JP2008091438A - Coil component, and electronic circuit using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust and correct electric characteristic of a coil component through electric control by a simplified structure. <P>SOLUTION: The coil component 1 is provided with a magnetic core including at least a core, a winding coil 10, and a bimorph piezoelectric material 9. The core is divided into fixed cores 7, 8 and a movable core 11. The bimorph piezoelectric material 9 is constituted in the structure that the movable core 11 can be moved in the orthogonal direction to a magnetic flux energized by the winding coil 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coil component having a structure in which a piezoelectric body is assembled to a magnetic body, and an electronic circuit using the coil component.

  Conventionally, coil components that have been generally used have a magnetic core and a winding coil as a basic configuration. In recent years, electronic devices are being downsized and improved in quality, and electronic components such as coil components mounted on electronic devices are required to satisfy the same requirements for downsizing and high quality. By the way, as we try to reduce the size of the coil parts, the quality of the electrical characteristics of the coil parts is kept constant due to factors such as variations in magnetic core material, dimensions, manufacturing conditions, and winding conditions. It will be very difficult to keep on. As a result, coil parts that do not reach the required quality must be disposed of without being mounted on the required electronic equipment. For this reason, there has been a problem in that the product yield of coil components is deteriorated. Therefore, there has been a strong demand for a coil component having a function of adjusting electrical characteristics and correcting variations in electrical characteristics.

  Here, an example of a conventional coil component having a function of adjusting and correcting electrical characteristics will be described with reference to FIG. FIG. 9 shows an example of a cross-sectional view of the coil component 100 used mainly for receiving signal radio waves and the like. The coil component 100 holds a drum core 101 having a winding coil, a screw pot core 102 disposed so as to cover the drum core 101, a terminal block 104 having a plurality of terminal pins 103 implanted therein, and these components 101 to 104. It is comprised from the case 105 for doing. Conventionally, when the electrical characteristics of the coil component 100 (in this example, radio wave reception characteristics) vary, the electrical characteristics are adjusted by rotating the screw pot core 102 using a rotary tool or the like. That is, by adjusting the relative position between the screw pot core 102 and the drum core 101, that is, by adjusting the degree of magnetic coupling, the electrical characteristics are adjusted, and variations in the electrical characteristics are corrected.

  Conventionally, an electronic circuit controlled in an analog manner using such a coil component has been provided. Here, the conventionally used electronic circuit 110 will be described with reference to FIG. The electronic circuit 110 is a power supply device used as a DC / DC converter (DC-DC converter) that converts input DC power into another DC power. The input DC power is converted into AC power by a switching circuit 111 that is turned on / off by a PWM (Pulse Width Modulation) drive signal. The converted AC power is supplied to a smoothing circuit 112 that rectifies and smoothes AC to DC, and is output as DC power. The smoothing circuit 112 is a choke input type having a built-in choke coil.

  In order to suppress fluctuations in the output voltage output from the smoothing circuit 112, the output voltage of the smoothing circuit 112 is detected by the detection unit 113 used for feedback. The detected output voltage is multiplied by a predetermined coefficient and supplied to the adder 114. In the adder 114, the output voltage multiplied by a predetermined coefficient and the adjustment voltage supplied from the compensation circuit 117 are added and supplied to the error amplifier 116 as a feedback voltage. The error amplifier 116 compares the reference voltage from the reference voltage supply unit 115 that supplies the reference voltage with the feedback voltage supplied from the adder 114, and outputs the comparison result to the analog controller 118 that generates the PWM drive signal. To do. The analog controller 118 supplies the generated PWM drive signal to the switching circuit 111. In this way, feedback control of the entire electronic circuit 110 is performed. As described above, when the power supply apparatus is controlled by the conventional analog method, the operation is to suppress the fluctuation of the detected output. More specifically, the reference voltage is compared with an error amplifier, and a PWM drive signal that combines the two voltages is generated to adjust the fluctuating output voltage to the target voltage.

  Patent Document 1 discloses a conventional variable inductance element. In the variable inductance element disclosed in Patent Document 1, the relative position of the two cores can be changed by the action of the piezoelectric actuator. The inductance value is adjusted by changing the distance of the magnetic path (also referred to as a magnetic path length) by changing the relative position.

Patent Document 2 discloses a conventional coil component. The coil component disclosed in Patent Document 2 includes a coil wound to excite magnetic flux. Then, the gap dimension between two opposed cores is changed by the voltage applied to the piezoelectric body. The electrical characteristics (for example, inductance value) are adjusted by changing the gap size.
JP-A-8-213245 JP 2000-331840 A

  By the way, in order to adjust the electrical characteristics of the coil component 100, the operator must make adjustments and corrections while checking the electrical characteristics of the coil component 100 for each product. For this reason, there existed a subject that the operation | work which adjusts an electrical property became complicated and efficiency was bad.

The variable inductance element disclosed in Patent Document 1 and the coil component disclosed in Patent Document 2 both have the following common problems.
First, when the piezoelectric body is deformed, the outer dimension of the inductance element (coil component) changes. For this reason, it is necessary to set the mounting space based on the outer dimensions when the piezoelectric body is most deformed. This substantially goes against the demand for downsizing the inductance element (coil component).
In addition, the magnetic path length formed when a current is applied to the coil also changes. As a result, the inductance value: L decreases as the magnetic path length increases, and the L increases as the magnetic path length decreases. Furthermore, the amount of change in electrical characteristics is not purely affected by the amount of deformation of the piezoelectric body. For this reason, the amount of change in the magnetic path length must also be considered. As a result, the elements for adjusting and correcting the electrical characteristics (for example, the change amount of the magnetic path length) increase, and the control of the electrical characteristics becomes complicated.

  In addition, the piezoelectric bodies disclosed in Patent Documents 1 and 2 are both expected to be monomorph-type piezoelectric bodies based on their deformation modes. A monomorph type piezoelectric body generally has a small amount of deformation, and therefore has a small correction range and adjustment range for electrical characteristics. For this reason, there is a problem that it is not possible to meet the demand for adjusting and correcting the electrical characteristics significantly.

  In addition, the conventional electronic circuit 110 is controlled by an analog system, but the operation specifications vary in an electronic circuit (for example, a digital power supply circuit) controlled by a digital system. For this reason, it is required that the electrical characteristics of the coil component to be mounted can be easily changed. Since conventional coil parts have fixed electric characteristics (inductance and rated current), it is difficult to electrically adjust the electric characteristics. That is, when designing an analog power supply circuit, coil components having electrical characteristics corresponding to the set switching frequency, output current, output voltage, and the like had to be selected in advance. Further, even if the conventional coil component has a variable mechanism of electric characteristics, it must be manually adjusted like a screw core or the like. For this reason, it is difficult to control the electrical characteristics of the coil components with the drive signal so as to correspond to the digital power supply device.

  The present invention has been made in view of such a situation, and an object thereof is to be able to adjust and correct the electrical characteristics of coil components by electrical control having a simple structure. It is another object of the present invention to increase the correction range and adjustment range of the electrical characteristics of the coil component with high accuracy and to satisfy the demand for miniaturization of the coil component. Furthermore, it aims at providing the electronic circuit using the coil components of this invention which can respond to various operation | movement specifications.

  In order to achieve the above-described object, a coil component according to the present invention includes a magnetic core having at least a core portion, a winding coil, and a piezoelectric body. The core portion is divided into a fixed core portion and a movable core portion, and the piezoelectric body is configured to move the movable core portion in a direction orthogonal to the magnetic flux excited by the winding coil. It is characterized by that. The piezoelectric body employs a bimorph type piezoelectric body. And the coil component which concerns on this invention is employ | adopted for the electronic circuit.

The coil component according to the present invention has a simple structure, and can correct and adjust electrical characteristics by electrical control. For this reason, the correction range and the adjustment range of the electrical characteristics can be increased with high accuracy, and there is an effect that the demand for miniaturization is satisfied.
In addition, an electronic circuit employing this coil component can cope with various operation specifications, and thus has an effect of being excellent in electrical efficiency. And since it becomes unnecessary to enlarge the mounting space of a coil component, there exists an effect of becoming advantageous when reducing the electronic circuit board using the coil component of this invention, or an electronic device. Further, the path of the magnetic flux excited by the winding coil, that is, the distance of the magnetic path (also referred to as magnetic path length) does not change with the adjustment of the electrical characteristics. For this reason, when correcting and adjusting the electrical characteristics, it is only necessary to consider the size of the magnetic gap formed by the operation of the piezoelectric body, so that the inductance value: L can be easily controlled.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. This embodiment will be described as an example applied to a coil component 1 employed in a small-sized electronic device and electronic circuit.

  First, a configuration example of the coil component 1 will be described with reference to FIG. Fig.1 (a) is an external appearance perspective view of the rectangular parallelepiped coil component 1 which incorporated the winding coil mentioned later. The outer shape of the coil component 1 is configured by a cup core 2 integrally formed with a bottom surface and four surfaces perpendicular to the bottom surface, and a lid core 6 that covers the top of the coil component 1. The cup core 2 and the lid core 6 have a function of protecting a built-in winding coil and a piezoelectric body and generating a magnetic path by taking in a magnetic flux generated by the winding coil. The four corners formed in the cup core 2 are formed with a pair of piezoelectric terminal electrodes 3 and winding coil terminal electrodes 4. Coil terminal portions 5 corresponding to both end portions of the built-in winding coil are drawn out from the terminal electrode 4 for winding.

  FIG. 1B is an exploded perspective view of the coil component 1. Below, the structural example of the coil component 1 is demonstrated for every member. The cup core 2 made of sintered ferrite, metal-based magnetic material, or the like is a member formed in a substantially box shape. A trapezoidal fixed core portion 7 is formed near the center of the bottom surface of the cup core 2. The upper end surface of the fixed core portion 7 is cut obliquely with respect to the bottom surface of the cup core 2. The four corners of the cup core 2 are formed to be lower in height than other peripheral wall members. A pair of terminal electrodes 3 and 4 is formed at each of the four corners. The terminal electrode 3 is used to connect a bimorph piezoelectric body 9 that is greatly deformed by application of a voltage and a mounting substrate (not shown) of the coil component 1. The terminal electrode 4 is used to connect the coil terminal portion 5 of the winding coil 10 around which the coil is wound and a mounting substrate (not shown). On the peripheral wall portion of the cup core 2 and between the two terminal electrodes (for piezoelectric body) 3, there is a notch portion 13 for inserting and fixing the piezoelectric body terminal 12 which is one end of the bimorph piezoelectric body 9. Is formed.

  The winding coil 10 incorporated in the cup core 2 is a coil in which a conductive wire is wound around an air core by a general means. The conductive wire used for the winding coil 10 is coated with an insulating film around the copper core. Furthermore, it is desirable to use as a so-called fusion wire in which the surface portion of the insulating film is coated with a film that dissolves by heating, application of an organic solvent, ultraviolet irradiation, or the like. When the winding coil 10 is formed using a fusion wire, the coil shape wound with the air core can be maintained. Furthermore, there is an effect that handling of the winding coil 10 is facilitated in a later assembly process or the like.

  The lid core 6 is made of sintered ferrite, metal magnetic material, or the like. The lid core 6 includes a flat plate-like core member 14 as a component. Further, a fixed core portion 8 having a lower end surface formed obliquely with respect to the wide surface of the plate-like core member 14 is formed near the center of the lower surface of the plate-like core member 14. As described above, the magnetic core having the core portion is divided into the fixed core portions 7 and 8 and the movable core portion 11.

  The movable core portion 11 is also made of sintered ferrite, a metallic magnetic material, or the like. The movable core portion 11 is formed as a hexahedron having a trapezoidal longitudinal cross-sectional shape. The surface corresponding to the oblique side of the trapezoidal shape coincides with the upper end surface of the fixed core portion 7 formed on the cup core 2 and the lower end surface of the fixed core portion 8 formed on the lid core 6 when combined. is there. For this reason, in a state where no voltage is applied, the fixed core portions 7 and 8 and the movable core portion 11 remain in contact with each other and remain stationary even when the coil component 1 is assembled, so that the inductance value: L does not change. On the other hand, in a state where a voltage is applied, the movable core portion 11 moves due to the bending deformation of the bimorph piezoelectric body 9, so that the inductance value: L changes.

  One end of the bimorph type piezoelectric body 9 is fixed to the movable core 11 by means such as an adhesive. The other end is inserted and fixed in a notch 13 formed in the cup core 2. Thus, the bimorph piezoelectric body 9 has a so-called cantilever structure. The bimorph piezoelectric body 9 to which the drive signal (signal voltage) is applied is bent and deformed with the notch 13 as a fixed point. The movable core portion 11 can be moved in a direction orthogonal to the magnetic flux excited by the winding coil 10 by bending deformation of the bimorph piezoelectric body 9. As a result, a variable magnetic gap is formed in the magnetic path formed in the cup core 2 -the fixed core portion 7 -the movable core portion 11 -the fixed core portion 8 -the lid core 6 -the cup core 2. By adjusting the variable magnetic gap dimension according to the drive signal (signal voltage) applied to the bimorph piezoelectric body 9, various electrical characteristics of the coil component 1 can be accommodated.

  FIG. 1C is an example of an exploded perspective view of the coil component 1 shown in FIG. 1B viewed from the front in the x direction. Each member is given the same reference numeral as in FIG. In addition, since the structure of the coil component 1 is the same structure as the coil component 1 shown in FIG.1 (b), detailed description is abbreviate | omitted. Referring to FIG. 1C, it can be seen that the fixed core portion 8 is formed downward with respect to the plate-like core member 14.

  Next, a detailed configuration example of the bimorph piezoelectric body 9 will be described with reference to FIGS. FIG. 2 is an enlarged perspective view of the bimorph piezoelectric body 9 (also referred to as a piezoelectric actuator). The bimorph piezoelectric body 9 has a structure in which an elastic plate 21 made of phosphor bronze is sandwiched between two piezoelectric rectangular plates 22a and 22b made of a piezoelectric material. The elastic plate 21 is used as a center electrode. Electrodes 23a and 23b are formed at the ends of the piezoelectric rectangular plates 22a and 22b. By applying a drive signal (signal voltage) between the electrode-electrode or the electrode-elastic plate 21, the bimorph piezoelectric body 9 can be bent and deformed.

  The bimorph piezoelectric body 9 has an effective region (region corresponding to the effective length L in FIG. 2) that efficiently deforms and deforms when a voltage is applied, and is deformed flexibly because it is located far from both the electrodes 23a and 23b. There is a region (a portion indicated by a hatched portion in FIG. 2) that is small even if this does not occur or even if a deformation is caused. The region where bending deformation hardly occurs is an adhesive fixing region 24 for bonding the movable core portion 11. When the movable core portion 11 is bonded and fixed to the adhesive fixing region 24, the movable core portion 11 can be moved by a desired amount of displacement without hindering the bending deformation of the bimorph piezoelectric body 9. At this time, the portion where the electrodes 23a and 23b are formed and the vicinity thereof are inserted and fixed in the notch 13 formed in the cup core 2 described above.

  Next, a driving method of the bimorph piezoelectric body 9 (piezoelectric actuator) will be described with reference to the schematic diagram of FIG. There are two types of driving methods for the bimorph piezoelectric body 9: a series type and a parallel type, and basically both types can be adopted. FIG. 3A is a configuration example of a series-type bimorph piezoelectric body 39. FIG. 3B shows a configuration example of a parallel bimorph piezoelectric body 49.

The series-type bimorph piezoelectric body 39 shown in FIG. 3A has a configuration in which an elastic plate 31 is sandwiched between two piezoelectric rectangular plates 32a and 32b. Each of the piezoelectric rectangular plates 32 a and 32 b is polarized in a direction toward the elastic plate 31. A positive electrode 33a and a negative electrode 33b are formed on the piezoelectric rectangular plates 32a and 32b, respectively. The bimorph piezoelectric body 39 is held by the notch 34. Voltages _{V 1} to the voltage source 30 is applied, the positive electrode 33a, is applied to the bimorph piezoelectric 39 via the negative electrode 33b. The bimorph type piezoelectric element 39 is displaced amount: displaced by delta _1.

The series-type bimorph piezoelectric body 39 employs a circuit system in which a voltage is applied to the positive electrode 33a and the negative electrode 33b formed on the respective piezoelectric rectangular plates 32a and 32b. Displacement of the series type bimorph piezoelectric 39: delta ₁ is determined by the following equation (1).

On the other hand, the parallel bimorph piezoelectric body 49 shown in FIG. 3B also has a configuration in which the elastic plate 41 is sandwiched between two piezoelectric rectangular plates 42a and 42b. A positive electrode 43 is formed on the piezoelectric rectangular plate 42a. Each of the piezoelectric rectangular plates 42 a and 42 b is polarized in a direction from the elastic plate 41 toward the positive electrode 43. The bimorph piezoelectric body 49 is held by the notch 44. The voltage V ₁ applied by the voltage source 40 is applied to the bimorph piezoelectric body 49 via the positive electrode 43 and the elastic plate 41. The bimorph type piezoelectric element 49 is displaced amount: delta ₂ just displaced.

The parallel bimorph piezoelectric body 49 employs a circuit system in which a voltage is applied to the positive electrode 43 and the elastic plate 41 (which is made of phosphor bronze and has conductivity) formed on one piezoelectric rectangular plate 42a. Displacement of the parallel type bimorph piezoelectric 49: delta ₂ is determined by the following equation (2).

Here, from the equations (1) and (2), it is understood that the coefficient is “3/2” in the series type, but the coefficient is “3” in the parallel type. Therefore, when the driven bimorph piezoelectric 9 (piezoelectric actuator) in parallel type, twice the displacement amount with respect to a series type: delta ₂ just displaced. Therefore, as in the coil component 1 according to the present invention, it is desirable to adopt a parallel type for the purpose of increasing the correction range and the adjustment range of the electrical characteristics.

  Next, an example of a state in which a voltage is applied to the bimorph piezoelectric body 9 to bend and deform and a state in which the bimorph piezoelectric body 9 is not bent and deformed will be described with reference to FIG. FIG. 4A is an example of an external perspective view of the coil component 1. However, since FIG. 4A is the same as FIG. 1A already described, detailed description thereof is omitted. FIG. 4B is an example of a cross-sectional view taken along lines A-A ′ and B-B ′ of the coil component 1 in a state where the bimorph piezoelectric body 9 is not driven. FIG. 4C is an example of a sectional view taken along the lines A-A ′ and B-B ′ of the coil component 1 in a state where the bimorph piezoelectric body 9 is bent and deformed (driven) to the maximum.

  FIG. 4B shows a state in which a driving signal (signal voltage) is not applied to the bimorph piezoelectric body 9 and the movable core portion 11 is not moved. At this time, the magnetic path 26 is formed in the coil component 1 in the order of the cup core 2 -the fixed core portion 7 -the movable core portion 11 -the fixed core portion 8 -the lid core 6 -the cup core 2. And the fixed core part 7-movable core part 11-fixed core part 8 are aligned on the coaxial line 25, and the magnetic gap is in the minimum state. At this time, only a boundary surface exists between the fixed core portion 7, the movable core portion 11, and the fixed core portion 8. When a current is applied to the winding coil 10 in this state, a high inductance value: L is obtained.

  On the other hand, FIG. 4C shows a state in which a driving signal (signal voltage) is applied to the bimorph piezoelectric body 9 and the movable core portion 11 is bent and deformed to the maximum. At this time, the magnetic path 26 is formed in the coil component 1 in the order of the cup core 2 -the fixed core portion 7 -the movable core portion 11 -the fixed core portion 8 -the lid core 6 -the cup core 2. Then, the fixed core portion 7 -the movable core portion 11 -the fixed core portion 8 is in a state in which the movable core portion 11 is shifted with respect to the coaxial line 25, and a magnetic gap 27 is formed on the upper and lower end surfaces of the movable core portion 11. . When a current is applied to the winding coil 10 in this state, the inductance value L is lower than that in the state of FIG.

Here, Table 1 shows the relationship between the value of the applied voltage, the amount of displacement of the bimorph piezoelectric body 9 with the application of the voltage, the value of inductance: L value of coil component 1 and rated current: IDC (20 ° C.). The specification of the coil component 1 at this time is described below.
-Coil component 1 ... Vertical dimension: 50 mm x Horizontal dimension: 50 mm x Thickness dimension: 30 mm
Winding coil 10 Conductive wire diameter: 300 μm, Number of turns: 15 turns Bimorph type piezoelectric body 9 Effective length: 20 mm, overall thickness: 0.25 mm, elastic plate thickness: 0.05 mm, nonlinear correction coefficient α: 2, Drive system: Parallel type

  From Table 1, it can be seen that the inductance value: L changes in the range of 10.2 μH to 0.85 μH by changing the voltage value applied to the bimorph piezoelectric body 9 from 0V to 15.0V. Moreover, it turns out that rated current value: IDC changes in the range of 4.3A-25.2A. Here, the inductance value: L is given by the following equation (3).

Now, let us consider changing the inductance value L by adjusting the number of turns of the winding coil 10 without moving the movable core portion 11, that is, without changing the size of the magnetic gap. The number of turns of the winding coil 10 can be estimated from the following equation (4). From Table 1, the following conditions are used as reference values.
・ Applied voltage: 0V
・ Inductance value: 10.2μH
-Virtual number of winding coil 10: 15 Ts

And it substitutes in Formula (3) as a coefficient: X = (micro | micron | mu) ₀ * micro * (A / L), The winding number: N of the winding coil 10 in a reference value is calculated.

  Table 1 shows the number of turns: Ts of the winding coil 10 calculated from the equation (4) as “virtual number of turns”. That is, a series of operations of applying a drive signal (signal voltage) to the bimorph piezoelectric body 9 to drive the movable core portion 11 and changing the magnetic gap dimension is performed by changing the winding number of the winding coil 10 from 4.5 Ts to It can be said that it is equivalent to the operation adjusted in the range of 15 Ts. In addition, the amount of displacement of the movable core portion 11 driven by the bimorph piezoelectric body 9 can be changed steplessly by controlling the drive signal (signal voltage). For this reason, the range which can correct | amend and adjust the electrical property of the coil component 1 becomes wide. Furthermore, even fine adjustment of electrical characteristics that cannot be handled only by adjusting the number of turns of the winding coil 10 can be sufficiently handled.

  The coil component 1 according to this embodiment is configured such that the movable core portion 11, which is a magnetic core having at least a core portion, is movable in a direction orthogonal to the magnetic flux (magnetic path) excited by the winding coil 10. It is desirable that By configuring the coil component in this way, the electrical characteristics can be adjusted and corrected without changing the outer dimensions, particularly the height dimension, of the coil component 1. In generating a dimensional change of the magnetic gap, the outer dimension of the coil component 1 is not changed. Therefore, a minimum mounting space is sufficient for mounting the coil component 1. For this reason, as compared with the structure of the conventional coil component (inductance element) disclosed in Patent Document 1 or 2, the electronic device or electronic circuit on which the coil component 1 is mounted while satisfying the demand for miniaturization of the coil component 1 This has the effect of contributing to the downsizing of the substrate.

  Further, by adopting a bimorph type piezoelectric body that bends and deforms more greatly than a monomorph type piezoelectric body, the moving range of the movable core portion 11 is expanded. As a result, the correction range and adjustment range of the electrical characteristics can be widened. Further, by finely controlling the voltage applied to the bimorph type piezoelectric body 9, the amount of displacement of the bimorph type piezoelectric body 9 can be finely controlled, so that the electrical characteristics of the coil component 1 can be adjusted and corrected with high accuracy. There is an effect.

  Next, a coil component 50 according to a second embodiment of the present invention will be described with reference to FIGS. First, a configuration example of the coil component 50 will be described with reference to FIG. However, in FIGS. 5 and 6, members similar to those already described in FIG. 1 are given the same reference numerals and detailed description thereof is omitted. FIG. 5A is an external perspective view of a rectangular parallelepiped coil component 50 incorporating a winding coil described later. The outer shape of the coil component 50 is configured by a cup core 2 integrally molded with a bottom surface and four surfaces perpendicular to the bottom surface, and a lid core 56 that covers the top of the coil component 50. The cup core 2 and the lid core 56 have a function of protecting a built-in winding coil and a piezoelectric body and generating a magnetic path by taking in a magnetic flux generated by the winding coil. On the peripheral wall portion of the cup core 2, a notch 53 b for fixing a bimorph piezoelectric body 59 described later is formed. Although not shown in FIG. 5A, a notch 53a is formed on the opposite side of the peripheral wall where the notch 53b is formed.

  FIG. 5B is an exploded perspective view of the coil component 50. Below, the structural example of the coil component 50 which concerns on this invention is demonstrated for every member. A rectangular parallelepiped fixed core portion 57 is formed near the center of the bottom surface of the cup core 2. The upper end surface of the fixed core portion 57 is parallel to the bottom surface of the cup core 2. A pair of terminal electrodes 3, 4 are formed at four corners of the cup core 2. The terminal electrode 3 is used to connect a bimorph piezoelectric body 59 that is greatly deformed by application of a voltage and a mounting substrate (not shown) of the coil component 50. The terminal electrode 4 is used to connect the coil terminal portion 5 of the winding coil 10 around which the coil is wound and a mounting substrate (not shown). On the peripheral wall portion of the cup core 2, between the two terminal electrodes (for piezoelectric body) 3 and the terminal electrode (for winding coil) 4, piezoelectric body terminals 62 a, which are both ends of the bimorph piezoelectric body 59, Notches 53a and 53b for inserting and fixing 62b are formed.

  The lid core 56 is made of sintered ferrite, metallic magnetic material, or the like. Near the center of the lower surface of the plate-shaped core member 14 constituting the lid core 56, a fixed core portion 58 having a lower end surface formed in parallel with the wide surface of the plate-shaped core member is formed.

  The movable core portion 61 is also made of sintered ferrite, a metallic magnetic material, or the like. The movable core part 61 is formed as a hexahedron whose longitudinal section is rectangular. The upper and lower surfaces of the rectangular shape are shaped to match the upper end surface of the fixed core portion 57 formed on the cup core 2 and the lower end surface of the fixed core portion 58 formed on the lid core 56 when combined. For this reason, in a state where no voltage is applied, the fixed core portions 57 and 58 and the movable core portion 61 are kept in contact with each other and remain stationary, so that the inductance value: L does not change. On the other hand, in a state where a voltage is applied, the movable core portion 61 moves due to the bending deformation of the bimorph piezoelectric body 59, so that the inductance value: L changes. The movable core portion 61 of the bimorph piezoelectric body 59, the fixed core portion 57 of the cup core 2, and the fixed core portion 58 of the lid core 56 have a structure in which a magnetic body portion and a nonmagnetic body portion are alternately stacked in the lateral direction. . As described above, the magnetic core having the core portion is divided into the fixed core portions 57 and 58 and the movable core portion 61.

  The movable core portion 61 is fixed to the central portion of the bimorph piezoelectric body 59 by means such as an adhesive. Both ends are inserted and fixed in notches 53 a and 53 b formed in the cup core 2. Thus, the bimorph type piezoelectric body 59 has a so-called both-end support structure. The bimorph piezoelectric body 59 to which the drive signal (signal voltage) is applied is bent and deformed with the notches 53a and 53b as fixed points. Due to the bending deformation of the bimorph piezoelectric body 59, the movable core portion 61 can be moved in a direction orthogonal to the magnetic flux excited by the winding coil 10. As a result, a variable magnetic gap is formed in the magnetic path formed by the cup core 2 -the fixed core portion 57 -the movable core portion 61 -the fixed core portion 58 -the lid core 56 -the cup core 2. By adjusting the variable magnetic gap dimension according to the drive signal (signal voltage) applied to the bimorph piezoelectric body 59, various electrical characteristics of the coil component 50 can be made to correspond.

  FIG. 5C is an example of an exploded perspective view of the coil component 50 shown in FIG. 5B viewed from the front in the x direction. Each member is given the same reference numeral as in FIG. The configuration of the coil component 50 is the same as that of the coil component 50 shown in FIG. Referring to FIG. 5C, it can be seen that the fixed core portion 58 is formed downward with respect to the plate-like core member 14.

  Next, an example of a state in which a voltage is applied to the bimorph piezoelectric body 59 to bend and deform and a state in which the bimorph piezoelectric body 59 is not bent and deformed will be described with reference to FIG. FIG. 6A is an example of an external perspective view of the coil component 50. However, since FIG. 6A is the same as FIG. 5A already described, detailed description thereof is omitted. FIG. 6B is an example of a cross-sectional view along the C-C ′ line and the D-D ′ line of the coil component 50 in a state where the bimorph piezoelectric body 59 is not driven. FIG. 6C is an example of a cross-sectional view taken along lines C-C ′ and D-D ′ of the coil component 50 in a state where the bimorph piezoelectric body 59 is bent and deformed (driven) to the maximum.

  FIG. 6B shows a state in which a driving signal (signal voltage) is not applied to the bimorph piezoelectric body 59 and the movable core portion 61 is not moved. At this time, a magnetic path 66 is formed in the coil component 50 in the order of cup core 2 -fixed core portion 57 -movable core portion 61 -fixed core portion 58 -lid core 56 -cup core 2. And the arrangement | sequence of the magnetic body part formed in the fixed core part 57 of the cup core 2, the movable core part 61, and the fixed core part 58 of the lid | cover core 56 and the nonmagnetic body part has gathered uniformly. For this reason, the magnetic flux excited by applying a current to the winding coil 10 passes only through the magnetic body. For this reason, a high inductance value: L can be obtained.

  On the other hand, FIG. 4C shows a state where a drive signal (signal voltage) is applied to the bimorph piezoelectric body 59 and the movable core portion 61 is bent and deformed to the maximum. At this time, a magnetic path 56 is formed in the coil component 50 in the order of cup core 2 -fixed core portion 57 -movable core portion 61 -fixed core portion 58 -lid core 56 -cup core 2. In a state where the bimorph piezoelectric body is bent and deformed to the maximum, the movable core portion is displaced. That is, the arrangement of the magnetic body portion and the non-magnetic body portion of the movable core portion is reversed with respect to the arrangement of the magnetic body portion and the non-magnetic body portion of the core portion of the cup core 2 and the lid core 56. The effect is the same as that formed. When a current is applied to the winding coil 10 in this state, the inductance value L is lower than that in the state of FIG.

  Further, for example, when the bimorph type piezoelectric body 59 is bent and deformed by half of the maximum deformation amount, the movable core portion 61 is arranged with respect to the arrangement of the magnetic body portion and the nonmagnetic body portion of the fixed core portion 58 of the cup core 2 and the lid core 56. The arrangement of the magnetic part and the non-magnetic part is such that the magnetic part and the non-magnetic part are shifted from each other by half. In this case, although the movable core portion 61 does not form a complete magnetic gap, the magnetic resistance increases as compared with the case where the bimorph piezoelectric body is not driven. For this reason, the inductance value: L decreases.

  In the coil component 50 according to the second embodiment, the movement of the movable core portion 61 by the bimorph piezoelectric body 59 is controlled by a drive signal (signal voltage), as in the operation and effect of the first embodiment. It can be changed steplessly. For this reason, the electric characteristics are corrected and the adjustable range is wide. Furthermore, there is an effect that it is possible to sufficiently cope with a fine adjustment region that cannot be dealt with by adjusting the number of turns of the winding coil 10.

  Next, an example of an electronic circuit according to the third embodiment of the present invention will be described with reference to FIG. The coil components according to the first and second embodiments described above have a narrow range of fine adjustment to correct slight variations in electrical characteristics represented by inductance value: L and rated current: IDC. To a wide range enough to change the number of turns of the winding coil.

  That is, by using the coil component according to the present invention, an electronic circuit (for example, a power supply circuit) that has been conventionally driven in an analog system can be configured with one model and one specification. Then, only by rewriting the program, it can be applied to a digital electronic circuit that can cope with various power supply specifications (current, voltage, output, response, etc.).

  FIG. 7 shows an example of the internal configuration of an electronic circuit controlled by a digital drive system that employs the coil component of the present invention. The electronic circuit 70 is a power supply device used as a DC / DC converter (DC / DC converter) that converts input DC power into another DC power. The input DC power is converted into AC power by a switching circuit 71 that is turned on / off by a PWM drive signal. The converted AC power is supplied to a smoothing circuit 72 that rectifies and smoothes AC to DC, and is output as DC power. The smoothing circuit 72 is a choke input type incorporating the coil component of the present invention.

  In order to suppress fluctuations in the output voltage output from the smoothing circuit 72, the output voltage is detected by the detection unit 73. The detected output voltage is supplied to an AC / DC converter (AC / DC converter) 74 in place of the conventionally used error amplifier and compensation circuit. In the DC / AC conversion unit 74, the output voltage supplied from the detection unit 73 and the reference voltage supplied from the reference voltage supply unit 75 are input. The AC / DC converter 74 supplies the generated feedback voltage to a digital signal processor (DSP) 76. The digital signal processing unit 76 supplies the generated PWM drive signal to the switching circuit 71. Thus, the entire feedback control is performed by supplying the PWM drive signal.

By mounting the coil component according to the present invention on the digital drive type electronic circuit 70, the inductance value L can be optimized as appropriate. That is, the electronic circuit 70 can be suitably operated when changing the switching frequency (f _r ) or changing the load current in order to change the response speed of the power supply.

This reactance: can be estimated from the X _L equation for calculating (5).
X _L = 2πf · L (Expression 5)

For example, if an inductance of 4.7 μH is necessary when f _r = 1 MHz, the required inductance value L is calculated as 2.35 μH when f _r = 2 MHz. Further, if f _r = 4 MHz, the required inductance value: L is calculated to be about 1.2 μH. That is, the specification change of the electrical characteristics is included in the change range of the inductance value: L shown in Table 1 described above. For this reason, it is shown that the coil component which concerns on this invention can be employ | adopted suitably.

  Since the electronic circuit 70 according to the present embodiment is mounted with the coil component of the present invention, it is possible to correct and adjust the variation in the electrical characteristics of the coil component with high accuracy. For this reason, the electronic circuit excellent in adjustment efficiency can be formed. A case is assumed in which the coil component is mounted on a digitally controlled electronic circuit (for example, a power supply device) corresponding to various specifications by changing the program. Even in such a case, the electrical characteristics of the coil components can be changed in various ways according to the drive signal (signal voltage) without changing the coil components mounted on the board, and it can easily cope with correction and adjustment of the electrical properties. There is an effect that can be done.

  The coil parts and the electronic circuit using the coil parts according to the first to third embodiments described above have a simple structure. As this structure, it is desirable that the magnetic core having the core is divided into a fixed core and a movable core. For this reason, the electrical characteristics can be easily corrected and adjusted by electrical control. For this reason, the correction range and the adjustment range of the electrical characteristics can be increased with high accuracy, and there is an effect that the demand for miniaturization is satisfied. In addition, an electronic circuit employing this coil component can cope with various operation specifications, and thus has an effect of being excellent in electrical efficiency. And since it becomes unnecessary to enlarge the mounting space of a coil component, there exists an effect of becoming advantageous when reducing the electronic circuit board using the coil component of this invention, or an electronic device. In addition, the movement of the movable core due to the application of voltage only moves, and the path of the magnetic flux excited by the winding coil, that is, the distance of the magnetic path (magnetic path length) changes as the electrical characteristics are adjusted. There is nothing to do. Therefore, only the operation of the piezoelectric body that moves the magnetic core contributes to the correction and adjustment of the electrical characteristics, and there is an effect that the inductance value: L can be easily controlled.

  In the coil component according to the present embodiment, the piezoelectric body is preferably configured so that the movable core portion can be moved in a direction orthogonal to the magnetic flux (magnetic path) excited by the winding coil. By configuring the coil component in this way, the electrical characteristics can be adjusted and corrected without changing the outer dimensions, particularly the height dimension, of the coil component. And when generating the dimensional change of a magnetic gap, it is set as the structure which does not change the external dimension of a coil component. For this reason, a minimum mounting space is sufficient for mounting coil components.

  Further, by adopting a bimorph type piezoelectric body that bends and deforms more greatly than a monomorph type piezoelectric body, the moving range of the movable core portion is expanded. As a result, there is an effect that the correction range and adjustment range of the electrical characteristics can be widened. Further, by finely controlling the voltage applied to the piezoelectric body, it is possible to finely control the amount of displacement of the piezoelectric body that is bent and deformed. For this reason, the electrical characteristics of the coil component can be adjusted and corrected with high accuracy.

  In addition, by configuring a movable magnetic core as a movable core, the magnetic flux that leaks when a signal voltage is applied to the bimorph piezoelectric body to increase the magnetic gap is shielded by the cup core and lid core. can do. As a result, there is an effect that external electronic devices or electronic components are not adversely affected by leakage magnetic flux.

  In the first and second embodiments described above, the bimorph piezoelectric body is used to drive the movable core portion. However, the movable core portion may be moved using a monomorph piezoelectric body. Although the amount of displacement is small, similar functions and effects can be obtained. Even when a coil component using a monomorph piezoelectric body is mounted on an electronic circuit, the same functions and effects as those of the third embodiment described above can be obtained.

  In the first and second embodiments described above, the parallel bimorph piezoelectric body is used. However, even if the movable core portion is moved using the series bimorph piezoelectric body, the displacement Although the amount is small, similar functions and effects can be obtained. Even when a coil component using a series-type bimorph piezoelectric body is mounted on an electronic circuit, the same functions and effects as those of the third embodiment described above can be obtained.

  Further, in the above-described third embodiment example, the electronic circuit in which the coil component according to the present invention is mounted is described as an example applied to the power supply apparatus. However, the coil component according to the present invention is applied to other electronic circuits. You may make it mount.

  Moreover, the movable core part should just be comprised so that the movable core part which is a magnetic body core which has at least a core part can move in the direction orthogonal to the magnetic flux (magnetic path) excited by the winding coil. For this reason, the shape of a movable core part can take various shapes irrespective of the embodiment mentioned above. Further, the direction in which the movable core portion is moved is not limited to the direction orthogonal to the magnetic flux (magnetic path), and the magnetic gap may be changed without changing the external dimensions of the coil components. Various modifications are possible.

  In the first to third embodiments described above, the movable core is supported by a single bimorph piezoelectric body, and the movable core is moved between the lid core and the core formed on the cup core. Thus, the inductance value: L was adjusted. Here, the core part formed in the lid core and the cup core, and the modification of a movable core part are demonstrated with reference to FIG. FIG. 8 is a configuration diagram showing an example of the movable core portion 81 of the coil component 80 according to another embodiment. However, in FIG. 8, members similar to those already described in FIG. 1 are given the same reference numerals and detailed description thereof is omitted.

FIG. 8A is an example of a top view of the coil component 80 from which a lid core (not shown) is removed in a state where no voltage is applied to the bimorph type piezoelectric body. In the cup core 2, notches 83 a and 83 b are formed near the center of the peripheral wall. A cylindrical movable core portion 81 is placed at the center of the winding coil 10. The movable core portion 81 includes a bimorph piezoelectric body 89a that extends from the notch portion 83a toward the central axis of the movable core portion 81, and a bimorph that extends from the notch portion 83b toward the central axis of the movable core portion 81. It is supported by the type piezoelectric body 89b.
FIG. 8B is an example of an exploded perspective view of the fixed core portion 88 of the lid core, the movable core portion 81, and the fixed core portion 87 of the cup core 2 in a state where no voltage is applied to the bimorph piezoelectric body. It is. The fixed core portion 88 of the lid core, the movable core portion 81, and the fixed core portion 87 of the cup core 2 have a cylindrical shape with different heights, and the magnetic body portion and the nonmagnetic body portion are alternately arranged along the circumference. The configuration is arranged in Here, paying attention to the movable core portion 81, magnetic body portions 81a whose both end surfaces are formed in a fan-shaped column shape and nonmagnetic body portions 81b whose both end surfaces are also formed in a fan-shaped column shape are alternately stacked in the circumferential direction. It is. And the whole is formed in the column shape by laminating | stacking the some magnetic body part 81a and the nonmagnetic body part 81b in the circumferential direction. Similarly, the fixed core portion 87 of the cup core 2 and the fixed core portion 88 of the lid core are alternately arranged with magnetic body portions 87a and 88a and non-magnetic body portions 87b and 88b formed in fan-shaped columnar end surfaces. It is formed in a cylindrical shape. In a state where no voltage is applied to the bimorph piezoelectric bodies 89a and 89b, the bimorph piezoelectric bodies 89a and 89b are not bent and deformed. For this reason, the magnetic parts 87a, 81a, 88a and the non-magnetic parts 87b, 81b, 88b are stacked in the height direction at the same position in the circumferential direction.

FIG. 8C is an example of a top view of the coil component 80 from which a lid core (not shown) is removed in a state where a voltage is applied to the bimorph type piezoelectric body. At this time, it can be seen that the bimorph piezoelectric bodies 89 a and 89 b are bent and deformed in the opposite direction with respect to the central axis of the movable core portion 81.
FIG. 8D is an example of an exploded perspective view of the fixed core portion 88 of the lid core, the movable fixed core portion 80, and the fixed core portion 87 of the cup core 2 in a state where a voltage is applied to the bimorph piezoelectric body. is there. In a state where a voltage is applied, the movable core portion 81 is rotationally driven minutely by the bending and deformation of the bimorph piezoelectric bodies 89a and 89b. At this time, the magnetic body portions 87a and 88a and the non-magnetic body portion 81b are stacked in the height direction at the same position in the circumferential direction. Thus, by arranging the magnetic part and the non-magnetic part, it can be regarded as an action equivalent to a magnetic gap.
Thus, even when the core member in which the magnetic body portions and the non-magnetic body portions are alternately arranged is used, the same functions and effects as those of the first and second embodiment examples described above can be obtained. Needless to say, when the coil component 80 is mounted on an electronic circuit, the functions and effects described in the third embodiment can be obtained.

It is the block diagram which showed the example of the coil components which concern on the 1st Example of this invention. It is the block diagram which showed the example of the bimorph type piezoelectric material which concerns on the 1st Example of this invention. It is the block diagram which showed the example of the series type | mold of the bimorph type piezoelectric material which concerns on the 1st Example of this invention, and a parallel type | mold. It is the block diagram which showed the operation example of the bimorph type piezoelectric material which concerns on the 1st Example of this invention. It is the block diagram which showed the example of the coil components which concern on the 2nd Example of this invention. It is the block diagram which showed the operation example of the bimorph type piezoelectric material which concerns on the 2nd Example of this invention. It is the block diagram which showed the internal structural example of the electronic circuit (power supply circuit) which mounts the coil components which concern on the 3rd Example of this invention. It is the block diagram which showed the example of the movable core part which concerns on the other embodiment of this invention. It is the cross-sectional block diagram which showed the example of the conventional coil components. It is the block diagram which showed the internal structural example of the electronic circuit (power supply circuit) which mounts the conventional coil components.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Coil components, 2 ... Cup core, 3 ... Terminal electrode (for piezoelectric bodies), 4 ... Terminal electrode (for winding coils), 5 ... Coil terminal part, 6 ... Cover core, 7, 8 ... Fixed core part, DESCRIPTION OF SYMBOLS 9 ... Bimorph type piezoelectric material, 10 ... Winding coil, 11 ... Movable core part, 12 ... Piezoelectric terminal, 13 ... Notch part, 14 ... Plate-shaped core member, 21 ... Elastic plate, 22a, 22b ... Piezoelectric rectangular plate 23a, 23b ... electrodes, 24 ... adhesion fixing region, 25 ... coaxial wire, 26 ... magnetic path, 27a, 27b ... magnetic gap, 50 ... magnetic coil, 70 ... electronic circuit

Claims (3)

A magnetic core having at least a core part;
Winding coil,
In a coil component comprising a piezoelectric body,
The core is divided into a fixed core and a movable core,
The said piezoelectric body is comprised so that the said movable core part can be moved to the direction orthogonal to the magnetic flux excited by the said coil | winding coil, The coil components characterized by the above-mentioned. The coil component according to claim 1,
The said piezoelectric body is a bimorph type piezoelectric body, The coil component characterized by the above-mentioned. An electronic circuit comprising the coil component according to claim 1.

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