DE102022000926A1 - Electronic circuit and process for its production, as well as improved active power semiconductor for installation in the electronic circuit and process for its production - Google Patents

Abstract

The invention is based on an electronic circuit with a first circuit board (8) and at least one second circuit board (9) arranged in parallel with at least one active power semiconductor (1) with one or more control connections (3, 4) and with several power connections (2, 5), with a control circuit for controlling the at least one active power semiconductor (1) and a power circuit, the control connection or connections (3, 4) being connected to the control circuit and the power connections (2, 5) being connected to the power circuit. According to the invention, the power circuit is arranged on the first circuit board (8) and the control circuit on the second circuit board (9), the power connections (2, 5) of the at least one active power semiconductor (1) being connected to the power circuit on the first circuit board (8) and the control connection or connections (3, 4) are soldered to the control circuit on the second circuit board (9).

Description

The invention relates to an electronic circuit and a method for producing it according to the preamble of claim 1 or claim 8, as well as an improved active power semiconductor for installation in the electronic circuit and a method for producing it according to the preamble of claim 5 or claim 6 .

New types of transistor modules are available on the market, which primarily contain SiCFETs in different topologies (e.g. as half or full bridge circuits). The transistor modules are intended for direct PCB assembly and have contact pins. They have high performance in relation to their size with a current carrying capacity of around 200 A per transistor functional element. The module must be mounted with the underside directly on a heat sink to dissipate the power loss. A circuit board is placed on the top, which simultaneously handles the wiring of the power circuit and the control circuit. The transistor modules are designed with their contact pins for press-fit or soldered connections to the circuit board. The power range of these new modules enables applications up to the 100 kW range, at least in terms of the semiconductor specifications.

Due to ever higher switching frequencies made possible by modern semiconductors, ever more comprehensive measures must be taken to isolate the control circuits so that they remain largely unaffected by the power switched at high frequency. This can be achieved to a certain extent through optimized conductor tracks on the printed circuit boards used using multi-layer technology. Additional isolation measures are also possible. However, the measures mentioned require a lot of space. The maximum performance listed above can hardly be increased through these measures.

Instead of using the transistor modules described above, such circuits for high performance can also be implemented using discrete power semiconductors. Corresponding active power semiconductors in a housing for THD soldering technology (Through Hole Technology) are now available on the market. These components even have a Kelvin connection for control. An additional ground connection is therefore led out of the semiconductor component as an additional pin (Kelvin connection) as a reference potential for the gate connection. This eliminates ground loops between the control and power circuits. The component no longer has three but four connection pins. This allows the control circuit to be easily separated from the power circuit, although there is still a galvanic connection between the two. Since several discrete power semiconductors have to be used to achieve the same performance class as the transistor modules described above, a relatively large-area structure is necessary here. A lot of space is also required in order to be able to shield the control circuit from the power circuit. This large-scale structure is not only a space problem, but also creates significant parasitic effects.

It was therefore the object of the invention to create an electronic circuit, a method for producing it, an improved active power semiconductor for installation in the electronic circuit and a method for producing it. The new electronic circuit should have the highest possible efficiency and low parasitic capacitances while also requiring little space. Nevertheless, the electronic circuit should also be usable at high frequencies and for high power.

The object is achieved according to the invention by an electronic circuit and a method for producing it according to claim 1 or claim 8, as well as an improved active power semiconductor for installation in the electronic circuit and a method for producing it according to claim 5 or claim 6. Further details and advantages of the invention result from the subclaims.

Because the power circuit is arranged on the first circuit board and the control circuit on the second circuit board and in that the power connections of the at least one active power semiconductor are soldered to the power circuit on the first circuit board and the control connection(s) are soldered to the control circuit on the second circuit board, An excellent spatial separation of the control circuit and power circuit is possible with a very small size of the electronic circuit. The control circuit includes the actual control for switching the at least one active power semiconductor, as well as the driver or drivers for it. The entire control circuit operated at low voltage is therefore arranged on a separate circuit board and is therefore not disturbed by a power circuit operated at high switching frequency. Additional shielding measures are usually not necessary because the power circuit is on a separate circuit board. Nevertheless, the control circuit and the power circuit are connected via the connections of the at least one active power semiconductor over very short current-carrying distances tied together. The structure of the electronic circuit according to the invention ensures high efficiency and has only low parasitic capacitances. By arranging the control circuit on its own circuit board, the influence of high-frequency vibrations on the control circuit can be avoided. Possible feedback on the control circuit is also minimized. The shortest possible connections within the gate control circuit greatly reduce parasitic effects. The electronic circuit is therefore ideal for high-frequency switching of high electrical power.

Electronic circuits according to the state of the art mostly use multilayer printed circuit boards. In order to be able to switch high outputs, very wide conductor tracks must be provided. Under certain circumstances, additional copper structures may even be necessary in order to be able to provide the necessary cable cross-sections. Since in the electronic circuit according to the invention the power circuit is arranged on a different circuit board than the control circuit, the first circuit board on which the power circuit is arranged can be designed as a metal core circuit board. Creating the necessary current-carrying capacity is easily possible in this way, since a higher current density within the conductor tracks can be utilized due to better heat dissipation.

Despite the high efficiency of the electronic circuit according to the invention, a not inconsiderable amount of heat is generated by the flow and switching losses of the at least one active power semiconductor. In order to be able to dissipate this well, the first circuit board is soldered to a heat sink on the side opposite the at least one active power semiconductor. The heat sink can be either a heat sink in which the heat is dissipated via a coolant inside the heat sink, for example a cooling fluid guided through the heat sink, or a heat sink that is cooled from the outside, for example with air.

When equipping the first circuit board with several active power semiconductors and a corresponding arrangement of the components on the first circuit board, it might be possible to connect the second circuit board with the control circuit only via the control connections of the active power semiconductors, which are bent upwards and soldered in the receiving holes, to the first Connect circuit board. However, spacers are advantageously provided between the first circuit board and the second circuit board. This not only has advantages during manufacturing, but can also prevent vibrations from being transmitted from the power circuit to the control circuit during operation.

An improved active power semiconductor is required to construct the electronic circuit according to the invention. In this improved active power semiconductor, several power connections are aligned in one direction and the control connection or connections are aligned in the opposite direction. This allows an active power semiconductor to be soldered directly to two circuit boards. This also makes it possible to separate the power circuit and control circuit on two independent circuit boards without having to accept long current paths.

Active power semiconductors in an SMD (Surface Mounted Device) housing are a mass-produced product that comes onto the market in such a way that all connections can be soldered to a circuit board using an SMD process. In order to be able to implement the electronic circuit according to the invention, improved active power semiconductors must therefore be manufactured from commercially available active power semiconductors. According to the invention, an active power semiconductor with an SMD housing, which is intended for soldering to a circuit board and has one or more control connections aligned in the direction of the circuit board to be soldered and a plurality of power connections also aligned in the direction of the circuit board to be soldered, is fed to a bending device and the or the control terminals aligned in the direction of the circuit board to be soldered are bent in the opposite direction.

In order to achieve this special alignment of the connections, the control connection(s) can be bent in the desired direction as described above. However, it is also possible to shorten the control connection or connections to a short piece that is led straight out of the housing and to weld a piece of conductive material in the desired length and direction to the shortened control connection or connections.

The connections of an active power semiconductor are very thin and are mainly held in position by the housing. In order to prevent the housing from being damaged during the bending process (e.g. getting hairline cracks) or even breaking and thus being destroyed, the control connections to be bent are clamped close to the housing.

To produce the electronic circuit according to the invention, at least one improved active power semiconductor, as described above is described, manufactured in the same way as described above. Furthermore, a first circuit board is equipped with electronic components for the power circuit, spacers for a second circuit board and at least one improved active power semiconductor. A second printed circuit board is provided with one or more receiving holes for the control connection(s) of the at least one improved active power semiconductor and is equipped with electronic components for the control circuit. Then the second circuit board is placed on the first circuit board. In the next step, both circuit boards are soldered together in one operation. The step for producing the at least one improved active semiconductor is advantageously carried out first. The two circuit boards can then be assembled in parallel. Of course, it is also possible to process all steps serially.

If the assembly of the circuit boards is to be carried out in an assembly machine, it makes sense to place the two circuit boards in a common holder so that the assembly machine does not have to be converted to different widths of the circuit boards. Both circuit boards can be populated on the holder in one go.

The receiving holes in the second circuit board are filled with solder paste, for example, before the soldering process, so that a good electrical transition can be generated between the at least one control connection of the at least one improved active semiconductor and the control circuit during the soldering process. However, it must be avoided that the solder paste - when heated during the soldering process - runs down out of the mounting holes. It must also be prevented that a short circuit occurs between the control connections due to solder running down the control connections. The control terminal(s) of the at least one improved active power semiconductor to be soldered to the second circuit board are therefore provided with a safeguard against the leakage of solder from the receiving holes of the second circuit board during the soldering process. This can advantageously be done by introducing a high-temperature-resistant adhesive between the control connections or by attaching silicone washers to the free ends of the control connections.

The first circuit board is advantageously provided with a heat sink. The time at which the first circuit board and heat sink are brought together basically depends on the manufacturing process.

The electronic circuit according to the invention can advantageously be manufactured completely in an appropriately equipped placement machine. However, it is also possible to use handling robots for individual or all production steps. The second circuit board can also be placed on the first circuit board either with a handling robot or with the assembly machine. When using one or more handling robots to assemble the circuit boards, the heat sink can be coupled to the first circuit board before assembly.

With certain assembly machines, the height for continuous circuit boards is limited. With a higher heat sink, this can mean that the throughput height of the assembly machine is no longer sufficient for a circuit board that is already coupled to the heat sink. In this case, it makes sense to add the heat sink only after it has been fitted. For example, the two assembled circuit boards can be brought together very precisely in the machine. The two circuit boards can then be inserted into another holder in which the heat sink is already located, so that the circuit boards are brought together with the heat sink only behind the assembly machine.

Further details and advantages of the invention result from the description of an exemplary embodiment, which is explained in detail with reference to the drawing.

• 1 ein erfindungsgemäßer verbesserter aktiver Leistungshalbleiter in Seitenansicht,
• 2 das Bauteil aus 1 in Vorderansicht,
• 3 die nach oben gebogenen elektrischen Anschlüsse des Bauteils aus den 1 und 2,
• 4 eine schematische Seitenansicht der erfindungsgemäßen elektronischen Schaltung,
• 5 eine schematische Darstellung des Biegevorgangs in einer Biegevorrichtung nach einem ersten Ausführungsbeispiel,
• 6 ein Teil der Biegevorrichtung nach 5,
• 7 ein Teil einer Biegevorrichtung nach einem zweiten Ausführungsbeispiel,
• 8 ein Ablaufdiagramm zur Herstellung der erfindungsgemäßen elektronischen Schaltung und
• 9 Schaltbild für ein in der Schaltung nach 4 verwendetes SiC-MOSFET-Bauteil.

It shows:

• 1 an improved active power semiconductor according to the invention in side view,
• 2 the component 1 in front view,
• 3 the upwardly curved electrical connections of the component from the 1 and 2 ,
• 4 a schematic side view of the electronic circuit according to the invention,
• 5 a schematic representation of the bending process in a bending device according to a first exemplary embodiment,
• 6 part of the bending device 5 ,
• 7 a part of a bending device according to a second exemplary embodiment,
• 8th a flow chart for producing the electronic circuit according to the invention and
• 9 Circuit diagram for one in the circuit 4 SiC MOSFET component used.

In the 1 and 2 A SiC MOSFET is shown as an example in an SMD housing with 7 connection pins and the drain connection 2 as an active power semiconductor 1. Pin 3 is designed as a gate connection, pin 4 as a driver source connection and the 5 pins 5 are designed as power source connections (see also the circuit diagram). 9 ). Both the gate terminal 3 and the driver-source terminal 4, both of which are to be connected to the low-power control and driver circuit, are bent upwards.

A SiC MOSFET is only mentioned here as an example. However, it should be emphasized that the invention of course also applies to other active power semiconductors in an SMD housing with connection pins protruding from the housing. Even active power semiconductors in a different package such as GaNFETs can be used. In such components, where all connections are usually designed as soldering surfaces facing downwards, changes must be made so that the connections for the control and driver circuit are led out upwards and thus have a short path to an upper circuit board (see 4 ) can be connected.

A snippet from 2 , which enlarges only shows the two upwardly curved pins 3 and 4, is in 3 shown. An elastic adhesive 6 is inserted between the two pins 3 and 4. This adhesive 6 is intended to prevent the liquefied solder from running between the pins 3 and 4 during the soldering process from the receiving holes 10 of an upper circuit board 9 with the control and driver circuit attached above the active power semiconductor 1 or above the power semiconductors 1 and in this way Short circuit is generated or a proper soldering point is then missing in the receiving holes 10. The adhesive 6 can be applied with a handling robot directly after the bending process.

In 3 Another possibility is indicated, which is also intended to prevent liquid solder from flowing out of the receiving holes 10 of the upper circuit board 9: for this purpose, a silicone disk 7 can also be placed on each of the upwardly bent pins 3 and 4 using a handling robot. Any openings in the silicone washers 7 must be so narrow that the silicone washers 7 enclose the pins tightly and are held securely there. They may only be moved minimally downwards through the circuit board 9 when the upper circuit board 9 is put on, so that the lower openings of the receiving holes 10 are securely closed.

In 4 An electronic circuit is now shown in which four active power semiconductors 1 are connected in parallel. Directly behind the visible power semiconductors 1, another four power semiconductors can be arranged, which are also connected in parallel. These two legs can then be connected in series. With this arrangement, powers above 50 kW can be easily switched. It is ideal for use in high-power voltage converters. For example, if three such legs are connected together, a frequency converter circuit can be implemented to control the speed of electric motors up to 200 kW.

The lower circuit board 8 is mounted on a heat sink 11 (heat sink) which has a coolant inflow 12 and a coolant outflow 13. Depending on the geometry of the circuit structure, the coolant channels 12 and 13 can be perpendicular to the in 4 direction shown. In any case, the heat sink 11 is designed so that the best possible cooling of the active power semiconductors 1 is guaranteed.

In the exemplary embodiment shown, 4 active power semiconductors are connected in parallel on the lower circuit board 8 and soldered there to their power source connections 5 and the drain connections 2. The upwardly bent pins 3 and 4 (the gate connection and the driver source connection) are soldered into the receiving holes 10 of the upper circuit board 9. In order to stabilize the upper circuit board 9, it is connected to the lower circuit board 8 via the spacers 11. Only the power electronics are installed on the lower circuit board 8, while only the control and driver circuit is installed on the upper circuit board 9. So only the lower circuit board 8 needs to be actively cooled.

Based on 5 until 7 The bending process for the driver source 3 and the gate connection 4 will now be explained. In principle, the lower circuit board 8 and the upper circuit board 9 can be assembled with a handling robot or with an automatic assembly machine. When using an automatic placement machine, the bending device is advantageously integrated into the placement machine.

Pins 3 and 4 (driver source connection and gate connection) are advantageously bent upwards immediately after the active power semiconductors 1 have been removed from the packaging or from a magazine. In order to avoid damage, it must be prevented that mechanical stresses are introduced into the housing of the active power semiconductor 1 during the bending process will carry. For this purpose, an upper clamping stamp 15 and a lower clamping stamp 16 are provided. With these two clamping stamps 15 and 16, which are moved to pins 3 and 4 from above and below, respectively, the two pins are clamped and thus fixed in their position.

In a first exemplary embodiment, the upper clamping stamp 15 is rectangular in cross section. One edge (seen in the drawing below on the right) is provided with a bending radius (not shown) to prevent the two pins 3 and 4 from tearing during bending and thereby possibly becoming unstable or even breaking off. The clamping position with the clamping stamps 15 and 16 moved to pins 3 and 4 is in 5a shown. The bending punch, which also has a rectangular cross section in this exemplary embodiment, is located in its rest position below pins 3 and 4.

To carry out the bend now - as in 5b shown - the bending punch 17 moves upwards. The pins 3 and 4 are bent over the edge with the bending radius of the upper clamping stamp 15 and pressed against the straight front surface of the upper clamping stamp 15, which is located behind the right vertical edge of the upper clamping stamp 15 in the drawing. The bending punch 17 only acts on pins 3 and 4, while the remaining pins 5 (power source connections) are not affected by the bending process and remain in their original position.

5C shows a position corresponding to that in 5A position shown, in which the bending punch 17 is already in its rest position below the original position of the pins. As opposed to 5A However, pins 3 and 4 are already in their upwardly bent position.

In order to be able to insert the two pins 3 and 4 into the two mounting holes 10 when placing the upper circuit board 9 and solder them there, the distance between the two upwardly bent pins 3 and 4 is too small. The two pins must therefore be bent apart in a V shape. This process is in the 5d until 5f shown. For this purpose, the shaping die 18 is provided with the shaping stamp 19. These components are in 6 explained in more detail.

The forming die 18 has a V-shaped die recess 20. The shape of the shaping stamp 19 is adapted to the die recess 20. Its thickness corresponds to the depth of the die recess 20. On its underside, the forming punch 19 is shaped approximately to a point, so that it is ensured that it can penetrate between the two free ends of the parallel, upwardly bent pins 3 and 4.

5d now shows a position of the bending device in which the shaping die 18 has moved up to the upper clamping punch 15 together with the shaping punch 19 that can be moved therein. The upwardly bent pins 3 and 4 are now located within the die recess 20 and are therefore in 5d not visible.

As shown in Fig. 5e, the forming stamp 19 is now moved downwards into the in 6b move to the position shown. The lower tip of the shaping punch 19 forces itself between the free ends of the two pins 3 and 4 and presses them outwards onto the side walls of the die recess 20. The shaping die 19 is now moved upwards again and the shaping die 18 is brought back into its rest position ( please refer 5a , 5b , 5c , 5f) , the pins 3 and 4 are bent upwards and run in such a way that the distance between the two pins is greatest at the level of their free ends and is sufficient to be able to place the upper circuit board 9 and insert the pins into the two receiving holes 10. The two receiving holes 10 are spaced apart from one another to such an extent that problem-free soldering without bridging between the receiving holes 10 is possible.

In 5f The rest position of the bending device is now shown, in which the upper 15 and the lower clamping stamp 16 have moved apart again, the finished bent power semiconductor 1 can be removed and the bending device can be equipped with a new power semiconductor.

Below, another option will be described as an example through which pins 3 and 4 can be bent into the required position. In the 5 The shaping die 18 shown with the shaping stamp 19 is not required. Instead, a modified upper clamping punch 15a and a modified bending punch 17a must be used.

The corresponding components are in 7 shown, where 7a a front view of the upper clamping stamp 15a and 7b shows a top view of the upper clamping punch 15a and the bending punch 17a. It can be seen that the upper clamping stamp 15a has a V-shaped straight surface 21 in the middle on its front side. Outside this straight surface 21 there are two angled surfaces 22 which have a small angle of less than 10 ⁰ with respect to the straight surface 21. A bending radius is again formed on the lower edge of these angled surfaces 22, which is also at the angle mentioned runs to the lower edge of the straight surface 21. The straight surface 21 merges into the respective angled surface 22 via a connecting slope 23.

The corresponding side of the bending punch 17a is roof-shaped. The roof slope is adapted to the angled surfaces 22 of the upper clamping stamp 15a.

If the bending punch 17a is now as in 5b As shown move upwards, the pins 3 and 4 are not bent over a straight edge as in the first described exemplary embodiment, but over an angled edge. The pins 3 and 4 are already in the V-shaped position, in which the free ends are at a greater distance from one another than the ends fixed in the housing. The connecting bevels 23 of the upper clamping stamp 15a serve for guidance so that a precisely defined position can be achieved.

• im ersten Verfahrensstrang mit den Verfahrensschritten 25 bis 27 wird die untere Leiterplatte 8 mit dem Leistungskreis vorbereitet,
• im zweiten Verfahrensstrang mit den Verfahrensschritten 28 bis 30 werden die aktiven Leistungshalbleiter 1 zur Bestückung der unteren Leiterplatte 8 vorbereitet und
• im dritten Verfahrensstrang mit den Verfahrensschritten 32 bis 34 wird die obere Leiterplatte 9 mit der Steuer- und Treiberschaltung vorbereitet.

The method according to the invention is now described below using: 8th described. The procedure is divided into 3 procedural strands:

• In the first process strand with process steps 25 to 27, the lower circuit board 8 is prepared with the power circuit,
• In the second process strand with process steps 28 to 30, the active power semiconductors 1 are prepared for equipping the lower circuit board 8 and
• In the third process strand with process steps 32 to 34, the upper circuit board 9 is prepared with the control and driver circuit.

In the first process step 25 of the first process strand, a metal core circuit board is prepared for equipping electronic components on its top side and for mounting a heat sink on its underside. The circuit board 8 is advantageously prepared for assembly with SMD components. The soldering paste is then applied accordingly. Since these are known procedures, these sub-steps do not need to be described in detail. The underside of the circuit board 8 is advantageously treated only with flux.

In method step 26, the heat sink 12 is now placed on the underside of the metal core printed circuit board prepared in this way. With a larger heat sink, dowel pins or guide grooves can also be provided, which hold the heat sink in position until the soldering process. In order to ensure a secure connection with good temperature transfer between the lower metal core circuit board 8 and the heat sink 12, the heat sink 12 can also be treated with flux and a suitable solder foil can be applied to the heat sink.

If the PCBs are to be assembled in an assembly machine, it makes sense to bring the heat sink 12 together with the lower circuit board 8 only after the two circuit boards have been assembled and stacked on top of each other, since the height of the assembly machine may not be sufficient to accommodate the lower circuit board together with it Heat sink is sufficient.

In the next method step 27, the spacers 11 are then attached, via which the connection to the upper circuit board 9 is later established. The spacers 11 are advantageously also connected to the lower circuit board 8 via soldering paste and then soldered to the lower circuit board 8 in the later soldering process.

In the parallel second process strand, the active power semiconductors 1 are prepared so that they can later be incorporated into the assembly of the lower circuit board 8. For this purpose, the power semiconductors 1 are removed in method step 28 either directly from the packaging or from a magazine and inserted into a bending device.

In method step 29, the gate connection 3 and the driver source connection 4 are bent upwards as already described above in the text.

In method step 30, the space between the two upwardly bent pins 3 and 4 is then filled either with an elastic adhesive or with covering material 6 or silicone washers 7 are placed on the free ends of the upwardly bent pins 3 and 4. When applying the glue, make sure that the free ends of the upwardly bent pins 3 and 4 that are yet to be soldered remain free of glue. The improved active power semiconductors 1 prepared in this way are temporarily stored in a memory until the lower circuit board 8 is assembled.

The process steps 28 to 30 of the second process strand are repeated until there are as many prepared power semiconductors 1 in the buffer as they are needed to equip the lower circuit board 8.

In the third process strand, in process step 32, the upper circuit board 9 is with the on Reception holes 10 for the upwardly curved pins 3 and 4 of the prepared power semiconductor 1 are provided. The upper circuit board 9 is also a circuit board that is equipped with SMD components.

In method step 33, the soldering paste is now also applied to the upper circuit board 9. The receiving holes 10 for the upwardly curved pins 3 and 4 of the improved active power semiconductor 1 must also be filled with solder paste (according to a known THR process). Likewise, the places on the underside of the upper circuit board 9, where the spacers 11 will later be placed, are provided with solder paste. Alternatively, the spacers 11 can also be coated on their top with solder paste.

After these preparations, both circuit boards 8 and 9 can be populated. The assembly can take place in an assembly machine or with a handling robot. In the first case, the bending device can be integrated directly into the placement machine. When using a handling robot, it makes sense to place both the lower 8 and the upper circuit board 9 on a holding device in the working area of the handling robot. The assembly can then be carried out one after the other or in parallel by at least two handling robots. When using an assembly machine, the circuit boards 8 and 9 are also inserted into a common holder and fed together to the assembly machine on this holder.

In method step 31, the electronic components for the power circuit are placed on the lower circuit board 8. This also includes the already prepared active power semiconductors 1 stored in the buffer. It also includes a connection terminal, which must be accessible even after the upper circuit board 9 has been put on, so that the necessary lines can also be connected after the soldering process.

In method step 34, the upper circuit board 9 is populated by putting on all the components necessary for the control and driver circuit. When using an automatic placement machine, method steps 31 and 34 are advantageously carried out in parallel in the placement machine.

After both circuit boards 8 and 9 have been fitted with the electronic components, both circuit boards 8 and 9 are connected to one another in method step 35. For this purpose, an exact positioning of the upper circuit board 9 over the lower circuit board 8 is necessary. After positioning, either the upper circuit board 9 is lowered or the lower circuit board 8 is raised. The upwardly bent pins 3 and 4 of the power semiconductors 1 penetrate into the receiving holes 10 in the upper circuit board 9 filled with solder paste. The circuit boards 8 and 9 are brought together until the upper circuit board 9 rests on the spacers 11. It can be attached using screws or glued with a high-temperature-resistant adhesive.

However, the upper circuit board 9 is also advantageously soldered to the spacers 11. When using an automatic placement machine, this process step is advantageously also carried out in the placement machine.

The adhesive 6 between the upwardly bent pins 3 and 4 of the power semiconductor 1 or the silicone washers 7 attached to the free ends now close the receiving holes 10 in the upper circuit board 9 downwards. In this way, no solder can run out of the receiving holes 10 during the soldering process.

The soldering process can now be carried out in method step 36. During this soldering process, both the components of the upper circuit board 9 and the components of the lower circuit board 8 and the heat sink 12 are soldered at the same time. This ensures that the thermal load on the electronic components is as low as possible.

List of reference symbols:

1

active power semiconductor

2

Drain connection

3

Gate connector

4

Driver source connection

5

Power source connections

6

Glue

7

Silicone discs

8th

lower circuit board

9

upper circuit board

10

Location holes

11

Spacers

12

Heat sink

13

Coolant inflow

14

Coolant drain

15

upper clamping stamp

16

lower clamping stamp

17

Bending punch

18

forming die

19

forming stamp

20

Die recess

21

straight surface

22

angled surface

23

Connection slope

24

Lower edge of the angled surface with bending radius

25

Preparing the metal core circuit board

26

Attaching the heat sink

27

Attaching the spacers

28

Inserting the power semiconductors into the bending device

29

Bending process

30

Installing protection against solder leakage

31

Assembling the metal core circuit board

32

Making the mounting holes in the upper circuit board

33

Preparing the top circuit board

34

Populating the upper circuit board

35

Merge the two circuit boards

36

Soldering the electronic circuit

Claims (10)

Electronic circuit with a first circuit board (8) and at least one second circuit board (9) arranged in parallel with at least one active power semiconductor (1) with one or more control connections (3, 4) and with several power connections (2, 5), with a control circuit for controlling the at least one active power semiconductor (1) and a power circuit, the control connection or connections (3, 4) being connected to the control circuit and the power connections (2, 5) being connected to the power circuit, characterized in that the power circuit is on the first Circuit board (8) and the control circuit are arranged on the second circuit board (9) and that the power connections (2, 5) of the at least one active power semiconductor (1) are connected to the power circuit on the first circuit board (8) and the control connection(s) (3 , 4) are soldered to the control circuit on the second circuit board (9). Electronic circuit according to Claim 1 , characterized in that the first circuit board is designed as a metal core circuit board. Electronic circuit according to one of the Claims 1 until 2 , characterized in that the first circuit board (8) is soldered to a heat sink (12) on the side opposite the at least one active power semiconductor (1). Electronic circuit according to one of the Claims 1 until 3 , characterized in that spacers (11) are provided between the first circuit board (8) and the second circuit board (9). Improved active power semiconductor (1) with one or more control connections (3, 4) and several power connections (2, 5) for installation in an electronic circuit according to one of Claims 1 until 4 , characterized in that a plurality of power connections (5) are aligned in one direction and the control connection or connections (3, 4) are aligned in the opposite direction. Method for producing an improved active power semiconductor Claim 5 , characterized in that an active power semiconductor (1) with an SMD housing which is intended for soldering to a circuit board and one or more control connections (3, 4) aligned in the direction of the circuit board to be soldered and several also in the direction of the circuit board to be soldered Circuit board-aligned power connections (5), is fed to a bending device and the one or more control connections (3, 4) aligned in the direction of the circuit board to be soldered are bent in the opposite direction (29). Procedure according to Claim 6 , characterized in that during the bending process (29) the control connections (3, 4) to be bent are clamped close to the housing (15, 16). Method for producing an electronic circuit according to one of Claims 1 until 4 , characterized in that at least one improved active power semiconductor Claim 5 in proceedings according to one of the Claims 6 until 7 is produced (29), a first circuit board (8) is equipped (26, 27, 31) with electronic components for the power circuit, spacers (11) for a second circuit board (9) and at least one improved active power semiconductor (1), that a second circuit board (9) is provided with one or more receiving holes (11) for the control connection or connections (3 4) of the at least one improved active power semiconductor (1). (32) and is equipped with electronic components for the control circuit (34), that the second circuit board (9) is placed on the first circuit board (8) (35) and that both circuit boards (8, 9) are soldered together in one operation (36). Procedure according to Claim 8 , characterized in that the control connections (3, 4) of the at least one active power semiconductor (1) to be soldered to the second circuit board (9) are secured with a fuse (6, 7) to prevent solder from leaking out of the receiving holes (11) during the soldering process ) of the second circuit board (9) are provided (30). Method according to at least one of the Claims 8 until 9 , characterized in that the first circuit board (8) is provided with a heat sink (12).

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