effect of the shield winding N3, for example, by reducing only noise of a specific range of frequency components.

In the winding component shown in FIG.
Not all of the leakage magnetic flux that links to other circuits / devices has a bad effect. For example, let us consider a magnetic flux having the same frequency component as the switching frequency, which passes through a position slightly deviated from the gap 6 and goes in and out between the drum core 1 and the pot core 2. The magnetic flux of the detouring switching frequency component is less likely to adversely affect peripheral circuits and devices depending on the switching frequency selected at the time of designing the power supply circuit. Conversely, the energy between the primary winding and the secondary winding is reduced. Useful for communication. Therefore, if the CR series circuit shown in FIG. 4 is connected to the shield winding 7 and the frequency selection range determined by the shield winding 7 (N3) and the capacitor (C3) is set to a particularly problematic frequency band, While reducing harmful noise in the shield winding 7 (N3), it is possible to obtain an effect of preventing unnecessary consumption of useful magnetic flux energy.

FIG. 5 shows a second embodiment of the winding component according to the present invention. FIG. 5 shows the upper surface of the terminal block in a state where the core is not mounted, similarly to FIG. The winding component shown in FIG. 5 uses a short ring 8 made of a closed-loop conductor instead of the shield winding 7 of the first embodiment shown in FIG. The short ring 8 has substantially the same structure as the winding component shown in FIG. 1 in which the shield winding 7 is wound by one turn and the shield winding 7 is short-circuited. Therefore, the same effect as that of the first embodiment can be obtained with the winding component of the second embodiment using the short ring 8 shown in FIG.

In the embodiment of the present invention described above, in the first embodiment, the respective lead portions 7a and 7b of the shield winding 7 are connected to the other terminal pins 5d and 5c. The parts 7a and 7b may be connected to the same terminal pin. However, in this case, the shield winding 7 can be used only in a short-circuit state. As shown in FIG. 4, when the noise reduction has frequency selectivity, the circuit element connected to bring the shield winding 7 into a closed circuit state is not a series circuit of the resistor R3 and the capacitor C3, but other components. May be connected, for example, an LC filter circuit.

Further, in each of the first and second embodiments, the shield winding 7 or the short ring 8 is provided on the upper surface (core mounting surface) of the terminal block 4.
If the position is not extremely far from the gap 6, the shield winding 7 or the short ring 8 may be provided on the lower surface of the terminal block 4 or the like. The present invention is not limited to the core and the terminal block having the shapes shown in the drawings as the embodiments, but can be applied to various shapes without departing from the gist of the present invention.

[0016]

As described above, the winding part for a power supply of the present invention is characterized in that a shield winding or a loop-shaped conductor is arranged near an opening of a cylindrical portion of a core such as a pot type. And According to such a structure, the leakage magnetic flux radiated from the vicinity of the core gap toward the surrounding space is weakened by the action of the shield winding or the loop-shaped conductor, and at the same time, a part of the energy of the radiated magnetic flux is reduced. Is consumed in the shield winding 7 and the circuit elements connected to the shield winding 7. As a result, noise generated in the peripheral circuits and devices due to the leakage magnetic flux is reduced, and adverse effects on the operation caused by the noise are reduced.

In the case where a shield winding is applied, connecting a filter circuit between the winding ends allows the noise reduction effect to have frequency selectivity. As a result, it is possible to obtain an additional effect that unnecessary magnetic flux energy is prevented from being unnecessarily consumed while reducing harmful noise. Therefore, according to the present invention, it is possible to provide a power supply winding component that causes less noise and has less possibility of adversely affecting the operation of peripheral circuits and devices.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section at a predetermined position of a first embodiment of a power supply winding component according to the present invention.

FIG. 2 is a diagram showing an upper surface of a terminal block in a state where a core is not mounted, in a first embodiment of a power supply winding component according to the present invention.

FIG. 3 is a circuit diagram showing one use form of a power supply winding component according to the present invention.

FIG. 4 is a diagram showing an example of a circuit connected to a shield winding when the power supply winding component according to the present invention is used.

FIG. 5 is a diagram showing an upper surface of a terminal block in a state where a core is not mounted, in a second embodiment of the power supply winding component according to the present invention.

FIG. 6 is a diagram showing a cross section at a predetermined position of a conventional power supply winding component.

[Explanation of symbols]

1: pot core (second core) 1a: cylindrical portion
2: Drum core (first core) 2a: Tsuba
2b: winding winding part 3: winding 3a: winding lead 4: terminal block 4a to 4f: groove 5a to
5d: Terminal pin 6: Air gap 7: Shield winding 7a: Lead 8: Short ring

Claims (6)

[Claims] A first core formed with a winding, a winding part on which the winding is wound, and a flange; and the first core when fitted with the first core. A second core having a cylindrical portion formed so as to cover the periphery of the winding portion of the core; and a second core having a cylindrical portion formed around the opening portion of the cylindrical portion of the second core. A winding part for a power supply, wherein a winding is arranged. 2. A first core formed with a winding, a winding part on which the winding is wound, and a flange, and the first core when fitted with the first core. A power supply winding component comprising: a second core having a cylindrical portion formed so as to cover a periphery of a winding winding portion of the core; and a terminal block on which the first core is mounted. A winding part for a power supply, characterized by winding a shield winding around. 3. The power supply according to claim 2, wherein a step is provided on the mounting surface of the first core of the terminal block, and the shield winding is wound around a vertical portion of the step. Winding parts. 4. The method according to claim 1, wherein the first core is a drum core.
The winding part for a power supply according to any one of claims 1 to 3, wherein the second core is a pot-shaped core. 5. The power supply winding component according to claim 1, wherein a filter circuit is connected to the shield winding. 6. A first core formed with a winding, a winding part on which the winding is wound, and a flange, the first core being fitted to the first core when the first core is fitted to the first core. A second core having a cylindrical portion formed so as to cover the periphery of the winding portion of the core; and a second core having a cylindrical portion formed around the opening portion of the cylindrical portion of the second core. A winding part for a power supply, comprising a conductor in a shape of a circle.