JP6563739B2 - Voltage converter - Google Patents

Description

  The present invention relates to a voltage converter.

  Conventionally, in an insulated transformer, the number of turns of a coil is determined based on a relationship with a voltage conversion target value and the like. When such a coil is formed on a substrate, it is necessary to form a spiral pattern corresponding to the number of turns, and the substrate becomes large in the planar direction.

  Thus, a technique has been proposed in which a coil is formed over multiple layers using a multilayer substrate on which patterns are formed in multiple layers (see, for example, Patent Document 1). According to this, the expansion in the plane direction of the substrate can be suppressed because the coil is formed over multiple layers.

Japanese Patent Application Laid-Open No. 2014-175631

  Here, in a general multilayer substrate manufacturing apparatus, the thickness of the multilayer substrate to be manufactured is limited, and the number of layers in one multilayer substrate is limited. Therefore, in order to secure a layer number exceeding the limit, it is conceivable to prepare two multilayer substrates and electrically connect the two multilayer substrates with metal pins or the like.

  However, in such a case, it cannot be said that the positioning accuracy of the two multilayer substrates is never good. For this reason, when a center tap type transformer, which preferably has high symmetry, is formed on the substrate, the symmetry cannot be ensured, which adversely affects performance.

  The present invention has been made to solve such a problem, and the object of the present invention is to make it easy to ensure symmetry when two multilayer substrates are stacked to form a two-stage structure. An object of the present invention is to provide a voltage conversion device capable of performing

The voltage converter according to the present invention includes a primary winding, a first secondary winding, and a second secondary winding, and an output wiring is drawn from between the two secondary windings. The voltage converter includes a center tap type transformer in which the primary winding is driven in an antiphase in a time-sharing manner, and the two secondary windings are driven in an antiphase in response to the driving, A multilayer substrate in which a primary winding and the two secondary windings are formed as patterns of different layers, and rectifying an output voltage when the two secondary windings are driven in opposite phases A rectifier circuit formed on the multilayer substrate; and an output bus bar that is a metal plate that outputs a voltage rectified by the rectifier circuit , wherein the multilayer substrate is provided at an intermediate portion of the primary winding. The pattern was folded 180 degrees at the exposed front and back surfaces. Is a stepped structure, which has a pattern to output a voltage rectified by the rectifier circuit in each stage has a through pin for electrically connecting the pattern to each other in the respective stages, the output bus bars, It is disposed between the multilayer substrates having a two-stage structure, and is connected to the through pin .

  According to the voltage conversion device of the present invention, the multilayer substrate has a two-stage structure that is bent at 180 degrees at the portion where the front and back surfaces of the pattern are exposed at the intermediate portion of the primary winding. Multi-layer substrates can be stacked to form a two-stage structure, and bend at 180 degrees at the exposed part. As a result of the connection, misalignment is less likely to occur. Therefore, when two multilayer substrates are stacked to form a two-stage structure, the symmetry can be easily ensured.

Furthermore , since the rectifier circuit is formed on the multilayer substrate, the rectifier circuit is provided on the multilayer substrate on which the transformer is formed, so that the distance between the two can be shortened, the impedance can be reduced, and the loss can be reduced. it can.

In addition , the output bus bar is disposed between the multi-layer substrates having a two-stage structure, and in order to ensure conduction by the through pins, the output bus bar is sandwiched between the multi-layer substrates, so that The output bus bar can be arranged so as to be the center of symmetry, which can contribute to further ensuring symmetry.

  According to the present invention, it is possible to provide a voltage conversion device capable of easily ensuring the symmetry when two multilayer substrates are stacked to form a two-stage structure.

It is a circuit block diagram of the voltage converter which concerns on this embodiment. It is a perspective view which shows the hardware constitutions of the voltage converter shown in FIG. It is a disassembled perspective view of the voltage converter shown in FIG. FIG. 3 is a plan view showing a developed state of the multilayer substrate shown in FIG. 2. It is a top view which shows the pattern of each layer formed in the multilayer substrate shown in FIG. It is a figure which shows the lamination | stacking state of the winding in multilayer board | substrate MB shown in FIG. FIG. 3 is a first schematic cross-sectional view illustrating a stacked state of the voltage conversion device illustrated in FIG. 2. FIG. 3 is a second schematic cross-sectional view showing a part of the stacked state of the voltage conversion device shown in FIG. 2.

  Hereinafter, the present invention will be described according to preferred embodiments. Note that the present invention is not limited to the embodiments described below, and can be appropriately changed without departing from the spirit of the present invention. Further, in the embodiment described below, there is a part where illustration or description of a part of the configuration is omitted, but details of the omitted technology are within a range in which there is no contradiction with the contents described below. Needless to say, known or well-known techniques are applied as appropriate.

  FIG. 1 is a circuit configuration diagram of a voltage conversion device 1 according to the present embodiment. As shown in FIG. 1, the voltage conversion apparatus 1 according to the present embodiment includes a transformer 10 and a rectifier circuit 20, and a smoothing circuit 30 is connected to the rectifier circuit 20.

  The transformer 10 includes a primary winding T1, a first secondary winding T21, and a second secondary winding T22, and the first secondary winding T21 and the second secondary winding T22. Is a center tap type transformer in which output wiring is drawn out from between.

  The primary winding T1 is driven by the bridge circuit BC in the opposite phase in a time division manner (see symbols a and b). That is, the bridge circuit BC applies an AC voltage to the primary winding T1. The secondary windings T21 and T22 are driven in opposite phases in accordance with the driving of the primary winding T1. Specifically, the first secondary winding T21 is driven when the current flows in the direction of the symbol a with respect to the primary winding T1, and the second current when the current flows in the direction of the symbol b. Secondary winding T22 is driven. Thus, the secondary windings T21 and T22 are driven in opposite phases in accordance with the driving of the primary winding T1.

  The rectifier circuit 20 is for rectifying (rectifying) the voltage at the time of driving the two secondary windings T21 and T22, that is, the AC voltage, and the smoothing circuit 30 is for smoothing the DC voltage. is there. In the present embodiment, the rectifier circuit 20 includes two switch elements SW and a control circuit SC that turns on and off the two switch elements SW for each of the two secondary windings T21 and T22. The rectifier circuit 20 turns the AC voltage into DC by turning on and off the two switch elements SW provided for each of the two secondary windings T21 and T22. The smoothing circuit 30 includes a coil L connected in series to the output line L1 of the center tap, and a capacitor C provided in parallel on the output side of the coil L. Note that the rectifier circuit 20 and the smoothing circuit 30 are not limited to the above-described configurations, and may be known or other known configurations.

  2 is a perspective view showing a hardware configuration of the voltage converter 1 shown in FIG. 1, and FIG. 3 is an exploded perspective view of the voltage converter 1 shown in FIG. 4 is a plan view showing a developed state of the multilayer substrate shown in FIG. The voltage conversion device 1 includes a lower metal plate MP, a multilayer board MB on the metal plate MP, a magnetic core MC, an output bus bar OB, and an insulating heat dissipation sheet IHS.

  The metal plate MP is a metal plate on which the above-described other components are placed, and a plurality of fins F are formed on the opposite surface opposite to the surface side shown in FIGS. It has a function to dissipate the generated heat.

  The multilayer substrate MB is a substrate on which patterns P (patterns P1 to P4 described in detail in FIG. 5 described later) are formed in multiple layers. In the present embodiment, the multilayer substrate MB includes a pattern P (see FIG. 4) on two layers of the front surface and the back surface, and further includes a two-layer pattern formed in the substrate MB, and has a four-layer pattern P. It has become.

  In the multilayer substrate MB, the primary winding T1 of the transformer 10 and the two secondary windings T21 and T22 are formed as patterns of different layers. As shown in FIGS. 2 to 4, the multilayer substrate MB is formed into a predetermined shape by cutting the base material portion after the formation of the metal pattern P, and is bent in 180 degrees at the bent portion BP. The structure is shown (FIG. 2 shows a state of being bent by 180 degrees, and FIGS. 3 and 4 show a state of being unfolded by 180 degrees). Note that the bent portion BP is a portion of only the pattern P as will be described later, and is a portion where the base portion is scraped away and the front and back surfaces of the pattern P are exposed. Needless to say, the base material of the multilayer substrate MB is cut into a predetermined shape that does not hinder the bending of 180 degrees.

  Furthermore, in the state in which the multilayer substrate MB has a two-stage structure bent at 180 degrees, the primary winding T1, the first secondary winding T21, and the second secondary winding T22 are metal plates. It is formed side by side in the direction perpendicular to the MP (hereinafter referred to as the vertical direction), and the central base material portion of the windings T1, T21, T22 is scraped off to form an opening OP.

  The magnetic core MC has an 8-shaped magnetic path when viewed from the side, and includes an upper core member MC1 and a lower core member MC2 each having an E shape and a plan view when viewed from the side. . Here, each of the upper core member MC1 and the lower core member MC2 includes a columnar middle leg MC3, and the middle leg MC3 is inserted into the opening OP. Because of the relationship that the middle leg MC3 is inserted into the opening OP, the primary winding T1 and the two secondary windings T21 and T22 of the transformer 10 are wound around the middle leg MC3.

  Moreover, the rectifier circuit 20 is mounted on the multilayer substrate MB, and four switch elements SW constituting the rectifier circuit 20 are mounted as shown in FIGS. Although not shown, the control circuit SC is also mounted on the multilayer substrate MB. Furthermore, the multilayer substrate MB is fixed to the metal plate MP via the screw SC1.

  The output bus bar OB is a metal plate that outputs the voltage from the rectifier circuit 20. The output bus bar OB is a member disposed between the stages of the multilayer board MB having a two-stage structure, and is fixed to the multilayer board MB by screws (through pins) SC2. The output bus bar OB is a member connected to the output wiring L1 shown in FIG. 1 on the circuit.

  The insulating heat radiation sheet IHS is interposed between the stages of the multi-layer substrate MB having a two-stage structure, in particular, at locations where the primary winding T1, the first secondary winding T21, and the second secondary winding T22 are formed. It is a member. Note that the insulating heat radiation sheet IHS is not limited to being interposed only at the locations where the windings T1, T21, T22 are formed, and may be provided so as to include other locations (for example, locations where the switch element SW is formed). .

  Next, details of the pattern structure of the multilayer substrate MB will be described. 5 is a plan view showing the pattern of each layer formed on the multilayer substrate shown in FIG. 2, wherein (a) shows the pattern of the first layer, (b) shows the pattern of the second layer, c) shows the pattern of the third layer, and (d) shows the pattern of the fourth layer. FIG. 6 is a diagram illustrating a stacking state of windings in the multilayer substrate MB illustrated in FIG.

  As shown in FIG. 5A, in the first layer, a part of the first secondary winding T21 and a part of the second secondary winding T22 are applied to the base material B1 having a predetermined shape. A pattern P1 to be formed is formed. More specifically, the base material B1 is cut into a predetermined shape, so that the base material B1 is separated into two parts, ie, a first secondary winding T21 side and a second secondary winding T22 side. As shown in FIGS. 5A and 6, the pattern P <b> 1 has one coil portion P <b> 1 a as one part of the first secondary winding T <b> 21 and the other separated pattern P <b> 1. The side constitutes a one-turn coil portion P1b as a part of the second secondary winding T22. Further, as shown in FIG. 6, the coil portion P1a is at the uppermost position and the coil portion P1b is at the lowermost position in the laminated state because of the two-stage structure in which the multilayer substrate MB is bent at the bent portion BP. . In the first layer, signal introduction holes H are formed on both the one side and the other side where the base material B1 is separated.

  As shown in FIG.5 (b), in the 2nd layer, the pattern P2 which comprises a part of primary winding T1 with respect to the base material B2 of a predetermined shape is formed. In the second layer, the base material B2 is scraped into a predetermined shape and divided into two members, but the pattern P is not divided into two members and is a bent portion corresponding to an intermediate portion of the primary winding T1. The BP remains connected. Further, as shown in FIGS. 5B and 6, the pattern P <b> 2 constitutes a two-turn coil part P <b> 2 a on one side of the bent part BP and a two-turn coil part P <b> 2 b on the other side of the bent part BP. Configure. Note that, as shown in FIG. 6, the coil part P2a is the second position from the top in the stacked state, and the coil part P2b is from the bottom because of the two-stage structure in which the multilayer substrate MB is bent at the bent part BP. Second position. Further, in the second layer, similarly to the first layer, signal introduction holes H are formed on both one side and the other side of the base material B2.

  As shown in FIG.5 (c), in the 3rd layer, the pattern P3 which comprises the remainder of the primary winding T1 is formed with respect to the base material B3 of predetermined shape. In the third layer, the base material B3 is scraped into a predetermined shape and separated into two members, and the pattern P3 is also separated into two members. Further, as shown in FIGS. 5C and 6, the pattern P <b> 3 constitutes a three-turn coil part P <b> 3 a on one separated side, and constitutes a three-turn coil part P <b> 3 b on the other separated side. . Note that, as shown in FIG. 6, the coil part P3a is the third position from the top in the laminated state, and the coil part P3b is from the bottom because of the two-stage structure in which the multilayer substrate MB is bent at the bent part BP. This is the third position.

  Here, each coil part P3a, P3b has the signal introduction part Si connected to the signal introduction hole H, respectively. The signal introduction part Si is a part electrically connected to the bridge circuit BC shown in FIG. In addition, the third layer coil portion P3a and the second layer coil portion P2a are electrically connected through a through hole SH. The third layer coil portion P3b and the second layer coil portion P2b are also electrically connected through the through hole SH. Therefore, the current from the bridge circuit BC flows, for example, in the order of the third layer coil unit P3a, the second layer coil unit P2a, the second layer coil unit P2b, and the third layer coil unit P3b. It becomes.

  As shown in FIG. 5D, in the fourth layer, the remaining portion of the first secondary winding T21 and the remaining portion of the second secondary winding T22 are configured with respect to the base material B4 having a predetermined shape. A pattern P4 is formed. More specifically, the base material B4 is cut into a predetermined shape, so that the base material B4 is separated into two parts, ie, a first secondary winding T21 side and a second secondary winding T22 side. And as shown in FIG.5 (d) and FIG. 6, as for the pattern P4, the separated one side comprises the coil part P4a of 1 turn as the remainder of the 1st secondary winding T21, and the separated other side is One coil portion P4b is configured as the remaining portion of the second secondary winding T22. Further, as shown in FIG. 6, the coil part P4a is the fourth position from the top in the laminated state, and the coil part P4b is from the bottom because of the two-stage structure in which the multilayer substrate MB is bent at the bent part BP. It will be the fourth position.

  Further, in the fourth layer, signal introduction holes H are formed on both the one side and the other side where the base material B4 is separated. Here, since the signal introduction holes H are formed in the first layer and the second layer, there is no problem if the signal introduction holes H in the fourth layer are not provided. The introduction hole H is formed, and is configured to be electrically connected to the bridge circuit BC from either the front or back direction of the signal introduction part Si.

  FIG. 7 is a first schematic cross-sectional view illustrating a stacked state of the voltage conversion device 1 illustrated in FIG. 2. In FIG. 7, for convenience of explanation, a part of the configuration is omitted and illustrated. Further, in FIG. 7, the size of the fin F is larger than that of the fin F shown in FIG. Furthermore, the arrows shown in FIG. 7 indicate the heat conduction state.

  First, as shown in FIG. 7, a plurality of metal fins F are provided on the back side of the metal plate MP (only one fin F is shown in FIG. 7) to constitute a heat sink HS. Further, the metal plate MP includes a plurality of protrusions Pr1 and Pr2 that are formed by being embossed toward the surface side.

  The first protrusion Pr1 is in contact with the insulating heat radiation sheet IHS disposed between the steps of the multilayer substrate MB. Further, the second projecting portion Pr2 is in contact with the pattern P4 of the fourth layer on the upper stage side of the multilayer substrate MB. The second projecting portion Pr2 is not limited to the fourth layer pattern P4, and may be in contact with the pattern P of another layer.

  Further, as shown in FIGS. 5A and 5D, the root side (switch element) excluding the coil portions P1a, P1b, P4a, and P4b of the first layer pattern P1 and the fourth layer pattern P4. On the SW mounting side), a contact portion CP is formed in contact with the first projecting portion Pr1 or the second projecting portion Pr2 via the insulating heat radiation sheet IHS. In the present embodiment, the second layer and the third layer are electrically separated from the coil portions P2a, P2b, P3a, and P3b, and the formation positions correspond to the contact portions CP of the first layer and the fourth layer. A temporary contact portion PCP is provided.

  Furthermore, a penetrating member PM that electrically (thermally) connects the contact portions CP of each layer on the upper side of the multilayer substrate MB is provided (see FIG. 7). For this reason, the heat of the upper stage generated at the time of voltage conversion is dissipated by the heat sink HS through the penetrating member PM and the plurality of protrusions Pr1 and Pr2.

  In the example shown in FIG. 7, the heat radiation on the upper stage side has been described. However, the same applies to the lower stage side, and the metal plate MP is provided with a protrusion for heat dissipation on the lower stage side, and the protrusion is formed on the lower stage side. It is in contact with the pattern P of any layer or the insulating heat radiation sheet IHS.

  FIG. 8 is a second schematic cross-sectional view showing a part of the stacked state of the voltage conversion device 1 shown in FIG. In FIG. 8, for convenience of explanation, a part of the configuration is omitted for illustration. As shown in FIG. 2 and the like, the output bus bar OB is disposed between the stages when the multilayer board MB is bent at 180 degrees to form a two-stage structure. Here, at least a part of the first and fourth layer patterns P1, P4 (excluding the coil portions P1a, P1b, P4a, P4b and the contact portion CP) is an output part OS (see FIG. 5). The output part OS is electrically connected by the metal screw SC2 shown in FIGS. 2 and 3, and is connected to the output bus bar OB via the screw SC2.

  The second layer and the third layer also have a temporary output part POS at a position corresponding to the output part OS, and the temporary output part POS is also electrically connected by a metal screw SC2.

  With the configuration as described above, the coil portions P1a, P1b, P4a, and P4b are electrically connected to the output bus bar OB. As a result, the output bus bar OB on the output line L1 side of the center tap can be arranged so as to be the center of symmetry, making it easier to ensure symmetry.

  Next, the manufacturing method of the voltage converter 1 which concerns on this embodiment is demonstrated. First, the multilayer substrate MB on which the predetermined pattern P is formed is manufactured by a manufacturing apparatus. At this time, the pattern P2 corresponding to the intermediate portion of the primary winding T1 is formed so that the upper and lower surfaces (front and back surfaces) are exposed as shown in FIG. Further, the pattern P of each layer is also manufactured as shown in FIG.

  Next, the switch element SW is mounted on the multilayer substrate MB, and the two-stage structure is formed by bending 180 degrees at the bent portion BP of the pattern P2 corresponding to the intermediate portion, and the output bus bar OB is disposed between the stages. Screwing is performed by the screw SC2. Further, an insulating heat radiation sheet IHS is also disposed between the stages.

  Thereafter, the magnetic core MC is attached, and the multilayer board MB is screwed and fixed to the metal plate MP with a screw SC1. At this time, each protrusion Pr formed on the metal plate MP comes into contact with the pattern P of any layer of the multilayer substrate MB or the insulating heat dissipation sheet IHS disposed between the steps.

  Thus, according to the voltage conversion device 1 according to the present embodiment, the multilayer substrate MB is bent at 180 degrees at the bent portion BP where the front and back surfaces of the pattern P2 are exposed at the intermediate portion of the primary winding T1. In addition, since the two multi-layer substrates MB can be stacked to form a two-stage structure, and the folded portion BP is bent at 180 degrees, two completely separated stages are stacked. Compared with the case where it is set as a step, the displacement is less likely to occur due to the connection at the bent portion BP. Accordingly, when the two multilayer substrates MB are stacked to form a two-stage structure, it is possible to easily ensure the symmetry.

  Further, since the rectifier circuit 20 is formed on the multilayer substrate MB, the rectifier circuit 20 is provided on the multilayer substrate MB on which the transformer 10 is formed, the distance between the two is shortened, the impedance is reduced, and the loss Can be reduced.

  In addition, the output bus bar OB is disposed between the multi-layer boards MB having a two-stage structure, and the output bus bar OB is sandwiched between the multi-layer boards MB in order to secure conduction by the screws SC2. The output bus bar OB on the wiring L1 side can be arranged to be the center of symmetry, which can contribute to further ensuring symmetry.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments, and may be modified without departing from the spirit of the present invention, and may be appropriately changed within a possible range. These techniques may be combined.

  For example, in the present embodiment, the coil portions P1a, P1b, P2a, P2b, P3a, P3b, P4a, and P4b are not limited to the stacking order shown in FIG.

  Furthermore, any of the coil portions P1a, P1b, P2a, P2b, P3a, P3b, P4a, and P4b may not be provided, and other coil portions may be added. For example, the fourth layer coil portions P4a and P4b may not be provided.

1: Voltage converter 10: Transformer 20: Rectifier circuit 30: Smoothing circuit BP: Bending part MB: Multilayer substrate MP: Metal plate OB: Output bus bar P: Pattern SC1: Screw SC2: Screw (through pin)
T1: primary winding T21, T22: secondary winding

Claims (1)

A primary winding, a first secondary winding, and a second secondary winding are provided, and an output wiring is drawn from between the two secondary windings, and the primary winding is time-division And a voltage conversion device having a center tap type transformer in which the two secondary windings are driven in opposite phases in response to the driving,
A multilayer substrate in which the primary winding and the two secondary windings are formed as different layer patterns ;
Rectifying an output voltage when the two secondary windings are driven in opposite phases, and a rectifier circuit formed on the multilayer substrate;
An output bus bar that is a metal plate that outputs the voltage rectified by the rectifier circuit ;
The multi-layer substrate has a two-stage structure bent at 180 degrees at a portion where the front and back surfaces of the pattern are exposed at an intermediate portion of the primary winding, and outputs a voltage rectified by the rectifier circuit. It has a pattern on each stage, and has a through pin that electrically connects the patterns on each stage,
The output bus bar is disposed between the multilayer substrates having a two-stage structure, and is connected to the through pin .

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