JP2014155392A - Electronic component and dc-dc converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic component for a parallel-connected DC-DC converter capable of suppressing a reduction in inductance due to magnetic saturation, and a DC-DC converter using the same.SOLUTION: An electronic component 10A is the one which is included in a DC-DC converter 1 in which a plurality of DC-DC converter circuits 2, 3 are connected in parallel, and each output is added up to produce one output. The electronic component 10A comprises a body 20, and spiral-shaped inductors L1, L2 constituting part of each of the plurality of DC-DC converter circuits 2, 3 and disposed in the body 20. Each of the inductors L1, L2 is stacked one on top of another so that their center axes approximately match.

Description

  The present invention relates to an electronic component and a DC-DC converter, and more particularly to an inductor used for a DC-DC converter connected in parallel.

  With the recent increase in functionality and speed of electronic devices, the current supplied from the power supply circuit is increasing. Accordingly, DC-DC converters called multi-phase DC-DC converters are widely distributed.

  In the multi-phase DC-DC converter, as described in Patent Document 1, a plurality of DC-DC converters are connected in parallel, and the outputs of the DC-DC converters are added and output. Thereby, in a multiphase DC-DC converter, the load to each DC-DC converter is reduced and it respond | corresponds to the large current supplied from a power supply circuit. Further, output noise (ripple) is reduced by shifting the output phase of each DC-DC converter.

  By the way, since the multi-phase DC-DC converter is composed of a plurality of DC-DC converters, the circuit includes a plurality of inductors. When a current more than expected flows through these inductors, magnetic saturation occurs and the inductance value decreases. As a result, the power conversion efficiency of the multiphase DC-DC converter is reduced. However, further increases in supply current are expected in the future. Considering these circumstances, it is required that the inductance value of the inductor used in the multi-phase DC-DC converter does not decrease even when a current larger than the current flows.

Japanese Patent No. 4229177

  Therefore, an object of the present invention is to provide an electronic component for a DC-DC converter connected in parallel and a DC-DC converter using the same, which can suppress a decrease in inductance value due to magnetic saturation. is there.

  An electronic component according to a first embodiment of the present invention is an electronic component included in a DC-DC converter in which a plurality of DC-DC converter circuits are connected in parallel and the outputs are added to form one output. And a plurality of spiral inductors constituting a part of each of the plurality of DC-DC converter circuits and provided in the main body, and each of the plurality of spiral inductors Are stacked such that the central axes of the plurality of inductors substantially coincide with each other.

  A DC-DC converter according to a second embodiment of the present invention is a DC-DC converter in which a plurality of DC-DC converter circuits are connected in parallel, and the outputs are added together to form one output. Each of the plurality of DC-DC converter circuits includes an electronic component having a plurality of spiral inductors provided in the main body, and each of the plurality of spiral inductors. The plurality of inductors are stacked so that their central axes substantially coincide with each other.

  According to the electronic component and the DC-DC converter, the plurality of spiral inductors are stacked so that the central axes thereof substantially coincide with each other. Thereby, the magnetic flux generated by the inductor interferes with each other, so that the region where the magnetic flux is concentrated is reduced. As a result, a decrease in inductance value due to magnetic saturation can be suppressed.

  According to the electronic component which is one embodiment of the present invention, it is possible to suppress a decrease in inductance value due to magnetic saturation.

It is a circuit diagram of a multi-phase DC-DC converter. It is an external appearance perspective view of the electronic component which is 1st Example. It is a disassembled perspective view of the electronic component which is 1st Example. It is sectional drawing of the electronic component which is 1st Example in the C1 cross section of FIG. It is the graph which showed the result at the time of experimenting in the 1st sample and the 2nd sample. It is a disassembled perspective view of the electronic component which is 2nd Example. It is sectional drawing at the time of dividing | segmenting an electronic component into two. It is sectional drawing of the electronic component which is 2nd Example in the C1 cross section of FIG. It is an external appearance perspective view of the electronic component which is 3rd Example.

  Embodiments of a multi-phase DC-DC converter and electronic components according to the present invention will be described below with reference to the accompanying drawings. In each figure, common parts and portions are denoted by the same reference numerals, and redundant description is omitted. 2 to 4 and FIGS. 6 to 9, the direction in which the central axes of the inductors L1, L2, L1B, and L2B extend is the z-axis direction, and the electronic component 10A is viewed in plan from the z-axis direction. , 10B, and 10C are defined as the x-axis direction and the y-axis direction. Note that the x-axis, y-axis, and z-axis are orthogonal to each other.

(Configuration of multi-phase DC-DC converter)
As shown in FIG. 1, the multi-phase DC-DC converter 1 has DC-DC converter circuits 2 and 3 connected in parallel, and the outputs of the DC-DC converter circuits 2 and 3 are added to form one output. The output phases of the DC-DC converter circuits 2 and 3 are variable by controlling the on / off timing of the transistors Tr1 and Tr2 by a driver IC (not shown).

(Configuration of DC-DC converter circuit)
The DC-DC converter circuit 2 is a step-down DC chopper circuit. Specifically, the DC-DC converter circuit 2 includes a transistor Tr1, a diode D1, an inductor L1, and a capacitor C1. The transistor Tr1 and the inductor L1 are connected in series. The diode D1 is connected between the ground and the transistor Tr1 and the inductor L1. The capacitor C1 is connected between the ground and the inductor L1 and the load R.

  The DC-DC converter circuit 2 steps down the DC voltage from the DC power supply V and outputs it to the load R by turning on / off the current I1 from the DC power supply V by the transistor Tr1. The inductor L1 and the capacitor C1 are for smoothing the output current from the DC-DC converter circuit 2. Specifically, when the transistor Tr1 is on, energy and charge are accumulated in the inductor L1 and the capacitor C1. When the transistor Tr1 is off, back electromotive force is generated by the energy accumulated in the inductor L1. Further, electric charges are discharged from the capacitor C1. As a result, even when the current I1 from the DC power supply V is interrupted by the transistor Tr1, power is stably supplied to the load R. The diode D1 is a freewheeling diode for protecting the transistor Tr1. The DC-DC converter circuit 2 configured as described above transmits the stepped-down current I1 from the DC power source V to the load R. The DC-DC converter circuit 3 also has the same configuration as the DC-DC converter circuit 2.

(Schematic configuration of electronic components)
As shown in FIG. 2, the electronic component 10A according to the first embodiment has a rectangular parallelepiped shape. Further, the electronic component 10A includes a main body 20, external electrodes 31 to 34, and inductors L1 and L2 (not shown in FIG. 2).

(Body structure)
As shown in FIG. 3, the main body 20 is configured by laminating insulator layers 22 a to 22 h so as to be arranged in this order from the positive direction side to the negative direction side in the z-axis direction. Moreover, each insulator layer 22a-22h has comprised the rectangular shape when planarly viewed from the z-axis direction. Therefore, the main body 20 formed by laminating the insulator layers 22a to 22h has a rectangular parallelepiped shape as shown in FIG. Furthermore, the insulator layers 22a to 22h are made of a magnetic material such as ferrite. Hereinafter, the surface on the positive side in the z-axis direction of each of the insulator layers 22a to 22h is referred to as an upper surface. Further, as shown in FIG. 2, in the main body 20, a surface on the positive side in the z-axis direction is a surface S1, a surface on the negative direction side in the y-axis direction is a surface S2, and a surface on the negative direction side in the z-axis direction is a surface. S3, the surface on the positive direction side in the y-axis direction is referred to as a surface S4.

(External electrode configuration)
As shown in FIG. 2, the external electrodes 31 to 34 are U-shaped electrodes provided on the surface of the main body 20. The materials of the external electrodes 31 to 34 are conductive materials such as Au, Ag, Cu, Pd, and Ni. The external electrodes 31 to 34 will be specifically described below.

  The external electrode 31 is provided across the region on the negative direction side from the center in the x-axis direction on each of the surfaces S1 to S3. The external electrode 31 functions as an input electrode of the inductor L1. That is, the current I1 from the DC power source V flows from the external electrode 31 to the inductor L1 via the transistor Tr1.

  The external electrode 32 is provided across the region on the positive direction side from the center in the x-axis direction on each of the surfaces S1 to S3. The external electrode 32 functions as an input electrode for the inductor L2. That is, the current I2 from the DC power source V flows from the external electrode 32 to the inductor L2 via the transistor Tr2.

  The external electrode 33 is provided across the region on the negative direction side from the center in the x-axis direction on each of the surfaces S1, S3, and S4. The external electrode 33 functions as an output electrode of the inductor L1. That is, the current I1 flowing from the external electrode 31 into the inductor L1 is output from the external electrode 33, merges with the current I2, and flows into the load R.

  The external electrode 34 is provided across the region on the positive direction side of the center in the x-axis direction on each of the surfaces S1, S3, and S4. The external electrode 34 functions as an output electrode of the inductor L2. That is, the current I2 flowing from the external electrode 32 into the inductor L2 is output from the external electrode 34, merges with the current I1, and flows into the load R.

(Inductor configuration)
The inductor L1 forms part of the DC-DC converter circuit 2 and is built in the electronic component 10A. The inductor L1 includes conductor layers 40 to 42 and via conductors 43 and 44. The material of the inductor L1 is a conductive material such as Au, Ag, Cu, Pd, Ni.

  As shown in FIG. 3, the conductor layer 40 is provided on the upper surface of the insulator layer 22b. The conductor layer 40 is a linear conductor layer provided along the outer edge of the insulator layer 22b. As a result, the conductor layer 40 has a substantially square shape when viewed in plan from the z-axis direction. However, the conductor layer 40 is divided in the vicinity of the corner formed by the outer edge on the negative direction side in the x-axis direction and the outer edge on the negative direction side in the y-axis direction in the insulator layer 22b. One end of the conductor layer 40 is exposed to the outside of the main body 20 from the outer edge of the insulator layer 22b on the negative side in the y-axis direction, and is connected to the external electrode 31. The other end of the conductor layer 40 is connected to one end of a via conductor 43 that penetrates the insulator layer 22b in the z-axis direction.

  As shown in FIG. 3, the conductor layer 41 is provided on the upper surface of the insulator layer 22c. The conductor layer 41 is a linear conductor layer provided along the outer edge of the insulator layer 22c. Thereby, the conductor layer 41 has a substantially square shape when viewed in plan from the z-axis direction. However, the conductor layer 41 is divided in the vicinity of the corner formed by the outer edge on the negative direction side in the x-axis direction and the outer edge on the negative direction side in the y-axis direction in the insulator layer 22c. One end of the conductor layer 41 is connected to the other end of the via conductor 43. The other end of the conductor layer 41 is connected to one end of a via conductor 44 that penetrates the insulator layer 22c in the z-axis direction.

  As shown in FIG. 3, the conductor layer 42 is provided on the upper surface of the insulator layer 22d. The conductor layer 42 is a linear conductor layer provided along the outer edge of the insulator layer 22d on the negative side in the x-axis direction. One end of the conductor layer 42 on the negative direction side in the y-axis direction is connected to the other end of the via conductor 44. The other end of the conductor layer 42 on the positive side in the y-axis direction is exposed to the outside of the main body 20 and connected to the external electrode 33.

  In the inductor L1 configured as described above, the conductor layers 40 to 42 and the via conductors 43 and 44 as a whole form a spiral shape that turns clockwise from the positive direction side to the negative direction side in the z-axis direction. doing. As a result, the current I1 flowing into the inductor L1 from the external electrode 31 turns in the main body 20 clockwise from the positive direction side to the negative direction side in the z-axis direction and is output from the external electrode 33.

  The inductor L2 forms part of the DC-DC converter circuit 3 and is built in the electronic component 10A. The inductor L2 includes conductor layers 50 to 52 and via conductors 53 and 54. The material of the inductor L2 is a conductive material such as Au, Ag, Cu, Pd, or Ni.

  As shown in FIG. 3, the conductor layer 50 is provided on the upper surface of the insulator layer 22f. The conductor layer 50 is a linear conductor layer provided along the outer edge of the insulator layer 22f on the positive side in the x-axis direction. One end of the conductor layer 50 on the negative side in the y-axis direction is connected to one end of a via conductor 53 that penetrates the insulator layer 22f in the z-axis direction. The other end of the conductor layer 50 on the positive side in the y-axis direction is exposed to the outside of the main body 20 and connected to the external electrode 34.

  As shown in FIG. 3, the conductor layer 51 is provided on the upper surface of the insulator layer 22g. The conductor layer 51 is a linear conductor layer provided along the outer edge of the insulator layer 22g. Thereby, the conductor layer 51 has a substantially square shape when viewed in plan from the z-axis direction. However, the conductor layer 51 is divided in the vicinity of the angle formed by the outer edge on the positive side in the x-axis direction and the outer edge on the negative direction side in the y-axis direction in the insulator layer 22g. One end of the conductor layer 51 is connected to the other end of the via conductor 53. The other end of the conductor layer 51 is connected to one end of a via conductor 54 that penetrates the insulator layer 22g in the z-axis direction.

  As shown in FIG. 3, the conductor layer 52 is provided on the upper surface of the insulator layer 22h. The conductor layer 52 is a linear conductor layer provided along the outer edge of the insulator layer 22h. As a result, the conductor layer 52 has a substantially square shape when viewed in plan from the z-axis direction. However, the conductor layer 52 is divided in the vicinity of the angle formed by the outer edge on the positive side in the x-axis direction and the outer edge on the negative side in the y-axis direction in the insulator layer 22h. One end of the conductor layer 52 is connected to the other end of the via conductor 54. The other end of the conductor layer 52 is exposed to the outside of the main body 20 from the outer edge of the insulator layer 22 h on the negative side in the y-axis direction, and is connected to the external electrode 32.

  In the inductor L2 configured as described above, the conductor layers 50 to 52 and the via conductors 53 and 54 as a whole have a spiral shape that rotates counterclockwise from the negative direction side in the z-axis direction toward the positive direction side. It is made. Thereby, the current I2 flowing into the inductor L2 from the external electrode 32 turns in the main body 20 counterclockwise from the negative direction side in the z-axis direction to the positive direction side, and is output from the external electrode 34. .

  Incidentally, the inductor L1 and the inductor L2 are stacked in the main body 20 of the electronic component 10 so that their central axes substantially coincide with each other. The current I1 passing through the inductor L1 turns clockwise from the positive direction side in the z-axis direction toward the negative direction side, whereas the current I2 passing through the inductor L2 is negative in the z-axis direction. Turn counterclockwise from the side toward the positive side. That is, the direction of the current I1 passing through the inductor L1 and the direction of the current I2 passing through the inductor L2 are opposite directions. Therefore, as shown in FIG. 4, the direction of the magnetic flux B1 generated in the inductor L1 by the current I1 is opposite to the direction of the magnetic flux B2 generated in the inductor L2 by the current I2.

(Production method)
A method for manufacturing the electronic component 10A configured as described above will be described below. In the following, although one electronic component 10A will be described, in practice, a mother laminated body in which a plurality of unfired main bodies 20 are connected is formed, and external electrodes 31 to 34 are formed after the mother laminated body is cut. Thus, a plurality of electronic components 10A are obtained.

  First, ceramic green sheets to be the insulator layers 22a to 22h are prepared. Specifically, ferric oxide (Fe 2 O 3), zinc oxide (ZnO), and nickel oxide (NiO) are weighed at a predetermined ratio, and then each material is put into a ball mill as a raw material to perform wet blending. The obtained mixture is dried and pulverized, and the obtained powder is calcined. Further, the calcined powder is wet pulverized by a ball mill, dried and then crushed to obtain a ferrite ceramic powder.

  A binder (vinyl acetate, water-soluble acrylic, etc.), a plasticizer, a wetting agent, and a dispersing agent are added to the ferrite ceramic powder and mixed by a ball mill, and then defoamed by decompression. The obtained ceramic slurry is formed into a sheet shape on a carrier sheet by a doctor blade method and dried to produce ceramic green sheets to be the insulator layers 22a to 22h.

  Next, in the ceramic green sheets to be the insulator layers 22b, 22c, 22f, and 22g, laser beams are irradiated to positions where the via conductors 43, 44, 53, and 54 are to be formed, thereby forming via holes. Further, the via conductors 43, 44, 53, 54 are formed by filling the via holes with a conductive paste mainly composed of Au, Ag, Pd, Cu, Ni, or the like. The step of filling the via hole with the conductive paste may be performed simultaneously with the step of forming conductor layers 40 to 42 and 50 to 52 described later.

  Next, a conductive paste mainly composed of Au, Ag, Pd, Cu, Ni or the like is applied to the surface of the ceramic green sheet to be the insulator layers 22b to 22d and 22f to 22h by screen printing or photolithography. To form conductor layers 40 to 42 and 50 to 52.

  Next, ceramic green sheets to be the insulator layers 22a to 22h are laminated and pressure-bonded so as to be arranged in this order to obtain an unfired mother laminated body. Thereafter, the unfired mother laminate is pressed by a hydrostatic pressure press or the like to perform main pressure bonding.

  Next, the mother laminate is cut into a main body 20 having a predetermined size by a cutting blade. Thereafter, the unfired main body 20 is subjected to binder removal processing and firing. The binder removal treatment is performed, for example, in a low oxygen atmosphere at 500 ° C. for 2 hours. Firing is performed, for example, at 800 ° C. to 900 ° C. for 2.5 hours.

  Next, external electrodes 31 to 34 are formed. First, an electrode paste made of a conductive material mainly composed of Ag is applied to the surface of the main body 20. Next, the applied electrode paste is baked at a temperature of about 800 ° C. for 1 hour. Thereby, the base electrodes of the external electrodes 31 to 34 are formed.

  Finally, Ni / Sn plating is applied to the surface of the base electrode. Thereby, the external electrodes 31 to 34 are formed. Through the above steps, the electronic component 10A is completed.

(effect)
According to the electronic component 10A configured as described above, it is possible to suppress a decrease in inductance value due to magnetic saturation. Specifically, the inductors L1 and L2 built in the electronic component 10A are stacked so that their central axes substantially coincide with each other, and further, the direction of the current I1 passing through the inductor L1 and the current I2 passing through the inductor L2 The direction of is the opposite direction. Therefore, as shown in FIG. 4, the direction of the magnetic flux B1 generated in the inductor L1 by the current I1 is opposite to the direction of the magnetic flux B2 generated in the inductor L2 by the current I2. As a result, the magnetic fluxes B1 and B2 cancel each other at the inner diameters of the inductors L1 and L2. As a result, magnetic saturation in the inductors L1 and L2 hardly occurs, and a decrease in the inductance values of the inductors L1 and L2 is suppressed. Accordingly, a decrease in power conversion efficiency in the multiphase DC-DC converter 1 is also suppressed.

  Here, this inventor experimented in order to clarify the effect which 10A of electronic components show | played. More specifically, the electronic component 10A was produced as a first sample. Further, a second sample was produced in which the inductors L1 and L2 in the electronic component 10A were built in separate main bodies, and these were arranged on the substrate and connected in parallel. The size of each sample is 2.5 mm × 2.0 mm × 1.2 mm for the first sample. In the second sample, the size of the main body including the inductor L1 and the main body including the inductor L2 are 2.5 mm × 2.0 mm × 0.6 mm, respectively.

  In the experiment, a direct current was passed through the first and second samples, and the current value was changed to measure the inductance value of the inductor L1 or the inductor L2 in each sample. In FIG. 5, the vertical axis represents the inductance value (μH), and the horizontal axis represents the current value (mA). The inductances of the inductor L1 and the inductor L2 are substantially the same.

  In the experiment, when a direct current was passed, as shown in FIG. 5, it can be seen that the decrease rate of the inductance value Ls1 of the first sample is lower than the decrease rate of the inductance value Ls2 of the second sample. This indicates that the magnetic saturation is suppressed by the magnetic flux B1 generated in the inductor L1 and the magnetic flux B2 generated in the inductor L2 canceling each other, and as a result, the decrease in the inductance value is suppressed.

  Incidentally, the electronic component 10A can contribute to miniaturization of the multi-phase DC-DC converter. Specifically, conventionally, inductors included in a multi-phase DC-DC converter are separately arranged on a substrate for each DC-DC converter circuit. However, the electronic component 10 </ b> A includes an inductor L <b> 1 that forms part of the DC-DC converter circuit 2 and an inductor L <b> 2 that forms part of the DC-DC converter circuit 3. That is, in the electronic component 10 </ b> A, a plurality of inductors conventionally arranged separately on the substrate can be covered with one electronic component. Thereby, in electronic component 10A, it can contribute to size reduction of a multi phase DC-DC converter.

  Further, in the electronic component 10A, the material of the insulator layers 22d and 22e sandwiched between the inductor L1 and the inductor L2 is a magnetic material, and the regions inside the inductors L1 and L2 are also filled with the magnetic material. As a result, the magnetic fluxes B1 and B2 can travel smoothly in the inductors L1 and L2, and the amount of magnetic fluxes that cancel each other increases. As a result, magnetic saturation in the inductors L1 and L2 hardly occurs, and a decrease in the inductance values of the inductors L1 and L2 is suppressed.

  Further, in the electronic component 10A, external electrodes 31 and 32 used as input electrodes are provided on the side surfaces S1 to S3. That is, in the electronic component 10A, the two input electrodes are provided on the same side surface. External electrodes 33 and 34 used as output electrodes are provided on the side surfaces S1, S3, and S4. That is, in the electronic component 10A, the two output electrodes are provided on the same side surface. Therefore, the electronic component 10A is easy to handle when mounted on the circuit board.

(Configuration of electronic component 10B)
Below, the structure of the electronic component 10B which is 2nd Example is demonstrated, referring drawings. In addition, FIG. 2 is used for the external view of 2nd Example.

  The main difference between the electronic component 10A and the electronic component 10B is the configuration of the inductors L1 and L2. In addition, the description overlapping with the contents of the electronic component 10A is omitted. The inductors in the electronic component 10B are inductors L1B and L2B.

  The inductor L1B is different from the inductor L1 in the conductor layer 42. A conductor layer different from the inductor L1 in the inductor L1B is defined as a conductor layer 42B. As shown in FIG. 6, the conductor layer 42B is provided on the upper surface of the insulator layer 22d. The conductor layer 42B is provided along the outer edge on the negative side in the x-axis direction and the outer edge on the positive direction side in the y-axis direction in the insulator layer 22d. Thereby, the conductor layer 42B has an L-shape when viewed in plan from the z-axis direction. One end of the conductor layer 42B is connected to the via conductor 44. The other end of the conductor layer 42B is exposed to the outside of the main body 20 from the outer edge of the insulator layer 22d on the positive side in the y-axis direction, and is connected to the external electrode 34.

  In the inductor L1B configured as described above, the conductor layers 40, 41, 42B and the via conductors 43, 44 as a whole spirally turn clockwise from the positive direction side to the negative direction side in the z-axis direction. Is made. As a result, the current I1 flowing into the inductor L1B from the external electrode 31 turns clockwise in the main body 20 from the positive direction side in the z-axis direction to the negative direction side in the z-axis direction, and from the external electrode 34 Is output.

  The inductor L2B is composed of conductor layers 50B, 51B, 52B and via conductors 53, 54. As shown in FIG. 6, the conductor layer 50B is provided on the upper surface of the insulator layer 22f. The conductor layer 50B is a linear conductor layer provided along the outer edge on the negative direction side in the x-axis direction and the outer edge on the negative direction side in the y-axis direction in the insulator layer 22f. Thereby, the conductor layer 50B has an L-shape when viewed in plan from the z-axis direction. One end of the conductor layer 50B is connected to one end of a via conductor 53 that penetrates the insulator layer 22f in the z-axis direction. The other end of the conductor layer 50 </ b> B is exposed to the outside of the main body 20 and connected to the external electrode 32.

  As shown in FIG. 6, the conductor layer 51B is provided on the upper surface of the insulator layer 22g. The conductor layer 51B is a linear conductor layer provided along the outer edge of the insulator layer 22g. Thereby, the conductor layer 51B has a substantially square shape when viewed in plan from the z-axis direction. However, the conductor layer 51B is divided in the vicinity of the corner formed by the outer edge on the negative direction side in the x-axis direction and the outer edge on the positive direction side in the y-axis direction in the insulator layer 22g. One end of the conductor layer 51 </ b> B is connected to the other end of the via conductor 53. The other end of the conductor layer 51 is connected to one end of a via conductor 54 that penetrates the insulator layer 22g in the z-axis direction.

  As shown in FIG. 6, the conductor layer 52B is provided on the upper surface of the insulator layer 22h. The conductor layer 52B is a linear conductor layer provided along the outer edge of the insulator layer 22h. Thereby, the conductor layer 52B has a substantially square shape when viewed in plan from the z-axis direction. However, the conductor layer 52B is divided in the vicinity of the corner formed by the outer edge on the negative direction side in the x-axis direction and the outer edge on the positive direction side in the y-axis direction in the insulator layer 22h. One end of the conductor layer 52 </ b> B is connected to the other end of the via conductor 54. The other end of the conductor layer 52B is exposed to the outside of the main body 20 from the outer edge of the insulator layer 22h on the positive side in the y-axis direction, and is connected to the external electrode 33.

  In the inductor L2B configured as described above, the conductor layers 50B to 52B and the via conductors 53 and 54 form a spiral shape that turns clockwise from the positive direction side to the negative direction side in the z-axis direction. Yes. As a result, the current I2 flowing into the inductor L2B from the external electrode 32 turns in the main body 20 clockwise from the positive direction side to the negative direction side in the z-axis direction and is output from the external electrode 33.

  By the way, when each of the inductors L1B and L2B is independently arranged on the circuit board, as shown in FIG. 7, a part of the magnetic fluxes B1 and B2 generated in the inductors L1B and L2B is part of each inductor L1B and L2B. In the vicinity of the end face in the z-axis direction, the travel proceeds in a direction orthogonal to the z-axis direction. As a result, regions A1 to A8 where the magnetic flux concentrates appear in the vicinity of the axial end faces of the coils L1B and L2B.

  On the other hand, in the electronic component 10B, the inductors L1B and L2B are stacked in the main body 20 so that their central axes substantially coincide with each other. The direction of the current I1 passing through the inductor L1B and the direction of the current I2 passing through the inductor L2B are the same direction. Thereby, the magnetic flux B1 generated in the inductor L1B by the current I1 and the magnetic flux B2 generated in the inductor L2B by the current I2 are integrated to form the magnetic flux B3. Thereby, the magnetic flux which has progressed in the direction orthogonal to the z-axis direction from the vicinity of the end surface on the negative direction side in the z-axis direction of the inductor L1 in the magnetic flux B1 is reduced. Further, in the magnetic flux B2, the magnetic flux that has progressed in the direction orthogonal to the z-axis direction from the vicinity of the positive end surface of the inductor L2 in the z-axis direction is reduced. That is, the magnetic flux B1 generated by the inductor L1B and the magnetic flux B2 generated by the inductor L2B are reduced in a region corresponding to A3 to A6 in FIG. As a result, as shown in FIG. 8, in the electronic component 10B, the concentration of magnetic flux is suppressed in the region sandwiched between the inductor L1B and the inductor L2B. As described above, in the electronic component 10B, the region where the magnetic flux is concentrated is reduced, and accordingly, magnetic saturation is relaxed, and a decrease in inductance value is suppressed.

(Configuration of electronic component 10C)
The configuration of the electronic component 10C according to the third embodiment will be described below with reference to the drawings.

  The main difference between the electronic component 10C and the electronic component 10A is that the external electrodes 33 and 34 are integrated as shown in FIG. This integrated external electrode is referred to as an external electrode 35. In addition, the description overlapping with the contents of the electronic component 10A is omitted.

  In the electronic component 10 </ b> C, the output from the inductor L <b> 1 and the output from the inductor L <b> 2 are added together by the external electrode 35. Therefore, a circuit for connecting the output from the inductor L1 and the output from the inductor L2 on the substrate becomes unnecessary. Thereby, the electronic component 10 </ b> C contributes to the miniaturization of the multiphase DC-DC converter 1. Furthermore, the man-hour for connecting each output can be reduced.

(Other examples)
The electronic component according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist thereof. For example, the number of DC-DC converters included in the multiphase DC-DC converter may be three or more. Further, the inductance values of the inductors L1 and L2 included in the first sample and the second sample are substantially the same value, but the inductances of the plurality of inductors included in the electronic component according to the present invention are the same. The value may be different.

  Furthermore, if the electronic component according to the present invention is not only a multi-phase DC-DC converter but also a DC-DC converter connected in parallel, the effect according to the present invention can be obtained. The electronic component according to the present invention may be used not only in a step-down DC-DC converter connected in parallel but also in a step-up DC-DC converter connected in parallel. Moreover, in the said Example, although electronic components 10A-10C were multilayer inductors, the spiral coil formed by winding a metal conducting wire, or the spiral coil formed by plating etc. on the printed circuit board, and the internal diameter part of the coil Alternatively, the electronic component may be configured such that the outer layer portion is covered with a resin containing magnetic powder such as metal magnetic powder.

  Furthermore, in the electronic component 10A, the external electrodes 31 and 34 may be used as input electrodes, and the external electrodes 32 and 33 may be used as output electrodes. At this time, the direction of the current I1 passing through the inductor L1 and the direction of the current I2 passing through the inductor L2 are the same direction. Therefore, in the electronic component 10A, when the external electrodes 31 and 34 are used as input electrodes and the external electrodes 32 and 33 are used as output electrodes, the effect exhibited by the electronic component 10A and the effect exhibited by the electronic component 10B are the same. is there. In the electronic component 10B as well, the electrodes used for input / output can be interchanged as described above.

  As described above, the present invention is useful for DC-DC converters connected in parallel and electronic components used therefor, and is particularly excellent in that a decrease in inductance value due to magnetic saturation can be suppressed.

L1, L2, L1B, L2B Inductor 1 Multi-phase DC-DC converter 2, 3 DC-DC converter circuit 10A-10C Electronic component 20 Main body

Claims (7)

An electronic component included in a DC-DC converter that connects a plurality of DC-DC converter circuits in parallel and adds each output to form one output,
The body,
A plurality of spiral inductors constituting a part of each of the plurality of DC-DC converter circuits and provided in the main body;
With
Each of the plurality of spiral inductors is stacked such that the central axes of the plurality of inductors substantially coincide with each other;
Electronic parts characterized by The DC-DC converter is configured such that each output phase from the plurality of DC-DC converter circuits is variable.
The electronic component according to claim 1. When viewed from the central axis direction of the inductor, the inner region of the inductor is made of a magnetic material,
The electronic component according to claim 1 or 2, wherein External electrodes that are output by adding the outputs together,
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The electronic component according to claim 1, wherein: A plurality of input external electrodes corresponding to respective inputs of the plurality of DC-DC converter circuits;
A plurality of output external electrodes corresponding to respective inputs of the plurality of DC-DC converter circuits;
Having
The electronic component according to claim 1, wherein: A DC-DC converter in which a plurality of DC-DC converter circuits are connected in parallel and each output is added to form one output,
Comprising a main body and an electronic component that forms a part of each of the plurality of DC-DC converter circuits and has a plurality of spiral inductors provided in the main body;
Each of the plurality of spiral inductors is stacked such that the central axes of the plurality of inductors substantially coincide with each other;
DC-DC converter characterized by this. Each of the plurality of DC-DC converter circuits has a variable output phase.
The DC-DC converter according to claim 6.

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