Circuit assembly comprising a switching element and a connecting pin for a reference potential

Abstract

The invention relates to a circuit assembly comprising a ceramic substrate which has an electrically conductive reference layer for an electrical reference potential on the rear face and which has an electrically conductive potential layer on the front face, the potential layer having a first subregion for a first electrical potential and a second subregion for a second electrical potential. The circuit assembly further comprises at least one switching element having a first contact region which is electrically conductively connected to the first subregion and having a second contact region which is electrically conductively connected to the second subregion. Furthermore, the circuit assembly comprises an electrically conductive connecting pin which runs through the ceramic substrate from the rear face to the front face of the ceramic substrate and which is electrically conductively connected to the reference layer.

Description

[0001] 24-1694

[0002] - 1 -

[0003] Circuit arrangement with a switching element and a connecting pin to a reference potential

[0004] The invention relates to a circuit arrangement with one or more switching elements, in particular for providing an inverter for the operation of an electric drive motor of a motor vehicle.

[0005] Today's available switching elements, such as Si-IGBTs and / or SiC MOSFETs, exhibit relatively low switching losses and can be operated at relatively high temperatures and / or relatively high switching frequencies. This makes it possible to increase the power and quality of inverters for operating an electric motor in a motor vehicle.

[0006] Parasitic capacitances in the vehicle's electrical drive system can (due to the relatively high switching frequencies) cause a common-mode current that flows from the inverter to other electrical components of the drive system. This common-mode current can lead to electromagnetic emissions in the vehicle's electrical drive system.

[0007] 28.01.202524-1694

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[0009] This document addresses the technical task of limiting the common-mode currents caused by the operation of a switching element to the immediate vicinity of the switching element in an efficient and reliable manner.

[0010] The problem is solved by the independent claim. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a dependent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent claim, which can be made the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can constitute an invention independent of the features of the independent claims.

[0011] According to one aspect, a circuit arrangement is described that comprises a ceramic substrate having an electrically conductive reference layer on its back side for an electrical reference potential, and an electrically conductive potential layer on its front side (opposite the back side) that has a first sub-area for a first electrical potential and a second sub-area for a second electrical potential. The first potential can be the positive potential of a DC voltage, and the second potential can be the negative potential of the DC voltage. The reference potential can correspond to ground. The ceramic substrate can be an active metal brazed (AMB) ceramic substrate, in particular.

[0012] The circuit arrangement further comprises at least one switching element having a first contact area which is electrically conductively connected to the first sub-area (e.g. via a bond wire), and which

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[0015] The switching element has a second contact area that is electrically connected to the second sub-area (e.g., via a soldered connection). The switching element may comprise a semiconductor-based switching element, in particular a MOSFET (metal oxide semiconductor field-effect transistor), especially a silicon carbide (SiC) MOSFET, and / or an IGBT (insulated gate bipolar transistor), especially a silicon (Si) IGBT.

[0016] Furthermore, the circuit arrangement includes an electrically conductive connecting pin that extends through the ceramic substrate from the back to the front and is electrically connected to the reference layer. The connecting pin can be located in a bore in the ceramic substrate that extends from the back to the front.

[0017] The electrically conductive potential layer on the front side of the ceramic substrate preferably has a recess for the connecting pin, wherein the recess is designed to electrically insulate the connecting pin from the first sub-region and from the second sub-region. The recess can completely enclose the connecting pin.

[0018] The connecting pin is preferably arranged in close proximity to the switching element. The ceramic substrate can, for example, have a certain thickness between its back and front surfaces. The connecting pin can be arranged along the front surface of the ceramic substrate at a distance from the switching element that is at most 10 times (i.e., at most 10 times), in particular at most 5 times or at most 2 times, the thickness of the ceramic substrate.

[0019] Thus, a circuit arrangement is described which has a connecting pin through which the reference potential can be applied directly to the front of the ceramic

[0020] 28.01.202524-1694

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[0022] Substrates are provided so that the common-mode current caused by the switching element can be dissipated in the immediate vicinity of the switching element. This allows electromagnetic emissions from the circuit arrangement to be reduced efficiently and reliably.

[0023] The circuit arrangement can include a first electrical component located on the front face of the ceramic substrate between the connecting pin and the first sub-area. Alternatively or additionally, the circuit arrangement can include a second electrical component located on the front face of the ceramic substrate between the connecting pin and the second sub-area. The first component and / or the second component can each include a Y-capacitor. This allows for the efficient and reliable reduction of electromagnetic emissions from the circuit arrangement.

[0024] The circuit arrangement can include a housing that encloses the ceramic substrate and the switching element. Furthermore, the circuit arrangement can have a contact element, in particular a pin, on the outside of the housing, which is electrically connected to the connecting pin on the front of the ceramic substrate. This efficiently provides external access to the reference potential, which has a low impedance.

[0025] According to another aspect, an inverter for an electric drive system of a (motor) vehicle is described, wherein the inverter comprises one or more circuit arrangements, each designed as described in this document.

[0026] According to another aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle)

[0027] 28.01.202524-1694

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[0029] described, which includes the circuit arrangement described in this document (e.g. as part of the vehicle's electric drive system).

[0030] It should be noted that the devices and systems described in this document can be used both alone and in combination with other devices and systems described in this document. Furthermore, any aspect of the devices and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways. Features listed in parentheses are to be understood as optional features.

[0031] The invention will now be described in more detail using exemplary embodiments.

[0032] Figure 1 shows an exemplary vehicle with a circuit arrangement;

[0033] Figure 2a shows a side view of an exemplary section of a circuit arrangement; and

[0034] Figure 2b shows a top view of an exemplary connecting pin to the reference potential of the circuit arrangement.

[0035] As stated at the outset, this document deals with the reduction of electromagnetic emissions caused by the operation of a switching element. In this context, Fig. 1 shows an exemplary vehicle 100 with a circuit arrangement 110 that causes electromagnetic emissions 115. The circuit arrangement 110 can, for example, be part of an inverter of the vehicle 100, which is configured to generate a multiphase alternating current for the operation of an electric drive motor (not shown) of the vehicle 100, based on the direct current supplied by an electrical energy storage device (not shown) of the vehicle 100.

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[0038] Fig. 2a shows a side view of an exemplary circuit arrangement 110, wherein the circuit arrangement 110 comprises at least one switching element 206 configured to be repeatedly opened and closed (e.g., at a specific switching frequency, such as 10 MHz or more). The switching element 206 can be a semiconductor-based switching element, in particular an IGBT (insulated-gate bipolar transistor) or a MOSFET (metal oxide field-effect transistor). The switching element 206 can be arranged on a ceramic-based substrate 202, wherein the ceramic substrate 202 has a conductive layer arranged on the front face of the electrically insulating ceramic substrate 202. The conductive layer can be divided into different sub-regions 205, 207, e.g., a first sub-region 205 for a first electrical potential (e.g., for a positive potential) and a second sub-region 207 for a second electrical potential (e.g.,(for a negative potential).

[0039] The switching element 206 can be a so-called vertical switching element 206, which has a first contact area (e.g., a source or a drain) on its upper side (facing away from the ceramic substrate 202) and a second contact area (e.g., a drain or a source) on its lower side (facing the ceramic substrate 202). The second contact area of ​​the switching element 206 can be electrically connected to the second sub-area 207, and the first contact area of ​​the switching element 206 can be electrically connected to the first sub-area 205 via a conductor element 203 (e.g., a so-called bond wire).

[0040] On the back side of the ceramic substrate 202 (facing away from the switching element 206) another electrically conductive layer 201 can be arranged, to which a reference potential, e.g. ground, is preferably applied.

[0041] The use of a ceramic substrate 202 is advantageous because the ceramic substrate 202 has a relatively high thermal conductivity, so that the

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[0044] The thermal power loss of the switching element 206, which arises during the operation of the switching element 206, can be reliably dissipated.

[0045] The circuit arrangement 110 shown in Fig. 2a has an electrically conductive connecting pin 210 extending from the rear to the front of the ceramic substrate 202, configured to provide the reference potential applied to the further layer (i.e., the reference layer) 201 directly to the front of the ceramic substrate 202. The connecting pin 210 may pass through a bore in the ceramic substrate 202. As can be seen from the top view in Fig. 2b, the electrically conductive layer (i.e., the potential layer) on the front of the ceramic substrate 202 may have a recess 212 around the connecting pin 210 to electrically isolate the connecting pin 210 from the one or more sub-regions 205, 207 of the electrically conductive (potential) layer on the front of the ceramic substrate 202.

[0046] The electrically conductive connecting pin 210 is preferably arranged as close as possible to the switching element 206. The connecting pin 210 thus makes it possible to place the reference potential in the immediate vicinity of the electrical contact areas of the switching element 206, so that common-mode currents in the immediate vicinity of the switching element 206 can be diverted to the reference potential in order to reduce the extent of electromagnetic emissions 115 of the circuit arrangement 110.

[0047] In the example shown in Fig. 2a, the circuit arrangement 110 has a first Y-capacitance 211, which is arranged between the connecting pin 210 and the first sub-area 205 (with the first potential). Furthermore, the circuit arrangement 110 has a second Y-capacitance 211, which is arranged between the connecting pin 210 and the second sub-area 207 (with the second potential). In this way, electromagnetic emissions 115 of the circuit arrangement 110 can be reduced in a particularly reliable manner.

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[0050] The circuit arrangement 110 can have a housing 220 that encloses the ceramic substrate 202 and the switching element 206. One or more contact elements 221, in particular pins, can be arranged on the outside of the housing 220, via which the circuit arrangement 110 can be integrated into a higher-level circuit. For example, the circuit arrangement 110 can be placed on a higher-level printed circuit board of a circuit of the vehicle's drive system 110 via the one or more contact elements 221. Examples of contact elements 221 are:

[0051] • a contact element 221 for the first potential;

[0052] • a contact element 221 for the second potential:

[0053] • a contact element 221 for the connecting pin 210; and / or

[0054] • a contact element 221 for a control port (e.g. for the gate) of the switching element 206.

[0055] The circuit arrangement 110 can thus have a contact element 221 on the outside of the housing 220 of the circuit arrangement 110, which is electrically connected to the connecting pin 210 on the front of the ceramic substrate 202. The one or more Y-capacitors 211 can optionally be connected to the contact element 221, e.g., if internal installation of Y-capacitors 211 within the housing 220 of the circuit arrangement 110 is not possible or desired.

[0056] Y-capacitors 211 can therefore be used to reliably prevent the propagation of common-mode current from the switching element 206 to other electrical components of the vehicle's electric drive system. The Y-capacitors 211 can each be arranged between the positive or negative terminal of the DC voltage and the reference potential. The connecting pin 210 described in this document provides a connection path to the reference potential, which has a particularly low impedance, thus preventing the propagation of the

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[0059] common-mode current can be prevented and / or spatially limited in a particularly reliable manner.

[0060] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures are intended only to illustrate the principle of the proposed devices and systems by way of example.

[0061] January 28, 2025

Claims

24-1694 - 10 - Claims 1) Circuit arrangement (110) comprising, - a ceramic substrate (202) having on a back side an electrically conductive reference layer (201) for an electrical reference potential, and having on a front side an electrically conductive potential layer having a first sub-area (205) for a first electrical potential and a second sub-area (207) for a second electrical potential; - at least one switching element (206) having a first contact area that is electrically conductively connected to the first sub-area (205), and having a second contact area that is electrically conductively connected to the second sub-area (207); and - an electrically conductive connecting pin (210) which extends through the ceramic substrate (202) from the back to the front of the ceramic substrate (202) and is electrically connected to the reference layer (201). 2) Circuit arrangement (110) according to claim 1, wherein - the potential layer on the front side of the ceramic substrate (202) has a recess (212) for the connecting pin (210); - the recess (212) is designed to electrically insulate the connecting pin (210) from the first sub-area (205) and from the second sub-area (207); and - the recess (212) completely encloses, in particular, the connecting pin (210). 3) Circuit arrangement (110) according to one of the preceding claims, wherein the connecting pin (210) is arranged in a bore of the ceramic substrate (202) extending from the back to the front of the 28.01.202524-1694 - 11 - ceramic substrate (202) runs. 4) Circuit arrangement (110) according to one of the preceding claims, wherein - the circuit arrangement (110) comprises a first electrical component (211) located on the front side of the ceramic substrate (202) between the connecting pin (210) and the first sub-area (205); and / or - the circuit arrangement (110) includes a second electrical component (211) which is located on the front of the ceramic substrate (202) between the connecting pin (210) and the second sub-area (205). 5) Circuit arrangement (110) according to claim 4, wherein the first component (211) and / or the second component (211) each comprise a Y-capacitance. 6) Circuit arrangement (110) according to one of the preceding claims, wherein the switching element (206) comprises, - a semiconductor-based switching element; and / or - a MOSFET, in particular a silicon carbide MOSFET; and / or - an IGBT, in particular a silicon IGBT. 7) Circuit arrangement (110) according to one of the preceding claims, wherein - the first potential is a positive potential of a DC voltage; - the second potential is a negative potential of the DC voltage; and / or - corresponds to the reference potential of a mass. 28.01.202524-1694 - 12 - 8) Circuit arrangement (110) according to one of the preceding claims, wherein - the circuit arrangement (110) comprises a housing (220) that encloses the ceramic substrate (202) and the switching element (206); and - the circuit arrangement (110) has on an outside of the housing (220) a contact element (221), in particular a pin, which is electrically connected to the connecting pin (210) on the front of the ceramic substrate (202). 9) Circuit arrangement (110) according to one of the preceding claims, wherein the ceramic substrate (202) comprises an active metal brazed, AMB, ceramic substrate, in particular is. 10) Inverter for an electric drive system of a vehicle (100), wherein the inverter comprises one or more circuit arrangements (110), each configured according to one of the preceding claims. January 28, 2025

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