DE102018007243B4 - Electrical circuit - Google Patents

Abstract

Electrical circuit (4), in particular of a household appliance (2), with a circuit carrier (8) to which an electrical or electronic component (10) is soldered, and with a metallic component (20) which is spaced from the circuit carrier (8) is, as well as with a spacer (12) which is arranged between the circuit carrier (8) and the metallic component (20) and rests against them, and which has a recess (14) within which the component (10) is arranged, wherein the recess (14) is filled by means of a potting compound (24), and wherein the spacer (12) is made from a foam, namely a polyurethane.

Description

The invention relates to an electrical circuit with a circuit carrier. For example, the electrical circuit is part of a household appliance. The invention also relates to a method for producing an electrical circuit.

A large number of devices have electrical circuits by means of which individual functions of the respective device are influenced. The electrical circuits themselves usually comprise a number of electrical and / or electronic components, which are usually stabilized with respect to one another by means of a circuit carrier and are in electrical contact with one another. In this case, depending on the quality of the respective components as well as an electrical current carried by means of them and the electrical voltage applied in each case, it is possible that a comparatively large power loss occurs. The power loss is mostly converted into heat, which leads to the respective component heating up. As a result, it is necessary to match the material of the component and its design to the heating, which increases manufacturing costs.

An alternative to this is cooling the respective component. A heat sink that is in thermal contact with the component is usually used for this purpose. Thus, comparatively inexpensive components can also be used. The component is, for example, mechanically fixed to the heat sink, in particular by means of an adhesive. With such a fastening, however, it is possible that the adhesive, the heat sink and / or the component have different coefficients of thermal expansion, which is why mechanical stresses arise in these during operation. The alternating mechanical stresses during the entire service life of the electrical circuit can lead to premature destruction of the component or detachment from the heat sink.

The invention is based on the object of specifying a particularly suitable electrical circuit and a particularly suitable method for producing an electrical circuit, wherein robustness is advantageously increased, production costs are expediently reduced, and production is simplified in particular.

With regard to the electrical circuit, this object is achieved according to the invention by the features of claim 1 and with regard to the method by the features of claim 10. Advantageous further developments and refinements are the subject of the respective subclaims.

The electrical circuit has an electrical or electronic component that is soldered to a circuit carrier. The electrical component is, for example, a capacitor, an electrical coil or an electrical choke. In particular, the electrical component is a resistor, for example an ohmic resistor, or a variable resistor. The resistance is particularly temperature-dependent. The electronic component is, for example, a microprocessor, in particular an integrated circuit. In the following, a component is understood to mean, in particular, an electrical or electronic component. The component is, for example, an active component or a passive component. In particular, the component is a semiconductor. The electrical circuit preferably comprises a plurality of such components which, for example, are structurally identical to one another or, particularly preferably, are at least partially different from one another.

The component, in particular the number of components, is mechanically stabilized by means of the circuit carrier. In this case, electrical contact is preferably also made between the component and a conductor track or the like of the circuit carrier. In particular, the components are interconnected with one another in such a way that a specific function is carried out during operation.

The electrical circuit also has a metallic component that is made, for example, from a single metal or different metals. For example, the metals are designed to be separable from one another. As an alternative to this, the metallic component is made from an alloy. The metallic component is spaced from the circuit carrier. In particular, there is no mechanical direct contact between the metallic component and the electrical circuit. This avoids an electrical short circuit. The metallic component is expediently spaced from the component so that damage to the component by the metallic component is avoided during assembly. An electrical short circuit is also avoided in this way and an electrical dielectric strength is thus increased.

In addition, the electrical circuit comprises a spacer which is arranged between the circuit carrier and the metallic component. The spacer rests against both the circuit carrier and the metallic component. In particular, the position of the circuit carrier with respect to the metallic component is stabilized by means of the spacer. The spacer is preferably in direct mechanical contact with the circuit carrier and / or the metallic component. Alternatively, between the spacer and the circuit carrier and / or the metallic Component still further components arranged. There is preferably a substantially flat contact with the circuit carrier and / or the metallic component, which increases robustness.

The spacer has a recess which is designed in particular to be continuous. The component is arranged within the recess. Thus, the component is at least partially surrounded by the spacer and at least partially protected by it. The recess itself is filled with a potting compound. For example, the recess is only partially filled with the potting compound, the component being expediently completely covered with the potting compound. Particularly preferably, the recess is completely filled with the potting compound. A material bond between the potting compound and the circuit carrier and / or between the potting compound and the metallic component is expediently implemented. Particularly preferably, however, the metallic component is glued to the circuit carrier by means of the potting compound, at least in the assembled state.

A thermal connection of the component takes place by means of the potting compound, so that heat is at least partially conducted to or away from the component during operation by means of the potting compound. The component and the spacer are at least partially stabilized by means of the sealing compound, which increases robustness. It is thus possible in particular to first solder the component to the circuit carrier and only then to fill the recess with the potting compound. Consequently, a comparatively time-consuming positioning of the component with respect to the circuit carrier is not necessary. Thus, the component can first be soldered to the circuit carrier before the recess is filled with the potting compound. Production is thus simplified. In addition, a mold for the casting compound is at least partially provided by means of the spacer, which additionally simplifies production. An uncontrolled escape of the casting compound is also avoided in this way, which on the one hand increases quality. On the other hand, consumption of the casting compound is reduced, which reduces manufacturing costs.

The electrical circuit is, for example, part of a device, such as a household appliance in particular. The household appliance is, for example, a large household appliance such as a refrigerator, a stove or an oven. The metallic component is preferably in thermal contact with an interior space of the household appliance, for example a cooling space or an oven space.

The potting compound preferably extends from the component to the metallic component, so that the metallic component is in thermal contact with the component by means of the potting compound. In this way, a heat transfer between the metallic component and the component is made possible. Robustness is also further increased in this way.

The potting compound is preferably designed to be thermally conductive. At least, however, the potting compound has a coefficient of thermal conductivity that is greater than that of air. In particular, the thermal conductivity is greater than 0.1 W / mK, greater than 0.2 W / mK, greater than 1 W / mK, greater than 10 W / mK, greater than 20 W / mK or greater than 100 W / mK. The component is thus thermally connected by means of the potting compound. The potting compound is, for example, a thermoplastic or a thermosetting plastic. The casting compound is particularly preferably a casting resin. The potting compound is expediently introduced into the recess by means of an injection molding process. In this way, a suitable filling of the recess is realized.

For example, only the component is arranged in the recess. The electrical circuit particularly preferably comprises a plurality of such components which are arranged within the recess. These components are thus also thermally contacted with the potting compound. As an alternative to this, the spacer has, for example, several such cutouts, each of the cutouts being assigned to at least one of the components.

The recess is particularly preferably delimited by means of the circuit carrier, the metallic component and the spacer. In other words, the circuit carrier, the metallic component and the spacer form the boundary for the recess, which is expediently designed to be closed. This means that no uncontrolled discharge of the potting compound is possible, which reduces material requirements. Hence, quality is improved. In particular, the recess is completely filled with the potting compound, so that the metallic component is in thermal contact with the circuit carrier and the component by means of the potting compound. The potting compound also stabilizes the circuit carrier with respect to the metallic component.

In this case, the spacer serves, in particular, essentially only to at least partially provide the delimitation of the recess. In other words, the mechanical integrity is expediently provided by means of the potting compound. It is thus possible for the spacer to essentially only perform the function of holding the potting compound in the recess Optimize assembly. Consequently, comparatively inexpensive material can be used. It is also possible in this way to reduce weight and manufacturing costs. In summary, preferably by means of the spacer, the circuit carrier is not stabilized with respect to the metallic component or is only stabilized by means of the spacer during assembly before the recess is filled with the potting compound. Production is thus further simplified, and comparatively easily machinable material can be used for the spacer.

For example, the component rests against the spacer. However, the spacer is particularly preferably at a distance from the component. In other words, the component is spaced from the delimitation of the recess. Thus, in particular, temperature transfer takes place only by means of the potting compound. Thermal stress on the spacer is therefore reduced. It is also possible to manufacture the spacer from a material with a comparatively low coefficient of thermal conductivity.

The spacer is made of a plastic. Machining of the spacer is thus simplified, in particular making the recess. In addition, it is possible to manufacture the spacer with the recess from the outset. The spacer is made from a foam. Thus, a weight of the spacer is reduced. in particular, the foam is designed in the shape of a sponge. Due to such a choice of material, a weight of the spacer is further reduced, so that the weight of the electrical circuit is reduced. Storage is also simplified. In addition, with such a choice of material, the spacer is at least partially elastically deformable, which simplifies assembly. A polyurethane is used as the foam. A foam which is sold under the name Poron by Rogers Corporation is preferably used as the material of the spacer.

For example, the spacer is placed essentially loosely on the circuit carrier and / or the metallic component. However, the spacer is particularly preferably attached to the circuit carrier or the metallic component, preferably to both. An adhesive is expediently used as the fastening means in each case. In other words, the spacer is glued to the circuit carrier and / or the metallic component. Robustness is thus increased before filling with the potting compound. Filling with the potting compound is also made easier since unintentional loosening of the metallic component and / or the circuit carrier is prevented. In this case, the spacer is suitably made from the foam, which is expediently provided with an adhesive layer on opposite sides, namely the side facing the metallic component and the side facing the circuit carrier. In other words, the spacer is provided with the adhesive layer on both sides.

In an advantageous alternative, the spacer is positively or non-positively connected to the circuit carrier or the metallic component or both. The form-fitting or force-fitting connection increases the robustness even before filling with potting compound. Filling with the potting compound is also made easier since unintentional loosening of the metallic component and / or the circuit carrier is prevented. In this case, the spacer is suitably made from the foam, which is expediently provided with a positive or non-positive connection on opposite sides, namely the side facing the metallic component and the side facing the circuit carrier. In other words, the spacer is provided on both sides with a form-fit or a force-fit connection.

For example, the circuit carrier is a molded interconnect device (MID). However, the circuit carrier is particularly preferably a printed circuit board that is flexible, for example. However, the printed circuit board is particularly preferably designed to be rigid, which increases robustness and reduces manufacturing costs. In particular, the circuit board is made of a glass fiber reinforced epoxy resin and expediently fulfills the material identifier FR 4th . The printed circuit board preferably comprises a number of conductor tracks, which are embedded, for example, in the epoxy resin or attached to the outside thereof. The conductor tracks are made from a copper, for example, expediently by means of etching. In this case, the component is preferably soldered to the conductor track, if any, and thus electrically contacted with it.

The metallic component is preferably or at least comprises a metal plate. The metal plate is suitably arranged parallel to the circuit carrier. In this case, the circuit carrier expediently has at least partially a flat design. In particular, the circuit carrier is designed as a printed circuit board. The metallic component and the circuit carrier are expediently not located in one plane but are offset from one another perpendicular to the respective direction of propagation. The offset is preferably bridged by means of the spacer. The projection of the metallic component onto the circuit carrier and vice versa at least partially overlap one another, perpendicular to the respective direction of propagation. Due to Such an arrangement simplifies assembly. In addition, it is simplified to seal the recess, so that the potting compound is prevented from escaping from it in a comparatively effective manner. A space requirement is also reduced.

In an alternative configuration, the circuit carrier has a geometric configuration suitable for a form fit, for example a latchable configuration. In a further alternative configuration, the circuit carrier has a geometric configuration suitable for a force fit. For example, this can be a recess and a counterpart reflecting the geometry of the recess, such as a cone and a conical counterpart or a hole and a counterpart corresponding to the cross section of the hole.

For example, the metallic component is a heat sink. In this case, the metallic component is designed, for example, as a metal plate or additionally has cooling fins, which preferably point away from the circuit carrier. The component is thus cooled during operation by means of the metallic component. The component is preferably a power semiconductor, for example a power semiconductor switch. The thermal coupling to the heat sink is preferably carried out by means of the potting compound. In an alternative embodiment, the component is, for example, a sensor, in particular a temperature sensor. Due to the potting compound, there is expediently a thermal coupling with the metallic component, so that the temperature of the metallic component is detected during operation by means of the component via the potting compound.

For example, the spacer is arranged on the circuit carrier or the metallic component during manufacture. Following this, for example, the recess is filled with the potting compound and the respective other component, that is to say the metallic component or the circuit carrier, is suitably positioned so that the spacer also rests against it. Particularly preferably, however, the spacer is initially arranged between the circuit carrier and the metallic component during assembly. The metallic component expediently has a hole which ends in the recess. The opening is expediently filled by means of the potting compound via the hole. Production is thus simplified. The metallic component expediently has two holes which both end in the recess and which are preferably spaced apart from one another. The recess is suitably filled with the casting compound via one of the holes, and any material located in the recess expediently escapes via the other of the holes, in particular air. It is thus possible to fill the recess essentially completely with the potting compound.

In an alternative to this, for example, the metallic component has the hole and the circuit carrier has a further hole which opens into the recess. The filling is preferably carried out via one of the holes, in particular that of the metallic component. The air suitably enters through the hole in the circuit board. In a further alternative, the metallic component is designed, in particular, to be intact, and the circuit carrier has a hole, preferably two holes, which open into the recess. The recess is expediently filled with the casting compound through at least one of the holes in the circuit carrier. The metallic component is thus intact, which simplifies manufacture. A comparatively large, undamaged surface of the metallic component is also implemented, which in particular improves heat dissipation if the metallic component is, for example, the heat sink. The introduction of the hole is also simplified.

For example, the component is a wired component, the assembly expediently taking place by means of a THT method. Particularly preferably, however, the component is a surface-mountable component which is expediently soldered to the circuit carrier by means of an SMD process. In this way, manufacturing costs are reduced. In addition, a manufacturing time is reduced. Miniaturization is also simplified in this way. In this case, despite the design of the component as a surface-mountable component (SMD component), a comparatively efficient thermal connection to the metallic component is made possible by means of the potting compound.

The electrical circuit particularly preferably has a contact pin which is soldered to the circuit carrier. The contact pin is in electrical contact with the component, for example directly or by means of a further component, for example a further component. The electrical contact is preferably made in each case by means of a conductor track of the circuit carrier. The contact pin itself is arranged outside the recess. This enables electrical contact to be made with the component located in the recess by means of the contact pin despite the potting compound. In particular, the contact pin is part of a connection terminal or the like. At least, however, the contact pin is preferably used to exchange signals with the component and / or to energize the component. Due to the contact pin, there is a comparatively simple connection to a line, like a cable. The contact pin is suitable for this, in particular provided and set up. The contact pin is made for example from a metal, in particular a copper. The contact pin is preferably made from the tinned copper, so that a comparatively high electrical conductivity is provided, with oxidation being avoided. For example, tinned CUSN6 is used.

The contact pin is particularly preferably located on the same side of the circuit carrier as the component. Assembly is simplified in this way. The contact point is preferably at a distance from the metallic component, so that an electrical short circuit is avoided. For example, the contact pin is mounted using a pin-in-paste process (THR process; “throughhole reflow” process). A reflow process is used for this, and a solder paste is expediently printed into an opening in the circuit carrier through which the contact pin is guided for assembly. It is thus possible to connect the contact pin and the component to the circuit carrier in one work step, at least if the component is preferably a surface-mountable component. Thus, only a single work step is required, which shortens manufacturing time and reduces manufacturing costs.

The circuit carrier expediently has two contact pins of this type which, for example, are structurally identical to one another. In this case, the two contact pins are preferably electrically contacted with the component and are each arranged outside the recess. The component is preferably connected in series between the contact pins, so that by means of the component, an electrical voltage applied between the contact pins during operation and / or an electrical current flowing between the contact pins can be at least partially influenced by means of the component.

The method is used to produce an electrical circuit which has a circuit carrier to which an electrical or electronic component is soldered and which includes a metallic component that is spaced apart from the circuit carrier. Furthermore, the electrical circuit has a spacer which is arranged between the circuit carrier and the metallic component and rests against the latter, and which has a recess. The component is arranged within the recess, the recess being filled by means of a potting compound.

The method provides that the circuit carrier with the electrical or electronic component soldered to it is provided. For this purpose, for example, the circuit carrier and the component are initially provided as two separate components and these are soldered to one another, for example in an SMD process. If the contact pin is present, the contact pin is expediently soldered to the circuit carrier in the same work step, preferably by means of a pin-in-paste process.

In a further work step, the spacer is arranged between the circuit carrier and the metallic component, so that the component is arranged within the recess, the spacer resting against the circuit carrier and the metallic component. In particular, a layer arrangement (sandwich arrangement) is implemented in this way. The spacer is preferably glued to the circuit carrier. Alternatively or particularly preferably in combination with this, the spacer is glued to the metallic component. In a further work step, the recess is filled or completely filled with the sealing compound. In this case, the potting compound is expediently at least partially liquid, which simplifies assembly. Thus, the component is thermally coupled to the metallic component. The potting compound is suitably cured after this, which increases robustness. For example, the casting compound is crosslinked or dried for this purpose.

The advantages and developments described in connection with the electrical circuit can also be applied to the method and vice versa.

• 1 schematisch vereinfacht ein Haushaltsgerät mit einer elektrischen Schaltung,
• 2 perspektivisch in einer halbtransparenten Darstellung die elektrische Schaltung,
• 3 die elektrische Schaltung in einer Schnittdarstellung, und
• 4 ein Verfahren zur Herstellung der elektrischen Schaltung.

An exemplary embodiment of the invention is explained in more detail below with reference to a drawing. Show in it:

• 1 schematically simplified a household appliance with an electrical circuit,
• 2 the electrical circuit in perspective in a semi-transparent representation,
• 3 the electrical circuit in a sectional view, and
• 4th a method of manufacturing the electrical circuit.

Corresponding parts are provided with the same reference symbols in all figures.

In 1 is schematically simplified a household appliance 2 shown in the form of a large household appliance. The household appliance 2 is a refrigerator and has an electrical circuit 4th on, by means of which an electric motor 6 is operated. This is done by means of the electrical circuit 4th depending on one in the refrigerator 2 prevailing temperature an energization of the electric motor 6 set. By means of the electric motor 6 is a refrigerant compressor operated so that an interior of the household appliance 2 is cooled.

In 2 is perspective in a semi-transparent representation of the electrical circuit 4th shown in 3 is shown in a sectional view along a sectional plane III. The electrical circuit 4th has a circuit carrier 8th in the form of a circuit board. The circuit board 8th is rigid and meets the material code FR 4th . Thus the circuit carrier is 8th made of a glass fiber reinforced epoxy resin to which conductor tracks (not shown) are connected.

On the circuit carrier 8th is an electrical or electronic component 10 soldered on. The electrical / electronic component 10 is a surface-mountable component and is attached to the circuit carrier by means of an SMD process 8th , namely at least one of the conductor tracks not shown, attached. On the circuit carrier 8th additional electrical and electronic components, not shown, are connected, which are suitable with one another and with the component by means of the conductor tracks, not shown 10 are electrically contacted. The electrical / electronic component 10 , hereinafter referred to simply as a component, is arranged on one side of the essentially flat circuit carrier on which a spacer 12th is put on. The spacer 12th is also essentially flat and parallel to the circuit carrier 8th arranged.

The spacer 12th has a continuous recess 14th on, within which the component 10 is arranged. Here is the component 10 from the limitation of the recess 14th spaced and is therefore not mechanically directly on the spacer 12th on. The spacer 12th is created from a foam that is made from a polyurethane. Thus, the spacer 12th has a foam-like consistency and is elastically bendable.

The spacer 12th is by means of a first adhesive layer 16 that is on one side of the spacer 12th is applied to the circuit carrier 8th glued in place. By means of a second adhesive layer 18th that is on top of the first layer of adhesive 16 opposite side of the spacer 12th is the spacer 12th on a metallic component 20th glued on. The metallic component 20th is a metal plate that runs parallel to the circuit board 8th is arranged. Thus, by means of the circuit carrier 8th , the spacer 12th as well as the metallic component 20th a sandwich arrangement (layer / layer structure) is realized. By means of the metallic component 20th is the recess 14th locked. Thus the recess is 14th by means of the circuit carrier 8th , the metallic component 20th and the spacer 12th limited. In summary, the metallic component 20th from the circuit carrier 8th spaced, and the spacer 12th is between the circuit carrier 8th and the metallic component 20th arranged and lies on these over the respective adhesive layers 16 , 18th on. Inside the recess 14th of the spacer 12th is the component 10 arranged.

The metallic component 20th has two holes 22nd on by the metallic component 20th reach through and in the recess 14th end, so flow there. The two holes 22nd are, for example, the same, or one of the holes 22nd has, as shown, an enlarged diameter. The holes 22nd run perpendicular to the expansion direction of the metallic component 20th and consequently also perpendicular to the circuit carrier 8th .

The recess 14th is about the holes 22nd by means of a potting compound 24 filled in and completely filled out by means of this. The casting compound is a casting resin, which in the liquid state through one of the holes 22nd into the recess 24 is introduced and cured there. The potting compound 24 has a comparatively large coefficient of thermal conductivity, at least one coefficient of thermal conductivity that is greater than 0.2 W / mK. Thus the component is 10 by means of the potting compound 24 thermal with the metallic component 20th contacted, and the metallic component 20th and the circuit carrier 18th are by means of the potting compound 24 stabilized to each other. During operation, a by means of the component 10 generated heat loss via the potting compound 24 to the metallic component 24 out, which thus acts like a heat sink. In an alternative embodiment, the component is 10 a temperature sensor, and by means of the potting compound 24 becomes an operating temperature of the metallic component 20th to the component 10 guided, due to the potting compound 24 electrical insulation is realized between them.

The electrical circuit also includes 4th two contact pins 26th made from tinned copper, namely tinned CUSN6. The two contact pins 26th are outside the recess 14th and are from the metallic component 20th spaced. The contact pins 26th are on the circuit board 8th soldered on, for which a pin-in-paste process is used. A large part of the contact pin is located here 26th on the side of the circuit board 8th on which the component is located 10 is located. The contact pins 26th are electrically connected to the inside of the recess by means of conductor tracks not shown 14th located component 10 electrically contacted. In the assembled state is on the contact pins 26th a electrical line connected, or the contact pins 26th are plugged into corresponding sockets. This is done by means of the contact pins 26th conducting an electrical current to the device 10 or applying and / or tapping one on the component 10 applied electrical voltage.

In 4th is a procedure 28 for making the electrical circuit 4th shown. In a first step 30th become the component 10 , any other electrical / electronic components and the contact pins 26th in a single process step on the circuit carrier 8th soldered on. A reflow process is used for this, so that the component 10 by means of an SMD process and the contact pins 26th using a THR process on the circuit carrier 8th are soldered on. Thus the circuit carrier is 8th with the component soldered to it 10 as well as the contact pins soldered to it 26th provided.

In a second step 32 becomes the spacer 12th on the circuit carrier 8th positioned and there by means of the first adhesive layer 16 attached. Here is the component 10 inside the recess 14th arranged. In a subsequent third step 34 becomes the metallic component 20th by means of the second adhesive layer 18th glued to the spacer. The metallic component 20th is arranged such that the holes 22nd in the recess 14th flow out. In summary, after completing the third step 34 the spacer 12th with the recess 14th such between the circuit carrier 8th and the metallic component 20th arranged that the component 10 is arranged within the recess, the spacer 10 on the circuit carrier 8th and on the metallic component 20th is applied.

In a subsequent fourth step 36 becomes the recess 14th by means of the potting compound 24 filled. This is about the hole 22nd , which has the larger diameter, the casting compound 24 filled. Over the other hole 22nd which escapes in front of it in the recess 14th air. By means of the spacer 12th is a form for the casting compound 24 provided, so that an uncontrolled escape of the potting compound 24 out of the recess 14th is avoided. When the recess 14th completely by means of the potting compound 24 is filled, it is cured so that a solid is formed by means of it. The potting compound 24 encloses the component 10 and is due to their adhesive properties on the circuit board 8th and on the metallic component 10 glued, thus by means of the potting compound 24 are stabilized to each other. Also is the component 10 by means of the potting compound 24 thermally with the metallic component 20th coupled.

The metallic component 20th shows the two holes 22nd on, one of which is the filling of the potting compound 24 and the other is used for ventilation. In a further variant, not shown in detail, the circuit carrier 8th the holes 22nd on that in the recess 14th ends and the filling with the potting compound 24 serve. In this case the metallic component is 20th preferably designed intact.

In summary, due to the combination of the component 10 , which is a surface-mountable component (SMD component), of the spacer 12th , which is made in particular from a foam plastic, as well as the contact pins 26th on the circuit carrier 8th , which is designed as a printed circuit board, created additional options for the component 10 as close as possible to the metallic component 20th place, i.e. at its effective range. Because of the potting compound 24 a comparatively efficient heat transfer and a mechanical fixation on the metallic component take place 20th .

Because of this type of structure, which is in particular a layer / layer structure, it is possible to adapt the coefficients of thermal expansion of the individual components, in particular the potting compound 24 on the circuit carrier 8th and / or on the metallic component 20th . Adaptation of temperature transitions between the respective components is also possible. In addition, due to such a type of arrangement of the component 10 also reduced manufacturing costs. Consequently, the connection of the metallic component in particular is summarized 20th by means of the potting compound 24 on the circuit carrier 8th realized.

The circuit carrier 8th is a comparatively solid base substrate, which in particular provides space for the component 10 as well as further electrical / electronic components and the conductor tracks connecting them. The contact pins in particular are used to carry on the respective electrical signal / current 26th used, which are expediently soldered to the circuit board in a pin-in-paste process.

As an application, by means of the component 10 a physical variable is converted into an electrically measurable variable, in particular a temperature into an electrical resistance. In other words, is the component 10 in this application a temperature sensor. The potting compound represents 24 the thermal and mechanical connection of the component 10 on the metallic component 20th for sure. The metallic component 20th is expediently designed as a metal plate. In particular, the metallic component is 20th created from a single metal or different metals. The circuit carriers 8th is a printed circuit board that expediently has the material identifier FR 4th is fulfilled and rigidly designed.

By means of the spacer 12th especially with the help of the two adhesive layers 16 , 18th , an assembly aid that can be used, for example, for the pre-application of the circuit carrier 8th on the metallic component 20th supported. The spacer is also used 12th keeping the distance between the circuit carrier 8th and the metallic component 20th so that they are not in direct contact with one another. Furthermore, the recess 14th by means of the spacer 12th sealed, so when filling the potting compound 24 this cannot escape. The spacer 12th is made, for example, from a Poron foam, that is to say a polyurethane, and is expediently designed to be adhesive on both sides, so suitably has the two adhesive layers 16 , 18th on. The two adhesive layers 16 , 18th simplify the production and expediently take essentially no further task after production. Thus, comparatively inexpensive adhesives can be used. The contact pins 26th are expediently made from a tinned copper, for example from a tinned CUSN 6 .

Inside the recess 14th is the component 10 arranged, with several such components in a variant not shown 10 in the recess 14th are arranged. The component 14th is, for example, active or passive and is in particular a temperature-sensitive semiconductor component that thus functions as a temperature sensor.

List of reference symbols

2

Home appliance

4th

electrical circuit

6

Electric motor

8th

Circuit carrier

10

electrical / electronic component

12th

Spacers

14th

Recess

16

first adhesive layer

18th

second adhesive layer

20th

metallic component

22nd

hole

24

Casting compound

26th

Contact pin

28

Procedure

30th

first step

32

second step

34

third step

36

fourth step

III

Cutting plane

Claims (10)

Electrical circuit (4), in particular of a household appliance (2), with a circuit carrier (8) to which an electrical or electronic component (10) is soldered, and with a metallic component (20) which is spaced from the circuit carrier (8) is, as well as with a spacer (12) which is arranged between the circuit carrier (8) and the metallic component (20) and rests against them, and which has a recess (14) within which the component (10) is arranged, wherein the recess (14) is filled by means of a potting compound (24), and wherein the spacer (12) is made from a foam, namely a polyurethane. Electrical circuit (4) according to Claim 1 , characterized in that the recess (14) is delimited by means of the circuit carrier (8), the metallic component (20) and the spacer (12). Electrical circuit (4) according to Claim 1 or 2 , characterized in that the component (10) is spaced from the delimitation of the recess (14). Electrical circuit (4) according to one of the Claims 1 to 3 , characterized in that the circuit carrier (8) is a printed circuit board. Electrical circuit (4) according to one of the Claims 1 to 4th , characterized in that the metallic component (20) is a metal plate which is arranged parallel to the circuit carrier (8). Electrical circuit (4) according to one of the Claims 1 to 5 , characterized in that the metallic component (20) is a heat sink. Electrical circuit (4) according to one of the Claims 1 to 6 , characterized in that the metallic component (20) has a hole (22), expediently two holes (22), which ends in the recess (14). Electrical circuit (8) according to one of the Claims 1 to 7th , characterized in that the component (10) is a surface-mountable component. Electrical circuit (8) according to one of the Claims 1 to 8th , characterized in that a contact pin (26) is soldered to the circuit carrier (8), which contact pin is in electrical contact with the component (10) and which is arranged outside the recess (14). Method (28) for producing an electrical circuit (4) according to one of the Claims 1 to 9 - A circuit carrier (8) with an electrical or electronic component (10) soldered to it is provided, - a spacer (12) made of a foam, namely a polyurethane, with a recess (14) between the circuit carrier (8) and a metallic component (20) is arranged, that the component (10) is arranged within the recess (14), the spacer (12) resting on the circuit carrier (8) and on the metallic component (20), and - the Recess (14) is filled by means of a potting compound (24).

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