JP6934378B2 - Power supply board - Google Patents

Description

The present invention relates to a power supply board. More specifically, the present invention relates to a power supply board mounted on an in-vehicle power conversion device.

In recent years, with the widespread use of hybrid vehicles and electric vehicles, automobiles are equipped with batteries that generate high voltage, such as lithium-ion batteries. On the other hand, automobiles are also equipped with many devices that operate at low voltage, such as electric mirrors and power steering. In addition, home appliances are driven by the battery of the car, and the battery of the car is charged from the AC power source for home use. In order to cope with these problems, automobiles are equipped with power conversion devices such as DC-DC converters and DC-AC inverters.

The power conversion device includes a power supply board to which power is input and output and a control board that controls the operation of the power supply board. The power supply board is equipped with elements (heat-generating elements) such as a transformer and a power transistor that generate heat when a large amount of current flows during operation. The power conversion device has a mechanism for dissipating heat from the heat generating element. For example, a power conversion device includes a heat sink. Further, in order to measure the temperature of the heat generating element, a heat sensor element may be mounted on the power supply board. A study on a power supply board and a power conversion device having the same has been reported in Japanese Patent Application Laid-Open No. 2013-22992.

Japanese Unexamined Patent Publication No. 2013-22992

As the voltage of the battery increases and the voltage increases, a plurality of heat-generating elements are mounted on the power board. The current flowing through these heat-generating elements is also increasing. It is an issue to dissipate heat more effectively from these heat-generating elements and to accurately measure the temperature of these heat-generating elements.

An object of the present invention is to provide a power supply substrate capable of accurately measuring the temperature of a heat generating element while achieving good heat dissipation.

The power supply board according to the present invention includes a circuit board in which a plurality of patterns including the first pattern are formed on the surface, and a plurality of heat generating elements located on the first pattern and electrically connected to the first pattern. , This first pattern is provided with an electrically isolated thermal sensor element. The first pattern includes a notch between adjacent heating elements. The heat sensor element is located in this notch.

The circuit board is provided with an input terminal, a current path from the input terminal to each of the heat-generating elements exists, and the heat-generating elements are arranged in a substantially row, up to these heat-generating elements. The length of the current path is longer in the order in which these heat-generating elements are arranged.
When n is a natural number and the number of the heat-generating elements is 2n, it is preferable that the heat sensor element is located between the n-th heat-generating element and the (n + 1) -th heat-generating element in the row. Is located.

The circuit board is provided with an input terminal, a current path from the input terminal to each of the heat-generating elements exists, and the heat-generating elements are arranged in a substantially row, up to these heat-generating elements. The length of the current path is longer in the order in which these heat-generating elements are arranged.
When n is a natural number and the number of the heat-generating elements is (2n + 1), it is preferable that the n-th heat-generating element in the above column and the (n + 1) -th heat-generating element are located between each other or (n + 1). The heat sensor element is located between the) th heat generating element and the (n + 2) th heat generating element.

Preferably, the heat sensor element is located closer to the heat generating element having the shorter current path among the heat generating elements located on both sides thereof.

When the circuit board is a multilayer board, preferably, a pattern that covers the first pattern and the heat sensor element and is electrically connected to the first pattern is formed in a layer below the surface of the circuit board. There is. More preferably, a pattern that covers the first pattern and the heat sensor element and is electrically connected to the first pattern is formed in all the layers below the surface of the circuit board.

In the power supply board according to the present invention, the plurality of heat generating elements are located on the first pattern formed on the surface of the circuit board and are electrically connected to the first pattern. This first pattern effectively contributes to heat dissipation from the heat generating element. This first pattern has a notch between adjacent heating elements. The heat sensor element is located in this notch. This thermal sensor element can be located near the heat generating element. This heat sensor element can accurately measure the temperature of the heat generating element. With this power supply board, the temperature of the heat-generating element can be measured accurately while achieving good heat dissipation.

FIG. 1 is an exploded perspective view showing a power converter in which a power supply board according to an embodiment of the present invention is used. FIG. 2 is a conceptual diagram showing the electronic substrate of FIG. FIG. 3 is a plan view showing a part of the surface of the power supply board of FIG. FIG. 4 is a plan view showing a state in which the heat generating element is not mounted on the power supply board of FIG. FIG. 5 is a plan view showing a part of the second layer of the power supply board of FIG.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

FIG. 1 is an exploded perspective view showing a power converter 4 in which a power supply board 2 according to an embodiment of the present invention is used. The power converter 4 includes a power supply board 2, a heat sink 6, a bus bar 8, a control board 10, and a lid 12.

The power supply board 2 takes a power source as an input and outputs a power source converted from the power source. The power supply board 2 generates heat when a large amount of current flows. The power supply board 2 is mounted on the inner surface of the heat sink 6. The heat from the power supply board 2 is mainly transferred to the heat sink 6 and dissipated from the heat sink 6. The heat sink 6 is made of a metal having excellent thermal conductivity. The bus bar 8 is located between the heat sink 6 and the power supply board 2. The bus bar 8 realizes wiring that allows a large current to flow. The control board 10 is laminated on the power supply board 2 on the opposite side of the heat sink 6. In the control board 10, elements such as IC chips and capacitors that generate less heat are mounted on a glass epoxy board. A signal for controlling the operation of the power supply board 2 is output from the control board 10. The circuit of the control board 10 and the circuit of the power supply board 2 form a circuit that performs a desired operation. For example, a DC-DC converter is configured. The lid 12 covers the heat sink 6. The lid 12 and the heat sink 6 form a housing for storing the power supply board 2 and the control board 10. The lid 12 is made of a metal having excellent thermal conductivity and conductivity. The lid 12 may be made of an insulating and low thermal conductive material.

FIG. 2 is a conceptual diagram showing the power supply board 2. The power supply board 2 includes a circuit board 14, a heat generating element 16, and a heat sensor element 18. In FIG. 2, the current path through the heating element 16 is also indicated by an arrow.

As shown in FIG. 2, the circuit board 14 includes a base material 20 and a plurality of patterns 22 formed on the surface of the base material 20. In FIG. 2 and FIG. 3-5 described later, the pattern 22 is shaded in order to make the figure easier to see. The pattern 22 is made of a conductive metal. The pattern 22 is typically made of copper. In this figure, among the plurality of patterns 22, the first pattern 22a, the second pattern 22b, and the third pattern 22c are simply shown. Other patterns 22 are omitted. The base material 20 is made of a material having excellent electrical insulation. In this embodiment, the substrate 20 is a glass epoxy. The circuit board 14 in which the base material 20 is made of glass epoxy has excellent mechanical strength and is inexpensive. The base material 20 may be made of a metal-based ceramic such as alumina.

Although not shown, a pattern is also formed on the back surface of the base material 20. Two layers for forming a pattern are also provided between the front surface and the back surface of the base material 20. In this embodiment, the circuit board 14 is a four-layer board. The substrate may be a two-layer substrate. The number of layers of the substrate may be more than 4.

As shown in FIG. 2, the heat generating element 16 is mounted on the surface of the circuit board 14. In the embodiment represented by this conceptual diagram, four heat generating elements 16 are located on the surface of the circuit board 14. These are almost lined up. Here, these are referred to as element T1, element T2, element T3, and element T4 in order from the top of FIG. In this embodiment, these elements T1-T4 are power transistors. Specifically, these elements T1-T4 are power MOSFETs. These are all the same power MOSFETs. The elements T1-T4 may be other transistors such as IGBTs.

As shown in FIG. 2, all the elements T1-T4 are located on the first pattern 22a. All the elements T1-T4 are electrically connected to the first pattern 22a. When the circuit board 14 is viewed from the back side, the elements T1-T4 are covered with the first pattern 22a except for a part thereof such as terminals that are not connected to the first pattern 22a.

FIG. 3 is an enlarged view of the elements T2 and the vicinity of the element T3. In this figure, the actual pattern is shown. As shown in FIG. 3, the first pattern 22a includes a notch 24 between the element T2 and the element T3.

As shown in FIG. 3, the heat sensor element 18 is located on the circuit board 14 at a portion of the notch 24 of the first pattern 22a. That is, the heat sensor element 18 is located between the element T2 and the element T3. The heat sensor element 18 is not located on the first pattern 22a. The thermal sensor element 18 is electrically insulated from the first pattern 22a. The thermal sensor element 18 includes two terminals. One terminal is connected to the second pattern 22b, and the other terminal is connected to the third pattern 22c. The thermal sensor element 18 is connected to another element (not shown) or a terminal of the circuit board 14 via the second pattern 22b and the third pattern 22c. The heat sensor element 18 can measure the temperature around it. As a result, the heat sensor element 18 measures the temperature of the heat generating element 16 located nearby. A thermistor is exemplified as a typical heat sensor element 18.

FIG. 4 shows a state in which the elements T2, T3 and the heat sensor element 18 are not mounted in FIG. FIG. 5 shows a pattern 22 formed on the second layer of the circuit board 14 below the position of FIG. In FIG. 5, the pattern 22 indicated by reference numeral A is a pattern 22 that is electrically connected to the first pattern 22a. As a part thereof is shown in FIGS. 4 and 5, when the circuit board 14 is viewed from the back side, the pattern A covers the first pattern 22a. That is, this pattern A exists below the first pattern 22a. This pattern A does not have a notch 24. This pattern A also covers the heat sensor element 18 when the circuit board 14 is viewed from the back side. That is, this pattern A exists under the heat sensor element 18.

Here, when "Pattern A covers the first pattern 22a", it is not necessary for the pattern A to cover the first pattern 22a 100%. If the pattern A covers most of the first pattern 22a, it is referred to as "the pattern A covers the first pattern 22a". Specifically, the pattern A may cover 60% or more of the area of the first pattern 22a. The meaning of "the pattern A covers the heat sensor element 18" is the same.

Although not shown, in this circuit board 14, a pattern (pattern A) electrically connected to the first pattern 22a is also formed on the third layer and the back surface. When the circuit board 14 is viewed from the back side, all of these patterns A cover the first pattern 22a on the surface. Each of these patterns A covers the heat sensor element 18. In all the layers below the surface, the pattern A exists under the first pattern 22a and the heat sensor element 18.

As shown in FIG. 3-5, a large number of through holes 26 are formed in the circuit board 14. The through holes 26 electrically connect the patterns 22 located in different layers to each other. The first pattern 22a and the pattern A of each layer are electrically connected by the through holes 26. Through-holes 26 promote heat conduction between patterns 22 in different layers. Through holes 26 effectively transfer heat between the first pattern 22a and patterns A in different layers. The through hole 26 contributes to heat dissipation.

As shown in FIG. 2, the circuit board 14 further includes an input terminal 28 having a current path to the heating element 16. For example, when the power converter 4 is a DC-DC converter, it is a terminal for a DC power supply as an input. The heat generating element 16 in which the current path from this terminal exists is, for example, a power MOSFET for a switch. In FIG. 2, the current path from the input terminal 28 is indicated by an arrow. As shown in the figure, there is a current path from the input terminal 28 to the first pattern 22a. The current flows from the first pattern 22a through the elements T1-T4, through the other element, the through hole 26, or the other pattern 22 to the terminal (not shown) on the output side. An element (not shown) may exist between the input terminal 28 and the first pattern 22a, and a current path may be formed between the input terminal 28 and the first pattern 22a via this element. The input terminal 28 and the first pattern 22a may be directly connected without the intervention of an element. That is, the first pattern 22a may extend to the position of the input terminal 28.

The length of the current path from the input terminal 28 to the heat generating element 16 is measured by the distance from the input terminal 28 to the terminal to which the current of the heat generating element 16 is input. This is defined as the length of the shortest path through pattern 22 and other elements on this current path. The current path from the input terminal 28 to the element T1 in FIG. 2 is shorter than the current path from the input terminal 28 to the element T2. The current paths to the element T2, the element T3, and the element T4 become longer in this order.

The effects of the present invention will be described below.

In the power supply board 2 according to the present invention, the plurality of heat generating elements 16 are located on the first pattern 22a formed on the surface of the circuit board 14, and are electrically connected to the first pattern 22a. The area of the first pattern 22a on which the plurality of heat generating elements 16 are mounted is large. The first pattern 22a effectively contributes to heat dissipation from the heat generating element 16. Good heat dissipation is realized in this power supply board 2.

The first pattern 22a includes a notch 24 between adjacent heating elements 16. The heat sensor element 18 is located in the notch 24. As a result, the heat sensor element 18 can be positioned near the heat generating element 16. The heat sensor element 18 can accurately measure the temperature of the heat generating element 16. In this power supply board 2, the temperature of the heat generating element 16 can be measured with high accuracy while achieving good heat dissipation.

As described above, the heat-generating elements 16 are arranged in a substantially row, and the length of the current path to these heat-generating elements 16 increases in the order in which the heat-generating elements 16 are arranged. At this time, the heat sensor element 18 is preferably located near the center of the row of the heat generating elements 16. The temperature of the heat generating element 16 tends to increase as the current path becomes shorter. This is because the position closer to the input terminal 28 has a higher current density. By arranging the heat sensor element 18 near the center of the row of the heat generating elements 16, the temperature close to the average of these plurality of heat generating elements 16 can be measured.

Here, the vicinity of the center of the row of the heat-generating elements 16 is the row excluding the number of heat-generating elements 16 that falls within 25% of the number of rows from both ends of the row, and the remaining heat-generating elements 16 , Refers to the position between adjacent heating elements 16. For example, when the number of heat-generating elements 16 is 5, it represents the position between adjacent heat-generating elements 16 in the three heat-generating elements 16 excluding one heat-generating element 16 from both ends of the row.

In the embodiment of FIG. 2, four heat-generating elements 16 are arranged side by side, and the heat sensor element 18 is located between the second heat-generating element 16 and the third heat-generating element 16. In this way, when the number of heat-generating elements 16 arranged in a row is an even number, that is, when n is a natural number and the number of heat-generating elements 16 is 2n, this row is counted from the one with the shortest current path. It is more preferable that the heat sensor element 18 is located between the n-th heat-generating element 16 and the (n + 1) -th heat-generating element 16. By doing so, it is possible to measure the temperature closer to the average of these plurality of heat generating elements 16.

When the number of heat-generating elements 16 arranged in a row is an odd number, that is, when n is a natural number and the number of heat-generating elements 16 is (2n + 1), the nth position in the row is counted from the one with the shortest current path. The heat sensor element 18 is located between the heat generating element 16 and the (n + 1) th heat generating element 16 or between the (n + 1) th heat generating element 16 and the (n + 2) th heat generating element 16. It is more preferable to do so. By doing so, it is possible to measure the temperature closer to the average of these plurality of heat generating elements 16.

When the number of heat generating elements 16 is (2n + 1), the heat sensor element 18 is located between the nth heat generating element 16 in the row and the (n + 1) th heat generating element 16. It is more preferable to be located between the (n + 1) th heat generating element 16 and the (n + 2) th heat generating element 16. As described above, the heat-generating element 16 having a short current path tends to have a higher temperature than the heat-generating element 16 having a long current path. In this way, by locating the heat sensor element 18 near the heat generating element 16 having a shorter current path, it is possible to prevent the temperature of the heat generating element 16 from being detected low.

As shown in FIG. 3, the distance between the heat sensor element 18 and the element T2 is closer than the distance between the heat sensor element 18 and the element T3. As described above, the heat sensor element 18 is preferably located near the heat generating element 16 having the shorter current path among the heat generating elements 16 located on both sides thereof. By doing so, it is possible to prevent the temperature of the heat generating element 16 from being detected as low.

As described above, the pattern A is formed on the second layer of the circuit board 14. As described above, it is preferable that a pattern that covers the first pattern 22a and the heat sensor element 18 and is electrically connected to the first pattern 22a is formed in a layer below the surface of the circuit board 14. By doing so, the heat of the heat generating element 16 is effectively transferred to this pattern via the first pattern 22a. This pattern contributes to heat dissipation from the heat generating element 16. Even in the circuit board 14 in which the base material 20 is made of glass epoxy, the heat from the heat generating element 16 is effectively released. By covering the heat sensor element 18 together with this pattern, the temperature of the heat generating element 16 can be accurately measured by the heat sensor element 18.

As described above, the pattern A is formed on the second layer, the third layer, and the back surface of the circuit board 14. As described above, it is more preferable that the first pattern 22a and the heat sensor element 18 are covered and electrically connected to the first pattern 22a in all the layers below the surface of the circuit board 14. By doing so, the heat of the heat generating element 16 is effectively transferred to all these patterns via the first pattern 22a. These patterns contribute to heat dissipation from the heat generating element 16. Even in the circuit board 14 in which the base material 20 is made of glass epoxy, the heat from the heat generating element 16 is released more effectively. By covering the heat sensor element 18 together with these patterns, the temperature of the heat generating element 16 can be accurately measured by the heat sensor element 18.

As described above, according to the present invention, it is possible to obtain a power supply board 2 capable of accurately measuring the temperature of the heat generating element 16 while realizing good heat dissipation. From this, the superiority of the present invention is clear.

The power supply board described above is used in various devices including electric power converters for automobiles.

2 ... Power supply board 4 ... Power converter 6 ... Heat sink 8 ... Bus bar 10 ... Control board 12 ... Lid 14 ... Circuit board 16 ... Heat generating element 18 ...・ Thermal sensor element 20, ・ ・ ・ base material 22 ・ ・ ・ pattern 22a ・ ・ ・ first pattern 22b ・ ・ ・ second pattern 22c ・ ・ ・ third pattern 24 ・ ・ ・ notch 26 ・ ・ ・ through hole

Claims (4)

A circuit board in which a plurality of patterns including the first pattern are formed on the surface, a plurality of heat-generating elements located on the first pattern and electrically connected to the first pattern, and the first pattern and electrical Equipped with an insulated thermal sensor element
The first pattern has a notch between adjacent heating elements.
The heat sensor element is located in this notch.
The above circuit board has an input terminal,
There is a current path from the input terminal to each of the heat generating elements.
The heat-generating elements are arranged in a row, and the length of the current path to these heat-generating elements is longer in the order in which the heat-generating elements are arranged.
With n as a natural number, the number of heat-generating elements is 2n.
The thermal sensor element is located between the n-th heat-generating element in the row and the (n + 1) -th heat-generating element.
A power supply board in which the heat sensor element is located near the heat generating element having the shorter current path among the heat generating elements located on both sides thereof. A circuit board in which a plurality of patterns including the first pattern are formed on the surface, a plurality of heat-generating elements located on the first pattern and electrically connected to the first pattern, and the first pattern and electrical Equipped with an insulated thermal sensor element
The first pattern has a notch between adjacent heating elements.
The heat sensor element is located in this notch.
The above circuit board has an input terminal,
There is a current path from the input terminal to each of the heat generating elements.
The heat-generating elements are arranged in a row, and the length of the current path to these heat-generating elements is longer in the order in which the heat-generating elements are arranged.
With n as a natural number, the number of heat-generating elements is (2n + 1).
Between the n-th heat-generating element and the (n + 1) -th heat-generating element in the above row, or between the (n + 1) -th heat-generating element and the (n + 2) -th heat-generating element, the above. The heat sensor element is located
The heat sensor element, of the heat generating element positioned on opposite sides, located close to the heating element towards the current path is short, the power supply board. A circuit board in which a plurality of patterns including the first pattern are formed on the surface, a plurality of heat-generating elements located on the first pattern and electrically connected to the first pattern, and the first pattern and electrical Equipped with an insulated thermal sensor element
The first pattern has a notch between adjacent heating elements.
The heat sensor element is located in this notch.
The circuit board is a multilayer board,
The lower layer from the surface of the circuit board, covering the first pattern and the heat sensor element, a pattern of connecting the first pattern and electrically are formed, the power supply board. The power supply board according to claim 3 , wherein a pattern that covers the first pattern and the heat sensor element and is electrically connected to the first pattern is formed on all layers below the surface of the circuit board.

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