JP2011130626A - Module for semiconductor switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a module for a semiconductor switch having a structure that achieves good heat dissipation and reduced erroneous switching operation, and also having improved reliability. <P>SOLUTION: The module for the semiconductor switch has the structure that conducts heat emitted from a semiconductor switch element to a heat sink separately arranged from a print substrate, and has the structure that separates a switching current path that serves as an input and output to the semiconductor switch element from a driving current path that drives the semiconductor switch element for switching operation, thereby each path is connected at a short distance. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor switch module, and more particularly to a semiconductor switch module used for a power conversion device that converts DC power into predetermined power by switching.

  2. Description of the Related Art Conventionally, a semiconductor switch module configured to switch a high voltage and large current at high speed using a switching function of a semiconductor element is known. For example, a power conversion device such as a switching power source or an inverter device. (See, for example, Patent Document 1 and Patent Document 2). An example of this type of conventional semiconductor switch module is illustrated in FIGS. In this case, the semiconductor switch module is configured as a surface mount type on an aluminum substrate with good thermal conductivity. The circuit configuration is illustrated in FIG. 4 and the structure of the module is illustrated in FIGS. 5 and 6. To do.

  FIG. 4 is a block diagram showing an example of the circuit configuration of the semiconductor switch module. As illustrated in FIG. 4, the semiconductor switch module includes two switch arms 1 a and 1 b as semiconductor switch circuits, a smoothing capacitor 2, a drive circuit 3, an input side terminal pair 4, and an output terminal 5. Yes. The switch arms 1a and 1b as semiconductor switch circuits are configured identically. That is, two semiconductor switch elements 11A and 11B are connected to each other in the switch arm 1a, and two semiconductor switch elements 11C and 11D are connected to each other in series on the switch arm 1b, and both ends thereof are common to the terminal pair 4 on the input side. The connection point of the two semiconductor switch elements is connected to the output terminal 5. The semiconductor switch elements 11A and 11C function as a high-side switch, and the semiconductor switch elements 11B and 11D function as a low-side switch. Each semiconductor switch element is assumed to be composed of two semiconductor elements.

  The smoothing capacitor 2 is also connected between the input terminal pair 4, and the switching noise generated by each semiconductor switch element is suppressed by making the impedance between the terminal pair low. The drive circuit 3 supplies a drive signal for turning on / off each of the semiconductor switch elements 11A, 11B, 11C, and 11D. The input terminal pair 4 is a terminal pair for connecting an input to the semiconductor switch module. The output terminal 5 is a terminal at which an output after switching by the semiconductor switch circuit appears.

  FIGS. 5 and 6 are a plan view and a side view, respectively, showing an example of the structure of the semiconductor switch module. In this example, the semiconductor switch module is configured as a surface mount type on an aluminum substrate in consideration of heat dissipation, and is configured with two semiconductor elements on the left end side of the aluminum substrate 6 as illustrated in FIG. The high-side switch semiconductor switch elements 11A and 11C have a part of the drive circuit 3 for supplying drive signals to these semiconductor switches and the output terminal 5 on the right side of the aluminum substrate 6 which is the right side of the area. The smoothing capacitor 2 and one of the input terminal pairs 4a are located in the central portion, the semiconductor switch elements 11B and 11D are located in the region on the right side, and the right end of the aluminum substrate 6 adjacent to the right side is one of the drive circuits 3. One of the part and the input terminal pair 4b is mounted.

Japanese Unexamined Patent Publication No. 2000-92847 (5th page, FIG. 1) JP 2004-335625 A (Page 12, FIG. 1)

  As described above, in a conventional semiconductor switch module configured in a surface mount type, as a semiconductor element constituting each semiconductor switch element, for example, a surface mount type FET (Field Effect Transistor) having a predetermined withstand power is used. Heat generated from the semiconductor element due to the loss during switching is conducted to the aluminum substrate 6 via a heat conductive insulating sheet or the like (not shown). The drive signal is supplied from the drive circuit 3 to the corresponding gate electrode of the FET. However, since the gate electrode has a high input impedance, it is easily affected by noise from the periphery. For this reason, it is necessary to arrange the drive circuit 3 in the vicinity of each corresponding semiconductor element. Furthermore, in order to reduce line drop and self-inductance due to the wiring pattern, it is desirable that the high-side switch and the low-side switch constituting one switch arm are connected to the smoothing capacitor 2 at a short distance.

  However, in the conventional semiconductor switch module described above, since the drive circuit 3 and each semiconductor element are arranged at a short distance, the high-side switch and the low-side switch cannot be connected at a short distance. For this reason, the wiring pattern between them cannot be shortened sufficiently, the surge voltage for each semiconductor element increases due to the temperature rise due to line drop and the influence of self-inductance, and the radiation noise increases and the semiconductor element may be destroyed. It was. Further, since a relatively large drain current switched by each semiconductor element flows around each of the drive circuits arranged in a distributed manner, a magnetic field generated by this current is coupled to the drive signal supplied from the drive circuit 3 to the semiconductor element. As a result, the semiconductor element malfunctions, and the high-side switch and the low-side switch in the same switch arm are both brought into conduction, and the semiconductor element may be damaged. Furthermore, since heat generated from the semiconductor element is repeatedly transmitted to the smoothing capacitor 2 through the aluminum substrate 6, a crack may occur in the electrode of the smoothing capacitor 2 due to a temperature cycle or the like.

  Thus, although the structure of the conventional semiconductor switch module is miniaturized by adopting the surface mount type, it is easily affected by heat generation and may cause an abnormality in the switching operation. It was not enough.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a module for a semiconductor switch having a structure in which good heat dissipation and switching malfunctions are reduced and reliability is improved. .

  In order to achieve the above object, the semiconductor switch module of the present invention has two semiconductor switch elements connected in series with each other, both ends of which are input terminal pairs, and the connection point of these two elements is the output side. A plurality of sets of switch arms connected to each of the terminals, a semiconductor switch circuit connected in parallel with a common input side terminal pair, a smoothing capacitor connected between the input side terminal pair, and the semiconductor In a semiconductor switch module in which a drive circuit for supplying a switch drive signal to each semiconductor switch element in the switch circuit is mounted on a printed circuit board, the smoothing capacitor and the smoothing capacitor are provided on one surface of the printed circuit board. The electrode leads of the two semiconductor switch elements constituting each switch arm in the semiconductor switch circuit are sandwiched between The semiconductor switch elements are mounted adjacent to each other in a direction orthogonal to the direction in which the electrode leads face each other, and the heat dissipation surface of each semiconductor switch element is the same side as the surface of the printed circuit board. An electrode of the semiconductor switch element that is commonly attached to a heat radiating plate provided in parallel with and spaced from the other surface of the printed circuit board, and is opposed to the other surface of the printed circuit board so as to sandwich the smoothing capacitor therebetween The input-side terminal pair and the output-side terminal are mounted on a portion corresponding to a region between leads, and the drive circuit is mounted on a portion facing the semiconductor switch element outside the region. To do.

  ADVANTAGE OF THE INVENTION According to this invention, while having the structure which reduced favorable heat dissipation and the malfunction of switching, the module for semiconductor switches which improved reliability can be obtained.

The block diagram which shows an example of the circuit structure of the module for semiconductor switches which concerns on this invention. The top view which shows an example of the structure of the module for semiconductor switches which concerns on this invention. The side view which shows an example of the structure of the module for semiconductor switches which concerns on this invention. The block diagram which shows an example of the circuit structure of the module for conventional semiconductor switches. The top view which shows an example of the structure of the conventional module for semiconductor switches. The side view which shows an example of the structure of the conventional module for semiconductor switches.

  The best mode for carrying out a semiconductor switch module according to the present invention will be described below with reference to FIGS. In the following embodiments, parts corresponding to the same components as those of the conventional semiconductor switch module described in the background art will be described using the same reference numerals as those used in the description of the background art.

  FIG. 1 is a block diagram showing a circuit configuration of an embodiment of a semiconductor switch module according to the present invention. In the present embodiment, the circuit configuration of the basic portion is such that a module is configured by the same blocks as the conventional circuit configuration illustrated in FIG.

  That is, the semiconductor switch circuit includes two switch arms 1a and 1b, a smoothing capacitor 2, a drive circuit 3, an input terminal pair 4, an output terminal 5, and a switch drive signal input terminal 8. In the switch arm 1a, two semiconductor switch elements 11A and 11B are connected in series with each other, both ends thereof are connected to the input terminal pair 4, and the connection point of these two semiconductor switch elements is connected to the output terminal 5a. Similarly, the switch arm 1b has two semiconductor switch elements 11C and 11D connected in series with each other, and both ends thereof are connected in parallel with the switch arm 1a with the input terminal pair 4 in common. It is connected to the output terminal 5b.

  In the present embodiment, each of the semiconductor switching elements 11A, 11B, 11C, and 11D is assumed to be further configured by individual semiconductor elements such as two FETs. In each switch arm, the semiconductor switch elements 11A and 11C function as a high-side switch, and the semiconductor switches 11B and 11D function as a low-side switch.

  Both ends of the smoothing capacitor 2 are connected to the input terminal pair 4, and the two switch arms 1 a and 1 b are connected in parallel. Suppresses high-frequency switching noise that occurs. The drive circuit 3 drives a switch drive signal sent from the outside, and supplies this to the individual semiconductor elements constituting the semiconductor switch elements 11A, 11B, 11C, and 11D as a drive signal. The input terminal pair 4 is a terminal pair for connecting an input to the semiconductor switch module, and is connected to, for example, an external DC power source. The output terminal 5 is a terminal for supplying the output after switching by this semiconductor switch module to an external load or the like. The switch drive signal input terminal 8 is a terminal for receiving a switch drive signal supplied from the outside.

  2 and 3 are a plan view and a side view showing an example of the structure of the module for semiconductor switch, respectively. As illustrated in FIGS. 2 and 3, the semiconductor switch module includes semiconductor switch elements 11A, 11B, 11C, and 11D that form a semiconductor switch circuit, a smoothing capacitor 2 (2a and 2b), a drive circuit 3, and an input. The printed circuit board 7 on which the terminal pair 4, the output terminal 5, and the switch drive signal input terminal 8 are mounted on the upper surface or the lower surface, and the heat radiation surface of each semiconductor switch element mounted on the printed circuit board 7 are attached in common. The flat heat sink 9 has a structure arranged in parallel to each other.

  On the lower surface side of the printed circuit board 7, semiconductor switch elements 11A, 11B, 11C, and 11D that form a semiconductor switch circuit, and two smoothing capacitors 2a and 2b are mounted. In the present embodiment, the semiconductor switch elements 11A to 11D are each composed of two individual semiconductor elements as described above, and these individual semiconductor elements are provided for each combination of two semiconductor switches constituting each switch arm. The electrode leads are mounted so as to face each other so as to sandwich the smoothing capacitor 2 and are adjacent to each other by two arms. That is, as shown in FIG. 2, the two individual semiconductor elements in the semiconductor switch element 11A forming the first arm 1a and the two individual semiconductor elements in the semiconductor switch element 11B are respectively sandwiched between the smoothing capacitors 2a. The individual semiconductor elements of the semiconductor switch elements 11C and 11D and the smoothing capacitor 2b forming the second arm 1b in the same manner as above are mounted on the paper surface of FIG. It is mounted adjacent to the lower side of the arm 1a. The individual semiconductor elements in each of the semiconductor switch elements are commonly attached to a planar heat radiating plate disposed in parallel with the printed circuit board 7 via a heat conductive insulating sheet 10.

  On the other hand, a drive circuit 3, an input terminal pair 4, an output terminal 5, and a switch drive signal input terminal 8 are mounted on the upper surface side of the printed circuit board 7. Among these, the input terminal pair 4 and the output terminal 5 are positioned on the upper surface side facing the smoothing capacitor 2, that is, between the electrode leads of the individual semiconductor elements of each arm mounted so that the electrode leads face each other. Implemented in the area. In FIG. 2, one side 4a of the input terminal pair is formed between the electrode leads of the individual semiconductor elements constituting the semiconductor switch element 11A and the semiconductor switch element 11B and in the region on the upper surface side of the printed circuit board facing the smoothing capacitor 2a. And the output terminal 5a, and similarly, between the electrode leads of the individual semiconductor elements constituting the semiconductor switch element 11C and the semiconductor switch element 11D, and on the upper surface side of the printed circuit board 7 facing the smoothing capacitor 2b The input terminal pair 4b and the output terminal 5b are mounted in the region. The drive circuit 3 is divided into four parts corresponding to the four semiconductor switch elements 11A to 11D, and is mounted on the upper surface side of the printed circuit board 7 facing the semiconductor elements constituting each semiconductor switch element. Further, switch drive signal input terminals 8a and 8b for receiving a switch drive signal supplied from the outside are mounted in a region where semiconductor switch elements forming two arms are adjacent to each other.

  In the semiconductor switch module of the present embodiment configured as described above, for example, a DC power supply is connected to the input terminal pair 4, and DC power from this DC power supply is supplied from the semiconductor switch elements 11A to 11D. In this semiconductor switch circuit, switching is performed by a switch driving signal applied to the switch driving signal input terminal 8. At this time, each of the semiconductor switch elements 11A to 11D in the semiconductor switch circuit is such that the high-side switch and the low-side switch in each switch arm are alternately turned on and the switches on different sides are simultaneously turned on or off between the switch arms. Switch control is performed by a drive signal from the drive circuit 3 so that the two switch states are alternately repeated at regular intervals. That is, the first switch state in which the semiconductor switch element 11A and the semiconductor switch element 11D are simultaneously turned on, and the semiconductor switch element 11B and the semiconductor switch element 11C are simultaneously turned off, the semiconductor switch element 11A and the semiconductor switch element 11D, Are switched off at the same time, and the second switch state in which the semiconductor switch element 11B and the semiconductor switch element 11C are simultaneously turned on is alternately repeated at regular intervals. Then, the electric power after switching is taken out from the output terminal 5.

  In such a switching operation, a loss occurs particularly at the timing when the switch state is switched, and the individual semiconductor elements constituting the semiconductor switch elements 11A to 11D generate heat. In this embodiment, these individual semiconductor elements are used. The heat radiating surface of the element is attached to a heat radiating plate 9 disposed at a distance from the printed board 7 via a heat conductive insulating sheet 10. For this reason, the heat generated from these elements is mainly dissipated from the heat radiating plate 9, and the heat conduction to the printed circuit board 7 is also reduced. Therefore, the temperature load such as the temperature cycle on the smoothing capacitor 2 mounted on the printed circuit board 7 is also sufficiently reduced, and the influence of heat generation on the smoothing capacitor 2 can be suppressed.

  The two semiconductor switch elements 11A and 11B and 11C and 11D connected in series constituting each arm are mounted on the printed circuit board 7 with the electrode leads facing each other so as to sandwich the smoothing capacitors 2a and 2b, respectively. Has been. For this reason, the connection between each other can be made a short-distance wiring pattern, the self-inductance of the wiring pattern can be reduced, and the influence of the line drop can be reduced even when a large current is handled. In addition, since the smoothing capacitor and the semiconductor switch element that is the source of switching noise are connected at a short distance, the effect of the smoothing capacitor on the switching noise can be further enhanced.

  Further, the drive circuit 3 that supplies a drive signal to each of the semiconductor switch elements 11A to 11D is provided on the surface of the printed circuit board 7 on the opposite side of each semiconductor switch element at a position facing each semiconductor switch element. The semiconductor switch elements are distributed and mounted so as to correspond to the semiconductor switch elements. For this reason, the connection distance between each drive circuit and the semiconductor switch element can be shortened, and the connection path can be separated from the current path handled by the semiconductor switch circuit. Therefore, it is possible to reduce the influence caused by coupling the switching current to the drive signal, to prevent malfunction of the semiconductor switch element, and to suppress the damage.

  As described above, in this embodiment, the heat generated from the semiconductor switch element is conducted to the heat radiating plate provided away from the printed circuit board, and the switching current serving as an input / output to the semiconductor switch element is reduced. The path and the path of the drive signal for driving the semiconductor switch element are separated from each other, and each path has a structure that enables connection at a short distance. As a result, it is possible to obtain a semiconductor switch module having a structure in which good heat dissipation and switching malfunctions are reduced and reliability is improved.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

DESCRIPTION OF SYMBOLS 1a, 1b Switch arm 2, 2a, 2b Smoothing capacitor 3 Drive circuit 4 Input terminal pair 5 Output terminal 6 Aluminum substrate 7 Printed circuit board 8 Switch drive signal input terminal 9 Heat sink 10 Thermal conductive insulating sheet 11A, 11B, 11C, 11D Semiconductor switch element

Claims (2)

Two semiconductor switch elements are connected in series with each other, a plurality of sets of switch arms each having both ends connected to the input side terminal pair and the connection point of these two elements to the output side terminal, the input side terminals A semiconductor switch circuit connected in parallel with a common pair;
A smoothing capacitor connected between the input-side terminal pair;
In a semiconductor switch module in which a drive circuit for supplying a switch drive signal to each semiconductor switch element in the semiconductor switch circuit is mounted on a printed circuit board,
On one side of the printed circuit board,
The smoothing capacitor;
The electrode leads of the two semiconductor switch elements constituting each switch arm in the semiconductor switch circuit are opposed to each other so as to sandwich the smoothing capacitor, and in a direction orthogonal to the direction in which the electrode leads are opposed by the number of arms. Install it next to each other,
The heat dissipating surface of each semiconductor switch element is commonly attached to a heat dissipating plate provided in parallel with the same side as the surface of the printed circuit board,
On the other side of the printed circuit board,
Mounting the input-side terminal pair and the output-side terminal on a portion corresponding to a region between the electrode leads of the semiconductor switch element opposed to sandwich the smoothing capacitor on one surface of the printed circuit board;
A module for a semiconductor switch, wherein the drive circuit is mounted on a portion facing the semiconductor switch element outside the region.   2. The semiconductor switch module according to claim 1, wherein the semiconductor switch element is composed of a plurality of individual semiconductor elements.

Images