WO2019161970A1

WO2019161970A1 - Device, in particular switch mode power supply unit

Info

Publication number: WO2019161970A1
Application number: PCT/EP2019/025034
Authority: WO
Inventors: Klaus Marahrens
Original assignee: Sew-Eurodrive Gmbh & Co. Kg
Priority date: 2018-02-20
Filing date: 2019-02-01
Publication date: 2019-08-29
Also published as: EP3756425A1; DE102019000699A1

Abstract

The invention relates to a device, in particular a switch mode power supply unit, which comprises a first printed circuit board and a second printed circuit board and also a first component, in particular a transistor, the second printed circuit board being mounted on the first printed circuit board using SMD technology and the first printed circuit board being populated with the first component using SMD technology, in particular the second printed circuit board and also the first component being surface-mounted on, in particular connected to a first face of the first printed circuit board by a solder connection.

Description

Device, in particular switching power supply

Description:

The invention relates to a device, in particular switching power supply.

SMD assembly of printed circuit boards with components is well known.

The invention is therefore the object of developing a switching power supply compact and high performance.

According to the invention the object is achieved in the device according to the features specified in claim 1.

Important features of the invention in the device are, the device, in particular switching power supply, a first circuit board and a second circuit board and a first component, in particular transistor, wherein the first circuit board with the second circuit board in SMD technology and the first component in SMD -Technique is equipped, in particular so the second circuit board and the first component surface mounted, in particular soldered, are on one side of the first circuit board.

The advantage here is that a simple manufacturing process is applicable and still a compact solution can be achieved. Because the second circuit board is in the SMD process

surface mountable and thus in the same manufacturing process step with the other components on one side of the first circuit board can be equipped. The second circuit board allows an increased number of turns of flat windings, which is executed in the layers of the two circuit boards. For both circuit boards are executable as multilayer printed circuit boards, so multi-layer printed circuit boards, which thus not only have two outer, so arranged on the outer surface copper layers but also inner layers, which are thus spaced by means of carrier material from the other layers. As a carrier material is a

Epoxy resin usable or similar, electrically highly insulation-resistant materials. Thus, high voltage intervals can be realized. In an advantageous embodiment, the first component has a particular cuboidal housing, on which a connection surface, in particular terminal pad, is arranged and on the other side a first connection foot and second

Connection feet are arranged, wherein the second connection feet are electrically connected to each other, in particular are connected in parallel, ie in each case have the same electrical potential, in particular wherein the number of second connection feet is five. The advantage here is that the current entering the component is divisible and thus a total of a strong current is controllable. Because the second connection feet are not overloaded, especially not overheated.

In an advantageous embodiment, the first component is a transistor, wherein the first connection foot is a control input, in particular gate,

wherein the second connection feet act as a supply input, in particular a source, and wherein the connection surface is a third connection of the transistor, in particular a drain. The advantage here is that the transistor is designed as a field effect transistor and thus only a small control current is to be initiated, yet high currents are switchable.

In an advantageous embodiment, the connection surface is electrically connected to a conductor track arranged on the surface of the side of the first printed circuit board facing away from the transistor, a cooling plate contacting the conductor track, in particular being heat-conductively connected to the conductor track, the first printed circuit board being screw-connected to the cooling plate, in particular, wherein the cooling plate carries and / or holds the first circuit board. The advantage here is that a wide connection surface is on the one hand used for surface mounting and on the other hand strong currents can be derived. In this case, the potential of the connection surface is preferably the same potential as the potential of the cooling plate, in particular

preferably electrical ground, in particular electrically ground In an advantageous embodiment, the housing of the transistor is cuboid. The advantage here is that the pad can be arranged on another side of the cuboid housing as the connection feet and thus a creepage distance is guided over an edge of the cuboid. Therefore, a long creepage distance and thus a high insulation resistance can be achieved.

In an advantageous embodiment, the first connection foot and the second form

Connection feet a straight row of connection feet, which are regularly spaced from each other. The advantage here is that a simple discharge of the current is made possible from the component.

In an advantageous embodiment, the first printed circuit board and the second printed circuit board are each multi-layered, in particular as a multilayer printed circuit board, wherein the two outer layers of the first circuit board at least in a conductor track each lead to low voltage, the two outer layers of the second circuit board at least in one Conductor each lead low voltage. The advantage here is that a winding can be arranged as a flat winding in several of the layers of the circuit boards. Each of the windings is thus arranged on a respective layer and the windings of a respective winding are electrically connected by means of a via.

In an advantageous refinement, the pair of layers of the first printed circuit board next to an outer layer of the first printed circuit board carries high voltage at least in one printed circuit trace, and / or the inner layers of the first printed circuit board lead in pairs alternately at least in a respective printed circuit trace high voltage or low voltage, wherein the each pair is formed in each case from each other next to each other adjacent layers. The advantage here is that between the high voltage leading layers low voltage leading layers are arranged and thus an increased distance between the high voltage leading camps is reachable. This also improves the insulation. The outer layers carry only low voltage and are therefore safe for people who touch the circuit board. Likewise, there is no risk of voltage breakdown for the two contacting arranged printed circuit boards. Because the outer layers are coated with an electrically insulating paint, which is indeed very thin, but sufficient insulation for the low voltage.

In an advantageous embodiment, the pair of layers of the second printed circuit board next to an outer layer of the second printed circuit board leads at least in one printed circuit to high voltage and the pair of layers arranged further inside the second printed circuit board leads to the pair next to the pair, at least in one printed circuit. The advantage here is that between two pairs of high voltage leading layers each have a pair of low voltage leading layers is arranged. In this way, a sufficiently high insulation distance can be achieved between the high-voltage pairs, although the printed circuit boards are made very thin-walled. The distances between the individual layers adjacent to each other are less than 2 mm, in particular less than 1 mm.

In an advantageous embodiment, the inner layers of the second printed circuit board lead in pairs alternately at least in a conductor track high voltage or low voltage, the respective pair is formed here in each case from each next adjacent layers. The advantage here is that between two pairs of high voltage leading layers each have a pair of low voltage leading layers is arranged. In this way, a sufficiently high insulation distance can be achieved between the high-voltage pairs, although the printed circuit boards are made very thin-walled. The distances between the individual mutually adjacent layers are less than 2 mm, in particular less than 1 mm.

In an advantageous embodiment, the high voltage is a voltage from the

Voltage range above 800 volts, especially measured against electrical ground and / or ground, and / or the low voltage is a voltage of less than 50 volts, in particular less than 48 volts, in particular measured against electrical ground and / or ground. The advantage here is that the voltage of a DC link of an inverter is used. In the motor operation of an electric motor, the converter feeds this electric motor and in generator operation the intermediate circuit voltage increases, in particular to or above 800 V, in particular measured against electrical ground and / or ground. ,

In an advantageous embodiment, the respective conductor carries a respective turn of a primary winding or secondary winding. The advantage here is that the windings are executable as concentric flat windings, in particular with the same maximum winding diameter.

In an advantageous embodiment, the first and the second printed circuit board turns of a primary winding and turns of a secondary winding, in particular wherein the primary winding high voltage leads and / or the first component controls the current flowing through the primary winding, in particular primary current, and / or wherein the secondary winding low voltage leads. The advantage here is that a device can be used which can switch high currents and thus "chop" the primary current flowing in the primary current. In this way, the secondary side one

sufficiently high AC voltage inducible despite the use of a small number of turns in both windings, especially in the primary winding. The secondary side feeds a rectifier from the secondary winding and thus provides a low voltage which is brought to a constant value by means of an electronic circuit, despite the voltage applied to the primary winding being variable.

Preferably, the voltage provided on the secondary side is detected and thereby regulated to a desired value by the first component being driven accordingly.

Preferably, the first component is controlled pulse width modulated and determines the pulse width as a manipulated variable from a regulator unit, in particular linear regulator unit, in particular P controller, PI controller or PID controller, which supplied the detected voltage and the setpoint is predetermined.

In an advantageous embodiment, a spool core has at least two parts, wherein at least one of the two parts has a middle leg and outer leg, wherein the middle leg protrudes through a recess of the first printed circuit board and through a recess of the second printed circuit board, wherein the turns of the primary winding and the secondary winding are guided around the center leg. The advantage here is that after surface mounting of the second circuit board on the first circuit board and thus after assembly of the first circuit board with components of the first part of the coil core coming from one side of the first circuit board forth and the other part of the coil core from the other side of the second PCB is coming forth pushed. Thus, then projects through the middle leg through the recess of the two circuit boards. The windings of both windings are around the

Center thighs led around. Thus, an effective inductive coupling between

Primary winding and secondary winding reachable. Since outer legs are also provided, which are connected on both sides of the first circuit board by means of a respective yoke part with the center leg, a high efficiency in the inductive coupling can be achieved.

Further advantages emerge from the subclaims. The invention is not limited to the combination of features of the claims. For the expert, further meaningful combination options of claims and / or individual arise

Claim features and / or features of the description and / or figures, in particular from the task and / or the task by comparison with the prior art task.

The invention will now be explained in more detail with reference to schematic illustrations:

FIG. 1 shows an oblique view of a switched-mode power supply according to the invention.

In the figure 2, the switching power supply is shown from a different angle.

As shown in the figures, the switching power supply has a first printed circuit board 7, which is equipped with components in SMD technology. The components have soldering surfaces or

Connection feet, which are suitable for surface mounting by soldering. Passing through feet through a through hole in the first

Circuit board 7 is omitted.

In addition, a second circuit board 3 is performed on its outer periphery with solder surfaces, directly on the first circuit board 7, in particular so touching, placed and connected by SMD technology, ie by soldering the solder pads of the second circuit board 3 with traces of the first circuit board. 7

The first and second printed circuit boards (3, 7) are each designed in multiple layers.

A coil core composed of two parts has three legs, wherein at least the middle of the three legs is guided through a recess passing through the first circuit board 7 and through the second circuit board 3.

The switching power supply has an inductive transformer, which has a primary winding and a secondary winding. The primary winding is flowed through by a transistor controlled by a high current, with voltages of more than 800 V are provided. Such voltages are referred to here and below as high voltage. On the secondary side, a low-voltage is provided.

Preferably, the first circuit board 7 is made of four layers and the second circuit board 3 eight layers.

In this case, two turns of the secondary winding are arranged in the two outer layers of the second printed circuit board 3 and thus lead to low voltage. Further turns of the Secondary winding are arranged on the first circuit board 7, namely on the two outer layers of the first circuit board 7 and in the two middle layers of the first

Circuit board 7, in particular in the fourth and fifth position of the first circuit board 7. These further turns thus also lead low voltage.

Two turns of the primary winding are arranged in the middle layers of the second printed circuit board 3, ie in the second and third layers of the second printed circuit board 3. Thus, the second and third layers of the second printed circuit board 3 carry high voltage.

Further turns of the primary winding are arranged in the second and third and sixth and seventh position of the first circuit board 7 and thus carry high voltage, that is more than 800 volts. In this case, the voltage is always measured against ground, in particular so that electrical ground.

Since in both circuit boards (3, 7), the two outer layers each carry low voltage, a direct, so touching, placing the second circuit board 3 on the first circuit board 7 allows without special measures to improve the electrical

Insulation resistance and / or insulation are necessary. So it is sufficient, for example, a thin layer of lacquer on the outer layers to obtain sufficient insulation.

Within the respective printed circuit board, the layers by means of carrier material of the printed circuit board 3 and 7 are each well spaced so that a sufficiently high insulation strength.

As described above, therefore, the secondary winding has the number of turns six and the primary winding also has the number of turns six.

In a further development, however, two or three turns of the primary winding can also be connected in parallel so that the primary current divides itself accordingly and the number of turns is three or two.

Since the second circuit board 3 as well as other components are surface mounted, the

Assembly of the first circuit board 7 with the components and also the second circuit board 3 in the same manufacturing process step executable. In this case, the components and also the second circuit board 3 are fixed by means of a holding device relative to the first circuit board 7 and then passed through a Wellenlötbad. Thus, then the SMD assembly is feasible in a simple manner.

One of these components is a transistor, which controls the primary current, that is, has to switch large currents. This is due to the transistor high voltage.

The transistor 1 has on its housing a connection surface 12, in particular

Pad for drain of the transistor 1, on, which is directly soldered to a conductor track, which is arranged on the outer surface of the first circuit board 7. The pad 12 thus abuts the housing and forms part of the surface of the transistor.

From the housing of the transistor 1 also protrude a connection foot 6 for the control input gate of the transistor 1 and five connection feet 5 for the supply terminal source of the transistor 1 out. In this case, the connection feet (5, 6) are placed on the surface of the first printed circuit board 7 and then solder-joined in the said manufacturing process step. By means of the parallel connection of the connection feet 5 for drain is a high current by means of

Transistor 1 controllable.

Characterized in that the connection pad 12 is arranged for drain at the bottom of the transistor 1 and the connection feet 5 on one side of the transistor 1 is a high distance between the drain and source and thus creepage distances for more than 800 volts, in particular more than 2000 volts feasible , In this case, the connection surface 12 is arranged on a region of the underside of the transistor 1 which is as far as possible from the connection feet 5. The connection feet are arranged for mechanical reasons and design reasons in the middle of the side of the transistor 1.

The housing of the transistor 1 is preferably designed cuboid.

The two parts (9, 10) of the spool core are pressed together by a clamp 1 1 and thus held together. Since the first of the two parts 9 coming from the top of the first circuit board 7 coming forth and the other of the two parts 10 coming from the bottom of the first circuit board 7 ago Preferably, low voltage is understood to mean a voltage of less than 50 volts, in particular less than 48 volts.

With the abbreviation NV for low voltage, and the abbreviation HV for the high voltage, the layers of the first circuit board 7 voltages in the order NV, HV, HV, NV.

The second circuit board 3 carries the layers in the order NV, HV, HV, NV, NV, HV, HV, NV.

The inner layers are thus subjected in pairs with the same voltage. The outer layers are each subjected to NV.

The first circuit board 7 is screw-connected to the cooling plate 2, in particular by means of screws 8. The T ransistor 1 is mounted on the side remote from the cooling plate side of the first circuit board 7 on this. Its pad 12 is preferably plated through to a conductor on the cooling plate 2 facing side of the first circuit board 7, which is thermally conductively connected to the cooling plate 2, so that the heat generated by the transistor 1 via the cooling plate 2 can be discharged to the environment.

In addition, the cooling plate 2 acts as a holding part for the first circuit board 7 and thus indirectly also for the components held by the first circuit board 7 and the second

PCB 3.

By means of another screw 13, the cooling plate is at another part of a

Electrical device can be screwed together.

In further embodiments of the invention, another even number of layers of the first circuit board 7 and / or another even number of layers of the second circuit board 3 is provided. Although in turn lead the outer layers low voltage NV, but the inner layers in turn lead in alternating order in pairs HV or NV. LIST OF REFERENCE NUMBERS

I transistor

2 cooling plate

3 second circuit board

4 solder pad

5 connection foot for Source

6 connection foot for gate

7 first circuit board

8 screw

9 spool core

10 spool core

I I clip

12 connection surface, in particular connection pad for drain

13 screw

Claims

claims:

1. Device, in particular switching power supply, comprising a first printed circuit board and a second printed circuit board and a first component, in particular transistor, characterized in that the first printed circuit board is equipped with the second printed circuit board in SMD technology and the first component in SMD technology, in particular So the second circuit board and the first component surface mounted, in particular soldered, are on one side of the first circuit board.

2. Apparatus according to claim 1,

characterized in that

the first component has in particular a cuboid housing, on which a connection surface, in particular connection pad, is arranged and on the other side of which a first connection foot and second connection feet are arranged, wherein the second connection feet are electrically connected to one another, in particular connected in parallel, ie in each case the same have electrical potential, in particular wherein the number of second connection feet is five. ,

3. Device according to at least one of the preceding claims,

characterized in that

the first component is a transistor, wherein the first connection foot is a control input, in particular gate,

wherein the second connection feet act as a supply input, in particular a source, and wherein the connection surface is a third connection of the transistor, in particular a drain.

4. Device according to at least one of the preceding claims,

characterized in that

the pad is electrically connected to a arranged on the surface of the side facing away from the transistor side of the first circuit board conductor, wherein a cooling plate touches the conductor, in particular thermally conductively connected to the conductor, wherein the first circuit board is screw-connected to the cooling plate, in particular wherein the cooling plate the first circuit board carries and / or holds.

5. Device according to at least one of the preceding claims,

characterized in that

the housing of the transistor is cuboidal.

6. Device according to at least one of the preceding claims,

characterized in that

the first connection foot and the second connection feet a straight row of

Form connecting feet, which are regularly spaced from each other.

7. Device according to at least one of the preceding claims,

characterized in that

the first printed circuit board and the second printed circuit board are each multi-layered, in particular each as a multilayer printed circuit board, wherein the two outer layers of the first printed circuit board at least in a conductor track each lead to low voltage, the two outer layers of the second printed circuit board at least in a conductor track each lead to low voltage ,

8. Device according to at least one of the preceding claims,

characterized in that

the respectively next to an outer layer of the first circuit board next adjacent pair of layers of the first circuit board leads at least in a conductor high voltage, and / or that the inner layers of the first circuit board in pairs alternately lead at least in a respective trace high voltage or low voltage, the respective pair here is formed in each case from each other next to adjacent layers.

9. Device according to at least one of the preceding claims,

characterized in that

each leading to an outer layer of the second circuit board next adjacent pair of layers of the second circuit board at least in a conductor high voltage and the further inside arranged in the second circuit board, in turn next pair next adjacent pair of layers at least in a conductor low voltage leads. and / or that the inner layers of the second printed circuit board lead in pairs alternately at least in a conductor track high voltage or low voltage, wherein the respective pair is formed here in each case from each next adjacent layers.

10. Device according to at least one of the preceding claims,

characterized in that

the high voltage is a voltage in the voltage range above 800 volts and / or that the low voltage is a voltage of less than 50 volts, in particular less than 48 volts.

1 1. A device according to at least one of the preceding claims,

characterized in that

the respective track is a respective turn of a primary winding or secondary winding.

12. Device according to at least one of the preceding claims,

characterized in that

the first and the second circuit board has turns of a primary winding and turns of a secondary winding, in particular wherein the primary winding carries high voltage and / or the first component controls the current flowing through the primary winding, in particular primary current, and / or the secondary winding carries low voltage.

13. Device according to at least one of the preceding claims,

characterized in that

a coil core has at least two parts, wherein at least one of the two parts has a middle leg and outer leg, wherein the center leg protrudes through a recess of the first circuit board and through a recess of the second circuit board, wherein the turns of the primary winding and the secondary winding around the center leg around are.