Semiconductor DC circuit breaker and semiconductor module

Abstract

The invention provides a semiconductor DC circuit breaker which has redundancy that can cut off current even if a semiconductor switching element for cutting off the current has a fault when an abnormal current is detected. A semiconductor DC circuit breaker (1) having a semiconductor switching element (21) that cuts off a main current when an abnormal current is detected, the semiconductor DC circuit breaker (1) comprising: a fuse (25) connected in series to the semiconductor switching element (21); an abnormal current detection unit (11) that detects an abnormal current; and a gate drive unit (12) that turns off the semiconductor switching element (21) when the abnormal current is detected by the abnormal current detection unit (11). The magnitude of the abnormal current that turns off the semiconductor switching element (21) is set to be smaller than the fusing current of the fuse (25).

Description

Technical Field

[0001] The invention relates to a semiconductor DC circuit breaker and a semiconductor module. Background Art

[0002] As a device for interrupting the current when an abnormal current is generated, there are, for example, a fuse, a mechanical DC circuit breaker, a semiconductor DC circuit breaker, and the like.

[0003] Although it is not a semiconductor DC circuit breaker, as a technology using a fuse, there is, for example, Patent Document 1. In the abstract and Figure 1 The following contents are recorded in the document: "A semiconductor module is provided that can continue to operate even if a short-circuit failure occurs in a semiconductor switching element during operation." and "The semiconductor module of an embodiment comprises: a first external terminal; a second external terminal; a first semiconductor switching element electrically connected between the first external terminal and the second external terminal and having a first gate electrode; a second semiconductor switching element electrically connected between the first external terminal and the second external terminal and having a second gate electrode relative to the first semiconductor switching element; a first fuse electrically connected between the first external terminal and the first semiconductor switching element; and a second fuse electrically connected between the second external terminal and the first semiconductor switching element."

[0004] In addition, as a semiconductor DC circuit breaker, there is, for example, Patent Document 2. In the abstract and Figure 1 The following contents are recorded in the document: "A semiconductor circuit breaker device having superior versatility compared to the past is provided." and "A semiconductor circuit breaker device 1 comprises: a semiconductor switch 20; a current sensor 30 for detecting a current value flowing through the semiconductor switch 20; and a control circuit 10 for disconnecting the semiconductor switch 20 based on a time-limited characteristic indicating a continuous conduction allowable time corresponding to the above current value."

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-47674

[0008] Patent Document 2: Japanese Patent Application Publication No. 2022-39777 Summary of the invention

[0009] Problems to be solved by the invention

[0010] According to Patent Document 1, in the Figure 6When a short circuit occurs in one of the plurality of semiconductor switch elements connected in parallel, the first fuse and the second fuse connected in series on both sides of the semiconductor switch element having the short circuit are cut off at the same time, and the current path to the gate electrode is disconnected, so that the remaining semiconductor switch elements can continue to operate. However, once the fuse is cut off, it cannot be used again.

[0011] On the other hand, if it is a semiconductor DC circuit breaker such as Patent Document 2, since the abnormal current is detected and disconnected by the semiconductor switch, it can be reused after disconnection. Compared with mechanical DC circuit breakers, semiconductor DC circuit breakers can quickly disconnect abnormal currents through the high-speed disconnection characteristics of semiconductors, and have the advantage of being able to suppress damage to the protected equipment.

[0012] However, semiconductor switching elements have problems such as occasional failures that may be caused by cosmic rays or the like.

[0013] The problem to be solved by the present invention is to provide a semiconductor DC circuit breaker having redundancy capable of interrupting current even when a semiconductor switching element for interrupting current when an abnormal current is detected fails, and a semiconductor module suitable for use therein.

[0014] Solutions to Solve Problems

[0015] The semiconductor DC circuit breaker of the present invention has, for example, a semiconductor switch element that disconnects the main current when an abnormal current is detected. The semiconductor DC circuit breaker is characterized in that it has: a fuse connected in series with the semiconductor switch element; an abnormal current detection unit that detects the abnormal current; and

[0016] A gate driving unit turns off the semiconductor switch element when the abnormal current is detected by the abnormal current detection unit, wherein the magnitude of the abnormal current that turns off the semiconductor switch element is set to be smaller than a melting current of the fuse.

[0017] In addition, the semiconductor module of the present invention, for example, comprises: a semiconductor switching element having a first main terminal and a second main terminal; a housing in which the semiconductor switching element is built-in; a first external terminal connected to the first main terminal; and a second external terminal connected to the second main terminal. The semiconductor module is characterized in that the semiconductor switching element is a bidirectional switch, which is formed by connecting a reference potential terminal of a first switching element having the first main terminal and a reference potential terminal of a second switching element having the second main terminal, and further comprises a fuse, which is connected in series with the semiconductor switching element and built-in to the housing.

[0018] Effects of the Invention

[0019] According to the present invention, a semiconductor DC circuit breaker having redundancy capable of interrupting current even when a semiconductor switching element for interrupting current when an abnormal current is detected fails, and a semiconductor module suitable for use therein can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a circuit diagram of the semiconductor DC circuit breaker and the semiconductor module of the first embodiment.

[0021] Figure 2 This is a perspective view of the semiconductor module of Example 1.

[0022] Figure 3 This is a perspective view of the interior of the semiconductor module of the first embodiment.

[0023] Figure 4 This is a top view of the interior of the semiconductor module of Example 1.

[0024] Figure 5 This is a top view of the interior of the semiconductor module of Example 1.

[0025] Figure 6 1 is a plan view of a first external terminal and a fuse of the semiconductor module according to the first embodiment.

[0026] Figure 7 This is a circuit diagram of a semiconductor DC circuit breaker and a semiconductor module according to a second embodiment.

[0027] Figure 8 This is a perspective view of the interior of the semiconductor module of the second embodiment.

[0028] Fig. 9 This is a top view of the interior of the semiconductor module of the second embodiment.

[0029] Fig.10 This is a circuit diagram of a semiconductor DC circuit breaker and a semiconductor module according to a third embodiment.

[0030] Fig.11 This is a circuit diagram of a semiconductor DC circuit breaker and a semiconductor module according to a fourth embodiment. DETAILED DESCRIPTION

[0031] In the following, embodiments of the present invention are described using the drawings. In each figure and each embodiment, the same or similar components are denoted by the same reference numerals, and repeated descriptions are omitted.

[0032] Example 1

[0033] Figure 1 This is a circuit diagram of the semiconductor DC circuit breaker and the semiconductor module of the first embodiment.

[0034] The semiconductor DC circuit breaker 1 of the first embodiment is connected between the power supply 3 and the protection target device 4, and disconnects the current when an abnormal current is detected. Here, the semiconductor DC circuit breaker 1 has: a semiconductor switch element 21, which disconnects the main current when an abnormal current is detected; a fuse 25, which is connected in series with the semiconductor switch element 21; an abnormal current detection unit 11, which detects an abnormal current; and a gate drive unit 12, which disconnects the semiconductor switch element 21 when an abnormal current is detected by the abnormal current detection unit 11. And, the magnitude of the abnormal current that disconnects the semiconductor switch element 21 is set to be smaller than the fusing current of the fuse 25. In addition, the fusing current of the fuse 25 is set to be less than the allowable current of the protection target device 4.

[0035] According to such a structure, when an abnormal current flows, the abnormal current can be detected, and the semiconductor switch element 21 can be disconnected before the fuse 25 is blown to cut off the current, so that the semiconductor DC circuit breaker 1 can be reused, and even if the semiconductor switch element 21 fails due to cosmic rays, etc., the current can be cut off by the fuse 25 connected in series being blown. That is, there is redundancy that the current can be cut off even if the semiconductor switch element 21 for cutting off the current when the abnormal current is detected fails.

[0036] The semiconductor switch element 21 is composed of a bidirectional switch, which is formed by connecting the reference potential terminal of the first switch element 21a and the reference potential terminal of the second switch element 21b. As a result, the current in either direction can be disconnected. In addition, when it is not necessary to disconnect in both directions, a semiconductor switch element 21 in one direction can also be used.

[0037] exist Figure 1 In the figure, an example of using MOSFET (Metal Oxide Semiconductor Field Effect Transistor) as the first switching element 21a and the second switching element 21b is shown, but the present invention is not limited to this, and other semiconductor switching elements such as IGBT (Insulated Gate Bipolar Transistor) may also be used.

[0038] When the semiconductor switch element 21 is a MOSFET, the reference potential terminal through which the main current flows is the source S, which is one of the main terminals. In addition, a diode 22 consisting of a body diode having a built-in MOSFET is connected in reverse parallel to the drain D, which is another main terminal through which the main current flows. In addition, a control signal from the gate drive unit 12 is input to the gate G to control on and off. In the case of an IGBT, the source is replaced by the emitter, the drain is replaced by the collector, and the diode 22 may be an external diode.

[0039] The semiconductor DC circuit breaker 1 includes a semiconductor module 2 having a built-in semiconductor switching element 21 .

[0040] Figure 2 is a perspective view of the semiconductor module of Example 1, Figure 3 is a perspective view of the interior of the semiconductor module of Example 1, Figure 4 as well as Figure 5 is a top view of the interior of the semiconductor module of Example 1, Figure 6 FIG. 1 is a top view of the first external terminal and the fuse of the semiconductor module of Example 1. Figure 5 In FIG. 1 , external terminals and auxiliary terminals and connecting wiring formed integrally with them are shown, but in FIG. Figure 4 They are omitted from the illustration.

[0041] The semiconductor module 2 includes a semiconductor switch element 21, a housing 38 in which the semiconductor switch element 21 is built, a first external terminal 31, and a second external terminal 32. The first external terminal 31 is connected to a first main terminal of the semiconductor switch element 21, and the second external terminal 32 is connected to a second main terminal of the semiconductor switch element 21. Figure 1 , an example is shown in which the first main terminal is the drain D of the first switching element 21 a and the second main terminal is the drain D of the second switching element 21 b .

[0042] Furthermore, in Embodiment 1, the fuse 25 connected in series with the semiconductor switch element 21 is also built into the case 38 of the semiconductor module 2. The built-in fuse 25 is formed by a part of the wiring in the case 38 and melts when a predetermined melting current flows.

[0043] In the first embodiment, as an example of the built-in fuse 25, Figure 6 As shown in FIG. 1 , the fuse 25 is formed by thinning a portion of the connection wiring 31a formed integrally with the first external terminal 31. Figure 1As shown, a fuse 25 can be provided between the semiconductor switch element 21 and the protected device 4. In addition, the method for forming the fuse 25 is not limited thereto, and for example, the fuse 25 can also be formed by thinning a portion of the connection wiring 31a formed integrally with the first external terminal 31, or by forming the connection wiring 31a from a material having a lower melting point than other portions.

[0044] The interior of the case 38 of the semiconductor module 2 is sealed by gel such as silicone gel (not shown), and the fuse 25 is also sealed by the gel. This improves the insulation withstand voltage of the fuse 25 and enables miniaturization.

[0045] In addition, the fuse 25 has parasitic resistance and parasitic inductance. Furthermore, the wiring of the semiconductor module 2 also has parasitic resistance and parasitic inductance. Figure 1 The parasitic resistance 23 shown includes the parasitic resistance of the wiring and the parasitic resistance of the fuse 25 , and the parasitic inductance 24 includes the parasitic inductance of the wiring and the parasitic inductance of the fuse 25 .

[0046] Therefore, the abnormal current detection unit 11 of the first embodiment also uses the parasitic resistance or parasitic inductance of the fuse 25 to detect the abnormal current based on the voltage including the voltage generated at both ends of the parasitic resistance or parasitic inductance of the fuse 25 .

[0047] Therefore, the semiconductor module 2 is configured as follows: as an external terminal connected to the outside of the box 38, a measurement terminal capable of measuring a voltage including a voltage generated across the parasitic resistance or parasitic inductance of the fuse 25 is provided. Figure 3 The abnormal current measurement auxiliary terminal 37 and the first drain sensing auxiliary terminal 35 are shown.

[0048] The auxiliary terminal 37 for abnormal current measurement is connected to Figure 1 The right side of the abnormal current detection unit 11 is connected to the terminal, Figure 3 In the embodiment 1, the auxiliary terminal 37 for abnormal current measurement is directly connected to the first external terminal 31. In addition, the auxiliary terminal 37 for abnormal current measurement is not limited to this, and can also be directly connected to the connection wiring 31a as long as it is closer to the first external terminal 31 than the fuse 25. In addition, in the embodiment 1, an example is shown in which the auxiliary terminal 37 for abnormal current measurement is set only in one of the two first external terminals 31, but it can also be set in the first external terminal 31 of the other party, or in both first external terminals 31. In addition, it is also possible to have only one first external terminal 31.

[0049] The first drain sense auxiliary terminal 35 is connected to Figure 1 The left side of the abnormal current detection unit 11 is connected to the terminal Figure 5The first drain sense pad 45 is connected. Thus, the potential of the drain D of the first switching element 21a can be measured. In addition, in Embodiment 1, two first drain sense auxiliary terminals 35 are provided, but only one may be provided. In addition, the first drain sense auxiliary terminal 35 is larger than the other auxiliary terminals and becomes an external terminal of a shape close to the first external terminal 31. Thus, the components of the AC terminals of the semiconductor modules used in the power conversion device and the like can be used. In addition, the first drain sense auxiliary terminal 35 is not limited to this, and a smaller shape similar to that of the other auxiliary terminals may be adopted.

[0050] like Figures 3 to 5 As shown, the semiconductor module 2 of the first embodiment includes six insulating substrates 47 on a base plate 39. A wiring layer 48 is formed on the insulating substrate 47, and a part of the wiring layer functions as a pad.

[0051] like Figure 4 As shown, among the three insulating substrates 47 on the upper side, the two larger ones are respectively equipped with a plurality of first switch elements 21a, which are connected by bonding materials such as solder, bonding wires 49, etc. The remaining one is an auxiliary substrate, which has a gate pad 43 connected to the gate G of the first switch element 21a, and a source sense pad 44 connected to the source sense of the first switch element 21a.

[0052] Similarly, among the three insulating substrates 47 on the lower side, the two larger ones are respectively equipped with a plurality of second switch elements 21b. The remaining one is an auxiliary substrate having a gate pad 43 connected to the gate G of the second switch element 21b and a source sense pad 44 connected to the source sense of the second switch element 21b.

[0053] Here, in order to ensure the current capacity, a plurality of first switching elements 21a and second switching elements 21b are used, and a dual parallel structure is formed on the insulating substrate 47 on the left and the insulating substrate 47 on the right, but it is not limited to this, and a three-parallel structure or more may be formed, or a single path may be formed without dividing into the left and right sides. In addition, a structure may be formed in which the gate pad 43 and the source sensing pad 44 are provided on the insulating substrate 47 on which the first switching element 21a and the second switching element 21b are mounted without using an auxiliary substrate. In addition, the first switching element 21a and the second switching element 21b may be mounted on one insulating substrate 47 without dividing into the upper side and the lower side. That is, the number of insulating substrates 47 is arbitrary.

[0054] like Figure 3 as well as Figure 5As shown, the semiconductor module 2 has a first external terminal 31, a second external terminal 32, a gate auxiliary terminal 33, a source sense auxiliary terminal 34, a first drain sense auxiliary terminal 35, a second drain sense auxiliary terminal 36, and an abnormal current measurement auxiliary terminal 37 as external terminals.

[0055] The first external terminal 31 is connected to the first drain pad 41 and to the drain D of the first switching element 21a so that the main current flows. The second external terminal 32 is connected to the second drain pad 42 and to the drain D of the second switching element 21b so that the main current flows.

[0056] The right gate auxiliary terminal 33 is connected to the upper gate pad 43 and to the gate G of the first switching element 21a. The left gate auxiliary terminal 33 is connected to the lower gate pad 43 and to the gate G of the second switching element 21b.

[0057] The right source sensing auxiliary terminal 34 is connected to the upper source sensing pad 44 and connected to the source sensing of the first switch element 21a. The left source sensing auxiliary terminal 34 is connected to the lower source sensing pad 44 and connected to the source sensing of the second switch element 21b.

[0058] The gate auxiliary terminal 33 and the source sense auxiliary terminal 34 are connected to the gate driving unit 12 , and the semiconductor switch element 21 is driven by a control signal from the gate driving unit 12 .

[0059] The first drain sense auxiliary terminal 35 and the abnormal current measurement auxiliary terminal 37 are already described, and thus description thereof is omitted.

[0060] The second drain sense auxiliary terminal 36 is connected to the second drain sense pad 46. Thus, the potential of the drain D of the second switching element 21b can be measured. In the first embodiment, only one second drain sense auxiliary terminal 36 is provided, but two or more may be provided.

[0061] Next, the clamp circuit of Example 1 will be described.

[0062] like Figure 1 As shown, in the first embodiment, the fuse 25 is connected in series. The fuse 25 needs to have a high current density so that it melts when a predetermined melting current flows, and therefore has a large inductance. If the inductance increases due to the series connection of the fuse 25, the surge voltage increases when the semiconductor switch element 21 is disconnected, and therefore a high withstand voltage element is required as the semiconductor switch element 21. However, the high withstand voltage of the semiconductor switch element 21 increases the on-resistance of the semiconductor switch element 21, and thus there is a problem that the loss increases.

[0063] Therefore, in the first embodiment, a clamp circuit is provided to suppress surge voltage. By providing a clamp circuit including the semiconductor switch element 21 in the path and excluding the fuse 25 in the path, the influence of the inductance of the fuse 25 can be suppressed.

[0064] In Embodiment 1, an example having two types of clamp circuits is shown.

[0065] The first clamp circuit is a clamp circuit composed of a path including a first switching element 21a, a Zener diode 26 connected between the gate G and the drain D of the first switching element 21a, and a gate driving unit 12. When an abnormal current is detected and the charge is passed through the gate of the first switching element 21a through the gate driving unit 12 to cut off the current flowing in the first switching element 21a, a drain surge voltage is induced. If a voltage exceeding the avalanche voltage is applied to the Zener diode 26, the avalanche current charges the gate G of the first switching element 21a, so that the switching speed can be slowed down and the device is slowly cut off. As a result, the maximum voltage between the source S and the drain D can be limited, and a semiconductor switching element 21 with a low withstand voltage can be used.

[0066] The Zener diode 26 connected to the first switching element 21a may be connected between the gate auxiliary terminal 33 of the first switching element 21a and the first drain sense auxiliary terminal 35. In addition, since the parasitic inductance is preferably small, a drain sense auxiliary terminal composed of a terminal smaller than the first drain sense auxiliary terminal 35 may be separately provided and connected thereto.

[0067] In addition, if Figure 1 As shown, similarly for the second switch element 21b side, by also providing a Zener diode 26 between the gate G and the drain D of the second switch element 21b, a clamp circuit including the second switch element 21b in the path is provided. The Zener diode 26 connected to the second switch element 21b may be connected between the gate auxiliary terminal 33 of the second switch element 21b and the second drain sense auxiliary terminal 36. Although it is also possible to connect to the second external terminal 32 instead of the second drain sense auxiliary terminal 36, the second drain sense auxiliary terminal 36 is preferred because the parasitic inductance is preferably small.

[0068] Since the fuse 25 is not included in the path of these first clamp circuits, a structure is formed in which the circuit is not affected even if the inductance increases by connecting the fuse 25 in series.

[0069] The second clamp circuit is a clamp circuit composed of a path including the semiconductor switch element 21 and the varistor 13 connected to both ends of the semiconductor switch element 21. Figure 1The inductance shown next to the varistor 13 is the parasitic inductance of the clamp circuit. The varistor 13 can use a metal oxide varistor (MOV: Metal Oxide Varistor), for example. If a voltage above a predetermined voltage is applied, the varistor 13 avalanches and the resistance decreases, and the current bypasses and flows to the varistor 13 side, so a semiconductor switch element 21 with a low withstand voltage can be used. In addition, the first clamp circuit applies a heat load to the semiconductor switch element 21 when the first clamp circuit is operated, so there is also an effect that the heat load can be reduced by the second clamp circuit.

[0070] One side of the varistor 13 may be connected to the first drain sense auxiliary terminal 35, and the other side may be connected to the second drain sense auxiliary terminal 36 or the second external terminal 32. Since the second external terminal 32 has a larger current capacity than the second drain sense auxiliary terminal 36, it is preferably connected to the second external terminal 32. Similarly, the first drain sense auxiliary terminal 35 preferably has a larger current capacity than other auxiliary terminals.

[0071] Since the fuse 25 is not included in the path of the second clamp circuit, even if the inductance increases due to connecting the fuse 25 in series, the circuit is not affected by the increase.

[0072] In addition, Figure 1 In the embodiment, the Zener diode 26 and the varistor 13 are provided outside the semiconductor module 2, but at least one of them may be built into the semiconductor module 2. Similarly, one or both of the abnormal current detection unit 11 and the gate drive unit 12 may be built into the semiconductor module 2.

[0073] As described above, according to the first embodiment, the semiconductor DC circuit breaker 1 having redundancy capable of interrupting current even when the semiconductor switching element 21 for interrupting current when abnormal current is detected fails, and the semiconductor module 2 suitable for use therein can be realized.

[0074] Example 2

[0075] Embodiment 2 is a modified example of Embodiment 1. Embodiment 2 is different from Embodiment 1 in the method of implementing fuse 25. Other than that, it is the same as Embodiment 1, so the description will be mainly focused on the differences, and duplicate description will be omitted.

[0076] Figure 7 is a circuit diagram of a semiconductor DC circuit breaker and a semiconductor module of Example 2, Figure 8 is a perspective view of the interior of the semiconductor module of Example 2. Fig. 9 This is a top view of the interior of the semiconductor module of the second embodiment. Figure 7 and Figure 1 correspond, Figure 8 and Figure 3 correspond, Fig. 9 is with Figure 4 The corresponding figure.

[0077] In the semiconductor DC circuit breaker 1 and the semiconductor module 2 of the second embodiment, the fuse 25 is formed between the source S as the reference potential terminal of the first switching element 21a and the source S as the reference potential terminal of the second switching element 21b. In addition, in this case, since the current path is connected in series, the fuse 25 and the semiconductor switching element 21 are interpreted as being connected in series.

[0078] In the second embodiment, the built-in fuse 25 is formed by a part of the wiring in the box 38, and will be melted when a predetermined fuse current flows, which is the same as the first embodiment, but Fig. 9 As shown in FIG. 1 , the bonding wire 49 connecting the insulating substrate 47 on which the first switching element 21 a is mounted and the insulating substrate 47 on which the second switching element 21 b is mounted is connected. Figure 4 The fuse 25 is small, and thus functions as the fuse 25. Therefore, it has an advantage of being easier to implement than the first embodiment. The fuse 25 of the second embodiment can also be sealed with gel.

[0079] However, in the second embodiment, the parasitic resistance 23 and the parasitic inductance 24 do not include the parasitic resistance and parasitic inductance of the fuse 25, so the sensitivity of detecting abnormal current is higher than that of the first embodiment. In addition, the first clamp circuit does not include the fuse 25 in the path, which is the same as the first embodiment, so the same effect is obtained, but the second clamp circuit includes the fuse 25 in the path, so the second clamp circuit is affected by the increase in inductance caused by connecting the fuse 25 in series, which is different from the first embodiment.

[0080] Example 3

[0081] Embodiment 3 is a modified example of Embodiment 1. Embodiment 3 is different from Embodiment 1 in that fuse 25 is provided outside semiconductor module 2. Other aspects are the same as Embodiment 1, so the description will be mainly focused on the differences and duplicate description will be omitted.

[0082] Fig.10 This is a circuit diagram of a semiconductor DC circuit breaker and a semiconductor module according to a third embodiment. Fig.10 is with Figure 1 The corresponding figure.

[0083] In the semiconductor DC circuit breaker 1 and the semiconductor module 2 of the third embodiment, the fuse 25 is provided outside the semiconductor module 2. Therefore, a general fuse 25 can be used.

[0084] Example 4

[0085] Embodiment 4 is a modified example of Embodiment 3. In Embodiment 4, the detection method of the abnormal current detection unit 11 is different from that of Embodiment 3. Other than this, the embodiment is the same as Embodiment 3, so the description will be mainly focused on the differences, and duplicate description will be omitted.

[0086] Fig.11 This is a circuit diagram of a semiconductor DC circuit breaker and a semiconductor module according to a fourth embodiment. Fig.11 is with Fig.10 The corresponding figure.

[0087] The semiconductor DC circuit breaker 1 and the semiconductor module 2 of the fourth embodiment are the same as those of the third embodiment, and the fuse 25 is provided outside the semiconductor module 2. Therefore, a general fuse 25 can be used.

[0088] Furthermore, the abnormal current detection unit 11 detects the abnormal current based on a voltage including a voltage generated across both ends of the parasitic resistance or the parasitic inductance of the fuse 25 .

[0089] Although the embodiments of the present invention have been described above, the present invention is not limited to the structures described in the embodiments, and various changes can be made within the scope of the technical concept of the present invention. In addition, some or all of the structures described in the embodiments can also be combined for application.

[0090] Explanation of symbols

[0091] 1—semiconductor DC circuit breaker, 2—semiconductor module, 3—power supply, 4—protected device, 11—abnormal current detection unit, 12—gate drive unit, 13—varistor, 21—semiconductor switching element, 21a—first switching element, 21b—second switching element, 22—diode, 23—parasitic resistance, 24—parasitic inductance, 25—fuse, 26—Zener diode, 31—first external terminal, 31a—connection wiring, 32—second external terminal, 33—gate auxiliary terminal Sub, 34—source sensing auxiliary terminal, 35—first drain sensing auxiliary terminal, 36—second drain sensing auxiliary terminal, 37—auxiliary terminal for abnormal current measurement, 38—box, 39—base plate, 41—first drain pad, 42—second drain pad, 43—gate pad, 44—source sensing pad, 45—first drain sensing pad, 46—second drain sensing pad, 47—insulating substrate, 48—wiring layer, 49—bonding lead, G—gate, S—source, D—drain.

Claims

1. A semiconductor DC circuit breaker having a semiconductor switch element for disconnecting a main current when an abnormal current is detected, wherein the semiconductor DC circuit breaker has: A fuse connected in series with the semiconductor switch element; an abnormal current detection unit that detects the abnormal current; and a gate driving unit that turns off the semiconductor switch element when the abnormal current is detected by the abnormal current detecting unit, The magnitude of the abnormal current that turns off the semiconductor switch element is set to be smaller than the melting current of the fuse.

2. The semiconductor DC circuit breaker according to claim 1, characterized in that: The abnormal current detection unit detects the abnormal current based on a voltage including a voltage generated across both ends of a parasitic resistance or a parasitic inductance of the fuse.

3. The semiconductor DC circuit breaker according to claim 1, characterized in that: A clamp circuit is provided, the clamp circuit including the semiconductor switch element in a path and excluding the fuse in the path.

4. The semiconductor DC circuit breaker according to claim 1, characterized in that: The semiconductor switch element is a bidirectional switch, and the bidirectional switch is configured by connecting a reference potential terminal of a first switch element and a reference potential terminal of a second switch element.

5. The semiconductor DC circuit breaker according to claim 1, characterized in that: The semiconductor switch element has a first main terminal and a second main terminal through which the main current flows. The semiconductor DC circuit breaker includes a semiconductor module, the semiconductor module including the semiconductor switch element, a housing in which the semiconductor switch element is built, a first external terminal connected to the first main terminal, and a second external terminal connected to the second main terminal. The fuse is built into the box of the semiconductor module.

6. The semiconductor DC circuit breaker according to claim 5, characterized in that: The fuse is formed by a part of the wiring in the box, and melts when the fuse current flows.

7. The semiconductor DC circuit breaker according to claim 6, characterized in that: The fuse is formed by making a portion of the connection wiring formed integrally with the first external terminal narrower or thinner, or by making the portion of the connection wiring thinner or thinner, or by making the portion of the connection wiring thinner or thinner by a material having a lower melting point than other portions.

8. A semiconductor module comprising: a semiconductor switch element having a first main terminal and a second main terminal; a housing in which the semiconductor switch element is built; a first external terminal connected to the first main terminal; and a second external terminal connected to the second main terminal, wherein the semiconductor module is characterized in that: The semiconductor switch element is a bidirectional switch, and the bidirectional switch is formed by connecting a reference potential terminal of a first switch element having the first main terminal and a reference potential terminal of a second switch element having the second main terminal. A fuse is also provided, which is connected in series with the semiconductor switch element and is built in the box.

9. The semiconductor module according to claim 8, characterized in that The fuse is formed by a part of the wiring in the box, and melts when a predetermined fusing current flows.

10. The semiconductor module according to claim 9, characterized in that The fuse is formed by making a portion of the connection wiring formed integrally with the first external terminal narrower or thinner, or by making the portion of the connection wiring thinner or thinner, or by making the portion of the connection wiring thinner or thinner by a material having a lower melting point than other portions.

11. The semiconductor module according to claim 9, characterized in that The fuse is formed between the reference potential terminal of the first switching element and the reference potential terminal of the second switching element.

12. The semiconductor module according to claim 8, characterized in that There is gel in the box. The fuse is sealed by the gel.

13. The semiconductor module according to claim 8, characterized in that A measurement terminal capable of measuring a voltage including a voltage generated at both ends of a parasitic resistance or a parasitic inductance of the fuse is provided as an external terminal connected to the outside of the box.

14. A semiconductor DC circuit breaker, characterized in that: have: The semiconductor module according to any one of claims 8 to 13; an abnormal current detection unit that detects an abnormal current based on a voltage including a voltage generated across both ends of a parasitic resistance or a parasitic inductance of the fuse; as well as a gate driving unit that turns off the semiconductor switch element when the abnormal current is detected by the abnormal current detecting unit, The magnitude of the abnormal current that turns off the semiconductor switch element is set to be smaller than the melting current of the fuse.

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