DE102019000699A1 - Device, in particular switching power supply - Google Patents

Abstract

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,
wherein 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.

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 Technology 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 surface mountable in the SMD process 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 the carrier material is an epoxy resin used or similar, electrically highly insulating 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 a connection pad, is arranged and on whose 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,
wherein a cooling plate touches the conductor track, in particular is connected in a heat-conducting manner to the conductor track,
wherein the first circuit board is 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 electrically earth, in particular electrical 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 connection feet form a straight row of connection feet, which are regularly spaced from one another. 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 in each case as a multilayer printed circuit board,
wherein the two outer layers of the first printed circuit board each lead to low voltage in at least one printed conductor,
wherein the two outer layers of the second circuit board at least in a conductor track each carry 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 leads at least in one printed circuit track to high voltage,
and or
The inner layers of the first circuit board lead in pairs alternately at least in a respective conductor track high voltage or low voltage, the respective pair is in this case each formed from each other next 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 refinement, the pair of layers of the second printed circuit board next to an outer layer of the second printed circuit board carries high voltage at least in one printed circuit trace and the pair of layers arranged next to the pair in the second printed circuit board leads to low voltage at least in one printed circuit trace. 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 in this case each formed from each other 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, in particular 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. The inverter feeds this electric motor in the motor operation of an electric motor and in the
regenerative operation increases the intermediate circuit voltage, in particular to or over 800 volts, 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 windings 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 wherein the secondary winding carries low voltage. 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, on the secondary side, a sufficiently high alternating voltage can be induced despite the use of a small number of turns in both windings, in particular 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 variable voltage applied to the primary winding. 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 the pulse width as a control variable from a regulator unit, In particular, linear regulator unit, in particular P-controller, PI controller or PID controller determines which of the detected voltage supplied and the desired value is specified.

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 circuit board and through a recess of the second 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 placement of the first circuit board
with components of the first part of the coil core coming from one side of the first printed circuit board coming forth and the other part of the coil core from the other side of the second printed circuit board coming forth is pushed. Thus, then projects through the middle leg through the recess of the two circuit boards. The windings of both windings are led around the middle leg. Thus, an effective inductive coupling between the primary winding and the secondary winding can be achieved. 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 skilled person, further meaningful combination options of claims and / or individual claim features and / or features of the description and / or figures, in particular from the task and / or the task posing by comparison with the prior art arise.

• In der 1 ist eine Schrägansicht eines erfindungsgemäßen Schaltnetzteils gezeigt.
• In der 2 ist das Schaltnetzteil aus einem anderen Blickwinkel gezeigt.

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

• In the 1 is an oblique view of a switching power supply according to the invention shown.
• In the 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 means of soldered connections. Passing through feet through a through hole in the first circuit board 7 so it does not apply.

There is also a second circuit board 3 executed on its outer periphery with solder pads, on the first circuit board 7 directly, in particular so touching, applied and connected by means of SMD technology, ie by means of solder connection of the solder pads of the second circuit board 3 with tracks of the first circuit board 7 ,

The first and second circuit boards ( 3 . 7 ) is multi-layered.

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

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 four layers executed and the second circuit board 3 achtlagig.

There are two turns of the secondary winding in the two outer layers of the second circuit board 3 arranged and thus lead low voltage. Further turns of the secondary winding are on the first circuit board 7 arranged, namely on the two outer layers of the first circuit board 7 and in the two middle layers of the first circuit board 7 , ie in particular in the fourth and fifth position of the first printed circuit board 7 , These further turns thus also lead to low voltage.

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

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

Because with both circuit boards ( 3 . 7 ) lead the two outer layers each low voltage, is a direct, so touching, placing the second circuit board 3auf 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 circuit board, the layers are by means of carrier material of the circuit board 3 and 7 each spaced so well that there is 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.

Because the second circuit board 3 like other components are also surface-mounted, the assembly of the first circuit board 7 with the components and also the second circuit board 3 executable in the same manufacturing process step. This will be the components and the second circuit board 3 by means of a holding device relative to the first printed circuit board 7 fixed 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 a connection surface on its housing 12 , in particular terminal pad for the drain of the transistor 1 , which is directly solderable to a conductor track, which on the outer surface of the first circuit board 7 is arranged. The connection surface 12 thus abuts the housing and forms part of the surface of the transistor.

From the case of the transistor 1 also protrude a connection foot 6 for the control gate of the transistor 1 and five connection feet 5 for the supply connection Source of the transistor 1 out. The connection feet ( 5 . 6 ) on the surface of the first circuit board 7 placed on and then soldered 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 the transistor 1 controllable.

Because of the pad 12 for drain at the bottom of the transistor 1 is arranged 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. Here is the connection area 12 at one as far as possible from the connection feet 5 removed area of the bottom of the transistor 1 arranged. The connection feet are for mechanical reasons and design reasons in the middle of the side of the transistor 1 arranged.

The case of the transistor 1 is preferably executed cuboid.

The two parts ( 9 . 10 ) of the spool core are from a bracket 11 pressed together and thus held together. Because the first of the two parts 9 from the top of the first circuit board 7 Coming here and the other of the two parts 10 from the bottom of the first circuit board 7 coming here

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 with the acronym HV for the high voltage, the layers of the first circuit board lead 7 Tensions in the order NV . HV . HV . NV ,

The second circuit board 3 leads the layers with 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 with NV applied.

The first circuit board 7 is with the cooling plate 2 screwed, in particular by means of screws 8th , The transistor 1 is on the side facing away from the cooling plate side of the first circuit board 7 stocked on this. Its interface 12 is preferably plated through to a conductor track on the cooling plate 2 facing side of the first circuit board 7 , which with the cooling plate 2 is thermally conductively connected, so that from the transistor 1 generated heat through the cooling plate 2 is dischargeable to the environment.

In addition, the cooling plate acts 2 as a holding part for the first circuit board 7 and thus indirectly for those of the first circuit board 7 held components and the second circuit board 3 ,

By means of another screw 13 the cooling plate is screw-connected to another part of an electrical appliance.

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 intended. Although in turn lead the outer layers low voltage NV but the inner layers lead in turn in alternating order in pairs HV or NV ,

LIST OF REFERENCE NUMBERS

1

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

8th

Schaube

9

Plunger

10

Plunger

11

clip

12

Pad, in particular pad for drain

13

screw

Claims (13)

Device, in particular switching power supply, comprising a first circuit board and a second circuit board and a first component, in particular transistor, characterized in that the first circuit board is equipped with the second circuit board in SMD technology and the first component in SMD technology, in particular so second printed circuit board and the first component surface mounted, in particular soldered, are on one side of the first circuit board. Device after Claim 1 , characterized in that the first component has a particular cuboid housing, on which a connection surface, in particular connection 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 connected in parallel are each having the same electrical potential, in particular wherein the number of second connection feet is five. 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 source, and wherein the connection surface is a third connection of the Transistor is, in particular drain. Device according to at least one of the preceding claims, characterized in that the connection surface 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 the first printed circuit board is screw-connected to the cooling plate, in particular wherein the cooling plate carries and / or holds the first printed circuit board. Device according to at least one of the preceding claims, characterized in that the housing of the transistor is cuboidal. Device according to at least one of the preceding claims, characterized in that the first connection foot and the second connection feet form a straight row of connection feet, which are regularly spaced from each other. Device according to at least one of the preceding claims, characterized in that the first printed circuit board and the second printed circuit board is in each case multi-layered, in particular 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 circuit board at least in a conductor track each lead low voltage. Device according to at least one of the preceding claims, characterized in that each closest to an outer layer of the first circuit board pair of layers of the first circuit board at least in a conductor high voltage, and / or that the inner layers of the first circuit board in pairs alternately at least in one respective Conductor high voltage or low voltage lead, the respective pair is in this case each formed of mutually next adjacent layers. Device according to at least one of the preceding claims, characterized in that each adjacent to an outer layer of the second circuit board next pair of layers of the second circuit board at least in a conductor high voltage and the further inside of the second circuit board arranged, in turn next pair next Lays 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. Device according to at least one of the preceding claims, characterized in that the high voltage is a voltage from 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. Device according to at least one of the preceding claims, characterized in that the respective conductor track is a respective turn of a primary winding or secondary winding. Device according to at least one of the preceding claims, characterized in that 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 current, in particular primary current controls and / or wherein the secondary winding carries low voltage. 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 are guided around the center leg.

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