Electronic device and retrofit device

Abstract

Electronic device (1) with a housing (3), a contact element, an electrical primary circuit (5) arranged in the housing (3), which comprises coils, capacitors and semiconductor elements arranged on a circuit board and electrically connected to one another according to a circuit diagram and which is electrically connected to the contact element, and at least one connector (7) provided on the housing (3), designed as an interface for connecting a further connector to the housing (3) and electrically connected to the electrical primary circuit (5) via a conductor (7A, 7B) running in the housing (3), characterized in that the conductor (7A, 7B) has an electrically contactable area and the electronic device (1) further an electronic retrofit device (21) arranged in the housing (3) with an additional board (23), wherein the retrofit device (21) has on the additional board (23) a secondary circuit (31) with a first electrical contact point and a second electrical contact point, and wherein the retrofitting device (21) is detachably electrically connected to the contactable region of the conductor (7A, 7B) via the first electrical contact point and is electrically connected to the contact element via the second electrical contact point.

Description

[0001] The invention relates to an electronic device having an electrical and / or electronic primary circuit and at least one connector configured as an interface for connecting another connector and having a conductor electrically connected to the primary circuit. Furthermore, the invention relates to an electronic retrofit device for an electronic device.

[0002] The design of electronic devices takes place in a planning phase in which the desired functionality of the electronic device is implemented using electronic components of an electronic and / or electrical primary circuit. For example, a primary circuit with coils, capacitors, and semiconductor elements (such as transistors and microchips) are arranged on a circuit board and electrically connected, for example, by soldering, according to a circuit diagram. Examples of this include high-frequency electronics devices (such as radios, RF amplifiers, microwave devices, radar devices), control electronics (such as programmable logic controllers, stepper motor controllers, industrial computers, vehicle control units), and power electronics (such as power supplies, power supplies, and solar inverters).

[0003] The functionality of an electronic device can be impaired during operation due to the application conditions. For example, the electronics of an electronic device can be susceptible to EMC interference (EMC: electromagnetic compatibility). EMC interference can, for example, arise within the device or be coupled into the device via the interface as soon as an application-specific peripheral device is connected to the interface via a cable. EMC emissions can, for example, be in the frequency range from 30 MHz to 400 MHz. EMC filters that act passively (filtering) or actively (counteracting) on ​​EMC interference can be integrated into the primary circuit. EMC filters are known in the art, see, for example, DE 11 2010 005 976 T5 or DE 10 2020 108 879 A1.However, EMC interference potentials often only become apparent under specific application conditions such as a connected cable or a specific incoming signal, whereby the application conditions cannot always be foreseen when designing the electronic device.

[0004] To avoid the need to redesign the electronic device to accommodate the functionality of a specific EMC filter, the creation of an EMC interference potential outside the housing of the electronic device on the cable can be counteracted using a folding ferrite core. Furthermore, an EMC filter can be provided (on the cable side). See, for example, DE 10 2018 107 116 B4 for an exemplary embodiment of an EMC-filtering cable receptacle or DE 10 2016 212 029 A1 for an EMC adapter with an EMC filter that is inserted between a cable and a component as a feedthrough filter.

[0005] DE 699 23 652 T2 further discloses a modular filtered connector (e.g., a socket) designed to connect a modular plug to a printed circuit board via end portions of conductors protruding from the socket housing. In the socket housing of the connector, capacitor modules are connected to the connector's conductors, providing a desired capacitance and capable of meeting a 1000 V dielectric strength requirement. The capacitor modules comprise U-shaped capacitor tracks arranged on one side of a dielectric substrate, each of which is connected to a conductor of the connector, and, arranged on the other side of the substrate, a large capacitor attenuator connected to the connector's ground.

[0006] More generally, after the design of an electronic device has been completed, an extension of the electronic device's functionality may be required, which must be implemented into the primary circuit as part of a time-consuming and costly redesign of the electronic device. The redesign may add electronic components such as inductors, capacitors, and semiconductor elements to the primary circuit.

[0007] The invention proposed herein particularly relates to such functional extensions of a primary circuit that independently process an incoming signal from an interface or that—such as the example of in-circuit EMC filtering—act on an unwanted signal or its generation. Examples of such upgrades include a filter circuit unit (e.g., the EMC filter explained above), an analysis circuit unit (e.g., a power test circuit for testing a functional state), or an output circuit unit (e.g., a light signal circuit for indicating a functional state) in the electronic device.Further retrofittable functionalities may include controlling additional interfaces, such as CAN (Controller Area Network) or Ethernet interfaces, HDMI (High Definition Multimedia Interface) interfaces, analog or digital IO ports, and communication interfaces. Such functionalities, which generally take into account the application conditions of the electronic device and the incoming signals, can be added to the electronic device as part of a revision and expansion of the primary circuit (generally in the form of a redesign).

[0008] The concepts disclosed herein are directed, at least in part, to improving one or more aspects described with regard to the functional expansion of electronic devices. Thus, one aspect of this disclosure is based on the object of simplifying the retrofitting process of a functionality such as EMC filtering during the manufacture of an electronic device, in particular, accelerating the manufacturing process and reducing the susceptibility to errors.

[0009] Another aspect of this disclosure is the task of being able to quickly expand finished electronic devices with retrofittable functionality.

[0010] At least one of these objects is achieved by an electronic device according to claim 1. Further developments are specified in the subclaims.

[0011] As an alternative to a new design, the functionality to be added can be provided according to the invention in a separate electrical and / or electronic secondary circuit of a retrofit device, wherein the retrofit device is designed in such a way that it can be installed (at least temporarily, i.e. before implementation of a new design) in an electronic device that is already intended for production and has been defined with regard to the primary circuit. In this case, the secondary circuit is spatially and electronically integrated into the existing implementation of the electronic device. This means that the geometric dimensions of the secondary circuit or the underlying additional board are adapted to the structure of the electronic device, in particular to the interior of a housing. For simple retrofitting, the electrical connectivity of the secondary circuit is simple - in contrast to the usual permanent soldering of, for example,EMC filter into the primary circuit. This allows a separate, subsequent retrofitting step to be carried out, reducing the time required and at least significantly reducing the risk of damage to the primary circuit.

[0012] In one aspect, an electronic device comprises a housing, a contact element, and an electrical primary circuit arranged in the housing, which is electrically connected to the contact element. Furthermore, the electronic device comprises at least one plug connector provided on the housing. The plug connector is designed as an interface for connecting a further plug connector to the housing and is electrically connected to the electrical primary circuit via a conductor running in the housing. The conductor has an electrically contactable region. The electronic device further comprises an electronic retrofit device arranged in the housing, said retrofit device having an additional board, wherein the retrofit device has a secondary circuit on the additional board with a first electrical contact point and a second electrical contact point.The retrofit device is detachably connected to the contactable area of ​​the conductor via the first electrical contact point and to the contact element via the second electrical contact point. The electronic device represents an electronic apparatus.

[0013] In a further aspect, an electronic retrofit device comprises an add-on board having a secondary circuit with a first electrical contact point and a second electrical contact point, wherein a first electrical contact means provides the first electrical contact point, and the retrofit device is detachably electrically connectable via the first electrical contact point to a contactable region of a conductor of an electronic device and via the second electrical contact point to a contact element of the electronic device. To effect electrical contact, the first electrical contact means mechanically contacts the contactable region of the conductor with the contact point.

[0014] In some further developments, the contactable area of ​​the conductor can be arranged spatially between the connector and the primary circuit.

[0015] For example, the conductor may be designed as a solder pin that is soldered to the primary circuit at a soldering point, wherein the contactable area of ​​the conductor is an input-side or output-side surface section of the soldering point.

[0016] In some embodiments, the housing can form the contact element and, in particular, form a shield GND potential for the primary circuit, for example. If the housing is then electrically connected to the second electrical contact point, the housing can also form a shield GND potential for the secondary circuit.

[0017] In some embodiments, the connector is mounted in a section of the housing and the conductor is a (output / input / GND) conductor of the connector running in the housing.

[0018] In some embodiments of the retrofit device, it can comprise a retaining plate that is electrically connected to the section of the housing. The housing can thus provide a counterforce to a compressive force that creates the electrical connection between the first electrical contact point and the contactable region of the conductor, for example, to create / ensure mechanical contact between the electrically conductive surfaces. For example, the retaining plate can be designed as a U-shaped sheet metal bracket.

[0019] In some further developments, an electrical connection between the additional board and the retaining plate can be formed by means of: - a cabinet bracket that engages in a recess of the additional board, - a solder connection between the retaining plate and a solder pin of the additional board or - a contact spring or a conductive material such as conductive rubber or conductive foam.

[0020] In general, the contact element is an electrically contactable element that, within the secondary circuit, can be at a designated potential, for example, or represent a signal input or output with a corresponding potential profile. In some embodiments, the electronic device can further comprise a sheet metal component as a (potential) contact element, which forms, for example, a GND potential for the primary circuit and is electrically connected to the second electrical contact point.

[0021] In some developments, the connector may have a further conductor which forms the contact element and is electrically connected to the second electrical contact point.

[0022] In some further developments, the additional board can be designed as a populated circuit board forming the secondary circuit.

[0023] In some further developments, the secondary circuit may include: - a filter circuit with electronic components such as ceramic capacitors and inductors, wherein the filter circuit is designed as an active or passive EMC filter circuit, - an additional circuit providing a power supply device and / or a further interface, or - generally an interface circuit that provides one or more interfaces such as CAN, HDMI or USB.

[0024] In some developments, the retrofit device may comprise a first electrical contact means that provides the first electrical contact point and mechanically contacts the contactable region of the conductor with the contact point to ensure electrical contact.

[0025] In some embodiments, the secondary circuit may comprise a second electrical contact means that provides the second electrical contact point for electrical connection to the contact element.

[0026] In some developments, the first electrical contact means and / or the second electrical contact means can: - be designed as part of a detachable plug-in, screw-in or clamp-in connection and / or - a contact spring or a spring contact connector, such as a pogo pin connector, or an elastically conductive material, such as a conductive rubber, or a clip connection.

[0027] In general, the electrical contact means can be designed for a detachable connection that mechanically creates the electrical connection.

[0028] In some developments, the retrofitting device can be arranged with respect to the contactable region of the conductor in such a way that for an electrical contact between the first electrical contact point and the contactable region of the conductor and / or for an electrical contact between the second electrical contact point and the contact element, a compressive force is exerted via the respective electrical contact means on the contactable region of the conductor and / or the contact element.

[0029] In some embodiments, the connector can be a connector plug or a connector socket, in particular a BNC plug or a BNC socket for connecting a coaxial cable, wherein the contactable area of ​​the conductor is in particular a DGND pin of a BNC socket. Additionally or alternatively, the connector can be provided for connecting the primary circuit to a peripheral device.

[0030] In some developments, the retrofit device can comprise a 3D molded part, in particular a 3D injection-molded part, with a printed conductor track and optionally an (integrated) electronic component of the secondary circuit, which is designed in particular as part of the plug connection.

[0031] With regard to the integration of an additional pluggable filter board (as an example of a retrofit device with an EMC filter as a secondary circuit), this can represent a simple and cost-effective solution for the production of retrofitted series products for a variety of EMC impacts at interfaces or EMC impacts due to EMC emissions from a plugged-in cable. This can result in the following advantages, for example: • When using a plug-in filter board in an electronic device, additional snap-on ferrites on the cable or feedthrough filters can be omitted. This indicates to the user of the electronic device that the product is of high quality. • An additional pluggable filter board can be used for various EMC problems on interfaces, connectors or cables, such as - Reduction of GND noise voltage on shielded cables and devices with a single GND; - Reduction of the GND noise voltage on shielded cables in devices with GND potential isolation; - Reduction of emissions from unshielded cables by filtering none or several critical wires / lines. • In the case of EMC issues at interfaces, an easily implemented retrofit can potentially avoid a product redesign (before market launch) altogether, thus shortening the time to market or bridging the time until a new primary circuit / assembly is available after a redesign with a high-quality product. A similar advantage generally arises for retrofits such as the aforementioned filter circuits, analysis circuits, power circuits, etc. • Compared to the alternative manual soldering of electronic components (e.g. capacitors of a filter circuit), there may be a time, cost and / or quality advantage in the production of appropriately retrofitted devices.

[0032] Preferred embodiments of such a retrofit device are to be adapted to the existing spatial conditions (dimensions of housing, interface (socket or plug) and primary circuit).

[0033] The retrofit device, and in particular a plug-in add-on board, can be implemented using common components, with the selection of components tailored to the application. For example, standard components such as a printed circuit board (PCB such as FR4 with copper), tinned sheet metal, electronic components such as capacitors and resistors, SMD clips / terminals, or springs can be used.

[0034] Disclosed herein are concepts that allow aspects of the prior art to be improved, at least in part. In particular, further features and their usefulness will become apparent from the following description of embodiments with reference to the figures. The figures show: Fig. 1 schematically shows an exemplary electronic device with a primary circuit arranged in a housing and connected to a connector, Fig. 2 shows the electronic device from Fig. 1 extended by an electronic retrofit device arranged in the housing, Fig. 3A shows schematically an exemplary additional board of the electronic retrofit device from Fig. 2, Fig. 3B shows the additional board of the electronic retrofit device with an exemplary bracket, Fig. 3C shows the assembled electronic retrofit device in a schematic sectional view to illustrate the mechanically effected electrical contact, Fig. 4 shows schematically an alternative embodiment of the additional board with regard to contacting, Fig. Figure 5 shows schematically an alternative arrangement in the retrofit device in the housing of an electronic device and Fig. Figure 6 illustrates exemplary arrangements of the retrofit device in the electronic device.

[0035] The aspects described herein are partly based on the realization that a non-soldered and thus detachable introduction of a secondary circuit, for example, by clipping or clamping an additional board (to provide mechanically supported electrical contact), can be easily incorporated into a manufacturing process. Such a retrofit process thus enables the production of a functional product, allowing for subsequent design adaptation.

[0036] The detachable electrical contact can be implemented, for example, using a detachable plug, screw, or clamp connection, a clip connection, a contact spring or a spring contact connector (such as a pogo pin connector), or an elastically conductive material (such as conductive rubber). This type of electrical contact has the advantage of being retrofittable by simply inserting and, for example, clamping on the additional board.

[0037] The inventors have generally recognized that, using the concepts proposed herein, it is possible to implement electronic devices early in a product, thereby learning about the application conditions of the electronic device and promptly addressing additional functionalities or requirements resulting from the application conditions by means of a retrofit device with an additional board.

[0038] The principle of an add-on board with a specific function—in the case of EMC, for example, reducing the GND noise voltage or subsequently filtering networks at interfaces—can be implemented differently depending on the given geometry. In the exemplary embodiment described in conjunction with the figures, the contacting required for retrofitting is achieved via conductive contact materials on the connector side inside the housing. Alternatively or additionally, an add-on board with an expanded function can be provided close to the primary circuit, for example, on the solder side of a printed circuit board. In general, contacting of a conductor of a plug or socket can be achieved using contact materials and contact configurations as known in the prior art.

[0039] In addition to the mounting and electrical connection of the add-on board to a primary circuit of an electronic device, it can also be screwed or bonded to the housing for mounting. This can be done particularly for a second electrical connection of the add-on board (e.g., to the housing).

[0040] In connection with the Fig. 1 to 3B, a first example of an electronic device 1 with a retrofit device 3 is described below.

[0041] Fig. Figure 1 shows the electronic device 1 with an (electrical and / or electronic) primary circuit 5 arranged in a housing 3. The housing 3 is partially shown schematically. Four connectors 7, 9, 11, 13 are arranged in pairs one above the other in a front wall 3A of the housing 3, which are electrically connected to the primary circuit 5 via conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B. The primary circuit 5 is formed, for example, on a PCB 15 and comprises a plurality of electronic components 6 (such as ceramic capacitors, inductors, electronic components, etc.). Fig. 1 shows areas of the conductors 7A, 7B, 9A, 9B, 11A that are accessible for retrofitting and can be used to contact a retrofit device. Such electrically contactable areas can, for example, be arranged so as to be accessible from the interior of the housing 3 during the design of the electronic device 1. Examples of the connectors 7, 9, 11, 13 are BNC sockets or BNC plugs, as used in high-frequency technology. For example, the connectors 7, 9, 11, 13 are mounted in the front panel 3A, insulated from the housing. In the example shown, the connectors 7, 9, 11, 13 are designed as a structural unit (for example, as a BNC 4-way socket). In exemplary embodiments, the primary circuit 5 is electrically shielded when the housing 3 is completely closed and is only connected to the external environment, ie, to other electronic devices / components, via the connectors 7, 9, 11, 13.

[0042] Fig. 2 shows the electronic device 1 of the Fig. 1, for the labeling of the corresponding components, refer to Fig. 1. The electronic device 1 is in Fig. 2 has been supplemented by a function that is provided by a retrofit device 21 built into the housing 3. The retrofit device 21 comprises an additional board 23 (see also Fig. 3A) and a U-shaped bracket 25 (see Fig. 3B). The holder 25 is clamped between the front wall 3A and the structural unit of the connectors 7, 9, 11, 13 and is thus electrically connected to the housing 3, for example made of metal. The additional board 23 is held by two side walls 25A of the holder 25 projecting into the interior of the housing 3 in such a way that an electrical connection is established between at least one electrical and / or electronic secondary circuit (see Fig. 3, secondary circuits 31) and at least one of the conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B. In particular, a detachable (not permanently connected / not soldered) electrical contacting option is implemented. Fig. 2 two clamping arms 27 on each of the side walls 25A, which are inserted through openings (see Fig. 3A, openings 29) protrude into the additional board 23 and (mechanically) clamp it. In other words, the holder 25 is designed to exert a clamping force on a rear side 23A of the additional board 23. When the housing 3 is closed, the secondary circuit and the primary circuit 5 are thus located within the housing 3.

[0043] Fig. Figure 3A shows a secondary circuit 31 specifically designed for retrofitting, which is provided on the additional board 23, for example an FR4. Electronic components 6 (such as ceramic capacitors, inductors, electronic components, etc.) of the secondary circuit 31 are shown in Fig. 3A. At least one of the secondary circuits 31 (in Fig. 3A all four secondary circuits 31) is electrically connected to one of the conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B by a contacting device 33 and is electrically connected to another electrical contact, for example the housing 3 or another of the conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B (see also Fig. 6 and corresponding description). Furthermore, one can see in Fig. 3A the openings 29, two each for each of the side walls 25A.

[0044] In Fig. 3B shows the retrofit device 21 in the non-installed state. Furthermore, it is shown how the holder 25 can be structurally / mechanically and electrically connected to the additional board 23. In the case of a stable mechanical design of the holder 25 (for example, as a U-shaped metal bracket), it can be seen that a clamping force can act on an inner side 23B of the additional board 23 in the installed state. The clamping force can, for example, ensure the electrical contact between the contacting devices 33 and contactable areas of the conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B through mechanical contact of electrically conductive surfaces. Examples of this are shown in the Fig. 3A-3C spring clips as contacting devices 33 are indicated schematically.

[0045] In Fig. 3C shows how the base 25B of the holder 25 is screwed between the housing wall 3A and the structural unit of the connectors 7, 9, 11, 13. The base 25B, for example, has recesses for the connectors 7, 9, 11, 13 protruding through the front wall 3A. The side walls 25A extend "around" the structural unit so that, with appropriate dimensions, the additional board 23 can be pressed against the conductors 7, 9, 11, 13.

[0046] A detachable retrofit, in particular one that does not rely on soldering, facilitates and enables the advantageous subsequent installation of a retrofit device 21; in particular, simple insertion and contacting of the secondary circuit 33 (e.g., by clamping on the additional board 23) allows for uncomplicated and solder-free implementation / retrofitting of additional functions in an already configured primary circuit 5.

[0047] The electrical contact to the secondary circuit 21 is made, for example, in the Fig. 3A-3C via a free conductor piece and a non-soldering mechanical connection, which represents a reversible fastening like the aforementioned detachable clamping. The non-soldering mechanical connection also represents a low-resistance connection based on pressure and preferably exhibits tolerance-compensating flexibility. Accordingly, the holder of the retrofit device can be attached to the housing 3 by generating / for generating a pressure force. The electrical connections to both the conductors and the housing can be established by clamping or clipping.

[0048] Fig. Figure 4 shows another exemplary embodiment of an additional board 23', which has spring clips 33' as contacting devices. When the additional board 23' is plugged in, the spring clips 33' clamp around the conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B, and thus—through mechanical contact—create reliable electrical contact between the secondary circuits 31 and the conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B.

[0049] Fig. 5 shows a further exemplary arrangement of an additional board 23" in a housing 3 of an electronic device 1'. Schematically, Fig. 5 shows a sectional view of how the conductors of the connector (conductors 7A and 11A are indicated by way of example) are soldered to the PCB 15, on which the primary circuit of the electronic device 1' is arranged. Schematically, soldered connection pins 35 are shown on a bottom side 15A of the PCB 15. For example, the connector can be a molded SUB-D connector, which does not allow an electrical connection with pins from the installation space. In this case, the additional board 23" can be inserted (clamped), for example, between a housing base 3B of the housing 3 and the bottom side 15A. Preferably, the additional board 23" is further dimensioned such that, for example (as in Fig. 5) by means of contact springs 33" a secondary circuit arranged on the additional board 23" can be connected to at least one of the conductors 7A, 7B, 9A, 9B, 11A, 11B, 13A, 13B. Furthermore, in Fig. 5 indicates that the secondary circuit of the additional board 23" can be electrically connected to the primary circuit of the electronic device 1' via at least one further contact spring 33" with another contact point (a connection pin 37 or also a solder-free copper area (e.g. a test point).

[0050] As a representative example of possible functions that can be implemented using the secondary circuit 31, an implementation of an EMC filter - in the case of galvanic isolation of the connector and the housing - is explained below.

[0051] During operation of an electronic device, the connector can generally be used as an output or input of the electronic device; i.e., a signal is tapped or fed via one of the connectors, e.g., with a coaxial connector and a coaxial cable. In an exemplary embodiment, the ground wire of the coaxial connector (the shield potential) can be highly insulated from the housing. In this case, the connector connection to the housing is mounted in the front panel in an insulated manner, thus providing DC isolation between the coaxial connector and the grounded housing.

[0052] During operation, reverse signals can develop in the shield of the coaxial cable, which represent an EMC interference potential. Such interference on the ground line can sometimes only be detected during the testing phase after the electronic device has been completed. According to the invention, EMC interference can now be reduced and preferably largely avoided using a retrofit device designed as an EMC filter unit that diverts the interference potential to the housing. For example, the retrofit device can be used with the EMC filter circuit (secondary circuit) provided on the additional board to provide a high-frequency connection between a ground connection of the plug connection, which is isolated from the housing, and the housing, without requiring a redesign of the electronic device. The EMC filter circuit is preferably positioned as close to the connector as possible (as in Fig. 3C) and connected to the ground wire, since short pins further reduce the susceptibility to induction.

[0053] Finally, Fig. 6 schematically shows an electronic device 101 with a housing 103 and a connector 107, wherein three exemplary configurations of a retrofit device for introducing additional functionality are shown in the housing 103. The configurations relate to the connection of a cable to the connector 107, and thus to the housing 103. In the housing 3, an electrical primary circuit is schematically shown on a PCB 115 with electronic components 6. The primary circuit is electrically connected to the connected cable via conductors running in the housing 103 through the plug connection.

[0054] In the first example, a retrofit device 121A provides a connection between a conductor 107A of the connector 107, in particular an electrically contactable area, and the housing 103, wherein the housing 103 represents a (potential) contact element of the secondary circuit 131A provided on an additional board 123A. The secondary circuit 131A has—shown schematically—a first electrical contact point 141A and a second electrical contact point 143A, at which it is detachably connected to the conductor 107A and the housing 103.

[0055] In the second example, a retrofit device 121B establishes a connection between two conductors 107A, 107B of the connector 107 via a secondary circuit 131B formed on an additional board 123B, wherein the secondary circuit 131B is in turn electrically connected to the housing 103 (contact points 141B, 143B).

[0056] In the third example, a retrofit device 121C includes a secondary circuit 131C mounted between the conductors 107A, 107B on an add-on board 123C. Each of the conductors includes a contact point 141C, 143C, which represents an electrically contactable area to which the secondary circuit 131C has been clamped, for example, to mechanically establish electrical contact.

Claims

[1] Electronic device (1) with a housing (3), a contact element, an electrical primary circuit (5) arranged in the housing (3), which comprises coils, capacitors and semiconductor elements arranged on a circuit board and electrically connected to one another according to a circuit diagram and which is electrically connected to the contact element, and at least one connector (7) provided on the housing (3), designed as an interface for connecting a further connector to the housing (3) and electrically connected to the electrical primary circuit (5) via a conductor (7A, 7B) running in the housing (3), characterized by , that the conductor (7A, 7B) has an electrically contactable area and the electronic device (1) further an electronic retrofit device (21) arranged in the housing (3) with an additional board (23), wherein the retrofit device (21) has on the additional board (23) a secondary circuit (31) with a first electrical contact point and a second electrical contact point, and wherein the retrofitting device (21) is detachably electrically connected to the contactable region of the conductor (7A, 7B) via the first electrical contact point and is electrically connected to the contact element via the second electrical contact point. [2] Electronic device (1) according to claim 1, wherein the contactable region of the conductor (7A, 7B) is spatially arranged between the connector (7) and the electrical primary circuit (5). [3] Electronic device (1) according to claim 1 or 2, wherein the conductor (7A, 7B) is designed as a solder pin which is soldered to the primary circuit (5) at a soldering point, and wherein the contactable region of the conductor (7A, 7B) is an input-side or output-side surface section of the soldering point. [4] Electronic device (1) according to one of the preceding claims, wherein the housing (3) forms the contact element and is electrically connected to the second electrical contact point and in particular forms a shield GND potential for the primary circuit (5). [5] Electronic device (1) according to one of the preceding claims, wherein the connector (7) is mounted in a portion of the housing (3) of the electronic device (1) and the conductor (7A, 7B) is a conductor of the connector (7) extending in the housing (3). [6] Electronic device (1) according to claim 5, wherein the retrofitting device (21) further comprises a holding plate which is electrically connected to the portion of the housing (3), and the housing (3) provides a counterforce to a compressive force causing the electrical connection between the first electrical contact point and the contactable region of the conductor (7A, 7B), and wherein the holding plate is designed in particular as a U-shaped sheet metal angle (25). [7] Electronic device (1) according to claim 6, wherein an electrical connection between the additional board (23) and the holding plate is formed by means of: - a cabinet bracket which engages in a recess (29) of the additional board (23), - a solder connection between the retaining plate and a solder pin of the additional board (23) or - a contact spring or a conductive material such as conductive rubber or conductive foam. [8] Electronic device (1) according to one of claims 1 to 3, further comprising a sheet metal component as a contact element, which forms a GND potential for the primary circuit (5) and is electrically connected to the second electrical contact point. [9] Electronic device (1) according to one of claims 1 to 3, wherein the connector (7) has a further conductor (7A, 7B) which forms the contact element and is electrically connected to the second electrical contact point. [10] Electronic device (1) according to one of the preceding claims, wherein the additional board (23) is designed as a populated circuit board forming the secondary circuit (31). [11] Electronic device (1) according to one of the preceding claims, wherein the secondary circuit (31) comprises - a filter circuit with electronic components, wherein the filter circuit is designed as an active or passive EMC filter circuit, - an additional circuit providing a power supply device and / or a further interface, or - an interface circuit that provides one or more interfaces. [12] Electronic device (1) according to one of the preceding claims, wherein the retrofitting device (21) comprises a first electrical contact means which provides the first electrical contact point and mechanically contacts the contactable region of the conductor (7A, 7B) with the contact point to ensure electrical contact, and / or where the secondary circuit (31) comprises a second electrical contact means providing the second electrical contact point for electrical connection to the contact element. [13] Electronic device (21) according to claim 12, wherein the first electrical contact means and / or the second electrical contact means - is designed as part of a detachable plug-in, screw-in or clamp-in connection and / or - comprises a contact spring or a spring contact plug or an elastically conductive material or a clip connection. [14] Electronic device (1) according to claim 12 or 13, wherein the retrofitting device (21) is arranged with respect to the contactable region of the conductor (7A, 7B) in such a way that for an electrical contact between the first electrical contact point and the contactable region of the conductor (7A, 7B) and / or for an electrical contact between the second electrical contact point and the contact element, a compressive force is exerted via the respective electrical contact means (33) on the contactable region of the conductor (7A, 7B) and / or the contact element. [15] Electronic device (1) according to one of the preceding claims, wherein the connector (7) is a connector plug or a connector socket and / or for connecting the primary circuit (5) to a peripheral device. [16] Electronic device (1) according to one of the preceding claims, wherein the retrofitting device (21) comprises a 3D molded part with a printed conductor track and with an integrated electronic component of the secondary circuit (31).

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