Silicon carbide bidirectional switching half-bridge power module

Abstract

This invention relates to a silicon carbide bidirectional switching half-bridge power module, belonging to the field of semiconductor device technology. The bidirectional switching half-bridge power module includes a module housing, a DBC (Diverterless Circuit Blocker), silicon carbide bidirectional switching units soldered onto the DBC, power terminals, signal terminals, and a thermistor. The silicon carbide bidirectional switching power module adopts a half-bridge structure, which consists of two bidirectional switching units. Each bidirectional switching unit is composed of two sets of silicon carbide MOSFETs connected with a common drain. The bidirectional switching half-bridge circuit is integrated on a single DBC, and the conductive areas of the silicon carbide chip and the DBC are connected by bonding wires to form the bidirectional switching units and the half-bridge structure, with corresponding power terminals and signal terminals led out. This invention achieves bidirectional conduction and bidirectional blocking of current, and is packaged as a bidirectional switching half-bridge structure, improving reliability, reducing parasitic inductance, increasing power density, and lowering the parasitic inductance of the power module.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device technology and relates to a silicon carbide bidirectional switching half-bridge power module. Background Technology

[0002] Bidirectional switching structures enable bidirectional conduction and blocking of current, and have broad application prospects and significant practical value in advanced power electronics topologies such as AC step-up / step-down circuits, current source inverters, Vienna rectifiers, T-type three-level inverters, and matrix converters. However, existing bidirectional switching structures typically use discrete component connections, resulting in low power density, low power rating, large parasitic inductance, poor symmetry, and low reliability, posing challenges and difficulties for their practical application.

[0003] High density, high efficiency, and high reliability are the trends in power electronics development. Employing power module packaging circuit topologies can effectively improve circuit reliability, power density, and reduce parasitic inductance. Silicon carbide, as a third-generation semiconductor material, possesses superior properties such as three times the bandgap and thermal conductivity of silicon, and ten times the breakdown field strength. Therefore, it exhibits higher voltage blocking capability, lower on-resistance, higher switching speed, higher operating temperature, and lower thermal resistance. Silicon carbide power modules offer advantages such as high operating temperature, high power density, and high reliability.

[0004] Benefiting from the superior switching and thermal performance of silicon carbide (SiC) devices, as well as the high reliability of power module packaging, SiC bidirectional switching half-bridge power modules have significant advantages and promising prospects in engineering applications. However, on the one hand, due to the ever-increasing current requirements of topologies such as AC boost circuits, a single SiC device is insufficient to meet the current demands, necessitating the use of multiple devices in parallel. On the other hand, the high switching speed of SiC devices and the requirement for symmetrical operation of bidirectional switching half-bridges place several technical requirements on SiC bidirectional switching half-bridge power modules, including low parasitic inductance, symmetrical layout, and parallel current sharing. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a silicon carbide bidirectional switching half-bridge power module with higher power density, higher power rating, lower parasitic inductance, and higher reliability.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A silicon carbide bidirectional switching half-bridge power module includes a DBC, silicon carbide bidirectional switching units soldered onto the DBC, power terminals, signal terminals, and a thermistor. The power module employs a half-bridge structure, which consists of two bidirectional switching units. Each bidirectional switching unit is composed of two sets of silicon carbide MOSFETs connected with a common drain. The bidirectional switching half-bridge circuit and terminals are integrated onto a single DBC by soldering. Bonding wires connect the silicon carbide chip and the conductive areas of the DBC, forming the bidirectional switching units and the half-bridge structure, and leading out corresponding power and signal terminals. The silicon carbide bidirectional switching units, power terminals, and signal terminals in the power module are arranged in a mirror-symmetrical layout.

[0008] In the lower bridge arm, the silicon carbide MOSFET chip Q 11 Q 12 The MOSFETs are connected in parallel, with their drains connected to the same point, their gates connected to the G1 terminal, and their sources connected to the N terminal. A common Kelvin source is also connected to the S1 terminal. (Silicon carbide MOSFET chip Q) 21 Q 22 The drains are connected to the same point, the gates are connected to the G2 terminal, and the sources are connected to the M terminal. A common Kelvin source is also connected to the S2 terminal. Q 11 Q 12 Parallel common drain and Q 21 Q 22 The parallel common drain connection forms a bidirectional switching structure with a common drain in the lower bridge arm; in the upper bridge arm, the silicon carbide MOSFET chip Q... 31 Q 32 The MOSFETs are connected in parallel, with their drains connected to the same point, their gates connected to the G3 terminal, and their sources connected to the M terminal. A common Kelvin source is also connected to the S3 terminal. (Silicon carbide MOSFET chip Q) 41 Q 42 The drains are connected to the same point, the gates are connected to the G4 terminal, and the sources are connected to the P terminal. A common Kelvin source is also connected to the S4 terminal. Q 31 Q 32 Parallel common drain and Q 41 Q 42 The parallel common drain connection forms a bidirectional switching structure with a common drain in the lower bridge arm; Q 11 Q 12 and Q 21 Q 22 The lower arm bidirectional open structure and Q 31 Q 32 and Q 41 Q 42 The lower bridge arm bidirectional switch structure is composed of sources connected to the M terminal, forming a bidirectional switch half-bridge structure.

[0009] The DBC component includes an upper DBC metal layer, a ceramic DBC layer, and a lower DBC metal layer; the silicon carbide MOSFET chip has a body diode, the drain is soldered to the corresponding conductive area of ​​the upper DBC metal layer, and the power source, Kelvin source, and gate are connected to the corresponding conductive area of ​​the upper DBC metal layer through bonding wires to form a bidirectional switching structure and a half-bridge topology.

[0010] Furthermore, the silicon carbide bidirectional switching unit is composed of two sets of silicon carbide MOSFET chips connected with a common drain, and each set of silicon carbide chips consists of two silicon carbide chips connected in parallel.

[0011] Furthermore, the two sets of silicon carbide MOSFETs are connected in parallel to bring out a common gate and Kelvin source.

[0012] Furthermore, the two sets of silicon carbide MOSFETs are connected in parallel to bring out a common gate and Kelvin source, which are then bonded to signal terminals via wire bonding.

[0013] Furthermore, the temperature-sensitive resistor is positioned close to the chip, and its measurement output is connected to the signal terminal of the temperature-sensitive resistor via a bonding wire.

[0014] Furthermore, the power terminals consist of pins soldered onto the DBC; the signal terminals include drive signal terminals and temperature-sensitive resistor terminals, which are also composed of pins soldered onto the DBC; the pins are soldered onto the DBC with a metal layer, leading out the power P terminal, N terminal, M terminal, gate signals G1, G2, G3, G4, and Kelvin source terminals S1, S2, S3, S4 to the outside of the pin module; the upper and lower metal layers of the DBC are made of copper.

[0015] Furthermore, the power module also includes a package housing with a through hole, allowing the terminal pins to extend from the end opposite to the metal layer on the DBC to the outside of the package housing; the package housing is equipped with a fixed terminal for easy connection to the heat sink.

[0016] The beneficial effects of this invention are as follows:

[0017] (1) The silicon carbide bidirectional switching half-bridge power module consists of two sets of parallel silicon carbide chips forming bidirectional switching units, which are packaged and integrated into a bidirectional switching half-bridge power module. Compared with the bidirectional switching half-bridge composed of discrete devices or bidirectional switching power modules of the same level, it has higher packaging integration, power density and reliability.

[0018] (2) The silicon carbide bidirectional switching half-bridge power module includes a silicon carbide MOSFET chip, power terminals, and drive signal terminals, which are mirror-symmetrical, thereby further reducing the parasitic inductance of the power module; the Kelvin source and gate of the silicon carbide MOSFET chip are led out to the drive signal terminals through bonding wires, and the drive signal terminals and power terminals are on different sides of the DBC, which reduces the influence of the power circuit on the drive circuit and improves the reliability of the power module drive; the temperature-sensitive resistor is set close to the chip, making the chip temperature detection more accurate.

[0019] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0021] Figure 1 A circuit diagram of the main body of the power module provided in an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of the overall structure of the packaging structure of the silicon carbide bidirectional switch half-bridge power module provided in an embodiment of the present invention;

[0023] Figure 3 A three-dimensional structural diagram of the power module body provided in an embodiment of the present invention;

[0024] Figure 4 for Figure 3 A front view of the main body of the power module;

[0025] Figure 5 for Figure 3 A top view of the main body of the power module;

[0026] Figure 6 for Figure 5 A magnified view of a silicon carbide MOSFET chip. Detailed Implementation

[0027] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0028] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0029] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0030] The circuits connecting each component are as follows Figure 1 As shown, in the lower bridge arm, the silicon carbide MOSFET chip Q... 11 Q 12 The MOSFETs are connected in parallel, with their drains connected to the same point, their gates connected to the G1 terminal, and their sources connected to the N terminal. A common Kelvin source is also connected to the S1 terminal. (Silicon carbide MOSFET chip Q) 21 Q 22 The drains are connected to the same point, the gates are connected to the G2 terminal, and the sources are connected to the M terminal. A common Kelvin source is also connected to the S2 terminal. Q 11 Q 12 Parallel common drain and Q 21 Q 22 The parallel common drain connection forms the bidirectional switching structure of the lower bridge arm. In the upper bridge arm, the silicon carbide MOSFET chip Q... 31 Q 32The MOSFETs are connected in parallel, with their drains connected to the same point, their gates connected to the G3 terminal, and their sources connected to the M terminal. A common Kelvin source is also connected to the S3 terminal. (Silicon carbide MOSFET chip Q) 41 Q 42 The drains are connected to the same point, the gates are connected to the G4 terminal, and the sources are connected to the P terminal. A common Kelvin source is also connected to the S4 terminal. Q 31 Q 32 Parallel common drain and Q 41 Q 42 The parallel common drain connection forms a bidirectional switching structure with a common drain in the lower bridge arm. Q 11 Q 12 and Q 21 Q 22 The lower arm bidirectional open structure and Q 31 Q 32 and Q 41 Q 42 The lower bridge arm bidirectional switch structure is composed of sources connected to the M terminal, forming a bidirectional switch half-bridge structure.

[0031] like Figure 2 As shown, the power module packaging structure provided in this embodiment includes a packaging shell and a power module body packaged in the packaging shell; the packaging shell has a corresponding through hole so that the terminal pin can extend from the end away from the metal layer on the DBC to the outside of the packaging shell; the packaging shell is equipped with a fixed terminal to facilitate connection with the heat sink. Figure 3 The middle section shows the three-dimensional structure of the power module body.

[0032] like Figure 5 As shown, the main body of the power module includes a housing, a DBC component, a silicon carbide MOSFET chip, and terminals; Figure 4 The DBC component includes an upper DBC metal layer, a ceramic DBC layer, and a lower DBC metal layer. The silicon carbide MOSFET chip has a body diode, with its drain soldered to the corresponding conductive area of ​​the upper DBC metal layer. The power source, Kelvin source, and gate are connected to the corresponding conductive area of ​​the upper DBC metal layer via bonding wires, forming a bidirectional switching structure and a half-bridge topology. The power terminals and signal terminals are pins soldered to the upper DBC metal layer, leading out the power P, N, and M terminals, gate signals G1, G2, G3, and G4, and Kelvin source terminals S1, S2, S3, and S4 to the outside of the module. The upper and lower DBC metal layers are made of copper.

[0033] High power density integration is an important development trend in power electronic switching power supplies. This invention is an integrated silicon carbide bidirectional switching half-bridge power module, which improves power density and reliability compared to bidirectional switching half-bridges composed of commercial discrete devices or bidirectional switching modules of the same level.

[0034] like Figure 1 and Figure 5 As shown, in practical applications, the commutation circuit of the silicon carbide bidirectional switching half-bridge power module is from the p end to the n end. The bidirectional switch between the P end and the M end is mirror-symmetrical with the bidirectional switch between the M end and the N end, that is, the power circuit is symmetrical, which improves the symmetry of the bidirectional operation of the bidirectional switching half-bridge, improves the parallel current sharing characteristics, and reduces the parasitic inductance of the power module. The parasitic inductance from the P end to the N end is 7.4nH.

[0035] The silicon carbide MOSFET chip used in this invention contains a body diode and a Kelvin source. The body diode improves the surface area utilization of the DBC and increases the power density of the silicon carbide bidirectional switching half-bridge power module. By bringing out the Kelvin source of the silicon carbide MOSFET chip, the power circuit and the drive circuit are decoupled, reducing the parasitic inductance of the drive circuit and the influence of the power circuit, improving the switching speed, reducing switching losses, and improving the reliability of the silicon carbide bidirectional switching half-bridge power module.

[0036] like Figure 5 As shown, the signal terminals of the Kelvin source and gate of the silicon carbide MOSFET chip and the power terminals of the silicon carbide bidirectional switching half-bridge power module are located on both sides of the DBC, respectively, realizing the separation of strong and weak currents, reducing the influence of the power circuit on the signal drive circuit, and improving the reliability of the silicon carbide bidirectional switching half-bridge power module.

[0037] like Figure 5 As shown, the thermistor is close to the lower silicon carbide MOSFET chip, and the electrodes at both ends of the thermistor are led out through the pin. The thermistor is close to the silicon carbide MOSFET chip, which improves the accuracy of the thermistor measurement and more accurately detects the junction temperature of the silicon carbide MOSFET chip.

[0038] Figure 6 for Figure 5 A magnified view of a silicon carbide MOSFET chip.

[0039] In this embodiment, insulating adhesive is provided inside the encapsulation housing to achieve sealing and electrical insulation protection inside the power module. Preferably, the insulating adhesive is silicone or resin.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A silicon carbide bidirectional switching half-bridge power module, comprising a DBC, a silicon carbide bidirectional switching unit soldered onto the DBC, power terminals, signal terminals, and a thermistor, characterized in that: This power module adopts a half-bridge structure, which consists of two bidirectional switching units. Each bidirectional switching unit is composed of two sets of silicon carbide MOSFETs connected by a common drain. The bidirectional switching half-bridge circuit and terminals are integrated on a DBC by soldering. The conductive areas of the silicon carbide chip and the DBC are connected by bonding wires to form the bidirectional switching unit and the half-bridge structure, and the corresponding power terminals and signal terminals are brought out. The silicon carbide bidirectional switching units, power terminals and signal terminals in the power module are arranged in a mirror symmetrical layout. In the lower bridge arm, the silicon carbide MOSFET chip Q 11 Q 12 The MOSFETs are connected in parallel, with their drains connected to the same point, their gates connected to the G1 terminal, and their sources connected to the N terminal. A common Kelvin source is also connected to the S1 terminal. (Silicon carbide MOSFET chip Q) 21 Q 22 The drains are connected to the same point, the gates are connected to the G2 terminal, and the sources are connected to the M terminal. A common Kelvin source is also connected to the S2 terminal. Q 11 Q 12 Parallel common drain and Q 21 Q 22 The parallel common drain connection forms a bidirectional switching structure with a common drain in the lower bridge arm; in the upper bridge arm, the silicon carbide MOSFET chip Q... 31 Q 32 The MOSFETs are connected in parallel, with their drains connected to the same point, their gates connected to the G3 terminal, and their sources connected to the M terminal. A common Kelvin source is also connected to the S3 terminal. (Silicon carbide MOSFET chip Q) 41 Q 42 The drains are connected to the same point, the gates are connected to the G4 terminal, and the sources are connected to the P terminal. A common Kelvin source is also connected to the S4 terminal. Q 31 Q 32 Parallel common drain and Q 41 Q 42 The parallel common drain connection forms a bidirectional switching structure with a common drain in the lower bridge arm; Q 11 Q 12 and Q 21 Q 22 The lower arm bidirectional open structure and Q 31 Q 32 and Q 41 Q 42 The lower bridge arm bidirectional switch structure is composed of sources connected to the M terminal, forming a bidirectional switch half-bridge structure. The DBC component includes an upper DBC metal layer, a ceramic DBC layer, and a lower DBC metal layer; the silicon carbide MOSFET chip has a body diode, the drain is soldered to the corresponding conductive area of ​​the upper DBC metal layer, and the power source, Kelvin source, and gate are connected to the corresponding conductive area of ​​the upper DBC metal layer through bonding wires to form a bidirectional switching structure and a half-bridge topology.

2. The silicon carbide bidirectional switching half-bridge power module according to claim 1, characterized in that: The silicon carbide bidirectional switching unit is composed of two sets of silicon carbide MOSFET chips connected with a common drain, and each set of silicon carbide chips consists of two silicon carbide chips connected in parallel.

3. The silicon carbide bidirectional switching half-bridge power module according to claim 1, characterized in that: The two sets of silicon carbide MOSFETs are connected in parallel to bring out a common gate and Kelvin source.

4. The silicon carbide bidirectional switching half-bridge power module according to claim 3, characterized in that: The two sets of silicon carbide MOSFETs are connected in parallel, with a common gate and Kelvin source, which are then bonded to the signal terminals via wire bonding.

5. The silicon carbide bidirectional switching half-bridge power module according to claim 1, characterized in that: The thermistor is positioned close to the chip, and its measurement output is connected to the signal terminal via a bonding wire.

6. The silicon carbide bidirectional switching half-bridge power module according to claim 1, characterized in that: The power terminals consist of pins soldered onto the DBC; the signal terminals include drive signal terminals and temperature-sensitive resistor terminals, which are also composed of pins soldered onto the DBC; the pins are soldered onto the DBC with a metal layer, leading out the power P terminal, N terminal, M terminal, gate signals G1, G2, G3, G4, and Kelvin source terminals S1, S2, S3, S4 to the outside of the pin module; the upper and lower metal layers of the DBC are made of copper.

7. The silicon carbide bidirectional switching half-bridge power module according to claim 1, characterized in that: The power module also includes a housing with a through hole, allowing the terminal pins to extend from the end opposite to the metal layer on the DBC to the outside of the housing; the housing is equipped with a fixed terminal for easy connection to the heat sink.

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