Common source configuration of two transistors

Abstract

The invention relates to a common source arrangement of two transistors, each having a source connection, a low-potential connection and a control connection, comprising: two control circuits for controlling one of the transistors in order to control a load current through the common source arrangement; a main current path of a load current; and a bypass current path for the load current, the bypass current path extending in parallel to a section of the main current path, one or more control preresistors being arranged in at least one of the control circuits, the source connections being electrically connected, the two low-potential connections and the two source connections being located in the main current path, wherein the bypass current path extends in parallel with a segment of the main current path, one half of the bypass current path is formed by a segment of the first control circuit, and the other half of the bypass current path is formed by a segment of the second control circuit, characterized in that at least one of the control preresistors is arranged in the bypass current path.

Description

Technical Field

[0001] This invention relates to a common-source configuration of two transistors. Background Technology

[0002] The following MOSFETs are known to have an additional pin besides the drain, source, and gate pins, known as the "Kelvin pin," see [link to relevant documentation]. Figure 1 and Figure 9 This fourth pin allows the gate control circuitry to bypass the inductance of the source pin, thus decoupling the gate controller, i.e., the gate control circuitry, from the load current circuitry. This improves switching speed and reduces the required switching energy, thereby significantly improving switching behavior. Because of the numerous advantages of the additional Kelvin pin, semiconductor device manufacturers are increasingly equipping MOSFETs with Kelvin pins, and some no longer offer them for the standard TO-247 case (through-hole package). Figure 10 The diagram shows a MOSFET with only three pins for the drain, source, and gate. Because the Kelvin and source pins are connected to the transistor's source junction on the "bare die" inside the transistor, for better distinction, the Kelvin pin can also be called the Kelvin source junction or Kelvin source pin, or the auxiliary source junction or auxiliary source pin, while the source pin is called the power source junction or power source pin. The term "power source junction" or "power source pin" is used because the load current flows through this junction, while a significantly smaller gate control current flows through the Kelvin source junction.

[0003] This situation is described in the journal "emobility tec" (Issue 01 / 2019), in the article "Potenzial von SiC voll ausschöpfen. SMD-MOSFETs mit Kelvin-Source-Pin" (Fully Utilizing the Potential of SiC: SMD-MOSFETs with Kelvin Source Pin), authors: Christian Felgemacher, Felipe Filsecker, Farhan Beg, Aly Mashaly, Seiya Kitagawa, pp. 14-17, HüthigMedien GmbH, Heidelberg, Germany, 2019. It can be found at https: / / www.rohm.de / documents / 4392907 / 6355683 / emobilitytec_0119_080319_Coverstory.pdf / ed87c1ee-02e2-a6ce-5f27-6785fd8405b5?t=1586410136257 (available online on March 13, 2024).

[0004] Not only MOSFETs, but also other types of transistors may have this fourth pin. For example, with... Figure 11 Compared to the 3-pin IGBT with diodes connected in parallel shown in the figure, Figure 12 A 4-pin IGBT with diodes connected in parallel is shown. In an IGBT, the fourth pin is referred to as the Kelvin emitter.

[0005] Further information regarding this situation can be found in the publication “TRENCHSTOP™ 5 IGBT in a Kelvin Emitter Configuration. Performance Comparison and Design Guidelines,” Application Note, Revision 1.0, dated October 16, 2014, 12 pages, Infineon Technologies AG, Munich, Germany, 2014, https: / / www.infineon.com / dgdl / Infineon-TRENCHSTOP5_in_TO-247-4pin-ApplicationNotes-v01_00-EN.pdf?fileId=5546d4624933b875014974f4d97e09ea (available online on March 13, 2024).

[0006] In bidirectional switching applications (AC switches) that require switching positive and negative currents or voltages, the common-source or common-emitter configuration (also known as a common-source circuit or common-emitter circuit) is one of the most common circuit configurations; it is also called a "back-to-back" configuration or "back-to-back" circuit (AC = Alternating Current). An embodiment of this common-source configuration is described in EP 1 271 743 A2 (Siemens AG), published January 2, 2003. The common-source or common-emitter configuration has the particular advantage that only one control signal is needed for both transistors; that is, for the control of a bidirectional semiconductor switch, a single-channel gate driver is sufficient.

[0007] To utilize the advantages of Kelvin junctions in a common-source or common-emitter configuration where two transistors are connected back-to-back, the Kelvin source or emitter junctions of the two transistors must be connected to each other; they then form the reference potential for the gate driver. A standard gate control circuit includes a gate driver that provides the output voltage or current and at least one gate pre-resistor, which is used to adjust the switching behavior of the gate driver. Although, as its name suggests, this gate pre-resistor is typically located before the gate junction, its placement anywhere in the gate control circuit is sufficient to adjust the gate control. Because the Kelvin source junction and the power source junction are connected internally within the transistor, a bypass current path is now formed in parallel with the load current path through the two Kelvin source junctions; see [link to relevant documentation]. Figure 2 A portion of the main current flows through this bypass current path. The division of current into the load current path and the bypass current path depends largely on the internal characteristics of the semiconductor, such as the resistance in the load current path and the bypass current path. However, the bypass current path is not designed for large, continuous currents, so manufacturers typically do not even recommend using Kelvin junctions in common-source configurations.

[0008] However, bypass current paths can form not only in transistors with Kelvin source or emitter terminals employing common-source or common-emitter circuits (“back-to-back” circuits), but also generally in all common-source or common-emitter circuits. That is, in common-source or common-emitter circuits, the gate control circuit is always guided through the source or emitter terminal. Depending on the connection method between the gate control circuit and the source or emitter terminal, bypass current paths not designed for load current may form in common-source or common-emitter circuits; see [reference needed]. Figures 3 to 5 . Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide an improved common-source configuration or common-emitter configuration. For the sake of simplicity, the term "common-source configuration" will be used only below; it includes back-to-back circuits of any two types of transistors, wherein the source terminals or emitter terminals of the transistors are electrically connected to each other.

[0010] According to the present invention, the above-mentioned technical problem is solved by a common-source configuration having the features of the present invention. A common-source configuration is a back-to-back connection of two transistors; in other words, it is a bidirectional semiconductor switch consisting of two transistors electrically connected to each other by their source terminals or emitter terminals. This common-source configuration has two control circuits for controlling one of the two transistors respectively; that is, a first control circuit is configured to control the first transistor, and a second control circuit is configured to control the second transistor. The transistors are controlled to control the load current through the common-source configuration. Hereinafter, the common-source configuration according to the present invention will also be referred to as a bidirectional semiconductor switch or simply a switch.

[0011] The common-source configuration of the two transistors has a main current path for the load current. Additionally, the common-source configuration of the two transistors has a bypass current path for the load current, wherein this bypass current path extends in parallel with a segment of the main current path. This bypass current path is formed by the wiring of two control circuits. One or more control pre-resistors are arranged in at least one of the control circuits. At least one of the control pre-resistors is arranged in the bypass current path. That is, at least one of the control pre-resistors is arranged in a segment of the bypass current path that simultaneously forms a segment of one of the control circuits.

[0012] According to the present invention, the first transistor of the two transistors has a first source terminal, a first low-potential terminal, and a first control terminal. The second transistor of the two transistors has a second source terminal, a second low-potential terminal, and a second control terminal. The two source terminals are electrically connected. The two low-potential terminals and the two source terminals are located in the main current path. A first control unit, a first control pre-resistor, and the first control terminal are located in a first control circuit configured for controlling the first transistor. A second control unit, a second control pre-resistor, and the second control terminal are located in a second control circuit configured for controlling the second transistor. A bypass current path extends in parallel with a segment of the main current path, half of the bypass current path being formed by a segment of the first control circuit, and the other half of the bypass current path being formed by a segment of the second control circuit.

[0013] This invention is based on the consideration that load current is undesirable through the bypass current path, as the bypass current path is not designed for load current and may also create interfering oscillating circuits: the oscillating behavior of these two parallel current paths (i.e., the main current path and the bypass current path) is a major problem. The bypass current path is typically longer and narrower, thus having greater parasitic inductance. In many cases, this, together with the gate capacitance in the control circuit, forms an undesirable oscillating circuit. Therefore, according to the invention, at least one control pre-resistor is arranged in the bypass current path: because the connector pin itself is implemented to be as low as possible in ohms (e.g., a value < 1 mOhm) through its internal structure, and the control pre-resistor, also known as the gate pre-resistor, is typically in the range of single-digit to at most double-digit ohms, only a relatively small, preferably negligible portion of the load current flows through the bypass current path, while the vast majority of the load current flows through the main current path designed for the load current.

[0014] The bidirectional semiconductor switch according to the invention is suitable for applications where current flows in both directions; that is, it can be used for AC applications, but also for DC applications with bidirectional current flow (DC = Direct Current). The switch has two transistors. The transistors can be bipolar transistors, FETs (e.g., MOSFETs, JFETs, SITs), IGBTs, GTOs, IGCTs, or other types of transistors. For different transistor types, the electrical connections of the transistors, which can be implemented by pins, wires, or metal sheets extending from the transistor housing, have different names, which are compared to each other in Table 1 for ease of understanding. Because the invention can be implemented using different transistor types and does not favor any particular transistor type, the general terms "source connector," "low-potential connector (or sink connector)," and "control connector" are used in the description of the invention for the electrical connections of the transistors; these general terms are given in the first column of Table 1.

[0015] Table 1: Names of Electrical Connectors for 3-Pin Transistors

[0016]

[0017] Design scheme of the present invention

[0018] Advantageous designs and extensions of the invention are given in the following description.

[0019] According to a preferred design of the present invention, the first control unit and the second control unit are identical. The advantage is that the control of the two transistors in a common-source configuration is achieved using only a single control unit, such as a single-channel gate driver.

[0020] According to a preferred embodiment of the present invention, the two transistors are each configured as 4-pin transistors, and each has a control terminal, a low-potential terminal, and two source terminals, wherein the first source terminal is referred to as a power source terminal, and the second source terminal is referred to as a Kelvin source terminal. Here, a bypass current path is formed by the two interconnected Kelvin source terminals.

[0021] The power source connector and the Kelvin source connector are two transistor connectors that are electrically connected at branch points to the transistor's internal source connectors (= emitter (bipolar transistor), = source (MOSFET), = emitter (IGBT)). That is, even for a transistor with four externally accessible connectors, current or voltage control is achieved through three internal connectors, but the transistor's internal source connectors branch outwards in their current path into two connectors: the power source connector and the Kelvin source connector. Here, the branch point is always located on the transistor's "bare die," otherwise it would be technically meaningless.

[0022] Because the present invention can be implemented using different types of 4-pin transistors and does not favor a particular type of transistor, the common names “power source connector”, “Kelvin source connector”, “low potential connector” and “control connector” are used in the description of the present invention for the four electrical connectors of the 4-pin transistors used in the present invention. These common names are given in the first column of Table 2.

[0023] Table 2: Names of Electrical Connectors for 4-Pin Transistors

[0024]

[0025] According to a preferred embodiment of the invention, the Kelvin source terminals of two 4-pin transistors are electrically connected to each other. That is, the two 4-pin transistors are wired together in a manner commonly referred to as a common-source configuration.

[0026] According to a preferred embodiment of the invention, at least one control pre-resistor is arranged in the electrical connection of the Kelvin source connector. In the prior art, i.e., in a conventional common-source configuration, the common ("standard") wiring (often referred to as the "gate wiring") of the control connector essentially consists of a series circuit of a control connector driver (= voltage source), a control pre-resistor (also referred to as the "control connector pre-resistor" or "gate pre-resistor"), and a semiconductor control contact "control connector". By controlling the pre-resistor, the manner in which the semiconductor control contact "control connector" is controlled by the control connector driver can be optimized.

[0027] Now, according to a preferred design of the invention, these control pre-resistors are removed from the wiring of the control connector (in a conventional common-source configuration, these control pre-resistors are located in the wiring of the control connector), and instead, these control pre-resistors are moved to the electrical connection of the Kelvin source connector. Mathematically, the voltage ratio remains unchanged by moving the control pre-resistors from the control connector to the Kelvin source connector according to the invention. Now, only the reference point (GND) of the control connector driver is no longer located on the common source potential, but on a virtual GND potential following the control pre-resistors; due to this change in location, the control pre-resistors can now also be referred to as source connector pre-resistors.

[0028] The preferred design of this invention is based on the understanding that moving the control pre-resistor from the control terminal to the Kelvin source terminal does not change the voltage ratio, but increases the load current in the main current path and decreases the load current in the parallel bypass current path.

[0029] If we observe the bypass current path, which extends in parallel with the main current path through the Kelvin source connector—the so-called "Kelvin path"—we can see that, according to a preferred design of the invention, two control pre-resistors are located in this bypass current path. Thus, a significantly higher total resistance is obtained in the Kelvin path compared to the resistance in the current path through the power source connector, the so-called "main current path," because the connectors themselves, not only the Kelvin source connectors but also the power source connectors, are implemented as relatively low-ohmic due to their internal structure (e.g., having a resistance value of < 1 Milli-Ohm: the Kelvin source connectors have significantly finer bonding lines compared to the power source connectors. That is, they are not as low-ohmic as possible, but they are low-ohmic to the necessary degree), while the control pre-resistors typically have resistance values ​​in the range of single digits to at most double digits. For example, assuming the transistor's Kelvin source terminal and power source terminal each have a resistance of 1 milli-ohm, and the transistor's control pre-resistor has a resistance of 1 ohm, then with these two resistors connected in series, the resistance in the bypass current path ("Kelvin path") is approximately 2000 times higher than in the main current path. Therefore, a maximum of one-two-thousandth of the load current flows through the parallel current path. Consequently, a significant portion of the load current no longer flows through the Kelvin source terminal, eliminating concerns about Kelvin source terminal overload, while retaining the advantages of the Kelvin source terminal in terms of switching behavior.

[0030] In other words, a significant advantage of this preferred design of the present invention is that the advantages of the Kelvin junction can be taken advantage of even for AC semiconductor switches and bidirectional DC semiconductor switches with a common-source configuration having Kelvin junctions, without having to tolerate semiconductor overload: the load current flowing through the bypass current path (i.e., the so-called "Kelvin path") connected in parallel with the main current path through the two Kelvin junctions is significantly reduced.

[0031] According to a preferred embodiment of the invention, the resistance in the bypass current path is at least ten times greater than the resistance in the main current path due to at least one control pre-resistor arranged in the bypass current path. The advantage is that the load current through the bypass current path connected in parallel with the main current path is significantly reduced compared to the load current through the main current path.

[0032] According to a preferred embodiment of the invention, the resistance in the electrical connection of the Kelvin source connector is at least ten times greater than the resistance in the electrical connection of the power source connector. The advantage is that the load current flowing through the current path (“Kelvin path”) connected in parallel with the main current path through the two Kelvin source connectors is significantly reduced compared to the load current flowing through the main current path.

[0033] According to a preferred embodiment of the invention, the resistance in the bypass current path is at least one thousand times greater than the resistance in the main current path due to at least one control pre-resistor arranged in the bypass current path. The advantage is that the load current through the bypass current path connected in parallel with the main current path becomes negligible compared to the load current through the main current path.

[0034] According to a preferred design of the invention, at least one of the transistors is a MOSFET, an IGBT, or a bipolar transistor. The advantage here is that commercially available and therefore inexpensive transistors can be used.

[0035] According to a preferred embodiment of the invention, the electrically connected control connector is connected to a control connector driver. The advantage here is that a single-channel gate driver is sufficient for controlling a bidirectional semiconductor switch.

[0036] According to a preferred design of the present invention, a control connector driver shared by two control circuits is arranged in the two control circuits; that is, the two control circuits share the same control connector driver (= gate driver). The advantage here is that, for the control of bidirectional semiconductor switches, a single-channel gate driver, which is less expensive than a dual-channel gate driver, is sufficient. Attached Figure Description

[0037] The features, characteristics, advantages, and implementations of the invention described above will become clearer and easier to understand through the following description of embodiments, which will be further described in detail with reference to the accompanying drawings. In the drawings, accordingly, the embodiments are shown schematically and not to scale:

[0038] Figure 1 A known 4-pin transistor is shown;

[0039] Figure 2 A known common-source configuration with two 4-pin transistors and a gate pre-resistor in each of the two gate control circuits is shown.

[0040] Figure 3 A known common-source configuration with two 4-pin transistors and a common gate front resistance for both gate control circuits is shown.

[0041] Figure 4 A known “simple” common-source configuration with two 3-pin transistors is shown;

[0042] Figure 5 A known “improved” common-source configuration with two 3-pin transistors and a gate pre-resistor in each of the two gate control circuits is shown.

[0043] Figure 6 This illustrates a design for two gate control circuits with a common gate pre-resistance. Figure 5 The known "improved" common-source configuration;

[0044] Figure 7 A common-source configuration according to the invention with two 4-pin transistors is shown;

[0045] Figure 8 A common-source configuration according to the invention with two 3-pin transistors is shown;

[0046] Figure 9 A MOSFET implemented using TO-247-4 is shown;

[0047] Figure 10 A MOSFET implemented using TO-247-3 is shown;

[0048] Figure 11 A 3-pin IGBT with diodes is shown; and

[0049] Figure 12 A 4-pin IGBT with diodes is shown. Detailed Implementation

[0050] Figure 1 A conventional 4-pin transistor T is shown, specifically a transistor with a Kelvin source junction K. The transistor shown is a MOSFET. In addition to the Kelvin source junction K, transistor T also has a low-potential junction D (“drain”), a power source junction S (“source”), and a control junction G (“gate”). Each of the four transistor junctions D, G, K, and S has a non-disappearing parasitic inductance L: Figure 1 In the diagram, the inductance of terminals D, G, K, and S is represented by electrical symbols for inductors ("conductor rings") and is marked using the reference numeral Lx, where x is replaced by one of the reference numerals D, G, K, and S for the terminals, respectively. The Kelvin source terminal K and the power source terminal S are electrically connected to the transistor's internal source terminal S' at the branch point P. That is, even for a transistor with four terminals that can be electrically contacted externally, current or voltage control is achieved only through three internal terminals. However, the transistor T's internal source terminal S' branches outward in its current path to terminals K and S, resulting in two terminals: the power source terminal S and the Kelvin source terminal K. The MOSFET transistor T inherently possesses a body diode.

[0051] Figure 2A conventional bidirectional semiconductor switch with a common-source configuration is shown, having two 4-pin transistors, here MOSFETs, and a gate pre-resistor in each of the two gate control circuits. The bidirectional semiconductor switch has two 4-pin transistors T1 and T2, namely a first 4-pin transistor T1 and a second 4-pin transistor T2. These transistors have control terminals G1 and G2, low-potential terminals D1 and D2, power source terminals S1 and S2, and Kelvin source terminals K1 and K2, respectively. Here, the control terminals G1 and G2 of the two transistors T1 and T2 are electrically connected in control terminal contact GD. Here, the power source terminals S1 and S2 of the two transistors T1 and T2 are electrically connected in power source terminal contact 8. And here, the Kelvin source terminals K1 and K2 of the two transistors T1 and T2 are electrically connected in Kelvin source terminal contact 6. The Kelvin source terminal K1 and the power source terminal S1 of the first transistor T1 are electrically connected to the internal source terminal S'1 of the first transistor T1 at the branch point P1 of the first transistor T1. The Kelvin source connector K2 and power source connector S2 of the second transistor T2 are electrically connected to the internal source connector S'2 of the second transistor T2 at the branch point P2 of the second transistor T2.

[0052] The control connectors G1 and G2, which are electrically connected to each other, are electrically connected to the control connector driver 4 (voltage source) in the control connector contact GD. To take advantage of the Kelvin source connectors K1 and K2, the two Kelvin source connectors K1 and K2 are connected to each other in the Kelvin source connector contact 6, forming a reference potential for the control connector driver 4, which provides the output voltage and output current. Between the control connector contact GD and the transistors T1 and T2, the control connectors G1 and G2 respectively have control pre-resistors R1 and R2, which can be used to adjust the switching behavior.

[0053] Furthermore, the control connector driver 4 is electrically connected to the Kelvin source connectors K1 and K2, which are electrically connected to each other, at the Kelvin source connector contact point 6. This results in two control circuits 31 and 32 with the control connector driver 4 as a common voltage source: a first control circuit 31 for controlling the first transistor T1 and a second control circuit 32 for controlling the second transistor T2.

[0054] The diodes required for bidirectional switching, connected in anti-parallel to transistors T1 and T2, are inherently present in the MOSFET. Only in the case of IGBTs do these diodes need to be constructed using external components, because IGBTs do not inherently possess such diodes due to their final P-channel layer; for more information, please refer to [link to relevant documentation]. Figure 11 and Figure 12 .

[0055] The bidirectional semiconductor switch guides load current in two parallel current paths between two low-potential terminals D1 and D2: on one hand, in the main current path 10, which includes power source terminals S1 and S2 connected to each other in power source terminal contact 8; on the other hand, in the bypass current path = Kelvin path 12, which includes Kelvin source terminals K1 and K2 connected to each other in Kelvin source terminal contact 6.

[0056] The distribution of load current largely depends on the internal characteristics of the bidirectional semiconductor switch (e.g., resistance). However, Kelvin path 12 is not designed for large, continuous currents, so manufacturers of 4-pin transistors generally do not even recommend using the Kelvin source terminals K1, K2 of both transistors T1, T2 in a common-source configuration. That is, it is technically feasible not to use Kelvin source terminals K1, K2, but this would obviously lose the positive effects that can be achieved by using Kelvin source terminals K1, K2. However, the bigger problem with bypass current path = Kelvin path 12 is that it may create interfering oscillation circuits.

[0057] and Figure 2 similar, Figure 3 This illustrates an alternative to a known common-source configuration with two 4-pin transistors. Figure 2 Each of the control circuits 31 and 32 shown has a different common-source configuration for its own control pre-resistors R1 and R2. Figure 3 The common-source configuration shown has a common control pre-resistor R12 for both control circuits 31 and 32. In addition, Figure 2 and Figure 3 The common-source configuration shown is the same.

[0058] Figure 4A known “simple” common-source configuration with two 3-pin transistors T1 and T2 is shown. Here, these transistors are MOSFETs: the explicitly labeled diodes 21 and 22 represent the body diodes inherently present in the MOSFET. The two source terminals S1 and S2 of transistors T1 and T2 are electrically connected in source terminal contact 8. The two gate terminals G1 and G2 of transistors T1 and T2 are arranged in control circuits 31 and 32, respectively, and each has a separate control pre-resistor R1 and R2. The two control circuits 31 and 32 are supplied with voltage by a common control terminal driver 4. The control circuits 31 and 32 extend from the control terminal driver 4 through source terminal contact 8 to the two source terminals S1 and S2, respectively, and return from there to the control terminal driver 4 through gate terminals G1 and G2. The main disadvantage of this “simple” circuit is that the path length w of the control circuits 31 and 32, which coincide with the main current path 10, is relatively long: because there is a significant inductive load on these paths w, the switching behavior of the control circuits 31 and 32 is significantly degraded. This is exactly as described. Figure 5 The motivation shown is to separate the main current path 10 from the control circuits 31 and 32 as early as possible. This is also the motivation for equipping transistors with Kelvin sources.

[0059] Figure 5 A known "improved" common-source configuration is shown, featuring two 3-pin transistors and control pre-resistors R1 and R2 in two control circuits 31 and 32, respectively. Figure 4 Compared to the common-source configuration shown, Figure 5 The improvement in the common-source configuration shown is that the path length w of the control circuits 31 and 32, which coincide with the main current path 10, is shortened. In this way, the inductance in the control circuits 31 and 32 is reduced, thus improving their switching behavior. The shortening of the path length w is achieved by dividing the previously shared section of the control circuits 31 and 32 between the GND (-) of the control connector driver 4 and the main current path 10 into two separate branches of the control circuits 31 and 32 at the branch point 7. These two separate branches are then connected to the main current path 10 at the separation point 9, respectively. In this way, the bypass current path 12 for the load current is achieved through the two separate branches of the control circuits 31 and 32 extending between the branch point 7 and the separation point 9, respectively.

[0060] Figure 6 This illustrates a control pre-resistor shared by two control circuits 31 and 32. Figure 5 The known "improved" common-source configuration. (And...) Figure 5 Each of the control circuits 31 and 32 shown has a different common-source configuration for its own control pre-resistors R1 and R2. Figure 6The common-source configuration shown has a common control pre-resistor R12 for both control circuits 31 and 32. In addition, Figure 5 and Figure 6 The common-source configuration shown is the same.

[0061] Figure 7 A bidirectional semiconductor switch with two 4-pin transistors in a common-source configuration according to the present invention is shown. It largely corresponds to... Figure 2 The diagram shows a conventional bidirectional semiconductor switch using a common-source configuration, but the decisive difference lies in the arrangement of the control pre-resistors R1 and R2 within the bypass current path 12. That is, due to the control pre-resistors R1 and R2 in the bypass current path 12, only a relatively small, preferably negligible, portion of the load current still flows through the bypass current path 12, while the vast majority of the load current flows through the main current path 10, which is designed for the load current. Therefore, there is no longer a significant load current flowing through the bypass current path = Kelvin path 12, and thus there is no need to worry about overloading the Kelvin source terminals K1 and K2; however, the advantages in switching behavior achievable through the use of Kelvin source terminals K1 and K2 are retained.

[0062] Figure 8 A common-source configuration according to the invention, having two 3-pin transistors, is shown. To illustrate the essential features of the common-source configuration according to the invention, it is compared with... Figure 5 The known "improved" common-source configuration is compared. Figure 8 The common-source pole configuration shown largely corresponds to Figure 5 The conventional common-source configuration is shown, but the decisive difference lies in the fact that the control pre-resistors R1 and R2 are arranged in the bypass current path 12. Due to the control pre-resistors R1 and R2 in the bypass current path 12, only a relatively small, preferably negligible portion of the load current still flows through the bypass current path 12, while the vast majority of the load current flows through the main current path 10 designed for the load current.

[0063] Figure 9 A known 4-pin MOSFET is shown in an implementation with a TO-247-4 housing. The 4-pin MOSFET has a Kelvin source junction K, a low-potential junction D (“drain”), a power source junction S (“source”), and a control junction G (“gate”).

[0064] Figure 10 A known 3-pin MOSFET with an implementation having a TO-247-3 housing is shown. The 3-pin MOSFET has a low-potential terminal D (“drain”), a source terminal S (“source”), and a control terminal G (“gate”).

[0065] Figure 11 A circuit diagram of a known 3-pin IGBT with a separate freewheeling diode is shown; while MOSFETs inherently have a body diode, a separate diode must be provided for IGBTs without an inherent diode if bidirectional applications require it. This 3-pin IGBT can be packaged in a TO-247-3 case. The 3-pin IGBT has a low-potential terminal C (“collector”), a source terminal E (“emitter”), and a control terminal G (“gate”).

[0066] Figure 12 A circuit diagram of a known 4-pin IGBT with a separate freewheeling diode is shown. This 4-pin IGBT can be packaged in a TO-247-4 case. The 4-pin IGBT has a Kelvin source terminal E' (“Kelvin emitter” or “auxiliary emitter”), a power source terminal E (“emitter”), a low-potential terminal C (“collector”), and a control terminal G (“gate”).

[0067] List of reference numerals

[0068] 4 Control connector driver

[0069] 6 Kelvin source connector contact points

[0070] 7GND branch point

[0071] 8 Power source connector contact points, source terminal connector contact points

[0072] 9. The separation point between the main current path and the control circuit

[0073] 10 Main Current Path

[0074] 12 bypass current circuit

[0075] 21 diode

[0076] 22 diode

[0077] 31 Control Circuit

[0078] 32 control circuits

[0079] DT's low-potential connector

[0080] D1T1 low-potential connector

[0081] D2T2 low-potential connector

[0082] GD control connector contact points

[0083] GT control connector

[0084] GND

[0085] G1T1 control connector

[0086] G2T2 control connector

[0087] KT Kelvin source connector

[0088] K1T1 Kelvin source connector

[0089] K2T2 Kelvin source connector

[0090] LDD inductors

[0091] LGG inductors

[0092] LKK's inductors

[0093] LSS inductance

[0094] PT branch points

[0095] branch point of P1T1

[0096] branch point of P2T2

[0097] R1T1 control pre-resistor

[0098] R2T2 control pre-resistor

[0099] ST's power source connector

[0100] S1T1 power source connector

[0101] S2T2 power source connector

[0102] S'T's internal source connector

[0103] S'1T1 internal source connector

[0104] S'2T2 internal source connector

[0105] T transistor

[0106] The first transistor of the T1 bidirectional semiconductor switch

[0107] The second transistor of the T2 bidirectional semiconductor switch

Claims

1. A common-source configuration for two transistors (T1, T2), said common-source configuration having: - Two control circuits (31, 32) are used to control one of the transistors (T1, T2) respectively, in order to control the load current through the common-source configuration. - The main current path of the load current (10), and - A bypass current path (12) for the load current, which extends in parallel with a section of the main current path (10). in, One or more control pre-resistors (R1, R2, R12) are arranged in at least one of the control circuits (31, 32). in, - The first transistor (T1) of the two transistors (T1, T2) has a first source terminal (S1), a first low-potential terminal (D1) and a first control terminal (G1). - The second transistor (T2) of the two transistors (T1, T2) has a second source terminal (S1), a second low-potential terminal (D1), and a second control terminal (G1). Among them, the two source connectors (S1, S2) are electrically connected. Among them, two low-potential terminals (D1, D2) and two source terminals (S1, S2) are located in the main current path (10). The first control unit (4), the first control pre-resistor (R1), and the first control connector (G1) are located in the first control circuit (31) of the control circuits (31, 32) used to control the first transistor (T1). The second control unit (4), the second control pre-resistor (R2), and the second control connector (G2) are located in the second control circuit (32) of the control circuits (31, 32) used to control the second transistor (T2). The bypass current path (12) extends in parallel with the main current path (10) in segments. One half of the bypass current path (12) is formed by segments of the first control circuit (31), and the other half of the bypass current path (12) is formed by segments of the second control circuit (32). Its features are, At least one of the control pre-resistors (R1, R2, R12) is arranged in the bypass current path (12).

2. The common-source configuration according to claim 1, wherein, The first control unit (4) and the second control unit (4) are the same.

3. The common source configuration according to any one of the preceding claims, in, The two transistors (T1 and T2) each have four terminals, including control terminals (G1 and G2), low-potential terminals (D1 and D2), power source terminals (S1 and S2), and Kelvin source terminals (K1 and K2). The bypass current path (12) is formed by two Kelvin source terminals (K1, K2) connected to each other.

4. The common source configuration according to any one of the preceding claims, wherein, Because at least one control pre-resistor (R1, R2, R12) is arranged in the bypass current path (12), the resistance in the bypass current path (12) is at least ten times greater than the resistance in the main current path (10).

5. The common-source configuration according to claim 4, wherein, Because of at least one control pre-resistor (R1, R2, R12) arranged in the bypass current path (12), the resistance in the bypass current path (12) is at least one thousand times greater than the resistance in the main current path (10).

6. The common-source configuration according to any one of the preceding claims, wherein, At least one of the transistors is a MOSFET, an IGBT, or a bipolar transistor.

7. The common-source configuration according to any one of the preceding claims, wherein, The control connector driver (4) shared by the control circuits (31, 32) is arranged in the control circuits (31, 32).

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