KR20170026153A - Ferrite core, electronic component and power supply - Google Patents

Abstract

The present invention provides a ferrite core having low saturation magnetostriction around 100C and high saturated magnetic flux density, suppressing noise reverberation when driving. MnZn ferrite comprises: 51.5-54.5 mol% of oxidized steel (Fe_2O_3); 6.5-12.5 mol% of zinc oxide (ZnO); and residues containing manganese oxide as a main ingredient. The main ingredient comprises: 50-4000 ppm of Li_2CO_3; 100-8000 ppm of TiO_2; and 500-4000 ppm of CoO.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a ferrite core, an electronic component,

The present invention relates to a ferrite core having a low saturation magnetostriction at about 100 ° C, suppressing noise at the time of driving, and high saturation magnetic flux density.

A ferrite sintered body is used as a core material of a power transformer or the like. The ferrite sintered body forming the core (magnetic core) is called a ferrite core, and MnZn ferrite containing Mn and Zn is widely used. In recent years, a saturation magnetic flux density at a high temperature has been required as the size of a power source is reduced.

For example, in the ferrite of Patent Document 1, it is preferable that the composition is such that 52 to 56 mol% of Fe ₂ O ₃ , 6 to 14 mol% of ZnO, 4 mol% or less of NiO, 0.01 to 0.6 mol% of CoO, SiO ₂ : 0.0050 to 0.0500 wt% and CaO: 0.0200 to 0.2000 wt%, and further contains Ta ₂ O ₅ , ZrO ₂ , Nb ₂ O ₅ , V ₂ O ₅ , K ₂ O, TiO ₂ , SnO ₂ and HfO ₂ , and has a high saturation magnetic flux density.

On the other hand, it is also important for the sound generated when the power source is driven. For example, in Patent Document 2, a vibration damper is sandwiched between a leg and a leg of a core having a plurality of leg portions, Characterized in that the transformer is provided with a transformer which is reduced or prevented.

Japanese Patent Publication No. 3968188 Japanese Unexamined Patent Application Publication No. 2013-118308

It is generally known that the sound is caused by magnetostrictive vibration. In Patent Document 2, although the sound resonance is reduced, the magnetostriction which is the cause of the resonance of the sound is not reduced, which is not a fundamental solution. In addition, there is also a problem in that the use of the vibration damper causes cost and labor in manufacturing.

Accordingly, an object of the present invention is to provide a ferrite core capable of solving the above-mentioned problems of the prior art. In particular, the present invention is to provide a ferrite core exhibiting a high saturation magnetic flux density while suppressing noise at the time of driving by reducing magnetostriction at 100 占 폚.

For this purpose, the present inventors paid attention to the composition of iron oxide, manganese oxide, and zinc oxide as the main components contained in the MnZn ferrite, and the compositions of lithium carbonate, cobalt oxide, and titanium oxide as subcomponents. As a result, it has been found that saturation magnetostriction is small at 100 占 폚, sounding at the time of driving is suppressed, and a high saturation magnetic flux density can be realized, and thus the present invention has been accomplished.

That is, the ferrite core according to the present invention comprises MnZn-based ferrite including a main component in which iron oxide is 51.5 to 54.5 mol% in terms of Fe ₂ O ₃ , zinc oxide is 6.5 to 12.5 mol% in terms of ZnO, , Characterized in that it contains Li in an amount of 50 to 4000 ppm in terms of Li ₂ CO ₃ , Ti in an amount of 100 to 8000 ppm in terms of TiO ₂ , and Co in an amount of 500 to 4000 ppm in terms of CoO Is a ferrite core.

In the ferrite core of the present invention, as the subcomponents, it is preferable that Si contains 50 to 300 ppm in terms of SiO ₂ and 200 to 3000 ppm in terms of CaCO _{3 in} terms of CaCO ₃ with respect to the main component.

In addition, the ferrite core of the present invention, as additives, for the main component, Nb ₂ O ₅ in terms of 50 to 750ppm of Nb, Ta ₂ O 50 to ₅ equivalent to 50 to 1500ppm of Ta, V ₂ O ₅ equivalent to 1000ppm V, and Sn having 500 to 13000 ppm in terms of SnO ₂ .

By suppressing saturation magnetostriction at 100 deg. C, it is possible to suppress sounding at the time of driving and realize a high saturation magnetic flux density.

[Fig. 1] (a) is a perspective view showing an E-shaped ferrite core (magnetic core) according to the present embodiment. (b) is a perspective view showing a transformer in which two E-type cores are arranged inside to face each other according to the present embodiment.
2 is a block diagram of a switching power supply;
3 is a block diagram showing a main part of a vehicle equipped with a switching power supply unit.

First, reasons for limiting the components in the present invention will be explained.

In the ferrite core of the present invention, the amount of Fe as a main component is 51.5 to 54.5 mol% in terms of Fe ₂ O ₃ . In addition, in the following, it is denoted an amount of the title is "the amount of Fe as Fe ₂ O ₃ in terms of" simply Fe ₂ O ₃ and the like. If the amount of Fe ₂ O ₃ is less than 51.5 mol%, saturation magnetostriction at 100 ° C is reduced but the saturation magnetic flux density is reduced. On the other hand, if the amount of Fe ₂ O ₃ exceeds 54.5 mol%, the saturation magnetostriction at 100 ° C becomes large. Therefore, in the present invention, the amount of Fe ₂ O ₃ is set to 51.5 to 54.5 mol%. The preferred amount is 51.5 to 53.5 mol%.

The transfer of ZnO affects saturation flux density and saturation magnetostriction. If the amount of ZnO is less than 6.5 mol%, the saturation magnetostriction becomes large. If the content of ZnO exceeds 12.5 mol%, the saturation magnetic flux density at 100 캜 becomes small. Therefore, in the present invention, the amount of ZnO is set to 6.5 to 12.5 mol%. The ferrite core of the present invention is mainly composed of MnO except the inevitable impurities.

Next, the subcomponent in the present invention will be described.

In the ferrite core of the present invention, the amount of Li as a subcomponent is 50 to 4000 ppm in terms of Li ₂ CO ₃ . Li ₂ CO ₃ is effective in suppressing magnetostriction, and in order to obtain such effect, 50 ppm or more is added to the main component. However, if the added amount is too large, the saturation magnetic flux density becomes small. Therefore, in the present invention, the amount of Li ₂ CO ₃ is 4000 ppm or less. The preferred amount is 1000 to 2500 ppm.

In the ferrite core of the present invention, the amount of Ti as a subcomponent is 100 to 8000 ppm in terms of TiO ₂ . TiO ₂ can replace tetravalent Ti ions with Fe in the spinel lattice to reduce magnetostriction. In order to obtain such an effect, 100 ppm or more is added to the main component. However, if the added amount is too large, the saturation magnetic flux density becomes small. Therefore, in the present invention, the amount of TiO ₂ is set to 8000 ppm or less. The preferred amount is 500 to 5000 ppm.

In the ferrite core of the present invention, the amount of Co as a subcomponent is 500 to 4000 ppm in terms of CoO. CoO is effective in suppressing magnetostriction, and in order to obtain such effect, at least 500 ppm of CoO is added to the main component. However, if the addition amount thereof is too large, the saturation magnetic flux density becomes small. Therefore, in the present invention, the amount of CoO is 4000 ppm or less. The preferred amount of CoO is 500 to 3000 ppm.

Further, when Li, Ti, and Co are simultaneously added, the effect is further enhanced. Li or Co is solved in the B site of the spinel crystal to obtain a magnetostrictive effect. However, when these are added alone, they are employed not only in the B site but also in the A site, so that sufficient effect can not be obtained with respect to the added amount. However, by simultaneously adding Ti, it is considered that Li and Co are easily dissolved in the B site, and that a larger magneto-suppressive effect than that added alone is obtained.

The ferrite core of the present invention has a saturation magnetic flux density at 100 占 폚 of as high as 380 mT or higher by appropriately selecting the above composition, and saturation magnetization at 100 占 폚 is reduced, thereby suppressing the sounding during driving.

In the present invention, the core loss can be suppressed by restricting the subcomponent as follows. The ferrite core of the present invention may contain, as a subcomponent, SiO ₂ in the range of 50 to 300 ppm and CaCO ₃ in the range of 200 to 3000 ppm. Si and Ca are segregated in the grain boundaries to form a high-resistance layer, which contributes to low loss and has an effect of improving the sintering density as a sintering aid. When Si is less than 50 ppm in terms of SiO ₂ or Ca is less than 200 ppm in terms of CaCO ₃ , the above effect can not be sufficiently obtained. Further, when Si exceeds 300 ppm in terms of SiO ₂ , or when Ca exceeds 3000 ppm in terms of CaCO ₃ , deterioration of core loss due to abnormal (abnormal) grain growth becomes large. It is preferable that SiO ₂ is 50 to 150 ppm and CaCO ₃ is 500 to 2000 ppm, SiO ₂ is 75 to 125 ppm, and CaCO ₃ is 800 to 1600 ppm.

The ferrite core of the present invention may contain, as a subcomponent, Nb ₂ O ₅ in the range of 50 to 750 ppm and Ta ₂ O ₅ in the range of 50 to 1500 ppm. Nb and Ta are components that act to increase the grain boundary resistance (grain boundary resistance). When Nb is less than 50 ppm in terms of Nb ₂ O ₅ , or when Ta is less than 50 ppm in terms of Ta ₂ O ₅ , there is no improvement effect. When Nb exceeds 750 ppm in terms of Nb ₂ O ₅ , or when Ta exceeds 1500 ppm in terms of Ta ₂ O ₅ , since the core loss increases due to abnormal grain growth, Nb ₂ O ₅ is in the range of 50 to 750 ppm And Ta ₂ O ₅ was limited to a range of 50 to 1500 ppm. It is preferable to contain Nb ₂ O ₅ in the range of 100 to 300 ppm and Ta ₂ O ₅ in the range of 100 to 600 ppm.

The ferrite core of the present invention may contain V ₂ O ₅ as a subcomponent within a range of 50 to 1000 ppm. V is a component that acts to increase the grain boundary resistance. When V is less than 50 ppm in terms of V ₂ O ₅ , there is no improvement effect. In addition, V has only a V ₂ O ₅ because V ₂ O ₅ when conversion exceeds 1000ppm the larger the core loss by the abnormal grain growth in the range of 50 to 1000ppm. When the content is increased, abnormal grain growth is caused, so that V ₂ O ₅ is preferably contained in the range of 100 to 500 ppm.

The ferrite core of the present invention may contain 500 to 13000 ppm of SnO ₂ as a subcomponent. SnO ₂ is present in some grain boundaries and is a component that reduces the loss by promoting grain boundary reoxidation during the cooling process after sintering. SnO ₂ is a quadrivalent ion that also substitutes atoms of the spinel lattice to lower the bottom temperature. However, when the added amount is too large, abnormal grain growth is caused and the loss is increased, so SnO ₂ is contained in the range of 500 to 13000 ppm. Preferably, SnO ₂ is contained in the range of 1000 to 8000 ppm. In addition, these components are not necessarily added in the form of an oxide, and they may be mixed in the form of a carbonate, for example.

The ferrite core of the present invention can suppress loss at 100 占 폚 by appropriately selecting the above composition.

Next, a suitable manufacturing method for the ferrite core according to the present invention will be described.

As the raw material of the main component, an oxide or a powder of a compound which becomes an oxide by heating is used. Specifically, Fe ₂ O ₃ powder, Mn ₃ O ₄ powder and ZnO powder can be used. The average particle diameter of each raw material powder may be suitably selected in the range of 0.1 to 3 占 퐉. The raw material powder of the main component is wet-mixed and then calcined. The firing temperature may be set to a predetermined temperature within the range of 800 to 1100 占 폚. The stabilization time of the preliminary firing may be suitably selected within the range of 0.5 to 5 hours. After the calcination, the calcining material is pulverized, for example, to an average particle diameter of about 0.5 to 3 mu m. Further, in the present invention, a powder of a composite oxide containing two or more kinds of metals may be used as a raw material for the main component, not limited to the raw material of the main component. For example, an aqueous solution containing iron chloride and manganese chloride is oxidatively roasted to obtain a composite oxide powder containing Fe and Mn. The powder may be mixed with ZnO powder to be a main component material. In this case, plasticization is unnecessary.

The subcomponent is added after the calcination. For the addition after the calcination, the subcomponent material may be added to the calcining material to perform the grinding, or the material of the subcomponent may be added and mixed after the calcination of the calcining material. However, Li ₂ CO ₃ , TiO ₂ , and CoO may be added to the calcining together with the raw material of the main component.

A powder of a compound which becomes an oxide or an oxide by heating may be used as a raw material of the subcomponent. Specifically, Li ₂ CO ₃ powder, Co ₃ O ₄ powder, TiO ₂ powder, SiO ₂ powder, CaCO ₃ powder, Nb ₂ O ₅ powder, Ta ₂ O ₅ powder, SnO ₂ powder and the like can be used.

The mixed powder composed of the main component and the subcomponent is granulated into granules so as to smoothly carry out a subsequent molding step. The assembly can be carried out, for example, using a spray dryer. A small amount of a suitable binder such as polyvinyl alcohol (PVA) is added to the mixed powder, sprayed with a spray dryer, and dried. The particle diameter of the obtained granules is preferably set to about 80 to 300 mu m.

The obtained granules are molded into a desired shape, for example, by using a press having a mold of a predetermined shape, and the formed body is provided in a firing step.

In the firing step, it is necessary to control the firing temperature and the firing atmosphere. The firing temperature can be suitably selected in the range of 1250 to 1500 占 폚, but firing is preferably performed in the range of 1300 to 1400 占 폚 in order to sufficiently draw the effect of the ferrite core of the present invention. In the firing atmosphere, the oxygen partial pressure may be appropriately adjusted in a mixed atmosphere of nitrogen and oxygen.

The fired ferrite core according to the present invention can obtain a relative density of 93% or more, more preferably 95% or more.

The ferrite core obtained by the present invention can be used for a transformer, and the transformer obtained by the present invention can be used for a switching power source device.

Fig. 1 (a) is a perspective view showing an E-shaped ferrite core (magnetic core) according to the present embodiment. As shown in Fig. 1 (a), an E-shaped ferrite core 10 is called an E-type core or the like and is used for a transformer or the like. As the transformer employing the E-type core such as the ferrite core 10, it is known that two E-type cores are disposed inside the transformer as shown in Fig. 1 (b).

2 is a block diagram showing a configuration of a switching power supply device.

2 is a device (DC / DC converter) for converting a DC input voltage V _in to a DC output voltage V _{out, and} is a device for removing a noise component included _{in the} DC output voltage V _in A transformer 203 for transforming the output of the switching circuit 202 and a transformer 203 for converting the output of the transformer 203 into a direct current And a smoothing circuit 205 for smoothing the output of the rectifying circuit. The use of the core according to the present invention as the core of the transformer 203 in the switching power supply apparatus 200 having such a configuration can suppress the sound generated in the transformer 203, Can be solved.

The switching power supply apparatus 200 shown in Fig. 2 is particularly suitable for use as a switching power supply apparatus for an automobile.

Fig. 3 is a block diagram schematically showing a main part of a vehicle equipped with a switching power supply 200. Fig.

3, when the switching power supply 200 is used for an automobile, the switching power supply 200 is installed between the high voltage battery 210, the electric appliance 220 and the low voltage battery 230 , The high voltage of about 144 V or about 288 V supplied from the high-voltage battery 210 is lowered to about 14 V, and the low voltage battery 230 is supplied to the electric device 220. Examples of the electric device 220 include an air conditioner and audio provided in an automobile.

The charging to the high-voltage battery 210 is performed by the electric power supplied from the electric power generator 240. [ The output of the high voltage battery 210 is also supplied to the motor 250 so that the motor 250 drives the driving system 260 based on the high voltage (about 144 V or about 288 V) supplied from the high voltage battery 210. In addition, in the fuel cell vehicle, the fuel cell main body becomes the power generation device 240, and in the hybrid car, the motor 250 also serves as the power generation device 240.

While the present invention has been described in its preferred embodiment, it is to be understood that the present invention is not limited to the above-described embodiment, and that various changes and modifications can be made without departing from the spirit and scope of the present invention. Needless to say,

[Example]

Hereinafter, the present invention will be described on the basis of specific examples.

As a raw material of the main component, Fe ₂ O ₃ powder, Mn ₃ O ₄ powder and ZnO powder, Li ₂ CO ₃ powder, TiO ₂ powder, Co ₃ O ₄ powder, SiO ₂ powder, CaCO ₃ powder, Nb ₂ O ₅ powder, V ₂ O ₅ powder, Ta ₂ O ₅ powder and SnO ₂ powder were used. The composition of the main component and the composition of the subcomponents are shown in Tables 1 to 3. In addition, in Table 1 and Table 2, 100 ppm of SiO ₂ , 1000 ppm of CaCO ₃ and 200 ppm of Nb ₂ O ₅ were added in addition to the materials shown in the table. These powders were wet mixed and then calcined in the air at 900 ° C for 3 hours.

A binder was added to the resulting mixture, granulated, and then molded to obtain a toroidal shaped body, an I-shaped shaped body, and an E-shaped shaped body. The molded body thus obtained was sintered at a temperature of 1300 ° C (with a stabilizer oxygen partial pressure of 2%) at a temperature of 1300 ° C under oxygen partial pressure control to obtain a toroidal ferrite core (outer diameter 20 mm, inner diameter 10 mm, thickness 5 mm) Length: 70 mm, width: 8 mm, thickness: 8 mm) and an E-shaped ferrite core (length: 40 mm, height: 15 mm, width: 5 mm).

Next, the measurement method of the present invention will be described.

The measurement of the magnetostriction at 100 占 폚 was carried out using a strain gage (KFG: general purpose foil strain gage) manufactured by Kyowa Tengyo. A strain gauge was attached to the center side of the I type ferrite core. The absolute value of the rate of change of the deformation amount at the time when the deformation amount is not changed by exciting the I core is defined as a saturation magnetostriction? S. In the following description, the absolute value of the rate of change of the deformation amount at the time when the deformation amount is not changed by energizing the I core is denoted by saturation magnetostriction or? S.

The sounding at 100 ° C was performed by installing the E-type core composition in a simple anechoic box. The measurement was carried out by setting the tip of the microphone of the core and the sound level meter at a distance of 30 mm. The sound pressure level was measured using a sound level meter (LA-5570) manufactured by Onosolki. The data represents the overall value (OA value) after the A characteristic conversion. The A characteristic is a frequency-weighted value representing the sound pressure level based on human auditory sense. The OA value is the sum of the sound pressure levels analyzed for frequency. The OA value was set to 45 dB or less, which is suitable for general use.

The saturation flux density Bs at 100 占 폚 was measured under a condition of an excitation magnetic field of 1194 A / m by a DC magnetization property testing apparatus (SK-110) manufactured by Metron Machinery to obtain a toroidal core. The saturation magnetic flux density Bs was set to 380 mT or more, which is necessary for use in a power transformer.

The core loss Pcv at 100 占 폚 was obtained by winding 5 primary side (5 primary side) and 5 secondary side winding by using a toroidal ferrite core and setting the maximum magnetic flux density at a frequency of 100 kHz to 200 mT ≪ / RTI > by means of an IWATSU manufactured BH analyzer (SY-8217).

From the above measurement results, the following can be known.

"-" in the table indicates that the material is not added.

(Table 1)

When the amount of Fe ₂ O ₃ is less than 51.5 mol% (see Comparative Example 1 and Comparative Example 2), the saturation magnetic flux density Bs at 100 ° C (hereinafter, "at 100 ° C" is omitted) becomes smaller than 380 mT. When the amount of Fe ₂ O ₃ exceeds 54.5 mol% (see Comparative Examples 7 and 8), the saturation magnetostriction becomes larger than 1.5 × 10 ^-6 and the OA value becomes larger than 45 dB.

If the amount of ZnO is less than 6.5 mol% (see Comparative Example 3 and Comparative Example 5), the saturation magnetostriction becomes larger than 1.5 x 10 ^-6 , and the OA value becomes larger than 45 dB. When the amount of ZnO exceeds 12.5 mol% (see Comparative Example 4 and Comparative Example 6), the saturation magnetostriction becomes small, but the saturation magnetic flux density Bs becomes smaller than 380 mT.

(Table 2)

When the amount of Li ₂ CO _{3 as} a subcomponent is less than 50 ppm (see Comparative Example 9), the saturation magnetostriction becomes large, and the OA value becomes larger than 45 dB. In addition, when the amount of Li ₂ CO ₃ exceeds 4000 ppm (see Comparative Example 10), the saturation magnetostriction becomes small, but the saturation magnetic flux density Bs becomes smaller than 380 mT.

When the amount of TiO _{2 as} a subcomponent is less than 100 ppm (see Comparative Example 11), the saturation magnetostriction becomes larger than 1.5 × 10 ^-6 , and the OA value becomes larger than 45 dB. In addition, when the amount of TiO ₂ exceeds 8000 ppm (see Comparative Example 12), the magnetostriction becomes small, but the saturation magnetic flux density Bs becomes smaller than 380 mT.

When the amount of CoO as a subcomponent is less than 500 ppm (see Comparative Example 13), the saturation magnetostriction becomes larger than 1.5 x 10 ^-6 , and the OA value becomes larger than 45 dB. When the amount of CoO exceeds 4000 ppm (see Comparative Example 14), the saturation magnetic flux density Bs becomes smaller than 380 mT.

The amount of Li ₂ CO ₃ was 50 to 4000 ppm as a subcomponent and the amount of TiO ₂ was 100 to 8000 ppm as a sub ingredient with respect to the main MnO content, and the content of Fe ₂ O ₃ was 51.5 to 54.5 mol%, the amount of ZnO was 6.5 to 12.5 mol% And the amount of CoO is 500 to 4000 ppm, the saturation magnetostriction at 100 ° C is 1.5 × 10 ^-6 or less, the OA value is 45 dB or less, and the saturation magnetic flux density Bs is 380 mT or more.

(Table 3)

The other subcomponents are as follows.

As described above, SiO ₂ and CaCO ₃ have an effect of contributing to low loss by forming a high resistance layer segregated in grain boundaries and improving the sintering density as a sintering assistant. However, as shown in Table 3, . That is, by adding SiO ₂ and CaCO ₃ , the core loss Pcv can be reduced. However, as shown in Table 3, when added too much, the core loss becomes poor (see Examples 20 to 27). Therefore, when SiO ₂ and CaCO ₃ are added, SiO ₂ is 50 to 300 ppm and CaCO ₃ is 200 to 3000 ppm.

Further, by adding Nb ₂ O ₅ and Ta ₂ O ₅ , the core loss Pcv can be reduced (see Examples 28 to 34). However, as in the case of SiO ₂ and CaCO ₃ , if too much is added, the core loss becomes worse. Therefore, the optimal amount of Nb ₂ O ₅ is 50 to 750 ppm or less and Ta ₂ O ₅ is 50 to 1,500 ppm or less.

Further, by adding V ₂ O ₅ , the core loss Pcv can be reduced (see Examples 35 to 37). However, as in the case of SiO ₂ and CaCO ₃ , if too much is added, the core loss becomes worse. Therefore, the optimum range of V ₂ O _{5 is set} to 50 to 1000 ppm or less.

Further, by adding SnO ₂ , the core loss Pcv can be reduced (see Examples 38 to 40). However, if SiO ₂ is added too much as in the case of CaCO ₃ , the core loss becomes worse. Therefore, the optimum range of the amount of SnO ₂ is 500 to 13000 ppm or less.

As described above, the ferrite core according to the present invention can sufficiently suppress the sounding of the core at the time of driving by reducing the saturation magnetization at around 100 DEG C, and can also increase the saturation magnetic flux density.

10 Ferrite core (magnetic core)
11 (heavy angle part)
12 (coil)
200 Switching power supply

Claims (5)

Wherein the main component is a MnZn ferrite containing 51.5 to 54.5 mol% of iron oxide in terms of Fe ₂ O ₃ , 6.5 to 12.5 mol% in terms of ZnO in terms of ZnO, and the balance being manganese oxide, ₂ to 50 parts by mass of Co in terms of CO ₃ , 100 to 8000 parts by mass of Ti in terms of TiO ₂ , and 500 to 4000 parts by mass of Co in terms of CoO. The ferrite core according to claim 1, wherein the ferrite core contains 50 to 300 ppm of Si in terms of SiO ₂ and 200 to 3000 ppm of Ca in terms of CaCO ₃ with respect to the main component. The method according to any one of claims 1 to 3, wherein the main component is Nb having 50 to 750 ppm in terms of Nb ₂ O ₅ , Ta having 50 to 1500 ppm in terms of Ta ₂ O ₅ , V having 50 to 1000 ppm in terms of V ₂ O ₅ And Sn of 500 to 13000 ppm in terms of SnO _{2, based} on the total weight of the ferrite core and the ferrite core. An electronic component comprising the ferrite core according to any one of claims 1 to 3. A power supply device comprising the electronic component according to claim 4.

Images