DE102024206500A1 - Electronic circuit, method and control device for operating an electronic circuit - Google Patents

Abstract

An electronic circuit (100) comprises a printed circuit board (105), a cooling element, a connecting device (115), and an insulating layer (120). An inner surface (150) of the cooling element (110) faces an inner surface (142) of the printed circuit board (105), the cooling element (110) forming at least one projection (154) on an outer surface (152) which is designed to extend into a channel (156) for guiding a cooling medium (200). The connecting device (115) is arranged in a space (170) between the printed circuit board (105) and the cooling element (110). The connecting device (115) forms a first connecting element (172a) with a base (174a) and a contact element (176a) adjacent to the base (174a), and a second connecting element (182a) with a base (184a) and a contact element (186a) adjacent to the base (184a). The undersides of the bases (174a, 184a) are arranged on the inside (150) of the cooling element (110). An upper surface of the contact element (176a) of the first connecting element (172a) is contacted on the inside (142) of the printed circuit board (105), with the contact element (186a) of the second connecting element (182a) extending at least partially through the through-hole (146) of the printed circuit board (105) of the electronic circuit (100). The insulating layer (120) is arranged on the outside (150) of the cooling element (110).

Description

The present invention relates to an electronic circuit, a method and a control device for operating an electronic circuit.

Parasitic stray inductances can occur in power electronics.

Against this background, the present invention provides an improved electronic circuit, an improved method, and an improved control device for operating an electronic circuit according to the main claims. Advantageous embodiments are described in the dependent claims and the following description.

The advantages achievable with the approach presented here consist in particular of creating an electronic circuit that can maximize the cooling performance of the electronic circuit.

An electronic circuit comprises a printed circuit board (PCB), a cooling element, a connector, and an insulating layer. The PCB has an outer surface and an inner surface opposite the outer surface. Additionally, the PCB has at least one conductive trace and at least one through-hole. The cooling element has an inner surface and an outer surface opposite the inner surface. The inner surface of the cooling element faces the inner surface of the PCB. The cooling element forms at least one projection on its outer surface, which is designed to extend into a channel for guiding a cooling medium. The connector is located in a space between the PCB and the cooling element. The connector forms a first connector with a base and a contact element adjacent to the base. A lower surface of the base is located on the inner surface of the cooling element. A top surface of the contact element contacts the inner surface of the PCB. The connector forms a second connector with a second base and a contact element adjacent to the second base. A lower surface of the second base is located on the inner surface of the cooling element. The contact element is at least partially routed through the through-hole of the circuit board of the electronic circuit. The insulating layer is located on the outside of the cooling element.

The printed circuit board can be manufactured cost-effectively and in large quantities. Due to its design, the connection element can reduce the height in the gap, thereby minimizing stray inductance. The first connection element can be at least partially T-shaped, and the second connection element can be at least partially L-shaped. The cooling element can incorporate a phase potential or a high-voltage potential. A component, such as a transistor, can be placed in the gap.

When designing power electronics for fast-switching applications, such as a gallium nitride transistor, correct layout design can be a crucial aspect to consider. The approach presented here can provide a current path layout geometry that reduces or eliminates parasitic leakage inductances, thus ensuring that the switching behavior of the fast-switching power electronics remains unaffected. In fast-switching applications, the leakage inductance (LCC) of a commutation loop can have the greatest impact on switching behavior and should be minimized as much as possible through proper layout. The gap height can be significantly reduced using the connection device to further reduce the corresponding leakage inductance (LCC).

The approach presented here, due to the insulating layer, enables the cooling element to achieve high thermal conductivity. Furthermore, heat dissipation can be increased because the distance between the component and the insulating layer can be large. This optimal cooling performance can lead to a low component temperature, reduced losses, and high performance of the power electronics.

The insulating layer can be roughened to facilitate contact between the outer surface of the cooling element and the cooling medium. Additionally or alternatively, the insulating layer can be metallized. This contact between the cooling element and the cooling medium can positively influence the cooling performance.

The cooling element can be made of copper. Copper has very good thermal conductivity.

The cooling element can form a further projection, which may be designed to extend into the channel for guiding a cooling medium or the cooling medium itself. An insulating layer can be arranged on the outer side of the projection, thereby enabling advantageous thermal conductivity.

The electronic circuit can have a retaining element to form the channel. The projection of this element can extend from the cooling element into the channel on the opposite side. A fluidic cooling medium, particularly oil or water, can be arranged and additionally or alternatively guided within the channel. Additionally or alternatively, the channel can be meandering along a main plane of extension of the cooling element. The cooling medium can advantageously be guided within the channel.

The electronic circuit can have a second cooling element with an inner surface and an outer surface opposite the inner surface. The inner surface of the second cooling element can face the inner surface of the printed circuit board. The second cooling element can form at least one further projection on its outer surface, which may extend into the channel or a further channel for conveying a cooling medium. The cooling element and the second cooling element can be identical, with the enclosing element being designed to separate the cooling elements from each other. The enclosing element can additionally form a second channel. The approach presented here can therefore also be understood as a separate heat sink with phase potential and high-voltage potential, with additional separate cooling water channels.

The enclosing element can include a separating element that can be designed to electrically isolate the cooling element and the second cooling element from each other. This allows for the advantageous design of separate heat sinks with phase potential and high-voltage potential.

The edging element can be configured to form the second channel, with the further projection extending from an opposite side of the edging element from the second cooling element into the second channel. The second channel can be configured to convey the cooling medium or a further cooling medium.

The separating element can form a subsection of the edging element.

The separating element can be designed to fluidically separate the channel and the second channel. In this way, the cooling medium can be arranged in one channel and the additional cooling medium in the second channel.

The electronic circuit can include at least one component, which may be located in the space between the printed circuit board and the heat sink. This component can be a high-side transistor or a low-side transistor. The heat sink may have a high-voltage potential, in which case the component can be a low-side transistor. A thermal interface material may be placed between the component and the inner surface of the heat sink.

A method for operating an embodiment of an electronic circuit mentioned herein comprises a step of guiding and/or conveying a cooling medium along the projection to cool the cooling element.

The approach presented here further creates a control device designed to perform, control, or implement the steps of a variant of the method presented here in appropriate facilities. This embodiment of the invention in the form of a device also allows the problem underlying the invention to be solved quickly and efficiently.

A control device can be an electrical device that processes electrical signals, such as sensor signals, and outputs control signals accordingly. The control device can have one or more suitable interfaces, which can be implemented in hardware and/or software. In a hardware implementation, the interfaces can, for example, be part of an integrated circuit in which the device's functions are implemented. The interfaces can also be separate integrated circuits or consist at least partially of discrete components. In a software implementation, the interfaces can be software modules that are present, for example, on a microcontroller alongside other software modules.

It is also advantageous to have a computer program product with program code that can be stored on a machine-readable medium such as semiconductor memory, hard disk memory or optical memory and is used to carry out the method according to one of the embodiments described above when the program is executed on a computer or device.

• 1 eine schematische Darstellung eines Ausführungsbeispiels einer elektronischen Schaltung;
• 2 eine schematische Darstellung eines Ausführungsbeispiels einer elektronischen Schaltung;
• 3 eine schematische Darstellung eines Ausführungsbeispiels einer elektronischen Schaltung;
• 4 ein Ablaufdiagramm eines Ausführungsbeispiels eines Verfahrens zum Betreiben einer elektronischen Schaltung; und
• 5 ein Blockschaltbild eines Ausführungsbeispiels einer Steuervorrichtung zum Betreiben einer elektronischen Schaltung.

The invention is explained in more detail by way of example with reference to the accompanying drawings. These show:

• 1 a schematic representation of an exemplary embodiment of an electronic circuit;
• 2 a schematic representation of an exemplary embodiment of an electronic circuit;
• 3 a schematic representation of an exemplary embodiment of an electronic circuit;
• 4 a flowchart of an exemplary embodiment of a method for operating an electronic circuit; and
• 5 A block diagram of an exemplary embodiment of a control device for operating an electronic circuit.

In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, without repeating these elements.

1 Figure 1 shows a schematic representation of an embodiment of an electronic circuit 100. More precisely, a longitudinal section through the electronic circuit 100 is shown.

The electronic circuit 100 comprises a printed circuit board 105, a cooling element 110, a connecting device 115, and an insulating layer 120. Optionally, the electrical circuit 100 comprises a mounting element 125, a second cooling element 130, and at least one component 135a.

The printed circuit board 105 has an outer surface 140 and an inner surface 142 opposite the outer surface 140. Additionally, the printed circuit board 105 has a conductor track 144, a through-hole 146, and, for example, a second through-hole 148. The conductor track 144 is, for example, located on the inner surface 142 of the printed circuit board 105.

The cooling element 110 has an inner surface 150 and an outer surface 152 opposite the inner surface 150. The inner surface 150 of the cooling element 110 faces the inner surface 142 of the circuit board 105. The insulating layer 120 is located on the outer surface 152 of the cooling element 110.

The cooling element 110 forms at least one projection 154 on its outer surface 152. According to one embodiment, the cooling element 110 forms a plurality of projections 154, here by way of example only four projections 154. The projections 154 extend into a channel 156 for guiding a cooling medium, wherein the cooling medium is in 1 not shown. The cooling medium is guided, for example, between the projections 154.

According to one embodiment, the channel 156 is formed by the edging element 125. In this way, the projections 154 extend into the channel 156. A fluidic cooling medium, such as that used in [reference to specific example], can be arranged in the channel 156. 2 shown.

The second cooling element 130 has an inner surface 160 and an outer surface 162 opposite the inner surface 160. The inner surface 160 of the second cooling element 130 faces the inner surface 142 of the circuit board 105.

The second cooling element 130 forms at least one projection 164 on its outer surface 162. According to one embodiment, the second cooling element 130 forms a plurality of projections 164, here, for example, four projections 164. The projections 164 extend into the channel 156 or another channel for guiding a cooling medium. The cooling medium is guided, for example, between the projections 164. The projections 164 can also be configured as multiple pins. This so-called pin fine structure increases the cooling performance of the heat sink and is prior art.

The cooling elements 110 and 130 are arranged adjacent to each other, with the enclosing element 125 having a separating element 168 located between the cooling elements 110 and 130. In this way, the separating element 168 electrically isolates the cooling elements 110 and 130 from one another. For example, cooling element 110 has a high-voltage potential, and cooling element 130 has a phase potential.

The separating element 168 only partially protrudes into the channel 156, so that the projections 154, 164 are not separated and the cooling medium flows through the channel 156.

The insulating layer 120 is arranged, for example, along the outer surface 152 of the cooling element 110 and along the outer surface 162 of the second cooling element 130. The insulating layer 120 is also arranged, for illustrative purposes only, on an outer surface of the separating element 168.

The insulating layer 120, for example, contacts the cooling medium, wherein the insulating layer 120 can be at least partially roughened according to one embodiment, so that the surface area is increased and the cooling performance is improved.

According to one embodiment, the cooling element 110 and/or the second cooling element 130 has a copper material, wherein the insulating layer 120 is, for example, metallized.

The connecting device 115 is arranged in a space 170 between the printed circuit board 105 and the cooling element 110 and/or the second cooling element 130. The connecting device 115 has a first connecting element 172a, which forms a base 174a and a contact element 176a adjacent to the base 174a. A bottom surface of the base 174a is located on the inner surface 150 of the cooling element 110, with a top surface of the contact element 176a contacting the inner surface 142 of the printed circuit board 105. The first connecting element 172a is, for example, T-shaped and can be referred to as a gate-source connector. Adjacent to the first connecting element 172a, for example, is the component 135a, which is located on the inner surface 150 of the contact element 110. More precisely, an electrically and thermally conductive layer, such as a solder or sintered layer 178a, is arranged between the component 135a and the inner surface 150 of the cooling element 110. The component 135a and the first connecting element 172a are connected and/or contacted, for example, by means of bond wires 180.

The connecting device 115 has a second connecting element 182a, which forms a second base 184a and a contact element 186a adjacent to the second base 184a. A bottom surface of the second base 184a is located on the inner side 150 of the cooling element 110, with the contact element 186a extending at least partially through the through-hole 146 of the circuit board 105. The second connecting element 182a is, for example, L-shaped and can be referred to as an HV connector. The second connecting element 182a reduces, for example, the height hcc of the gap 170.

According to one embodiment, the connecting device 115 has a third connecting element 172b, which is, for example, shaped identically to the first connecting element 172a. A lower surface 174b of the third connecting element 172b is arranged on the inner surface 160 of the second cooling element 130. A top surface 176b of the third connecting element 172b is contacted on the inner surface 144 of the circuit board 105.

The electronic circuit 100, for example, has a further component 135b, which is located adjacent to the third connecting element 172b in the space 170.

The additional component 135b is, for example, arranged on the inner surface 160 of the second cooling element 130. More precisely, a thermal interface material 178b is arranged between the additional component 135b and the inner surface 160 of the second cooling element 130. The additional component 135b and the third connecting element 172b are, for example, connected and/or contacted by means of bond wires 180, with the third connecting element 172b also being connected to the component 135a by means of bond wires 180. The additional component 135b is merely an example of a transistor, more precisely a semiconductor transistor and/or a high-side transistor, which can also be referred to as an HS transistor. The component 135a is also merely an example of a transistor, more precisely a semiconductor transistor and/or a low-side transistor, which can also be referred to as an LS transistor.

The connecting device 115, for example, has a fourth connecting element 182b, which is shaped identically to the second connecting element 182a (for illustrative purposes only) and can be designated as an HV+ connector. A bottom surface 184b of the fourth connecting element 182b is located on the inner surface 160 of the second cooling element 130. More precisely, the fourth surface 184b is a layer 185 located between the surface 184b and the inner surface 160 of the second cooling element 130. The layer 185 is, for example, a prepreg layer. According to one embodiment, the first connecting element 172a and the third connecting element 172b have at least part of the layer 185. A contact element 186b of the fourth connecting element 182b extends at least partially through the further through-opening 148 of the printed circuit board 105.

In an operational state, the electronic circuit 100 has a current path 190 running partially through it. This path is shown by arrows only as an example and, according to the embodiment shown here, runs counterclockwise. More precisely, the current path 190 runs through the conductor track 144 in the circuit board 105 and through the connecting elements 182a, 182b along the inner sides 150, 160 of the cooling elements 110, 130. The current path 190 also runs through the bases 174a, 174b of the connecting elements 172a, 172b and the thermal interface material 178a, 178b.

By arranging the connecting device 115 in the electronic circuit 100, the height hcc in the space 160 is reduced, the low height hcc resulting in an advantageous geometry of the current path 190, which enables low leakage inductance.

In an operational state of the electronic circuit 100, component 135a, for example, heats up. The electrically and thermally conductive layer 178a conducts the heat emanating from component 135a to the cooling element 110. The insulating layer 120, arranged between the cooling element 110 and the cooling medium, conducts the heat to the cooling medium in the channel 156. In this way, the cooling capacity is maximized. The arrangement of the cooling elements 110, 130, and/or the insulating layer 120 results in advantageous cooling of the electronic circuit 100.

The approach presented here maximizes cooling performance by placing a single insulating layer 120 exclusively between the cooling medium and the cooling element 110, which can also be referred to as a heat sink. This requires, for example, two separate cooling elements 110 and 130, which can also be called copper heat sinks. Cooling element 110 has a high-voltage potential, and the second cooling element 130 has a phase potential. The connecting device 115, which can also be referred to as a die, is sintered directly onto the cooling elements 110 and 130. This allows the heat to be dissipated directly, and the insulating layer 120 with thermal conductivity is applied much later and is distributed over a significantly larger area.

In the approach presented here, for example, a commutation loop, i.e., the current path 190, is closed with a minimal gap by the connection device 115, which can also be referred to as a board-to-board connector. Gate and source signals can also be routed to the circuit board 105 via the connection device 115.

Snubber capacitors and the gate circuit, i.e., resistor and capacitor, are placed, for example, on circuit board 105, not shown here. Alternatively, a partial and very simple layer 185 of prepreg and copper can be applied for the gate circuit.

The cooling medium is, for example, a non-conductive liquid such as oil, to remove the insulating layer 120. The surface of the insulating layer 120 is roughened, for example, to increase the area wetted by the cooling water. Additionally or alternatively, the insulating layer 120 can be re-metallized to achieve better heat transfer to the cooling medium.

2 Figure 1 shows a schematic representation of an embodiment of an electronic circuit 100. More precisely, a longitudinal section through the electronic circuit 100 is shown. The electronic circuit 100 is similar to or corresponds to the electronic circuit from Figure 1. 1 , except that the cooling medium 200 is shown and that the edging element 125 and/or the separating element 168 are designed differently.

According to one embodiment, the edging element 125 forms the channel 156 and a second channel 205. The separating element 168 forms, for example, a section of the edging element 125. The separating element 168 extends such that it fluidly separates the channel 156 and the second channel 205. The cooling medium 200 is arranged, for example, in the channel 156, while the cooling medium 200 or a second cooling medium 210 is arranged in the second channel 205.

In other words, it shows 2 two separate cooling elements 110, 130 with phase potential and HV potential with additional separate channels 156, 205, which can also be referred to as cooling water channels.

The approach presented here is a further development of the separate heat sink with phase potential and HV potential. 1 with the addition that channels 156 and 205 are also separate. Thus, for example, no additional insulation layer is needed in the heat stack, and maximum thermal performance can be achieved. Furthermore, the cooling medium 200 and 210 do not need to be completely electrically insulated, and the risk of power outages due to conductive parts in the cooling medium 200 and 210 is prevented.

The cooling medium 200 can, for example, be recombined after a certain distance, as its electrical resistance is then sufficiently high. This distance is slightly increased, for example, by a meandering path for the cooling medium 200.

According to one embodiment, the cooling medium 200 consists of several phases with the same electrical potential, for example HV potential, connected without a specific distance, since their potential is the same.

With a slightly different structure and a chip where the gate contact is on the other side, it is possible to increase the electrical potential The terminal of the second cooling element 130 is set to HV+ potential. All cooling fluids from multi-phase heat sinks with HV+ potential can then be connected to each other without a specific distance, since their potential is the same.

3 Figure 1 shows a schematic representation of an embodiment of an electronic circuit 100. The electronic circuit 100 is similar to or corresponds to the electronic circuit from Figure 1. 2 , except that a top view is shown.

The edging element 125 and/or the separating element 168 separates the cooling elements 110, 130 and the channels with the cooling medium 200, 205 from each other.

4 Figure 400 shows a flowchart of an embodiment of method 400 for operating an electronic circuit. The electronic circuit is similar to or corresponds to the electronic circuit shown in one of the figures described above.

Method 400 includes a step 405 of guiding and/or conveying a cooling medium along the projection to cool the cooling element.

5 Figure 1 shows a block diagram of an exemplary embodiment of a control device 500 for operating an electronic circuit. The control device 500 is designed to execute the method from 4 or to target and/or operate a similar process.

For this purpose, the control device 500 has a guiding and/or conveying unit 505 designed to guide the cooling medium along the projection in order to cool the cooling element.

The embodiments described and shown in the figures are only examples. Different embodiments can be combined completely or with respect to individual features. An embodiment can also be supplemented by features from another embodiment.

Furthermore, the process steps according to the invention can be repeated and carried out in a different order than described.

If an embodiment includes an “and/or” connection between a first feature and a second feature, this can be interpreted as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature.

Reference sign

100

electronic circuit

105

Circuit board

110

Cooling element

115

Connection device

120

Insulating layer

125

edging element

130

second cooling element

135a

component

135b

further component

140

outer side of the circuit board

142

Inside of the circuit board

144

conductor track

146

Passage opening

148

further passageway

150

Inside of the cooling element

152

Outside of the cooling element

154

Cooling element projection

156

channel

160

Inside of the second cooling element

162

Outside of the second cooling element

164

The projection of the second cooling element

168

Separating element

170

space

172a

first connecting element

172b

third connecting element

174a

base of the first connecting element

174b

third floor

176a

Contact element of the first connecting element

176b

Contact element of the third connecting element

178a

thermal conductivity material

178b

thermal conductivity material

180

Bond wire

182a

second connecting element

182b

fourth connecting element

184a

second floor

184b

fourth floor

185

layer

186a

Contact element of the second connecting element

186b

Contact element of the fourth connecting element

190

power path

200

Cooling medium

205

second channel

210

second cooling medium

400

Method for operating an electronic circuit

405

Step of leading or promoting

500

Control device for operating an electronic circuit

505

Unit for leading or promoting

Claims (15)

An electronic circuit (100) comprising the following features: a printed circuit board (105) with an outer surface (140) and an inner surface (142) opposite the outer surface (140), wherein the printed circuit board (105) has at least one conductor (144) and wherein the printed circuit board (105) has at least one through-hole (146); a cooling element (110) with an inner surface (150) and an outer surface (152) opposite the inner surface (150), wherein the inner surface (150) of the cooling element (110) faces the inner surface (142) of the printed circuit board (105), and wherein the cooling element (110) forms at least one projection (154) on the outer surface (152) which is designed to extend into a channel (156) for guiding a cooling medium (200); a connecting device (115) arranged in a space (170) between the printed circuit board (105) and the cooling element (110), wherein the connecting device (115) forms a first connecting element (172a) with a base (174a) and a contact element (176a) adjacent to the base (174a), wherein a bottom surface of the base (174a) is located on the inside (150) of the cooling element (110), wherein a top surface of the contact element (176a) contacts the inside (142) of the printed circuit board (105), and wherein the connecting device (115) forms a second connecting element (182a) with a second base (184a) and a contact element (186a) adjacent to the second base (184a), wherein a bottom surface of the second base (184a) is located on the inside (150) of the cooling element (110), wherein the contact element (186a) is at least partially passed through the through-hole (146) of the circuit board (105) of the electronic circuit (100); and an insulating layer (120) arranged on the outside (150) of the cooling element (110). Electronic circuit (100) according to Claim 1 , wherein the insulating layer (120) is roughened to allow the outside (150) of the cooling element (110) to contact the cooling medium (200), wherein the insulating layer (120) is metallized. Electronic circuit (100) according to one of the preceding claims, wherein the cooling element (110) comprises a copper material. Electronic circuit (100) according to one of the preceding claims, wherein the cooling element (110) forms a further projection which is designed to extend into the channel (156) for guiding a cooling medium (200). Electronic circuit (100) according to one of the preceding claims, with a edging element (125) to form the channel (156), wherein the projection (154) extends from a side of the edging element (125) opposite the cooling element (110) into the channel (156), in particular wherein a fluidic cooling medium (200) is arranged and/or can be guided in the channel (156), in particular oil or water, and/or wherein the channel (200) is formed in a meandering shape along a principal extension plane of the cooling element (110). Electronic circuit (100) according to one of the preceding claims, comprising a second cooling element (130) having an inner surface (160) and an outer surface (162) opposite the inner surface (160), wherein the inner surface (160) of the second cooling element (130) faces the inner surface (142) of the printed circuit board (105), wherein the second cooling element (130) forms at least one further projection (164) on the outer surface (162) which is designed to extend into the channel (156) or a second channel (205) for guiding a cooling medium (210). Electronic circuit (100) according to one of the preceding claims, wherein the edging element (125) has a separating element (168) configured to electrically isolate the cooling element (110) and the second cooling element (130) from each other. Electronic circuit (100) according to one of the Claims 5 until 7 , wherein the edging element (125) is designed to form the second channel (205), wherein the further projection (164) extends from an opposite side of the edging element (125) from the second cooling element (130) into the second channel (205). Electronic circuit (100) according to one of the preceding claims, wherein the separating element (168) forms a subsection of the edging element (125). Electronic circuit (100) according to one of the preceding claims, wherein the separating element (168) is designed to fluidically separate the channel (156) and the second channel (205). Electronic circuit (100) according to one of the preceding claims, comprising at least one component (135a) arranged in the space (170) between the circuit board (105) and the cooling element (110). Method (400) for operating an electronic circuit (100) according to one of the preceding Claims 1 until 11 , wherein the method (400) comprises the following step (405): guiding and/or conveying a cooling medium (200) along the projection (164) to cool the cooling element (110). Control device (500) configured to perform step (405) of the procedure (400) according to Claim 12 to be executed and/or controlled in a corresponding unit (505). Computer program product with program code for carrying out the procedure (400) according to Claim 12 , when the computer program product is executed on a control device (500). Machine-readable storage medium on which the computer program is stored according to Claim 14 is stored.