JP2012065408A - Dc-dc converter module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC-DC converter module in which a noise that is superposed on an output voltage is suppressed with higher efficiency.SOLUTION: Lower surface terminals 41-43 are formed on the lower surface of a magnetic material substrate 30. An upper surface electrode is formed on the upper surface of the magnetic material substrate 30. On the upper surface of the magnetic material substrate 30, a control circuit 31 containing a switching element, an input capacitor Ca, and an output capacitor Cb are mounted. Inside the magnetic material substrate 30, a smoothing coil L1 and inductors L2, L3, and L4 leading respectively to the lower surface terminals and the upper surface electrode are configured. The smoothing coil L1 is made from helical conductor. The inductors L2, L3, and L4 are made from a via conductor. The inductors L2, L3, and L4 penetrate vertically relative to the magnetic material substrate 30 at the central part in a winding range of the conductor constituting the smoothing coil L1.

Description

  The present invention relates to a DC-DC converter module configured by using, as a component mounting substrate, a magnetic substrate having a built-in magnetic element such as a smoothing coil or a transformer among main components and mounting various components such as a switching element thereon. Is.

  Patent Document 1 discloses a DC-DC converter module configured on a magnetic insulating substrate for the purpose of downsizing the DC-DC converter.

  In general, in a step-down DC-DC converter or a forward DC-DC converter, an input current input to a switching unit is pulsed. This pulsed input current is input to an input voltage source, a DC-DC converter module main body, When the current flows between the wires, noise (fundamental noise and harmonic noise of a pulsed current) is generated from the wiring. Therefore, it is configured such that a current path is completed in the module by supplying a pulsed current from a capacitor (input capacitor) connected to the input unit. However, when the DC-DC converter module is mounted on a circuit board of an electronic device, the input voltage source and the DC-DC converter module may be separated. Even if most of the pulse current flows to the input capacitor, a pulsed current also flows from the input voltage source to the DC-DC converter, so that the input voltage source and the DC-DC converter module are relatively far apart. If this is the case, the size of the loop of the current flowing through the wiring between them will increase, and as a result, the generation of electromagnetic noise will increase, which will be a problem.

  In the step-up DC-DC converter, since the output current output from the switching unit is pulsed, an output capacitor is provided so that the pulse current does not flow to the load side and no ripple occurs in the output voltage. Is provided. However, in order to allow most of the pulse current to flow through the output capacitor, the output capacitor must have a large capacity and a low resistance.

  Further, in the inverting DC-DC converter and the flyback DC-DC converter, the problems of both the step-down DC-DC converter and the step-up DC-DC converter occur.

  Patent Document 2 discloses a DC-DC converter module that suppresses the above-described electromagnetic noise and output voltage ripple. FIG. 1 is an exploded perspective view of a DC-DC converter module 51 disclosed in Patent Document 2. As shown in FIG. However, the perspective view is shown transparently to show the configuration of the inside and the bottom surface of the magnetic substrate.

  In FIG. 1, lower surface terminals 41 to 43 are formed on the lower surface of the magnetic substrate 30. On the upper surface of the magnetic substrate 30, an upper surface electrode (a pattern is not shown) is formed. Inside the magnetic substrate 30, a smoothing coil L1 and inductors L2, L3, and L4 connected between the lower surface terminal and the upper surface electrode are formed. The smoothing coil L1 is composed of a helical conductor. The inductors L2, L3, and L4 are configured by vias.

  A control circuit 31 including a switching element, an input capacitor Ca, and an output capacitor Cb are mounted on the upper surface of the magnetic substrate 30. These components are electrically connected to the upper surface electrode of the magnetic substrate 30.

JP 2006-42538 A Japanese Patent No. 4325747

  However, in the structure shown in FIG. 1, the solution that the output voltage is modulated in a rectangular wave shape when the coupling between the via conductor wiring penetrating the magnetic substrate and the magnetic flux of the coil is increased as the whole size is further reduced. There are issues to be addressed. The connection by the conductor (end surface conductor) formed on the end surface of the magnetic substrate does not have this problem, but there is a problem that the efficiency of the DC-DC converter decreases due to the DC resistance of the end surface conductor.

  Accordingly, an object of the present invention is to provide a DC-DC converter module that solves the above-described problems, suppresses noise superimposed on an output voltage and the like, and increases efficiency.

In order to solve the above problems, the DC-DC converter module of the present invention is configured as follows.
(1) A DC-DC converter module comprising a switching unit including a switching element and a magnetic element, an input capacitor provided on the input side of the switching unit, and an output capacitor provided on the output side of the switching unit. There,
A lower surface terminal including an input terminal, an output terminal, and a ground terminal is provided on the lower surface, and an upper surface electrode is formed on the upper surface, and the switching element, the input capacitor, and the output capacitor are mounted on the upper surface electrode, respectively. A substrate on which the magnetic element is configured,
The magnetic element includes a conductor wound in a coil shape,
A connection wiring that connects at least one of the input terminal, the output terminal, or the ground terminal and the upper surface electrode passes in a direction perpendicular to the substrate at the center of the winding range of the conductor of the magnetic element. It is characterized by being composed of an internal conductor.

  In Patent Document 1, a spiral plate coil pattern is formed on the first surface of the first magnetic substrate, and an IC chip is mounted on the second surface of the first magnetic substrate. ing. The coil conductor pattern and the IC chip are connected by a via conductor provided at the coil central portion of the first magnetic substrate. However, the connection through-hole between the coil and the IC is located at the center of the magnetic substrate only because one end of the spiral planar coil is located at the center of the magnetic substrate.

(2) A DC-DC converter module comprising a switching unit including a switching element and a magnetic element, an input capacitor provided on the input side of the switching unit, and an output capacitor provided on the output side of the switching unit. There,
An input terminal, an output terminal, and a ground terminal are provided on the lower surface, an upper surface electrode is formed on the upper surface, and the switching element, the input capacitor, and the output capacitor are mounted on the upper surface electrode, respectively, Comprising a substrate on which the magnetic element is configured;
The magnetic element includes a conductor wound in a coil shape,
The connection wiring that connects at least one of the input terminal, the output terminal, or the ground terminal and the upper surface electrode includes an internal conductor that passes through the inside of the board and an end face conductor that passes through the end face of the board. It is characterized by being configured.

(3) For example, the substrate described in (1) includes a magnetic layer and a nonmagnetic first wiring layer laminated on the upper surface of the magnetic layer, and the upper surface electrode is formed on the upper surface of the first wiring layer. A first in-plane wiring conductor that is formed and is electrically connected to the connection wiring is formed on the lower surface, and a first interlayer connection conductor that conducts between the upper surface electrode and the first in-plane wiring conductor is included therein.

(4) For example, the substrate according to (3) includes a nonmagnetic second wiring layer laminated on the lower surface of the magnetic layer, and the lower surface terminal (electrode) is formed on the lower surface of the second wiring layer, A second in-plane wiring conductor that conducts with the connection wiring is formed on the upper surface, and a second interlayer connection conductor that conducts between the lower surface terminal and the second in-plane wiring conductor is included therein.

(5) For example, the end face conductor described in (2) is a divided via formed by vertically dividing the center of a via filled with a conductive material.

(6) The internal conductors described in (1) to (5) are, for example, vias filled with a conductive material.

  According to the present invention, a highly efficient DC-DC converter module in which noise superimposed on an output voltage or the like is suppressed can be obtained.

FIG. 1 is an exploded perspective view of a DC-DC converter module 51 disclosed in Patent Document 2. As shown in FIG. FIG. 2 is an exploded perspective view of the step-down DC-DC converter module 51 according to the first embodiment. 3A is a cross-sectional view of the step-down DC-DC converter module 51, and FIG. 3B is a cross-sectional view of the step-down DC-DC converter module 50 shown in FIG. FIG. 4 is a circuit diagram of the step-down DC-DC converter module 51. FIG. 5 is an exploded perspective view of the step-down DC-DC converter module 52 according to the second embodiment. FIG. 6 is a circuit diagram of the step-down DC-DC converter module 52. FIG. 7 is a diagram showing the fluctuation characteristics of the output voltage with respect to the output current of the step-down DC-DC converter module 52. FIG. 8 is an exploded perspective view of the step-down DC-DC converter module 53 according to the third embodiment. FIG. 9 is a circuit diagram of the step-down DC-DC converter module 53. FIG. 10 is an exploded perspective view of the step-up DC-DC converter module 54 according to the fourth embodiment. FIG. 11 is a circuit diagram of the step-up DC-DC converter module 54. FIG. 12 is an exploded perspective view of the step-up DC-DC converter module 55 according to the fifth embodiment. FIG. 13 is a circuit diagram of the step-up DC-DC converter module 55. FIG. 14 is an exploded perspective view of the inverting DC-DC converter module 56 according to the sixth embodiment. FIG. 15 is a circuit diagram of the inverting DC-DC converter module 56. FIG. 16 is an exploded perspective view of the inverting DC-DC converter module 57 according to the seventh embodiment. FIG. 17 is a circuit diagram of the inverting DC-DC converter module 57. FIG. 18 is an exploded perspective view of the step-down DC-DC converter module 58 according to the eighth embodiment. FIG. 19 is a circuit diagram of the step-down DC-DC converter module 58. FIG. 20 is an exploded perspective view of a step-down DC-DC converter module 59 according to the ninth embodiment. FIG. 21 is a diagram illustrating an example of the upper and lower surfaces of the substrate provided in the DC-DC converter module according to the tenth embodiment and conductor patterns in the vicinity thereof.

<< First Embodiment >>
The step-down DC-DC converter module according to the first embodiment will be described with reference to FIGS.
FIG. 2 is an exploded perspective view of the step-down DC-DC converter module 51. 3A is a cross-sectional view of the step-down DC-DC converter module 51, and FIG. 3B is a cross-sectional view of the step-down DC-DC converter module 50 shown in FIG. FIG. 4 is a circuit diagram of the step-down DC-DC converter module 51. In FIG. 2, in order to show the configuration of the inside and bottom surface of the magnetic substrate, it is shown transparent. This drawing method is the same for the other embodiments described below.

  In FIG. 2, the magnetic substrate 30 is a magnetic ceramic multilayer substrate. Lower surface terminals 41 to 43 are formed on the lower surface of the magnetic substrate 30. On the upper surface of the magnetic substrate 30, an upper surface electrode (a pattern is not shown) is formed.

  On the upper surface of the magnetic substrate 30, a control circuit 31 including a switching element, an input capacitor Ca, and an output capacitor Cb are mounted. These components are electrically connected to the upper surface electrode of the magnetic substrate 30.

  Inside the magnetic substrate 30, a smoothing coil L1 and inductors L2, L3, and L4 connected between the lower surface terminal and the upper surface electrode are formed. The smoothing coil L1 is composed of a helical conductor. Inductors L2, L3, and L4 are formed of via conductors. These inductors L2, L3, and L4 pass in a direction perpendicular to the magnetic substrate 30 at the center of the winding range of the conductor that constitutes the smoothing coil L1.

  The smoothing coil L1 corresponds to a “magnetic element” recited in the claims. The inductances L2, L3, and L4 are connection wirings that connect at least one of an input terminal, an output terminal, and a ground terminal to the upper surface electrode, and correspond to an “internal conductor” recited in the claims.

  As shown in FIGS. 3 (A) and 3 (B), the smoothing coil L1 is composed of a substantially half-circular coiled conductor formed in each layer and via conductors connecting the layers. Thus, if the inductors L2, L3, L4 by the via conductor and the smoothing coil L1 exist in the same magnetic substrate 30, the inductors L2, L3, L4 and the smoothing coil L1 are magnetically coupled to some extent. Due to this magnetic coupling, rectangular wave noise is superimposed on the input / output voltage, or the ground potential of the control circuit varies due to the switching current, and the control circuit becomes unstable.

  In the DC-DC converter module having the conventional structure shown in FIG. 3B, inductors L2, L3, and L4 by through via conductors that connect the upper and lower sides of the substrate are arranged on the outer periphery of the substrate. In order to form the smoothing coil L1 having a large inductance value by effectively using the limited substrate area, it is important to increase the dimension D and form the coiled conductor as close to the outer periphery of the substrate as possible. Therefore, the gap g1 between the inductors L2, L3, and L4 due to the via conductor and the smoothing coil L1 due to the coiled conductor is reduced, and therefore the magnetic coupling between the smoothing coil L1 and the inductors L2, L3, and L4 is increased.

  On the other hand, in the first embodiment of the present invention, as shown in FIG. 3A, inductors L2, L3, and L4 made of via conductors are provided at the center of the winding range of the coiled conductor constituting the smoothing coil L1. Deploy. With this structure, the gap g2 between the inductors L2, L3, L4 and the smoothing coil L1 is increased (g2> g1), and the degree of magnetic coupling can be reduced. Furthermore, since the direction of the magnetic flux is in the thickness direction of the substrate at the center of the winding range of the conductor constituting the smoothing coil L1, the magnetic coupling with the inductors L2, L3, and L4 is also small.

  The step-down DC-DC converter 51 is mounted on the wiring board of the electronic device, and the input voltage source 9 is connected to the input terminal IN of the step-down DC-DC converter 51 as shown in FIG. 2 and 4, the input terminal IN corresponds to the lower surface terminal 41, the output terminal OUT corresponds to the lower surface terminal 43, and the ground terminal GND corresponds to the lower surface terminal 42, respectively. The other parts are denoted by the same reference numerals.

  The control circuit 31 includes a switching control circuit that performs switching control of the main switching element Q1 and the synchronous rectification element Q2. The switching control circuit in the control circuit 31 provides a dead time during which the main switching element Q1 and the synchronous rectifying element Q2 are not simultaneously turned on and alternately turns on / off.

  As described above, since the magnetic coupling between the smoothing coil L1 and the inductors L2 to L4 is small, unnecessary electromotive voltage is not generated in the inductors L2 to L4, and the ripple voltage generated in the input voltage and the output voltage is small. . Further, since the inductors L2 to L4 are short one-turn inductors, the magnetic flux generated by the wiring is not large and the influence on the adjacent wiring is small.

  Since the magnetic flux generated by the smoothing coil L1 is the largest in the DC-DC converter module 51, it is also important that the winding direction of the smoothing coil L1 and the wiring direction of the upper surface electrode are different by 90 degrees and the magnetic fields are orthogonal to each other. is there. As a result, the flux linkage is reduced and the magnetic coupling with the upper surface electrode can be reduced.

  In the example shown in FIGS. 2 and 3, the inductors L2, L3, and L4 made of via conductors are arranged at the center of the winding range of the coiled conductor constituting the smoothing coil L1. If it is difficult to place multiple via conductors in a narrow area, or if you want to avoid capacitive coupling between adjacent via conductors, only the via conductors that you want to avoid magnetic coupling are covered by the coiled conductor winding range. The other via conductors may be arranged at the end (corner) of the substrate.

  In the example shown in FIG. 4, the synchronous rectification element Q2 using the FET is provided, but this element may be replaced with a diode. Further, as the switching element, FIG. 4 illustrates a combination of a P-channel FET and an N-channel FET, but a combination of an N-channel FET and an N-channel FET may be used. Further, another element such as a bipolar transistor may be used as the switching element. The same applies to each of the embodiments shown in the second and subsequent embodiments.

  In the example shown in FIG. 5, the smoothing coil L <b> 1 is formed of a helical conductor, but may have other shapes such as a spiral shape. The same applies to each of the embodiments shown in the second and subsequent embodiments.

  Further, in the example shown in FIG. 4, a non-insulated step-down DC-DC converter is configured on the magnetic substrate, but an insulating forward DC-DC converter can also be configured in the same manner. That is, if a transformer is formed on the magnetic substrate 30 instead of the smoothing coil L1, inductors L2 and L3 are inserted in series with a current line (input line) flowing from the input voltage source 9 to the input terminal IN. It will be. Therefore, the pulse current flowing from the input voltage source 9 when the main switching element Q1 is turned on is effectively suppressed, and the pulse current containing a lot of high-frequency components flows almost completely through the input capacitor Ca and hardly flows out to the outside.

  As described above, in the “input current discontinuous-continuous output current” type DC-DC converter such as the step-down DC-DC converter and the forward DC-DC converter, the wiring of the input terminal is passed through the magnetic substrate. Is effective in suppressing noise.

<< Second Embodiment >>
A step-down DC-DC converter module according to a second embodiment will be described with reference to FIGS.
FIG. 5 is an exploded perspective view of the step-down DC-DC converter module 52, and FIG. 6 is a circuit diagram thereof.

  In FIG. 5, lower surface terminals 41 to 43 are formed on the lower surface of the magnetic substrate 30. On the upper surface of the magnetic substrate 30, an upper surface electrode (a pattern is not shown) is formed. A smoothing coil L1 and inductors L2 and L3 connected between the lower surface terminal and the upper surface electrode are formed inside the magnetic substrate 30. An end surface conductor S4 connected between the lower surface terminal and the upper surface electrode is formed on the end surface of the magnetic substrate 30. The smoothing coil L1 has a helical conductor. The inductors L2 and L3 are configured by via conductors.

  A control circuit 31 including a switching element, an input capacitor Ca, and an output capacitor Cb are mounted on the upper surface of the magnetic substrate 30. These components are electrically connected to the upper surface electrode of the magnetic substrate 30.

  The step-down DC-DC converter 52 is mounted on a wiring board of an electronic device, and an input voltage source 9 is connected to an input terminal IN of the step-down DC-DC converter 52 as shown in FIG. 5 and 6, the input terminal IN corresponds to the lower surface terminal 41, the output terminal OUT corresponds to the lower surface terminal 43, and the ground terminal GND corresponds to the lower surface terminal 42, respectively. The other parts are denoted by the same reference numerals.

  2 and 4 shown in the first embodiment is that the output capacitor Cb and the smoothing coil L1 are not connected only by the via conductor (inductor L4) inside the magnetic substrate 30, but the end face conductor S4. However, it is a point to connect. With this configuration, the problem of a reduction in efficiency of the DC-DC converter due to the direct current resistance of the end face conductor is solved. Further, since the resistance value and the inductance value of the connection portion between the output terminal OUT and the output capacitor Cb shown in FIG. 6 are reduced, the impedance of the output capacitor Cb with respect to the output ripple is reduced, and the output voltage ripple appears accordingly. The rectangular wave component is effectively suppressed.

  In this way, in the “input current discontinuous-output current continuous” type DC-DC converter such as the step-down DC-DC converter and the forward DC-DC converter, the wiring of the input terminal passes through the magnetic substrate, The wiring of the output terminal is preferably passed outside the magnetic substrate.

  FIG. 7 is a graph showing fluctuation characteristics of the output voltage with respect to the output current. The vertical axis represents the output voltage normalized with 1.00 when the output current is zero. The characteristic line A is the characteristic of the DC-DC converter module according to the second embodiment, and the characteristic line B is the characteristic of the DC-DC converter module when the inductor L4 by the via conductor shown in FIG. 5 is not provided. According to the second embodiment, it can be seen that the ratio of the change in the output voltage with respect to the change in the output current is about 1/5 compared to the case of the end face conductor alone.

<< Third Embodiment >>
A step-down DC-DC converter module according to a third embodiment will be described with reference to FIGS.
FIG. 8 is an exploded perspective view of the step-down DC-DC converter module, and FIG. 9 is a circuit diagram thereof.

  In FIG. 8, lower surface terminals 41 to 43 are formed on the lower surface of the magnetic substrate 30. On the upper surface of the magnetic substrate 30, an upper surface electrode (a pattern is not shown) is formed. A smoothing coil L1 and inductors L2 and L3 connected between the lower surface terminal and the upper surface electrode are formed inside the magnetic substrate 30. An end surface conductor S4 connected between the lower surface terminal and the upper surface electrode is formed on the end surface of the magnetic substrate 30. The smoothing coil L1 is composed of a helical conductor. The inductor L2 is also composed of a helical conductor. The inductor L3 is constituted by a via.

  A control circuit 31 including a switching element, an input capacitor Ca, and an output capacitor Cb are mounted on the upper surface of the magnetic substrate 30. These components are electrically connected to the upper surface electrode of the magnetic substrate 30.

  The step-down DC-DC converter 53 is mounted on the wiring board of the electronic device, and the input voltage source 9 is connected to the input terminal IN of the step-down DC-DC converter 53 as shown in FIG. 8 and 9, the input terminal IN corresponds to the lower surface terminal 41, the output terminal OUT corresponds to the lower surface terminal 43, and the ground terminal GND corresponds to the lower surface terminal 42, respectively. The other parts are denoted by the same reference numerals.

  The difference from FIG. 5 shown in the second embodiment is that the inductor L2 is formed of a helical conductor. With this structure, the inductance of the input wiring is further increased, and the effect of suppressing noise leakage is enhanced.

  The winding direction of the smoothing coil L1 and the winding direction of the inductor L2 are different by 90 degrees. That is, since the magnetic fields are orthogonal to each other, the magnetic coupling between the smoothing coil L1 and the inductor L2 becomes small, no unnecessary electromotive voltage is generated in L2, and the ripple voltage generated in the input voltage becomes small.

<< Fourth Embodiment >>
A step-up DC-DC converter module according to a fourth embodiment will be described with reference to FIGS.
FIG. 10 is an exploded perspective view of the step-up DC-DC converter module, and FIG. 11 is a circuit diagram thereof.

  In FIG. 10, lower surface terminals 41 to 43 are formed on the lower surface of the magnetic substrate 30. On the upper surface of the magnetic substrate 30, an upper surface electrode (a pattern is not shown) is formed. Inside the magnetic substrate 30, a smoothing coil L1 and inductors L2, L3, and L4 connected between the lower surface terminal and the upper surface electrode are formed. The smoothing coil L1 is composed of a helical conductor. The inductors L2, L3, and L4 are configured by via conductors.

  A control circuit 32 including a switching element, an input capacitor Ca, and an output capacitor Cb are mounted on the top surface of the magnetic substrate 30. These components are electrically connected to the upper surface electrode of the magnetic substrate 30.

  The step-up DC-DC converter 54 is mounted on a wiring board of an electronic device, and the input voltage source 9 is connected to the input terminal IN of the step-up DC-DC converter 54 as shown in FIG. 10 and 11, the input terminal IN corresponds to the lower surface terminal 43, the output terminal OUT corresponds to the lower surface terminal 42, and the ground terminal GND corresponds to the lower surface terminal 41. The other parts are denoted by the same reference numerals.

  The control circuit 32 includes a switching control circuit that performs switching control together with the switching element Q and the diode D.

  In the step-up DC-DC converter 54 shown in FIG. 11, inductors L2 and L3 are inserted in series in a path of current flowing from the output capacitor Cb to the load via the output terminal OUT.

  In the step-up DC-DC converter, the current flowing through the diode (output current) has a rectangular wave-like discontinuous waveform. However, since the inductors L2 and L3 are configured by vias inside the magnetic substrate 30 as shown in FIG. 10, the high-frequency component of the rectangular wave current is suppressed by the inductance. Therefore, the high frequency component almost completely flows through the output capacitor Cb and hardly flows out to the outside. Thereby, the ripple of the output voltage supplied from the output terminal to the load is suppressed, and the problem of noise generation on the output side can be solved.

  In this way, in the “continuous input current-discontinuous output current” type DC-DC converter such as the step-up DC-DC converter, it is possible to suppress noise by passing the wiring of the output terminal through the magnetic substrate. It is effective.

<< Fifth Embodiment >>
A step-up DC-DC converter module according to a fifth embodiment will be described with reference to FIGS.
12 is an exploded perspective view of the step-up DC-DC converter module 55, and FIG. 13 is a circuit diagram thereof.

  The difference from FIG. 10 and FIG. 11 shown in the fourth embodiment is that the connection between the input capacitor Ca and the input terminal IN is not connected only by the via conductor (inductor L4) inside the magnetic substrate 30, but the end face. The conductor S4 is also connected. With this configuration, the impedance of the input capacitor Ca with respect to the pulse current is reduced, and accordingly, the pulse current containing a large amount of high-frequency components almost completely flows through the input capacitor Ca and hardly flows out to the outside. Thereby, the problem of the noise accompanying using a DC-DC converter module can be made small.

  In this way, in the “continuous input current-discontinuous output current” type DC-DC converter such as the step-up DC-DC converter and the flyback DC-DC converter, the wiring of the output terminal is in the magnetic substrate. The wiring of the input terminal is preferably passed outside the magnetic substrate.

<< Sixth Embodiment >>
An inverting DC-DC converter module according to a sixth embodiment will be described with reference to FIGS.
FIG. 14 is an exploded perspective view of the inverting DC-DC converter module, and FIG. 15 is a circuit diagram thereof.

  In FIG. 14, lower surface terminals 41 to 43 are formed on the lower surface of the magnetic substrate 30. On the upper surface of the magnetic substrate 30, an upper surface electrode (a pattern is not shown) is formed. Inside the magnetic substrate 30, a smoothing coil L1 and inductors L2, L3, and L4 connected between the lower surface terminal and the upper surface electrode are formed. The smoothing coil L1 is composed of a helical conductor. Inductors L2, L3, and L4 are formed of via conductors.

  A control circuit 33 including a switching element, an input capacitor Ca, and an output capacitor Cb are mounted on the upper surface of the magnetic substrate 30. These components are electrically connected to the upper surface electrode of the magnetic substrate 30.

  The inverting DC-DC converter 56 is mounted on a wiring board of an electronic device, and an input voltage source 9 is connected to an input terminal IN of the inverting DC-DC converter 56 as shown in FIG. 14 and 15, the input terminal IN corresponds to the lower surface terminal 41, the output terminal OUT corresponds to the lower surface terminal 42, and the ground terminal GND corresponds to the lower surface terminal 43. The other parts are denoted by the same reference numerals.

  The control circuit 33 includes a switching control circuit that performs switching control of the switching element Q and the diode D together.

  In the inverting DC-DC converter 56 shown in FIG. 15, inductors L2 and L4 are inserted in series with a current line (input line) flowing from the input voltage source 9 to the input terminal IN. As shown in FIG. 14, the inductors L2 and L4 are constituted by vias inside the magnetic substrate 30, and due to the inductance, a pulse current flowing from the input voltage source 9 is effective when the switching element Q is turned on. To be suppressed. Therefore, the pulse current containing a lot of high frequency components almost completely flows through the input capacitor Ca and hardly flows out to the outside. Thereby, the problem of the noise accompanying using a DC-DC converter module can be made small.

  Further, in the inverting DC-DC converter 56 shown in FIG. 15, an inductor L3 is inserted in series in a path of current flowing from the output capacitor Cb to the load via the output terminal OUT.

  In the inverting DC-DC converter, the current (output current) flowing through the diode D becomes a rectangular wave-like discontinuous waveform. However, since the inductor L3 is constituted by a via inside the magnetic substrate 30 as shown in FIG. 14, the high frequency component of the rectangular wave current is suppressed by the inductance. Therefore, the high frequency component almost completely flows through the output capacitor Cb and hardly flows out to the outside. Thereby, the ripple of the output voltage supplied from the output terminal to the load is also suppressed, and the problem of noise generation on the output side can be solved.

  In the example shown in FIG. 15, the non-insulated inverting DC-DC converter is configured on the magnetic substrate, but an insulating flyback DC-DC converter can also be configured in the same manner. Since both the non-insulated inverting DC-DC converter and the insulating flyback DC-DC converter are “discontinuous input current-discontinuous output current”, the smoothing coil is formed on the magnetic substrate 30. It is clear that the same effect can be obtained if the transformer T is configured instead of L1.

  In such a DC-DC converter of "input current discontinuity-output current discontinuity" type such as an inverting DC-DC converter or a flyback DC-DC converter, the wiring of the input / output terminals is a magnetic substrate. It is desirable to pass inside.

<< Seventh Embodiment >>
An inverting DC-DC converter module according to a seventh embodiment will be described with reference to FIGS.
16 is an exploded perspective view of the inverting DC-DC converter module 57, and FIG. 17 is a circuit diagram thereof.

  The difference from the DC-DC converter module shown in the sixth embodiment is that the connection between the smoothing coil L1 and the input capacitor Ca is not connected by only the via conductor (inductor L4) inside the magnetic substrate 30, but the end face. The conductor S4 is also connected. With this configuration, the inductance of the wiring generated in the wiring of the ground terminal which is one of the lower surface terminals on the lower surface of the magnetic substrate 30 and the input capacitor Ca and the output capacitor Cb mounted on the upper surface of the magnetic substrate 30 is reduced, and the smoothing coil L1 The phenomenon that rectangular wave noise appears at the ground terminal on the bottom surface of the magnetic substrate is suppressed by the pulsating ripple current flowing through the magnetic substrate. Therefore, noise output to the outside can be further reduced.

  In such a DC-DC converter of “input current discontinuity-output current discontinuity” type such as an inverting DC-DC converter or a flyback DC-DC converter, the wiring of the ground terminal is the magnetic substrate 30. It is desirable to pass the wiring of the input / output terminals through the inside of the magnetic substrate.

<< Eighth Embodiment >>
A step-down DC-DC converter module according to an eighth embodiment will be described with reference to FIGS.
18 is an exploded perspective view of the step-down DC-DC converter module, and FIG. 19 is a circuit diagram thereof.

  In FIG. 18, lower surface terminals 41, 42, 44 are formed on the lower surface of the magnetic substrate 30. On the upper surface of the magnetic substrate 30, an upper surface electrode (a pattern is not shown) is formed. Inside the magnetic substrate 30, a smoothing coil L1 and inductors L2, L3, L4, and L5 connected between the lower surface terminal and the upper surface electrode are formed. The smoothing coil L1 is composed of a helical conductor. Inductors L2, L3, L4, and L5 are each formed of a via conductor.

  A control circuit 31 including a switching element, an input capacitor Ca, and an output capacitor Cb are mounted on the upper surface of the magnetic substrate 30. These components are electrically connected to the upper surface electrode of the magnetic substrate 30.

  The step-down DC-DC converter 58 is mounted on a wiring board of an electronic device, and an input voltage source 9 is connected to an input terminal IN of the step-down DC-DC converter 58 as shown in FIG. 18 and 19, the input terminal IN corresponds to the lower surface terminal 41, the output terminal OUT corresponds to the lower surface terminal 44, and the ground terminal GND corresponds to the lower surface terminal 42. The other parts are denoted by the same reference numerals.

  In the eighth embodiment, one end of the smoothing coil L1 is led out to the upper surface (component mounting surface) of the magnetic substrate 30 via an inductor L4 made of a via conductor, and further, the lower surface terminal 44 is passed via an inductor L5 made of a via conductor. Connected up to. With this configuration, the inductance of the smoothing coil L1 is increased by the inductor L4, and the output ripple determined by the inductance value of the smoothing coil L1 and the capacitance value of the output capacitor Cb is reduced. In addition, since the inductor L5 is provided in series with the output terminal, the rectangular wave component that appears in the ripple of the output voltage is effectively suppressed.

  Note that the connection wiring that connects both ends of the smoothing coil and the upper surface electrode with the inner conductor of the magnetic substrate 30 is not limited to the step-down DC-DC converter module, and is different from the step-up type and the inversion type. It can also be applied to a DC-DC converter module of the system, and the same effect can be obtained. Further, the present invention can be applied not only to a non-insulating DC-DC converter but also to other converters using a magnetic substrate such as an insulating DC-DC converter and an AC-DC converter.

<< Ninth embodiment >>
FIG. 20 is an exploded perspective view of a step-down DC-DC converter module 59 according to the ninth embodiment. What is different from the example shown in FIG. 2 in the first embodiment is the structure of the end face conductor S4. In the example shown in FIG. 20, the end surface conductor S4 is constituted by a divided via formed by vertically dividing the center of the via filled inside with a conductive material.

  By configuring the end face conductor in this manner, the cross-sectional area of the end face conductor can be increased, and the DC resistance and inductance of the end face conductor can be efficiently reduced. Therefore, high efficiency can be achieved. In addition, the configuration shown in FIG. 2 requires manufacturing steps because it requires the formation of vias built in the magnetic substrate 30 and the step of applying the external electrode paste to form the end face conductors. In this configuration, the via is formed in the state of the mother board (the state of the substrate before the division in which a plurality of individual products are gathered), and then cut along a line passing through the center of the via when the mother board is divided. Manufacturing cost can be reduced.

<< Tenth Embodiment >>
In the tenth embodiment, examples of the upper and lower surfaces of the substrate provided in the DC-DC converter module and conductor patterns in the vicinity thereof are shown. FIG. 21A is a cross-sectional view of the magnetic substrate 30. FIGS. 21B to 21F are plan views of the layers shown in FIG. In this example, the magnetic substrate 30 includes a magnetic layer 30M on which a magnetic body (for example, ferrite) is stacked and nonmagnetic layers 30T and 30B on which a nonmagnetic body (for example, nonmagnetic ferrite) is stacked. It is a multilayer substrate. An IC 70 or the like is mounted on the upper surface of the magnetic substrate 30.

  As shown in FIG. 21B, pads (upper surface electrodes) 61a to 61d for bump-connecting the terminals of the IC 70 are formed on the upper surface of the nonmagnetic layer 30T. In FIG. 21B, the broken line indicates the mounting area of the IC 70. In-layer wirings 63a to 63d are formed on the lower surface of the nonmagnetic layer 30T. Via conductors that connect the pads 61a to 61d and the in-layer wirings 63a to 63d are formed inside the nonmagnetic layer 30T.

  In the magnetic layer 30M, a coil is constituted by a helical conductor 64e. Further, via conductors (connection wirings) 64a to 64d are formed in the magnetic layer 30M at the center of the winding range of the helical conductor 64e. These via conductors 64a to 64d are electrically connected to the in-layer wirings 63a to 63d, respectively.

  In-layer wirings 65a to 65d that are electrically connected to the via conductors 64a to 64d are formed on the upper surface of the nonmagnetic layer 30B. External terminals 67a to 67d for mounting on a mounting board are formed on the lower surface of the nonmagnetic layer 30B. In the nonmagnetic layer 30B, via conductors for connecting the in-layer wirings 65a to 65d and the mounting external terminals (lower surface terminals) 67a to 67d are formed.

  FIG. 21 shows an example of the upper and lower surfaces of the substrate and the conductor patterns in the vicinity thereof, but the configuration of the upper and lower surfaces of the substrate can be applied to the DC-DC converters shown in the first to ninth embodiments.

Ca ... input capacitor Cb ... output capacitor D ... diode GND ... ground terminal IN ... input terminal L1 ... smoothing coils L2, L3, L4, L5 ... inductor OUT ... output terminal Q ... switching element Q1 ... main switching element Q2 ... synchronous rectifying element S4 ... End face conductor T ... Transformer 9 ... Input voltage source 30 ... Magnetic substrates 31, 32, 33 ... Control circuits 41-44 ... Bottom terminals 50-59 ... DC-DC converter modules 61a-61d ... Pads 63a-63d ... Layers Inner wiring 64a-64d ... via conductor 64e ... helical conductors 65a-65d ... in-layer wiring 67a-67d ... mounting external terminal 70 ... IC

Claims (6)

A DC-DC converter module comprising a switching unit including a switching element and a magnetic element, an input capacitor provided on the input side of the switching unit, and an output capacitor provided on the output side of the switching unit,
A lower surface terminal including an input terminal, an output terminal, and a ground terminal is provided on the lower surface, and an upper surface electrode is formed on the upper surface, and the switching element, the input capacitor, and the output capacitor are mounted on the upper surface electrode, respectively. A substrate on which the magnetic element is configured,
The magnetic element includes a conductor wound in a coil shape,
A connection wiring that connects at least one of the input terminal, the output terminal, or the ground terminal and the upper surface electrode passes in a direction perpendicular to the substrate at the center of the winding range of the conductor of the magnetic element. DC-DC converter module composed of internal conductors. A DC-DC converter module comprising a switching unit including a switching element and a magnetic element, an input capacitor provided on the input side of the switching unit, and an output capacitor provided on the output side of the switching unit,
An input terminal, an output terminal, and a ground terminal are provided on the lower surface, an upper surface electrode is formed on the upper surface, and the switching element, the input capacitor, and the output capacitor are mounted on the upper surface electrode, respectively, Comprising a substrate on which the magnetic element is configured;
The magnetic element includes a conductor wound in a coil shape,
The connection wiring that connects at least one of the input terminal, the output terminal, or the ground terminal and the upper surface electrode includes an internal conductor that passes through the inside of the board and an end face conductor that passes through the end face of the board. A DC-DC converter module configured as described above. The substrate includes a magnetic layer and a nonmagnetic first wiring layer laminated on the top surface of the magnetic layer,
The upper surface electrode is formed on the upper surface of the first wiring layer, and a first in-plane wiring conductor that is electrically connected to the connection wiring is formed on the lower surface, and between the upper surface electrode and the first in-plane wiring conductor. The DC-DC converter module according to claim 1, comprising a first interlayer connection conductor that conducts the current. The substrate includes a nonmagnetic second wiring layer laminated on a lower surface of the magnetic layer,
The lower surface terminal is formed on the lower surface of the second wiring layer, a second in-plane wiring conductor is formed on the upper surface, and is electrically connected to the connection wiring, and is internally provided between the lower surface terminal and the second in-plane wiring conductor. The DC-DC converter module according to claim 3, further comprising a second interlayer connection conductor that conducts the current.   3. The DC-DC converter module according to claim 2, wherein the end face conductor is a divided via formed by vertically dividing the center of the via filled inside with a conductive material. 4.   The DC-DC converter module according to claim 1, wherein the internal conductor is a via filled inside with a conductive material.

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