JP6936028B2 - Circuit board - Google Patents

Description

The present invention relates to a circuit board that can be used for in-vehicle electrical components and the like.

Various electrical components to be mounted on the vehicle must be arranged in a limited space inside the vehicle. Further, as the types and number of electrical components mounted on the vehicle increase, the space available for arranging each electrical component becomes even narrower. Further, in the case of electrical components of the power system, as the power consumed by the load increases, the size of various electronic components constituting the electrical components such as the power supply and the size of the housing of the device increase. It becomes difficult to install in the space of the specified volume. Therefore, a technique for miniaturizing electrical components and the like is required.

For example, Patent Document 1 shows a technique for reducing the area of an area on a substrate occupied by a chip component when arranging the chip component on the circuit board. That is, when a plurality of chip components intersect on a circuit board, the legs of one chip component are lengthened, the components are arranged three-dimensionally, and the plurality of chip components intersect at substantially the same position on a plane. I am devising.

Japanese Unexamined Patent Publication No. 2-288201

By using the technique of Patent Document 1, the area of the circuit board can be reduced. However, since the plurality of components are arranged three-dimensionally, the height of the entire circuit becomes high in terms of the dimension in the thickness direction of the circuit board. Moreover, since the height of the entire circuit is determined by the dimensions of each component, it occupies the space on the circuit board in a situation where many electronic components of various types having different dimensions are arranged on one circuit board. The height of electronic components varies from region to region.

When such a circuit board is housed in the housing of the device, the size of the housing is the dimension of the region having the highest height in the thickness direction in the circuit board, that is, the component having the highest height. It will be decided together. Therefore, wasteful spaces are formed between the housing and the circuit board in various regions other than the place where the tallest component is arranged on the circuit board. Therefore, the housing cannot be miniaturized, and the mounting density of substantially the components in the entire electrical component is lowered.

For example, when a DC / DC converter is configured on a circuit board, various electronic components having different sizes must be mounted on the circuit board in addition to a relatively large transformer. These electronic components include inductors, capacitors, transistors and the like. Further, a heat sink (radiator) is also required to suppress the temperature rise due to heat generation of electronic components such as transistors. When these components are arranged on one circuit board in a general manner, it is inevitable that a relatively large wasted space is formed between each of the low-height components and the housing. rice field.

The present invention has been made in view of the above circumstances, and an object of the present invention is a circuit capable of reducing wasted space formed in a housing for accommodating electrical components and increasing the mounting density of components. To provide a substrate.

In order to achieve the above-mentioned object, the circuit board according to the present invention is characterized by the following (1) to (4).
(1) The first plane, which includes a first plane and a second plane as an outer shape and has a block-like or similar outer shape, is spaced by a dimension based on the first dimension. The first substrate, which is fixedly arranged so as to face the
The first substrate is arranged substantially perpendicular to the first substrate, is fixedly arranged so as to face the second plane at intervals of a dimension based on the second dimension smaller than the first dimension, and is fixedly arranged so as to face the second plane. The second board to which the board and the electric circuit are connected,
With
Of a plurality of second electronic components that are smaller than the first electronic component and can be mounted on either the first substrate or the second substrate, the thickness direction dimension of the substrate is the second dimension. Only the second electronic component, which is larger and smaller than the first dimension, is selectively mounted on the first substrate, and only the second electronic component whose thickness direction dimension of the substrate is smaller than the second dimension is. selectively placed on the second substrate,
The first electronic component has a rectangular parallelepiped outer shape having a longitudinal direction, and the first plane and the second plane are among the six planes constituting the outer surface of the first electronic component. , Two planes that extend along the longitudinal direction and are orthogonal and adjacent to each other.
Each of the first substrate and the second substrate has a rectangular flat plate shape having a longitudinal direction in the same direction as the longitudinal direction.
Of the six planes constituting the outer surface of the first electronic component, two planes that are both end faces in the longitudinal direction of the first electronic component are exposed.
A circuit board characterized by that.

(2) The first electronic component is a transformer, and the first electronic component and a plurality of the second electronic components constitute a DC / DC converter.
The circuit board according to (1) above.

(3) The DC / DC converter is configured for in-vehicle use and has a function of stepping down the voltage of the in-vehicle battery.
The circuit board according to (2) above.

(4) At least one of the first substrate and the second substrate includes a heat sink for suppressing a temperature rise of the second electronic component.
The circuit board according to (1) above.

According to the circuit board having the configuration of (1) above, the first board and the second board are arranged so as to face the two outer planes of the first electronic component, respectively, and thus are placed on each board. Extra space in the thickness direction can be significantly reduced. Further, the second electronic component having a relatively high height is preferentially placed on only one of the first substrate and the second substrate, and the second electronic component having a low height is placed on the first substrate and the second substrate. Since it can be preferentially placed only on the other side of the two substrates, the height of the first substrate including various electronic components and the height of the second substrate including various electronic components can be made uniform. Therefore, it is possible to suppress the generation of wasted space due to the variation in the height of the parts. Further, since the first substrate and the second substrate are electrically connected to each other, the components of one electric circuit are distributed to the first substrate and the second substrate as needed. Can be placed in the same state. Therefore, even when a relatively large-scale electric circuit is configured, the number of electronic components mounted on each of the two substrates is reduced, and the area of each substrate is equal to that of each plane of the first electronic component. It becomes possible to limit to.

According to the circuit board having the configuration of (2) above, the first substrate and the second substrate are arranged so as to surround the transformer, which is the first electronic component, to form a DC / DC converter. Can be done. That is, since the other electronic components and each substrate are arranged around the transformer having the largest dimension among the various electronic components constituting the DC / DC converter, wasteful space is unlikely to occur.

By mounting a DC / DC converter composed of the circuit board having the above configuration (3) on the vehicle, the voltage of the in-vehicle battery is stepped down and the relatively low power supply voltage required by various electrical components on the vehicle as a power source. Can be generated. Further, since there is little wasted space, it can be housed in a relatively small housing, and it is easy to install it in a limited space on the vehicle.

According to the circuit board having the configuration of (4) above, the heat sink can suppress the temperature rise of the second electronic component, so that the electronic component that generates a large amount of heat can be mounted on the first substrate or the second substrate. Therefore, it becomes easy to configure a DC / DC converter that outputs a relatively large amount of power.

According to the circuit board of the present invention, it is possible to reduce the wasted space formed in the housing for accommodating the electrical components and increase the mounting density of the components. That is, since the first substrate and the second substrate are arranged so as to face the two outer planes of the first electronic component, the extra space in the thickness direction on each substrate is significantly reduced. can. Further, the second electronic component having a relatively high height is preferentially placed on only one of the first substrate and the second substrate, and the second electronic component having a low height is placed on the first substrate and the second substrate. Since it can be preferentially placed only on the other side of the two substrates, the height of the first substrate including various electronic components and the height of the second substrate including various electronic components can be made uniform. Therefore, it is possible to suppress the generation of wasted space due to the variation in the height of the parts. Further, since the first substrate and the second substrate are electrically connected to each other, the components of one electric circuit are distributed to the first substrate and the second substrate as needed. Can be placed in the same state. Therefore, even when a relatively large-scale electric circuit is configured, the number of electronic components mounted on each of the two substrates is reduced, and the area of each substrate is equal to that of each plane of the first electronic component. It becomes possible to limit to.

The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the embodiments described below (hereinafter referred to as "embodiments") with reference to the accompanying drawings. ..

1 (a) is a front view showing the appearance of the DC / DC converter, FIG. 1 (b) is a perspective view showing the appearance of the DC / DC converter, and FIG. 1 (c) is a view before assembling the DC / DC converter. It is a perspective view which shows the unfolded state of a main part. 2 (a) and 2 (b) are front views showing a state in which different substrates and high-frequency transformers face each other. 3 (a) and 3 (b) show an example (1) of a mounting structure of two adjacent substrates, FIG. 3 (a) is a front view, and FIG. 3 (b) is a perspective view. FIG. 4 is a front view showing an example (2) of a mounting structure of two adjacent substrates. FIG. 5 is a front view showing an example (3) of a mounting structure of two adjacent substrates. FIG. 6 is a block diagram showing a configuration example of an electric circuit of a DC / DC converter.

Specific embodiments of the present invention will be described below with reference to the respective figures.

First, the appearance and outline will be described.
Examples of the appearance of the DC / DC converter 10 configured by using the circuit board according to the embodiment of the present invention are shown in FIGS. 1 (a), 1 (b), and 1 (c). 1 (a) is a front view, FIG. 1 (b) is a perspective view, and FIG. 1 (c) is a perspective view showing a state in which the main parts before assembling the DC / DC converter are unfolded.

The DC / DC converter 10 is a predetermined power source required by various electrical components from a direct current (DC) power supply voltage (for example, a voltage of +12 [V]) output from an in-vehicle battery when mounted on a vehicle. It has a function of generating a stable DC voltage (for example, a voltage of + [5V]), and is configured in a shape suitable for in-vehicle use.

As shown in FIG. 1 (c), the DC / DC converter 10 includes a high-frequency transformer 13 and a first substrate 21, a second substrate 22, and a third substrate 23 as main components.

In the present embodiment, various components necessary for forming one DC / DC converter 10 are divided into three blocks. Then, the components of each of these three blocks are arranged in a dispersed state on the first substrate 21, the second substrate 22, and the third substrate 23.

The high-frequency transformer 13 is a component that insulates between the primary side and the secondary side of the circuit of the DC / DC converter 10 and is necessary for transformation, so that the loss with respect to the high-frequency current generated by switching the circuit does not increase. It is configured in. In this embodiment, the high frequency transformer 13 also functions as a step-down circuit.

As shown in FIG. 1 (c), the high-frequency transformer 13 is the component having the largest size among the components constituting the DC / DC converter 10. Further, the high frequency transformer 13 of the present embodiment has a substantially rectangular parallelepiped outer shape. Therefore, there are six flat surfaces on the outer surface of the high frequency transformer 13. Then, in FIGS. 1 (a) and 1 (b), the three planes 13a, 13b, and 13c of the six planes face each other, and the planes facing each other are substantially parallel to each other. As shown, the first substrate 21, the second substrate 22, and the third substrate 23 are arranged, respectively. The dimensions and areas of the first substrate 21, the second substrate 22, and the third substrate 23 are equal to or smaller than the dimensions of the surfaces of the opposing high-frequency transformers 13.

Further, in each of the first substrate 21, the second substrate 22, and the third substrate 23, the circuit component placement side surfaces 21a, 22a, and 23a face each of the planes 13a, 13b, and 13c of the high-frequency transformer 13. Have been placed. The circuits 21a, 22a, and 23a on the circuit component placement side are surfaces on which various electronic components 24 necessary for forming the DC / DC converter 10 are mounted.

Since the dimensions of each electronic component 24 change according to the type and function of each electronic component 24, the maximum dimensions in the thickness direction of each of the first substrate 21, the second substrate 22, and the third substrate 23 are the mounted electrons. It is determined according to the component 24. Further, since various types of electronic components 24 are mounted at various locations, irregularities and vacant spaces in the thickness direction exist on each of the circuit component arranging side surfaces 21a, 22a, and 23a.

Details will be described later, but in the present embodiment, the surfaces 21a, 22a, and 23a on the circuit component arrangement side are configured to have less unevenness and vacant space in the thickness direction. That is, since the planar shapes and areas of the first substrate 21, the second substrate 22, and the third substrate 23 are equivalent to the respective surfaces 13a, 13b, and 13c of the high-frequency transformer 13 facing each other, FIG. 1A is shown. And as shown in FIG. 1 (b), there is almost no wasted space.

That is, since the component mounting density of the DC / DC converter 10 can be increased and the outer shape is as simple as a rectangular parallelepiped, the DC / DC converter 10 can be housed in a relatively small housing.

In the example shown in FIG. 1 (c), the heat sinks 25 and 26 are mounted on the second substrate 22 and the third substrate 23, which are composed of thin circuit boards, respectively. These heat sinks 25 and 26 have a heat dissipation function for suppressing an excessive rise in the temperature of an electronic component 24 that generates heat, such as a transistor. That is, since the heat sinks 25 and 26 are made of metal and have a special surface shape so as to have a sufficiently large surface area, the heat of the electronic component 24 that generates heat can be efficiently released to the outside air.

The plurality of electronic components 24 that generate heat are centrally arranged on the second substrate 22 and the third substrate 23, and in consideration of thermal resistance, the heat sink 25 and the heat sink 25 so as to be in close contact with these electronic components 24. 26 are arranged. The electronic components 24 and the heat sinks 25 and 26 are electrically insulated from each other.

The plane shape and size of the heat sink 25 are adjusted so that the dimensions of each side of the second substrate 22 are equal to or smaller than the plane of the high frequency transformer 13 facing the second substrate 22. The relationship between the heat sink 26 and the third substrate 23 is the same as described above. Further, the heat radiating surfaces of the heat sinks 25 and 26 are arranged on one or both of the same surface as the circuit component arranging side surfaces 22a and 23a and the opposite surface.

Next, the details of the facing state between each substrate and the plane of the high-frequency transformer will be described.
A specific example of the facing state between the first substrate 21 and the high frequency transformer 13 is shown in FIG. 2A, and a specific example of the facing state between the second substrate 22 and the high frequency transformer 13 is shown in FIG. 2B.

As shown in FIG. 2A, a plurality of various types of electronic components 24a are mounted on the circuit component placement side surface 21a of the first substrate 21. The height dimension of each electronic component 24a in the substrate thickness direction (Y) varies, but in the present embodiment, the maximum thickness direction dimension H1max or less and the thickness direction maximum dimension H2max or more shown in FIG. 2B. Only electronic components 24a of size are selectively mounted on the first substrate 21. However, there is a relationship of (H1max> H2max). Further, electronic components that must be mounted on the first substrate 21 are exceptionally mounted on the first substrate 21 even if the height is equal to or less than the maximum dimension H2max in the thickness direction.

Further, as shown in FIG. 2B, a plurality of various types of electronic components 24b are mounted on the circuit component placement side surface 22a of the second substrate 22. The height dimension of each electronic component 24b in the substrate thickness direction (Y) varies, but in the present embodiment, only the electronic component 24a having a dimension equal to or less than the maximum thickness direction H2max is selectively mounted on the second substrate 22. Has been done.

As shown in FIG. 2A, fixing members 27A are fixed at a plurality of locations on the circuit component placement side surface 21a of the first substrate 21. The lower end of each fixing member 27A is fixed to the first substrate 21 by, for example, screwing. Each fixing member 27A has a shape such as a cylinder, and the height in the thickness direction of the substrate is formed to be the same as the maximum dimension H1max in the thickness direction.

As shown in FIG. 2A, the upper end of each fixing member 27A is adhered and fixed to the flat surface 13a with the circuit component placement side surface 21a of the first substrate 21 facing the flat surface 13a of the high frequency transformer 13. Of course, the upper end of the fixing member 27A may be fixed by a method other than adhesion. As a result, the distance between the circuit component placement side surface 21a and the flat surface 13a is maintained at a constant interval corresponding to the maximum dimension H1max in the thickness direction.

As shown in FIG. 2B, fixing members 27B are fixed at a plurality of locations on the circuit component placement side surface 22a of the second substrate 22. The lower end of each fixing member 27B is fixed to the second substrate 22 by, for example, screwing. Each fixing member 27B has a shape such as a cylinder, and the height in the thickness direction of the substrate is formed to be the same as the maximum dimension H2max in the thickness direction.

As shown in FIG. 2B, the upper end of each fixing member 27B is adhered and fixed to the flat surface 13b with the circuit component placement side surface 22a of the second substrate 22 facing the flat surface 13b of the high frequency transformer 13. Of course, the upper end of the fixing member 27B may be fixed by a method other than adhesion. As a result, the distance between the circuit component placement side surface 22a and the plane 13b is maintained at a constant distance corresponding to the maximum dimension H2max in the thickness direction.

In the present embodiment, as shown in FIG. 2A, only the electronic component 24a having a relatively large height dimension in the thickness direction is selectively mounted on the circuit component placement side surface 21a, and is shown in FIG. 2B. As described above, only the electronic component 24b having a relatively small height dimension in the thickness direction is selectively mounted on the circuit component placement side surface 22a. Therefore, the variation in height of each electronic component 24a mounted on the circuit component placement side surface 21a can be made relatively small, and the wasted space formed at this location can be reduced. In the above example, the height of the wasted space can be suppressed to H1max-H2max at the maximum.

Further, the height variation of each electronic component 24b mounted on the circuit component placement side surface 22a can be made relatively small, and the wasted space formed at this location can be reduced. In the above example, the height of the wasted space can be suppressed to H2max at the maximum.

Next, a structure for connecting adjacent substrates will be described.
<Structure example (1)>
An example (1) of a mounting structure of two adjacent substrates 21A and 22A is shown in FIGS. 3 (a) and 3 (b).

For example, as shown in FIGS. 1 (a), 1 (b), and 1 (c), the second substrate 22 is arranged at a position adjacent to one side of the first substrate 21, and the first substrate is arranged. The third substrate 23 is arranged at a position adjacent to the opposite side of the 21. Further, as shown in FIGS. 1A and 1B, it is necessary to arrange the second substrate 22 in a state substantially perpendicular to the first substrate 21 and maintain the connected state. There is. Further, as shown in FIGS. 1A and 1B, it is necessary to arrange the third substrate 23 in a state substantially perpendicular to the first substrate 21 and maintain the connected state. There is. As specific examples for realizing these, the structures shown in FIGS. 3 (a) and 3 (b) can be used.

In the structures shown in FIGS. 3A and 3B, an elongated connecting component 41 is mounted along one side at the end of the circuit component placement side surface 21a of the first substrate 21A. , An elongated connecting component 42 is mounted along one side at the end of the circuit component arranging side surface 22a of the second substrate 22A.

The connection component 41 is formed by arranging a large number of pins 41b arranged at regular intervals on an electrically insulating terminal block 41a formed of resin or the like, and each pin 41b extends in the thickness direction of the first substrate 21A. It forms elongated metal protrusions. The lower end of each pin 41b penetrates the terminal block 41a and the first substrate 21A, and is fixed to the circuit pattern (not shown) of the first substrate 21A by soldering 43.

The connecting component 42 includes a large number of pin accommodating portions 42b arranged side by side at regular intervals in an electrically insulating housing 42a formed of resin or the like, and a large number of pins 42c connected to each of them. The position and shape of each pin accommodating portion 42b of the connecting component 42 are configured to match each pin 41b of the connecting component 41.

Therefore, each pin 41b of the connecting component 41 can be inserted into each pin accommodating portion 42b of the connecting component 42 and integrated in the same manner as a general connector. Further, since each pin accommodating portion 42b has a built-in metal electrode, each pin 41b and each pin accommodating portion 42b are electrically connected in a state where the connecting component 41 and the connecting component 42 are connected. Can be done. Further, each pin accommodating portion 42b is connected to the pin 42c, and the pin 42c is connected to the circuit pattern (not shown) of the second substrate 22A by soldering 44.

Therefore, by adopting the structures shown in FIGS. 3 (a) and 3 (b), both of them are arranged vertically with each other in a state where one end of one substrate and one end of the other substrate are adjacent to each other. , This state can be maintained. Further, it becomes possible to electrically connect the internal circuits of two adjacent boards to each other.

<Configuration example (2)>
An example (2) of a mounting structure of two adjacent boards is shown in FIG.
In the configuration shown in FIG. 4, a large number of pins 45 are mounted in a state of being arranged at regular intervals in the vicinity of one side of the peripheral portion of the first substrate 21B. These pins 45 are fixed to the first substrate 21B by soldering, for example.

In the example shown in FIG. 4, the lower end side of the second board 22B is the circuit component placement side surface 21a in a state where the second board 22B is perpendicular to the circuit component placement side surface 21a of the first board 21B. It is in contact. Further, one surface of the second substrate 22B is arranged in contact with the pins 45 arranged in a row, and each pin 45 and the circuit pattern on the second substrate 22B are connected by soldering 46.

Therefore, even in the configuration shown in FIG. 4, the first substrate 21B and the second substrate 22B adjacent to each other can be maintained in a state of being vertically arranged with each other. Further, the internal circuit of the first substrate 21B and the internal circuit of the second substrate 22B can be electrically connected to each other.

<Structure example (3)>
An example (3) of the mounting structure of two adjacent boards is shown in FIG.
In the configuration shown in FIG. 5, one side of the peripheral portion of the first substrate 21C and one side of the peripheral portion of the second substrate 22C are arranged at positions adjacent to each other in a state of being substantially perpendicular to each other. ing. Then, the first substrate 21C and the second substrate 22C are mechanically connected and fixed by an L-shaped connecting member 48 made of metal or the like.

The vicinity of one end and the vicinity of the other end of the L-shaped connecting member 48 are fixed to the first substrate 21C and the second substrate 22C by screwing, respectively. Soldering may be used instead of screwing. Therefore, the positional relationship between the first substrate 21C and the second substrate 22C can be firmly maintained by the L-shaped connecting member 48.

In the example shown in FIG. 5, a flexible flat cable 47 is provided in order to electrically connect the internal circuit of the first substrate 21C and the internal circuit of the second substrate 22C. The flexible flat cable 47 is an aggregate in which a large number of electric wires are arranged side by side in a row, and is housed inside a flat, electrically insulating resin material that can be easily bent.

The vicinity of one end of the flexible flat cable 47 is connected to the internal circuit of the first substrate 21C for each internal electric wire, and the vicinity of the other end of the flexible flat cable 47 is the inside of the second substrate 22C for each internal electric wire. It is connected to the circuit. Therefore, the internal circuit of the first substrate 21C and the internal circuit of the second substrate 22C can be electrically connected via the flexible flat cable 47.

<Example of electrical circuit configuration>
FIG. 6 shows a configuration example of the electric circuit of the DC / DC converter 10. The DC / DC converter 10 can be changed to various configurations as needed. Further, in the DC / DC converter 10 shown in FIG. 6, for example, the power supply voltage output by the vehicle-mounted battery 30 (for example, a DC voltage of +12 [V]) is changed to the power supply voltage (for example, +5) required by various electrical components on the vehicle. It can be used to convert to a stable DC voltage of [V]).

The DC / DC converter 10 shown in FIG. 6 includes a smoothing circuit 11, a primary side switching circuit 12, a high frequency transformer 13, a control circuit 14, a rectifier circuit 15, and a smoothing circuit 16.

The smoothing circuit 11 is a circuit having a function of smoothing the DC power supply voltage input to the input terminal 10a, and includes, for example, a large-capacity capacitor as a part of the above-mentioned electronic component 24.

The primary side switching circuit 12 is a circuit for switching the current applied from the output of the smoothing circuit 11 to the primary side winding of the high frequency transformer 13 at high speed according to a predetermined control pulse. The primary side switching circuit 12 includes one or more switching devices such as a power transistor and a power MOS FET (field effect transistor) as a part of the above-mentioned electronic component 24.

Further, since the switching device in the primary side switching circuit 12 includes a switching device that generates a large amount of heat, the above-mentioned heat sink 25 or 26 is used as necessary in order to suppress the temperature rise.

The high-frequency transformer 13 contains a primary winding and a secondary winding that are electrically isolated from each other, and includes a circuit connected to the primary winding and a circuit connected to the secondary winding. Can be insulated. Further, by applying AC power to the primary winding, AC power can be induced in the secondary winding. In addition, the loss with respect to the high frequency current is relatively small, and the voltage can be converted according to the turns ratio of the winding. As shown in FIGS. 1 (a), 1 (b), and 1 (c), for example, the high-frequency transformer 13 is the component having the largest dimensions among the components constituting the DC / DC converter 10.

The control circuit 14 is a circuit for generating a control pulse signal for switching the primary side switching circuit 12, and includes, for example, an integrated circuit (IC) device as a part of the above-mentioned electronic component 24. There is. Further, the control circuit 14 performs control for stabilizing the output according to the feedback signal generated by the circuit connected to the secondary side of the high frequency transformer 13.

The rectifier circuit 15 is a circuit for rectifying AC power induced in the secondary winding of the high-frequency transformer 13 and converting it into DC power, and as a part of the above-mentioned electronic component 24, for example, a plurality of diodes or Includes switching device.

The smoothing circuit 16 is a circuit for smoothing the voltage of DC power obtained by the rectification of the rectifier circuit 15, and includes, for example, a large-capacity capacitor or an inductor (coil) as a part of the above-mentioned electronic component 24. ..

<Explanation of arrangement of each part>
For example, each component constituting the circuit of the DC / DC converter 10 as shown in FIG. 6 is generally arranged on a single circuit board, but FIGS. 1 (a) and 1 (b) show. In the DC / DC converter 10 shown in FIG. 1 (c), the DC / DC converter 10 is arranged in a dispersed state on any of the first substrate 21, the second substrate 22, and the third substrate 23, which are separated from each other. ..

As a specific example, each component of the primary side switching circuit 12 is arranged on the second substrate 22, each component of the control circuit 14 is arranged on the third substrate 23, and the smoothing circuit 11 is arranged on the first substrate 21. , The rectifier circuit 15, the smoothing circuit 16, and the like are assumed to be arranged.

Further, for the components that can be arranged on any of the first substrate 21, the second substrate 22, and the third substrate 23, as shown in FIGS. 2 (a) and 2 (b), the thickness direction of each component It is desirable to select the substrate to be arranged according to the dimensions (height) of. For example, a high-height component is placed on a specific substrate (first substrate 21 in FIG. 2A), and a low-height component is placed on another substrate (for example, the second substrate 22 in FIG. 2B). Deploy. As a result, the variation in the height of the components on each substrate is reduced, and the wasted space, that is, the space formed between the upper end of each component and the plane of the high-frequency transformer 13 facing each other is reduced.

Further, by dividing into a plurality of parts, the areas of the first substrate 21, the second substrate 22, and the third substrate 23 can be reduced. As a result, as shown in FIGS. 1 (a) and 1 (b), these can be arranged around the high-frequency transformer 13, and since the sizes of the respective surfaces are the same, extra space is created. Can be avoided.

In the DC / DC converter 10 shown in FIGS. 1 (a), 1 (b), and 1 (c), the first substrate 21, the second substrate 22, and the third substrate 23 are combined. Although the case is assumed, it may be composed of only two substrates such as the first substrate 21 and the second substrate 22. Further, when the high-frequency transformer 13 has a shape like a rectangular parallelepiped or a cube and has six planes, a maximum of six substrates are combined so as to face each of the planes of the high-frequency transformer 13. Can be placed around.

Here, the features of the above-described circuit board embodiments according to the present invention are briefly summarized and listed below in [1] to [5], respectively.
[1] The first plane with respect to the first electronic component (high frequency transformer 13) having a block shape or an outer shape similar to the block shape including the first plane (13a) and the second plane (13b) as the outer shape. A first substrate (first substrate 21) that is fixedly arranged so as to face the
A second substrate (second substrate 22) which is arranged substantially perpendicular to the first substrate, fixedly arranged so as to face the second plane, and to which the first substrate and an electric circuit are connected. )When,
With
The second electronic component, which is smaller than the first electronic component and can be mounted on both the first substrate and the second substrate, has a thickness direction dimension of the substrate higher than a predetermined height. Is placed on one of the first substrate and the second substrate, and when the height is equal to or less than the predetermined height, the substrate is placed on the other of the first substrate and the second substrate (FIG. 2 (a), see FIG. (B)),
A circuit board characterized by that.

[2] The first electronic component is a transformer, and the first electronic component and a plurality of the second electronic components constitute a DC / DC converter (10).
The circuit board according to the above [1].

[3] The DC / DC converter is configured for in-vehicle use and has a function (high-frequency transformer 13) for stepping down the voltage of the in-vehicle battery (30).
The circuit board according to the above [2].

[4] At least one of the first substrate and the second substrate includes heat sinks (25, 26) for suppressing a temperature rise of the second electronic component.
The circuit board according to the above [1].

[5] With respect to the first electronic component (high frequency transformer 13) having a block shape or an outer shape similar to the block shape including the first to third planes (13a, 13b, 13c) as the outer shape, the first plane is formed. The first substrate (first substrate 21), which is fixedly arranged so as to face each other,
A second substrate (second substrate 22) which is arranged substantially perpendicular to the first substrate, fixedly arranged so as to face the second plane, and to which the first substrate and an electric circuit are connected. )When,
The first substrate or the second substrate and the electric circuit are arranged substantially perpendicular to the first substrate or the second substrate, fixedly arranged so as to face the third plane, and the first substrate or the second substrate and the electric circuit are arranged. With the connected third board (third board 23),
With
The second electronic component, which is smaller than the first electronic component and can be mounted on either the second substrate or the third substrate, has a thickness direction dimension of the substrate higher than a predetermined height. Is mounted on one of the second substrate and the third substrate, and is mounted on the other of the second substrate and the third substrate when the height is equal to or less than the predetermined height.
A circuit board characterized by that.

10 DC / DC converter 11 Smoothing circuit 12 Primary side switching circuit 13 High frequency transformer 13a, 13b, 13c Flat surface 14 Control circuit 15 Rectifier circuit 16 Smoothing circuit 21,21A, 21B, 21C First board 21a, 22a, 23a Circuit component placement side Surface 22, 22A, 22B, 22C 2nd board 23 3rd board 24, 24a, 24b Electronic components 25, 26 Heat sink 27A, 27B Fixing member 30 In-vehicle battery 41, 42 Connection component 41a Terminal block 41b, 42c, 45 pin 42a Housing 42b Pin accommodating part 43, 44, 46 Soldering 47 Flexible flat cable 48 L-type connection member H1max, H2max Maximum dimensions in the thickness direction

Claims (4)

The first electronic component having a block shape or an outer shape similar to the block shape including the first plane and the second plane as the outer shape faces the first plane with a dimension based on the first dimension. The first substrate, which is fixedly arranged in the state,
The first substrate is arranged substantially perpendicular to the first substrate, is fixedly arranged so as to face the second plane at intervals of a dimension based on the second dimension smaller than the first dimension, and is fixedly arranged so as to face the second plane. The second board to which the board and the electric circuit are connected,
With
Of a plurality of second electronic components that are smaller than the first electronic component and can be mounted on either the first substrate or the second substrate, the thickness direction dimension of the substrate is the second dimension. Only the second electronic component, which is larger and smaller than the first dimension, is selectively mounted on the first substrate, and only the second electronic component whose thickness direction dimension of the substrate is smaller than the second dimension is. selectively placed on the second substrate,
The first electronic component has a rectangular parallelepiped outer shape having a longitudinal direction, and the first plane and the second plane are among the six planes constituting the outer surface of the first electronic component. , Two planes that extend along the longitudinal direction and are orthogonal and adjacent to each other.
Each of the first substrate and the second substrate has a rectangular flat plate shape having a longitudinal direction in the same direction as the longitudinal direction.
Of the six planes constituting the outer surface of the first electronic component, two planes that are both end faces in the longitudinal direction of the first electronic component are exposed.
A circuit board characterized by that. The first electronic component is a transformer, and the first electronic component and a plurality of the second electronic components constitute a DC / DC converter.
The circuit board according to claim 1. The DC / DC converter is configured for in-vehicle use and has a function of stepping down the voltage of the in-vehicle battery.
The circuit board according to claim 2. At least one of the first substrate and the second substrate includes a heat sink for suppressing a temperature rise of the second electronic component.
The circuit board according to claim 1.

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