JP2008177179A - Semiconductor module and plasma display with power recovery circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a semiconductor module, especially of a semiconductor module constituting a bi-directional switch for power recovery. <P>SOLUTION: The semiconductor module comprises a first metal base plate (101), and a second metal base plate (102). The first metal base plate is connected with the first node (N1) of the circuit of a bi-directional switch and mounts a first semiconductor element with a bonded electrode having the same potential as that of the first metal base plate. The second metal base plate is connected with the second node (N2) of the circuit and mounts a second semiconductor element with a bonded electrode having the same potential as that of the second metal base plate. The first and second metal bases are connected, respectively, with the nonbonded electrodes of the first and second semiconductor elements by metal wires (130) thus forming the circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power semiconductor module configured by combining a plurality of power semiconductor chips such as diodes and transistors, and a plasma display device having a power recovery circuit configured of such semiconductor elements.

  In a flat display device (hereinafter referred to as “plasma display device”) using an AC plasma display panel (hereinafter referred to as “PDP”), a bidirectional switch is used in a power recovery circuit. .

  For example, Patent Documents 1 and 2 disclose that this bidirectional switch is configured using one semiconductor switch in order to reduce the number of circuit elements and cost. In Patent Documents 1 and 2, a first diode array in which two diodes are connected in series with opposite polarities (hereinafter referred to as “reverse series”), a first diode array, and a first diode array are connected in parallel. A second diode string in which two diodes are connected in series with a polarity different from that of the diode string, and a connection point between two diodes in the first diode string and a connection point between two diodes in the second diode string. A bidirectional switch is disclosed that includes a semiconductor switch connected thereto. Since this bidirectional switch is similar to the diode bridge of the rectifier circuit when attention is paid to the connection form of four diodes, it will be hereinafter referred to as a bridge-type bidirectional switch.

  In a device using the bridge-type bidirectional switch described above (for example, a plasma display device), it is desired to modularize the bidirectional switch from the viewpoint of reducing manufacturing steps and cost by reducing the substrate size.

  A power semiconductor module technique used when modularizing a bridge type bidirectional switch or the like is disclosed in, for example, Patent Document 3.

JP 2004-215408 A JP 2006-72317 A JP-A-10-163416

  By the way, in a conventional power semiconductor module, as described in Patent Document 3, each chip of a semiconductor element is mounted on a wiring pattern formed on one surface of an insulating substrate (for example, an alumina substrate). The insulating substrate is bonded to a metal base plate serving as a heat diffusion plate by, for example, solder via a copper foil formed on the entire other surface.

  When such a module technology using an insulating substrate is applied to a semiconductor circuit having a small number of semiconductor elements (for example, a bridge type bidirectional switch), an expensive insulating substrate having a wiring pattern is used, and an insulating substrate provided with wiring is used. From the viewpoint of joining the metal base plate to the metal base plate, there is a risk of increasing the cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power semiconductor module with a further reduced cost and a plasma display device using the same.

  To achieve the above object, the present invention is characterized by the structure described in the claims.

  According to such a configuration, the metal base plate is constituted by a plurality of metal base plates, and semiconductor elements having junction electrodes of the same potential connected to the respective nodes constituting a predetermined circuit are respectively corresponded to the respective nodes. It is mounted directly on each metal base plate via the bonding electrode to constitute one predetermined circuit. Therefore, a plurality of semiconductor elements constituting one predetermined circuit can be mounted on a plurality of metal base plates without using an expensive insulating substrate on which a wiring pattern for mounting a semiconductor element chip is formed.

  ADVANTAGE OF THE INVENTION According to this invention, the plasma display apparatus provided with the low-cost semiconductor module and the electric power recovery circuit comprised by this semiconductor module can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, parts having common functions are denoted by the same reference numerals, and once described, repeated description is omitted to avoid complication.

  The semiconductor module according to the present embodiment is characterized in that a semiconductor element is mounted directly on a metal base plate which is a heat diffusion plate without using an expensive insulating substrate on which a wiring pattern is formed. In this case, since the metal base plate and the semiconductor element are electrically connected directly, the metal base plate has a potential of a bonding electrode bonded to the metal base plate of the semiconductor element. Therefore, the metal base plate is composed of a plurality of metal base plates, and a plurality of semiconductor elements each having a bonding electrode having the same potential as the metal base plate are placed for each metal base plate. And each semiconductor element is connected with a metal thin wire (for example, bonding wire), and one circuit is comprised as a whole.

  In the first embodiment, an embodiment of the present invention will be described using a bidirectional switch module capable of flowing a current bidirectionally as a semiconductor module.

  First, the bidirectional switch according to the first embodiment will be described.

  FIG. 1 shows a circuit of a bridge type bidirectional switch. As shown in FIG. 1, the bridge type bidirectional switch includes a first diode Di1, a second diode Di2, a third diode Di3, and a fourth diode Di4 connected between both ends of the switch (between the X terminal and the Y terminal). And a switch SW1.

  The first diode Di1 and the second diode Di2 are connected in reverse series and are inserted between the XY terminals. The third diode Di3 and the fourth diode Di4 are connected in reverse series with different polarities from the first diode Di1 and the second diode Di2, and the first diode Di1 and the second diode Di2 are reversed between the XY terminals. It is connected in parallel to the series-connected diode array. Focusing on the connection form of the first diode to the fourth diode, it is similar to a diode bridge used in a so-called rectifier circuit. In this sense, the bidirectional switch of this connection form is called a bridge type.

  Here, in order to facilitate the following description, a connection point of circuit elements is referred to as a node. That is, the connection point between the X terminal, the first diode Di1, and the third diode Di3 is the node N1, the connection point between the second diode Di2, the fourth diode Di4, and the Y terminal is the node N2, and the first diode Di1 and the second diode. A connection point with Di2 is referred to as a node N12, and a connection point between the third diode Di3 and the fourth diode Di4 is referred to as a node N34.

  The switch SW1 is connected between the node N12 and the node N34 defined as described above, and includes a semiconductor switch Q1. Here, a vertical MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used as the semiconductor switch Q1. The drain of the semiconductor switch Q1 is connected to the node N12, and the source is connected to the node N34. In the case of a MOSFET, a parasitic diode Di5 directed to the drain side is formed between the source and the drain. The source and gate of the semiconductor switch Q1 are pulled out to control the semiconductor switch Q1, and are connected to the Z terminal and the I terminal, respectively. As the semiconductor switch Q1, an IGBT (Insulated Gate Bipolar Transistor) or a bipolar transistor may be used instead of the MOSFET.

  Since the operation of the bridge type bidirectional switch is well-known, only an outline of the operation will be described.

  When a current is passed from the X → Y terminal side, a switch drive signal is applied between the I and Z terminals to turn on the semiconductor switch Q1. Then, a current flows from the X terminal side in the order of the first diode Di1 → the semiconductor switch Q1 → the fourth diode Di4, and is output from the Y terminal. Conversely, when a current is passed from the Y to the X terminal, the current flows from the Y terminal to the second diode Di2 → the semiconductor switch Q1 → the third diode Di3 and is output from the X terminal. In this way, the switching action is performed in both directions.

  Next, before explaining the main part of the present embodiment, a junction electrode of a semiconductor element when a semiconductor element is directly placed on a metal base plate which is a heat diffusion plate will be described with reference to FIG.

  2 to 4 are schematic cross-sectional configuration diagrams of semiconductor elements constituting the bridge type bidirectional switch. 2 is a configuration diagram of a diode, FIG. 3 is a configuration diagram of a MOSFET, and FIG. 4 is a configuration diagram of an IGBT. The operating principle of these semiconductor elements is well known and will not be described.

  As is apparent from FIGS. 2 to 4, the cathode electrode K of the diode is formed on the entire surface of one end surface of the diode chip, and the anode electrode A is locally formed on the other end surface. Further, the drain electrode D of the MOSFET is formed on the entire surface of one end face of the chip, and the source electrode S and the gate electrode G are locally formed on the other end face. Similarly, the collector electrode C of the IGBT is formed on the entire surface of one end surface of the chip, and the emitter electrode E and the gate electrode G are locally formed on the other end surface. Therefore, in general, the metal base plate and the diode are joined on the cathode electrode K surface, and the metal base plate and the MOSFET are joined on the drain electrode D surface. In the case of IGBT, it is performed on the collector electrode C surface. Hereinafter, for convenience of description, an electrode bonded to a metal base plate in these semiconductor elements is referred to as a “bonding electrode”. That is, the junction electrode with the metal base plate is the cathode electrode K for the diode, the drain electrode D for the MOSFET, and the collector electrode C for the IGBT.

  Next, the number of metal plates that are heat diffusion plates will be described. By the way, when considering modularization in which a semiconductor element is directly mounted on a metal base plate without using an insulating substrate, the metal base plate is a junction electrode (for example, cathode electrode K, drain electrode D, collector electrode) of the semiconductor element to be mounted. C) has the potential. Therefore, if the potential of the junction electrode of the semiconductor element is different, a metal base plate having a different number of potentials is required. Therefore, assuming that the semiconductor elements and the metal base plate are merely in one-to-one correspondence, as is apparent from FIG. 1, in the bridge type bidirectional switch, the number of semiconductor elements is four, that is, four diodes and one semiconductor switch. Therefore, 5 metal base plates are required.

  Therefore, the present inventors considered reducing the number of metal base plates, and reduced the number of metal base plates by using the following circuit characteristics.

  That is, paying attention to the node N12 of the bridge type bidirectional switch, the cathode electrodes (junction electrodes) of the first diode Di1 and the second diode Di2 connected to the node N12 are both on the node N12 side. The drain electrode (junction electrode) of the semiconductor switch Q1 connected to the node N12 is also on the node N12 side. That is, a plurality of semiconductor elements (here, the first diode Di1, the second diode Di2, and the semiconductor switch Q1) connected to one node (here, the node N12) are connected to the node via the junction electrodes. It can be mounted on one metal base plate via the junction electrode of each semiconductor element (details will be described later in FIG. 5). As a result, the number of metal base plates can be reduced to three (in other words, the number of metal base plates can be optimized), and in addition to not using an insulating substrate, the cost can be further reduced. Can do.

  Next, the main part of Example 1 according to the present invention will be described.

  FIG. 5 is a configuration diagram of a main part of the bridge-type bidirectional switch module according to the first embodiment. In FIG. 5, the bridge type bidirectional switch module in which the semiconductor elements are placed on the plurality of metal base plates is viewed from the semiconductor element side with the sealing resin omitted. In addition, a MOSFET is used here as the semiconductor switch. Of course, IGBTs or bipolar transistors may be used instead of MOSFETs.

  In the bridge-type bidirectional switch module of FIG. 5, the metal base plate has a first metal base plate 101 having a potential corresponding to the node N1, on which a semiconductor element having a junction electrode on the node N1 side is mounted, and the node N2. A semiconductor element having a junction electrode on the side is mounted, and a second metal base plate 102 having a potential corresponding to the node N2 and a semiconductor element having a junction electrode on the node N12 side are mounted to correspond to the node N12. A third metal base plate 112 having the above-described potential. Note that a semiconductor element having a junction electrode on the side of the node 34 is not connected to the node 34, and therefore there is no metal base plate having a potential corresponding to the node 34.

  Specifically, a third diode Di3 is placed on the first metal base plate 101, a fourth diode Di4 is placed on the second metal base plate 102, and a first diode is placed on the third metal base plate 112. A diode Di1, a second diode Di2, and a semiconductor switch Q1 are mounted.

  As is apparent from FIG. 1, the bridge type bidirectional switch includes X and Y terminals that are terminals of a current path, and I and Z terminals that control the semiconductor switch Q1. Therefore, as shown in FIG. 5, the first metal base plate 101 having the potential corresponding to the node N1 has the X terminal drawn from the chip mounting base, and the second metal base plate having the potential corresponding to the node N2. 102 also has a Y terminal drawn from the chip mounting base. Since the I and Z terminals are not connected to the bonding electrode, the lead terminals to be the I terminal and the Z terminal are provided separately from the metal base plate.

  FIG. 6 schematically shows a cross section of the first diode Di1, the semiconductor switch Q1, and the second diode Di2 mounted on the third metal base plate 112 in FIG. The cross-sectional structure of the diode is the same as in FIG. 2, but the semiconductor switch is a little different from the basic MOSFET diagram of FIG. 3 and uses a source (S) electrode provided on the left and right of the gate (G) electrode.

  Next, wiring (wiring) in the bridge type bidirectional switch module will be described. Since the junction electrode of the semiconductor element is joined and connected to the corresponding metal base plate, the wiring connection of the non-joint electrode will be mainly described.

  In FIG. 5, the A (anode) electrode of the first diode Di1 on the third metal base plate 112 is, for example, bonded to the first metal base plate 101 corresponding to the node N1 by a metal thin wire (wire) 130 (bonding or bumping). Connected using The A electrode of the second diode Di2 on the third metal base plate 112 is connected to the second metal base plate 102 corresponding to the node N2 by a thin metal wire 130. One source (S) electrode of the semiconductor switch Q1 on the third metal base plate 112 is connected to the A electrode of the third diode Di3 on the first metal base plate 101 by a metal thin wire 130, and the other S electrode is The thin metal wire 130 is connected to the A electrode of the fourth diode Di4 on the second metal base plate 102, and is also connected to the Z terminal. The gate (G) electrode of the semiconductor switch Q1 is connected to the I terminal by a thin metal wire 130.

  By the connection described above, the bridge type bidirectional switch circuit shown in FIG. 1 is configured. After wiring between a plurality of semiconductor elements, a bridge type bidirectional switch module is completed by sealing with a resin having good thermal conductivity (not shown).

  Since the surface of the metal base plate opposite to the semiconductor element mounting surface is a contact surface when attached to the heat radiating fin, a thin insulating film may be formed on this surface. For this reason, when sealing the bridge type bidirectional switch module with resin, it is needless to say that not only the semiconductor element mounting surface side but also the radiation fin mounting side surface side may be covered thinly. Of course, the thickness of the insulating film made of resin is set to a predetermined thickness in consideration of the potential of the metal base plate and heat conduction.

  FIG. 7 is a modification of the bridge type bidirectional switch module shown in FIG. This modification is different from the first embodiment only in that the bridge type bidirectional switch module is sealed in a so-called TO3P-like semiconductor package, and the semiconductor switch Q1 is the same as the basic MOSFET diagram of FIG. Others are the same as those in the first embodiment, and detailed description thereof is omitted.

  As described above, in this embodiment, a predetermined circuit (in this embodiment, a circuit of a bridge type bidirectional switch) is used without using an expensive insulating substrate on which a wiring pattern for mounting a semiconductor element chip is formed. Metal elements corresponding to semiconductor elements each having a junction electrode (for example, K electrode, D electrode, C electrode) of the same potential connected to each node (nodes N1, N2, N12 in the present embodiment) constituting each node. A semiconductor module (in this embodiment, a bridge type bidirectional switch module) that is mounted directly on the base plate to realize one predetermined circuit is configured. Therefore, the cost of the semiconductor module can be reduced. In addition, the number of metal base plates can be optimized.

  In this embodiment, a semiconductor module (bridge type bidirectional switch module in this embodiment) is used as the third metal base plate 112 on which the semiconductor switch Q1 having the largest power consumption is mounted, for example, a heat radiating fin (not shown). A mounting hole 140 is provided for use when mounting to the head. This hole is preferably provided in the vicinity of the substantially central portion of the mounted semiconductor element arrangement in order to effectively conduct heat to the radiating fin. Of course, the present invention is not limited to this, and mounting holes may be provided, for example, at the four corners of the semiconductor module. In this case, the mounting holes are not necessarily provided in the metal base plate.

In the first embodiment, an example in which the present invention is applied to a bridge-type bidirectional switch that is one form of the bidirectional switch is shown, but the present invention is not limited to this.

  Next, a case where the present invention is applied to an output stage of a sustain discharge driving circuit (hereinafter referred to as “sustain circuit”) in a plasma display device as a semiconductor module of a second embodiment will be described.

  First, the circuit of the output stage in the sustain circuit according to the second embodiment will be described.

  FIG. 8 is a circuit of the output stage in the sustain circuit according to the present embodiment. Note that the operation of the sustain output circuit is well known and is not related to the gist of the present invention, and therefore detailed description thereof is omitted.

  In FIG. 8, an output stage circuit in the sustain circuit (hereinafter abbreviated as “sustain output circuit”) is a first power supply (here, a sustain power supply Vs) as described in Japanese Patent Application Laid-Open No. 2005-266081, for example. Between the semiconductor switch Q41 connected to the semiconductor switch Q41, the semiconductor switch Q42 connected to a second power source (ground as a reference potential: hereinafter referred to as “GND”), and between the semiconductor switch Q41 and the semiconductor switch Q42 It comprises a diode Du and a diode Dd connected in series. A connection point Out between the diode Du and the diode Dd is an output of the sustain output circuit, and is connected to, for example, a scan electrode or a sustain electrode of a PDP (not shown). The diode Du and the diode Dd have a withstand voltage preventing function for the semiconductor switches Q41 and Q42, respectively.

Sustain output circuit, as is apparent from FIG. 8, a node N41 between the D electrode of the sustain power source Vs and the semiconductor switches Q41 (showing a pulled-out D electrode terminals by symbol D _41), and the S electrode of the semiconductor switches Q41 A node N42 between the A electrode of the diode Du, a node N43 (also an output terminal Out) between the K electrode of the diode Du and the A electrode of the diode Dd, and a node between the K electrode of the diode Dd and the D electrode of the semiconductor switch Q42 It has a N44, and S electrode of the semiconductor switch Q42 (indicating the S electrode terminals drawn out by the symbol _{S 42)} and a node N45 and GND. Reference numeral _{G 41} denotes a gate terminal, reference numeral _{G 42} drawn from the G electrode of the semiconductor switch Q41 is a gate terminal drawn from the G electrode of the semiconductor switch Q42.

  Here, in order to apply the present invention, a node having a junction electrode among these nodes N41 to N45 is considered. Then, the node N41 having the D electrode of the semiconductor switch Q41, the node N43 having the K electrode of the diode Du, and the node N44 having the K electrode of the diode Dd and having the D electrode of the semiconductor switch Q42 are found. Can do. That is, the number of metal base plates is three.

  FIG. 9 is a configuration diagram of a main part of the sustain output circuit module according to the second embodiment. In FIG. 9, the sustain output circuit module in which the semiconductor elements are mounted on the plurality of metal base plates is viewed from the semiconductor element side with the sealing resin omitted. In addition, a MOSFET is used here as the semiconductor switch. Of course, IGBTs or bipolar transistors may be used instead of MOSFETs.

  In the sustain output circuit switch module of FIG. 9, the metal base plate has a first metal base plate 141 having a potential corresponding to the node N41 and a node N43 side on which a semiconductor element having a junction electrode on the node N41 side is placed. The second metal base plate 143 having a potential corresponding to the node N43 and the semiconductor element having the junction electrode on the node N44 side are mounted to correspond to the node N44. It consists of a third metal base plate 144 having a potential. Note that a metal base plate does not exist at the node 42 and the node 45 because a semiconductor element having a junction electrode on each node side is not connected.

  Specifically, the semiconductor switch Q41 is mounted on the first metal base plate 141, the diode Du is mounted on the second metal base plate 143, and the diode Dd and the semiconductor switch are mounted on the third metal base plate 144. Q42 is placed.

As is apparent from FIG. 8, the sustain output circuit includes a D ₄₁ terminal connected to the sustain power source Vs, an S ₄₂ terminal connected to GND, a G ₄₁ terminal that controls the semiconductor switch Q _41, and a semiconductor switch Q _42. A _G42 terminal to be controlled and an output terminal Out are provided. Therefore, as shown in FIG. 9, the first metal base plate 141 having the potential corresponding to the node N41 has a D ₄₁ terminal extended from the chip mounting base, a second metal base having a potential corresponding to the node N43 The plate 143 also has an Out terminal drawn from the chip mounting base. Since the G ₄₁ , G ₄₂ , and S ₄₂ terminals are not connected to the bonding electrodes, the lead terminals that become the G ₄₁ terminal, the G ₄₂ terminal, and the S ₄₂ terminal are provided separately from the metal base plate.

  Next, wiring (wiring) in the sustain output circuit module will be described. Since the junction electrode of the semiconductor element is joined and connected to the corresponding metal base plate, the wiring connection between the non-joint electrodes will be mainly described.

In FIG. 9, the S electrode of the semiconductor switch Q41 of the first metal base plate 141 is connected to the A electrode of the diode Du of the second metal base plate 143 corresponding to the node N43 by a thin metal wire 130. Also, G electrode of the semiconductor switch Q41 is connected by a metal thin wire 130 to _{G 41} terminal.

The A electrode of the diode Dd on the third metal base plate 144 is connected to the second metal base plate 143 corresponding to the node N43 by a thin metal wire (wire) 130. Further, S electrode of the semiconductor switch Q42 on the third metal base plate 144 in _{S 42} terminal, and, G electrode is connected by a metal thin wire 130 to _{G 42} terminal.

  The connection described above forms the sustain output circuit shown in FIG. After the above-described wiring, a sustain output circuit module is completed by sealing with a resin having a good thermal conductivity (not shown).

  As described above, also in this embodiment, each of the components constituting one predetermined circuit (in this embodiment, a sustain output circuit) without using an expensive insulating substrate on which a wiring pattern for mounting a semiconductor element chip is formed. Semiconductor elements having junction electrodes (for example, K electrode, D electrode, C electrode) of the same potential connected to the nodes (nodes N41, N43, N44 in this embodiment) on the metal base plate corresponding to each of the nodes. A semiconductor module (in this embodiment, a sustain output circuit module) that realizes one predetermined circuit is configured directly. Therefore, the cost of the semiconductor module can be reduced. In addition, the number of metal base plates can be optimized.

  In the sustain output circuit of the second embodiment, the two diodes Du and Dd sandwiching the output terminal Out have a withstand voltage preventing function for the semiconductor switches Q41 and Q42, respectively. The presence or absence of these diodes depends on the circuit configuration of a power recovery circuit (not shown) used in combination with the sustain circuit, and depending on the circuit configuration, one of the two diodes may be unnecessary. Thus, the modularization of the sustain output circuit (third embodiment) when the lower diode Dd is required will be described below.

  In the third embodiment, unlike the second embodiment, the IGBT is used as the semiconductor switch. However, the present invention is not limited to this, and a MOSFET or a bipolar transistor may be used.

  FIG. 10 shows a sustain output circuit according to this embodiment. This sustain output circuit is the same as the sustain output circuit according to the second embodiment except that the diode Du is omitted. However, since an IGBT is used as a semiconductor switch, a diode that is not necessary in the case of a MOSFET is connected in reverse parallel to the semiconductor switch.

  In FIG. 10, the sustain output circuit includes a semiconductor switch Q51 connected to the sustain power source Vs, a semiconductor switch Q52 connected to GND as a reference potential, and a diode connected between the semiconductor switch Q51 and the semiconductor switch Q52. Dd and diodes Di51 and Di52 connected in parallel to semiconductor switches Q51 and Q52 with a reverse polarity (hereinafter referred to as “reverse parallel connection”). In this embodiment, the connection point Out between the emitter (E) of the semiconductor switch Q51 and the diode Dd is the output of the sustain output circuit.

Sustain output circuit, as is apparent from FIG. 10, the sustain power source Vs and the collector electrode of the semiconductor switch Q51: and (C electrode shows the C electrode terminals drawn out by the symbol _{C 51)} and a node N51 between the diode Di51, semiconductor A node N52 (also an output terminal Out) between the emitter electrode (E electrode) of the switch Q51 and the A electrode of the diode Dd, a K electrode of the diode Dd, a node N53 between the C electrode of the semiconductor switch Q52 and the diode Di52, a semiconductor and a node N54 between the GND and the E electrode of the switch Q52 (showing a pulled-out E electrode terminals by symbol _{E 52).} Incidentally, reference numerals _{G 51} denotes a gate terminal, reference numeral _{G 52} drawn from the G electrode of the semiconductor switch Q51 is a gate terminal drawn from the G electrode of the semiconductor switch Q52.

  Here, in order to apply the present invention, a node having a junction electrode among these nodes N51 to N54 is considered. Then, two nodes can be found: N51 having the C electrode of the semiconductor switch Q51 and the K electrode of the diode Di51, and N53 having the K electrode of the diodes Dd and Di52 and the C electrode of the semiconductor switch Q52. That is, unlike the second embodiment, the number of metal base plates is two. Conversely, since there are two metal base plates, a power recovery circuit that can eliminate the upper diode Du is used.

  FIG. 11 is a configuration diagram of a main part of a sustain output circuit module according to the third embodiment. In FIG. 11, a sustain output circuit module in which semiconductor elements are placed on a plurality of metal base plates is viewed from the semiconductor element side with the sealing resin omitted. Here, an IGBT is used as the semiconductor switch. Of course, MOSFETs and bipolar transistors may be used instead of IGBTs. In this embodiment, so-called TO3P is used as the module package.

  In the sustain output circuit switch module of FIG. 11, the metal base plate is mounted with a semiconductor switch Q51 having a junction electrode on the node N51 side and a diode Di51, and a first metal base plate 151 having a potential corresponding to the node N51. A semiconductor switch Q52 having a junction electrode on the node N53 side and a diode Di52 are mounted and a second metal base plate 153 having a potential corresponding to the node N53. In addition, since the semiconductor element which uses each node side as a joining electrode is not connected to the node 52 and the node 54, a metal base board does not exist. The wiring in the sustain output circuit module is clear from the description of the first and second embodiments, and the description thereof is omitted.

  As described above, also in this embodiment, each of the components constituting one predetermined circuit (in this embodiment, a sustain output circuit) without using an expensive insulating substrate on which a wiring pattern for mounting a semiconductor element chip is formed. A semiconductor element having a junction electrode (for example, K electrode, D electrode, C electrode) of the same potential connected to a node (nodes N51 and N53 in this embodiment) is directly provided on a metal base plate corresponding to each of the nodes. A semiconductor module (a sustain output circuit module in this embodiment) that is mounted to realize one predetermined circuit is configured. Therefore, the cost of the semiconductor module can be reduced. In addition, the number of metal base plates can be optimized.

  In the third embodiment, modularization of the sustain output circuit when the upper diode Du is not included in the two diodes Du and Dd and the lower diode Dd is present in the sustain output circuit of the second embodiment has been described.

  Next, modularization of the sustain output circuit in the case where the upper diode Du is provided and the lower diode Dd is not provided (Example 4) will be described. As the semiconductor switch, an IGBT is used as in the third embodiment.

  FIG. 12 shows a sustain output circuit according to this embodiment. This sustain output circuit is the same as the sustain output circuit of FIG. 8 according to the second embodiment except that the diode Dd is omitted. However, since an IGBT is used as a semiconductor switch, a diode that is not necessary in the case of a MOSFET is connected in reverse parallel to the semiconductor switch.

  In FIG. 12, the sustain output circuit includes a semiconductor switch Q51 connected to the sustain power source Vs, a semiconductor switch Q52 connected to GND as a reference potential, and a diode connected between the semiconductor switch Q51 and the semiconductor switch Q52. Du and diodes Di51 and Di52 connected in parallel to semiconductor switches Q51 and Q52 with a reverse polarity (hereinafter referred to as “reverse parallel connection”). In this embodiment, the connection point Out between the diode Du and the collector (C) of the semiconductor switch Q52 is the output of the sustain output circuit.

Sustain output circuit, as is clear from FIG. 12, (a withdrawn C electrode terminal was indicated at _{C 51)} C electrode of the sustain power source Vs and the semiconductor switches Q51 and node N61 and diode Di51, semiconductor switch Q51 A node N62 between the E electrode and the A electrode of the diode Du, a node N63 (also an output terminal Out) between the K electrode of the diode Du, the C electrode of the semiconductor switch Q52 and the diode Di52, and an E electrode (extracted) of the semiconductor switch Q52 and a node N64 between the GND of the E electrode terminal indicated by symbol _{E 52)} and. Reference numeral _{G 51} denotes a gate terminal, reference numeral _{G 52} drawn from the G electrode of the semiconductor switch Q51 is a gate terminal drawn from the G electrode of the semiconductor switch Q52.

  Here, in order to apply the present invention, a node having a junction electrode among these nodes N61 to N64 is considered. Then, two nodes can be found: N61 having the C electrode of the semiconductor switch Q51 and the K electrode of the diode Di51, and N63 having the K electrode of the diodes Du and Di52 and the C electrode of the semiconductor switch Q52. That is, the number of metal base plates is two as in the third embodiment. Conversely, since there are two metal base plates, a power recovery circuit that can delete the lower diode Dd is used.

  FIG. 13 is a configuration diagram of a main part of a sustain output circuit module according to the fourth embodiment. In FIG. 13, a sustain output circuit module in which semiconductor elements are placed on a plurality of metal base plates is viewed from the semiconductor element side with the sealing resin omitted. Here, an IGBT is used as the semiconductor switch. Of course, MOSFETs and bipolar transistors may be used instead of IGBTs. In this embodiment, so-called TO3P is used as the module package.

  In the sustain output circuit switch module of FIG. 13, the metal base plate is mounted with a semiconductor switch Q51 having a junction electrode on the node N61 side and a diode Di51, and a first metal base plate 161 having a potential corresponding to the node N61. A diode Du having a junction electrode on the node N63 side, a semiconductor switch Q52, and a diode Di52 are mounted, and the second metal base plate 163 has a potential corresponding to the node N63. In addition, since the semiconductor element which uses each node side as a joining electrode is not connected to the node N62 and the node N64, a metal base plate does not exist.

As is apparent from FIG. 12, the sustain output circuit includes a C ₅₁ terminal connected to the sustain power source Vs, an E ₅₂ terminal connected to GND, a G ₅₁ terminal for controlling the semiconductor switch Q51, and a semiconductor switch Q52. A _G52 terminal to be controlled and an Out terminal are provided. Among _{them, C 51} terminal is connected to the node N61 having junction electrodes, Out terminal connected to a node N63 having junction electrodes. Accordingly, as shown in FIG. 13, the first metal base plate 161 having the potential corresponding to the node N61 has a C ₅₁ terminal extended from the chip mounting base, also a having a potential corresponding to the node N63 2 The metal base plate 163 has an Out terminal drawn from the chip mounting base. Since the G ₅₁ , G ₅₂ , and E ₅₂ terminals are not connected to the bonding electrode, the lead terminals that become the G ₅₁ terminal, the G ₅₂ terminal, and the E ₅₂ terminal are provided separately from the metal base plate.

  Next, wiring in the sustain output circuit module will be described. Since the junction electrode of the semiconductor element is joined and connected to the corresponding metal base plate, the wiring connection between the non-joint electrodes will be mainly described.

  In FIG. 13, the semiconductor switch Q51 and the diode Di51 are mounted on the first metal base plate 161 corresponding to the node N61. A semiconductor switch Q52 and diodes Du and Di52 are mounted on the second metal base plate 163 corresponding to the node N63.

The E electrode of the semiconductor switch Q51 of the first metal base plate 161 is connected to the A electrode of the diode Du of the second metal base plate 163 by the metal thin wire 130, and is connected to the A electrode of the diode Di51, and the G electrode. It is connected by a metal thin wire 130 to _{G 51} terminal.

With E electrode of the semiconductor switch Q52 on the second metal base plate 163 are connected by a metal thin wire 130 to the A electrode of the diode _{Di52, E 52} are connected by a metal thin wire 130 to the terminal, G electrode to _{G 52} pin They are connected by a thin metal wire 130.

  With the connection described above, the sustain output circuit shown in FIG. 12 is configured. After the above-described wiring, a sustain output circuit module is completed by sealing with a resin having a good thermal conductivity (not shown).

  Next, a fifth embodiment that is a modification of the fourth embodiment will be described.

  In the sustain output circuit shown in FIG. 12, the switch drive signal (not shown) applied to the G electrode of the semiconductor switch Q51 generally uses the potential at the Out terminal as the virtual GND potential. Therefore, in FIG. 12, since the diode Du is between the E electrode and the Out terminal of the semiconductor switch Q1, a loss of drive voltage occurs. Accordingly, FIG. 14 shows a sustain output circuit in which the diode Du is arranged on the C electrode side and the loss of the drive voltage is reduced. Even in this circuit in which the diode Du is arranged on the C electrode side, the withstand voltage prevention function of the semiconductor switch Q1 can be achieved. The diode Di51 is a protective diode for the semiconductor switch Q1.

  FIG. 14 shows a sustain output circuit according to this embodiment. However, since an IGBT is used as a semiconductor switch, a diode that is unnecessary in the case of a MOSFET is connected in reverse parallel to the semiconductor switch.

  In FIG. 14, the sustain output circuit is connected in series from the sustain power supply side between the sustain power supply Vs and GND as the reference potential in order from the sustain power supply side, the diode Du having the A electrode on the sustain power supply side and the C electrode on the diode Du side And a semiconductor switch Q52 in which the E electrode side of the semiconductor switch Q51 is a C electrode. A protective diode Di51 is connected in reverse parallel to the semiconductor switch Q51, and a protective diode Di52 is connected in reverse parallel to the semiconductor switch Q52. In this embodiment, the connection point Out between the emitter (E) of the semiconductor switch Q51 and the collector (C) of the semiconductor switch Q52 is the output of the sustain output circuit.

As is apparent from FIG. 14, the sustain output circuit includes a node N71 (a terminal of the corresponding sustain power supply Vs is referred to as a Vs terminal) that is a connection point between the sustain power supply Vs and the diode Du, and a K electrode of the diode Du. , A node N72 that is a connection point between the C electrode of the semiconductor switch Q51 and the K electrode of the diode Di51, and a node N73 (output terminal Out) of the E electrode of the semiconductor switch Q51, the C electrode of the semiconductor switch Q52, and the K electrode of the diode Di52. But with any), and the E electrode of the semiconductor switch Q52 (showing a pulled-out E electrode terminals by symbol _{E 52)} and a node N74 and GND. Reference numeral _{G 51} denotes a gate terminal, reference numeral _{G 52} drawn from the G electrode of the semiconductor switch Q51 is a gate terminal drawn from the G electrode of the semiconductor switch Q52.

  Here, in order to apply the present invention, a node having a junction electrode is considered among these nodes N71 to N74. Then, two nodes can be found: N72 having the K electrode of the diodes Du and Di51 and the C electrode of the semiconductor switch Q51, and N73 having the C electrode of the semiconductor switch Q52 and the K electrode of the diode Di52. That is, the number of metal base plates is two as in the third embodiment.

  FIG. 15 is a configuration diagram of a main part of a sustain output circuit module according to the fifth embodiment. In FIG. 15, a sustain output circuit module in which semiconductor elements are placed on a plurality of metal base plates is viewed from the semiconductor element side with the sealing resin omitted. Here, an IGBT is used as the semiconductor switch. Of course, MOSFETs and bipolar transistors may be used instead of IGBTs. In this embodiment, so-called TO3P is used as the module package.

  In the sustain output circuit switch module of FIG. 15, the metal base plate is a first metal base plate having a potential corresponding to the node N72 by mounting the semiconductor switch Q51 having the junction electrode on the node N72 side and the diodes Du and Di51. 172 and a second metal base plate 173 having a potential corresponding to the node N73 on which the semiconductor switch Q52 having the junction electrode on the node N73 side and the diode Di52 are mounted. The node 71 and the node 74 are not connected to a semiconductor element having a junction electrode on each node side, and therefore there is no metal base plate.

As is apparent from FIG. 14, the sustain output circuit controls the Vs terminal connected to the sustain power source Vs, the E ₅₂ terminal connected to GND, the G ₅₁ terminal for controlling the semiconductor switch Q51, and the semiconductor switch Q52. G ₅₂ terminal and an Out terminal are provided. Among them, the Out terminal is connected to a node N73 having a junction electrode. Accordingly, as shown in FIG. 15, the second metal base plate 173 having a potential corresponding to the node N73 has an Out terminal drawn from the chip mounting base. Since the Vs, G ₅₁ , G ₅₂ , and E ₅₂ terminals are not connected to the bonding electrode, the lead terminals that become the Vs terminal, the G ₅₁ terminal, the G ₅₂ terminal, and the E ₅₂ terminal are provided separately from the metal base plate. ing.

  Next, wiring (wiring) in the sustain output circuit module will be described. Since the junction electrode of the semiconductor element is joined and connected to the corresponding metal base plate, the wiring connection between the non-joint electrodes will be mainly described.

  In FIG. 15, a semiconductor switch Q51 and diodes Du and Di51 are placed on the first metal base plate 172 corresponding to the node N72. A semiconductor switch Q52 and a diode Di52 are mounted on the second metal base plate 173 corresponding to the node N73.

E electrodes of the semiconductor switch Q51 of the first metal base plate 172, a metal is connected by a metal thin wire 130 to the second metal base plate 173 is connected to the A electrode of the diode Di51, the G electrode _{G 51} pin They are connected by a thin wire 130. The A electrode of the diode Du of the first metal base plate 172 is connected to the Vs terminal by a thin metal wire 130.

With E electrode of the semiconductor switch Q52 on the second metal base plate 173 are connected by a metal thin wire 130 to the A electrode of the diode _{Di52, E 52} are connected by a metal thin wire 130 to the terminal, G electrode to _{G 52} pin They are connected by a thin metal wire 130.

  With the connection described above, the sustain output circuit shown in FIG. 14 is configured. After the above-described wiring, a sustain output circuit module is completed by sealing with a resin having a good thermal conductivity (not shown).

  Next, a sixth embodiment which is a modification of the sustain output circuit of FIG. 8 will be described.

  In the sustain output circuit of FIG. 8, the diode Du disposed on the E electrode side of the upper semiconductor switch can be disposed on the C electrode side for the reason described in the fifth embodiment.

  FIG. 16 shows a sustain output circuit according to this embodiment. However, since an IGBT is used as a semiconductor switch, a diode that is unnecessary in the case of a MOSFET is connected in reverse parallel to the semiconductor switch.

  In FIG. 16, the sustain output circuit includes a diode Du having an A electrode on the sustain power supply side and a C electrode on the diode Du side, which are sequentially connected in series from the sustain power supply side between the sustain power supply Vs and the GND as the reference potential. A semiconductor switch Q51, a diode Dd in which the E electrode side of the semiconductor switch Q51 is an A electrode, and a semiconductor switch Q52 in which the diode Dd side is a C electrode. A protective diode Di51 is connected in reverse parallel to the semiconductor switch Q51, and a protective diode Di52 is connected in reverse parallel to the semiconductor switch Q52. In this embodiment, the connection point Out between the E electrode of the semiconductor switch Q51 and the A electrode of the diode Dd is the output of the sustain output circuit.

As is apparent from FIG. 16, the sustain output circuit includes a node N81 (a terminal of the corresponding sustain power supply Vs is referred to as a Vs terminal) that is a connection point between the sustain power supply Vs and the diode Du, and a K electrode of the diode Du. , A node N82 which is a connection point between the C electrode of the semiconductor switch Q51 and the K electrode of the diode Di51, a node N83 between the E electrode of the semiconductor switch Q51 and the A electrode of the diode Dd, a K electrode of the diode Dd and the semiconductor switch Q52 has a node N84 between the K electrodes of the C electrode and the diode Di52, (the pulled-out E electrode terminal indicated by symbol _{E 52)} E electrodes of the semiconductor switches Q52 and the node N85 and GND of. Reference numeral _{G 51} denotes a gate terminal, reference numeral _{G 52} drawn from the G electrode of the semiconductor switch Q51 is a gate terminal drawn from the G electrode of the semiconductor switch Q52.

  Here, in order to apply the present invention, a node having a junction electrode among these nodes N81 to N85 is considered. Then, two nodes can be found: N82 having the K electrodes of the diodes Du and Di51 and the C electrode of the semiconductor switch Q51, and N84 having the K electrodes of the diodes Dd and Di52 and the C electrode of the semiconductor switch Q52. That is, unlike the second embodiment, the number of metal base plates is two.

  FIG. 17 is a configuration diagram of a main part of the sustain output circuit module according to the sixth embodiment. In FIG. 17, a sustain output circuit module in which semiconductor elements are mounted on a plurality of metal base plates is viewed from the semiconductor element side, with the sealing resin omitted. Here, an IGBT is used as the semiconductor switch. Of course, MOSFETs and bipolar transistors may be used instead of IGBTs. In this embodiment, so-called TO3P is used as the module package.

  In the sustain output circuit switch module of FIG. 17, the metal base plate is a first metal base plate having a potential corresponding to the node N82 on which the semiconductor switch Q51 having the junction electrode on the node N82 side and the diodes Du and Di51 are mounted. 182 and a second metal base plate 184 having a potential corresponding to the node N84 on which the semiconductor switch Q52 having the junction electrode on the node N84 side and the diodes Dd and Di52 are mounted. In addition, since the semiconductor element which uses each node side as a joining electrode is not connected to the node 81, the node 83, and the node 85, a metal base plate does not exist.

As apparent from FIG. 16, the sustain output circuit controls the Vs terminal connected to the sustain power source Vs, the E ₅₂ terminal connected to GND, the G ₅₁ terminal for controlling the semiconductor switch Q51, and the semiconductor switch Q52. G ₅₂ terminal and an Out terminal are provided. However, since the Vs, G ₅₁ , G ₅₂ , E ₅₂ terminal, and Out terminal are not connected to the junction electrode, the lead terminals that become the Vs terminal, G ₅₁ terminal, G ₅₂ terminal, E ₅₂ terminal, and Out terminal are metal base plates. Separately, they are provided separately.

  Next, wiring (wiring) in the sustain output circuit module will be described. Since the junction electrode of the semiconductor element is joined and connected to the corresponding metal base plate, the wiring connection between the non-joint electrodes will be mainly described.

  In FIG. 17, a semiconductor switch Q51 and diodes Du and Di51 are mounted on the first metal base plate 182 corresponding to the node N82. A semiconductor switch Q52 and diodes Dd and Di52 are placed on the second metal base plate 184 corresponding to the node N84.

E electrodes of the semiconductor switch Q51 of the first metal base plate 182 is connected by a metal thin wire 130. Out terminal is connected to the A electrode of the diode Di51, G electrode connected by a metal thin wire 130 to _{G 51} pin Has been. The A electrode of the diode Du of the first metal base plate 172 is connected to the Vs terminal by a thin metal wire 130.

With E electrode of the semiconductor switch Q52 on the second metal base plate 174 are connected by a metal thin wire 130 to the A electrode of the diode _{Di52, E 52} are connected by a metal thin wire 130 to the terminal, G electrode to _{G 52} pin They are connected by a thin metal wire 130. Further, the A electrode of the diode Dd of the second metal base plate 184 is connected to the Out terminal by a metal thin wire 130.

  With the connection described above, the sustain output circuit shown in FIG. 16 is configured. After the above-described wiring, a sustain output circuit module is completed by sealing with a resin having a good thermal conductivity (not shown).

  As described above, also in this embodiment, each of the components constituting one predetermined circuit (in this embodiment, a sustain output circuit) without using an expensive insulating substrate on which a wiring pattern for mounting a semiconductor element chip is formed. A semiconductor element having a junction electrode (for example, K electrode, D electrode, C electrode) of the same potential connected to a node (nodes N82 and N84 in this embodiment) is directly provided on a metal base plate corresponding to each of the nodes. A semiconductor module (a sustain output circuit module in this embodiment) that is mounted to realize one predetermined circuit is configured. Therefore, the cost of the semiconductor module can be reduced. In addition, the number of metal base plates can be optimized.

  In the first to sixth embodiments described above, among the power semiconductor modules configured by combining a plurality of power semiconductor chips such as diodes, MOSFETs, IGBTs, and transistors, a bridge type used for a power conversion device, a PDP, and the like. Although the modularization of the bidirectional switch and the modularization of the sustain output circuit of the plasma display device have been described, the present invention is not limited to these. The present invention can be appropriately modified and used in accordance with various circuits.

1 is a circuit diagram of a bridge-type bidirectional switch according to Embodiment 1. FIG. An example of the diode which comprises the bridge type bidirectional switch which concerns on a present Example. An example of MOSFET which comprises the bridge type bidirectional switch which concerns on a present Example. An example of IGBT which comprises the bridge type bidirectional switch which concerns on a present Example. FIG. 2 is a main part configuration diagram of a bridge-type bidirectional switch module according to the first embodiment. FIG. 4 is a schematic cross-sectional view of a first diode Di1, a semiconductor switch Q1, and a second diode Di2 mounted on a third metal base plate 112 in FIG. The figure which shows the modification of the bridge type bidirectional | two-way switch module shown in FIG. FIG. 6 is a sustain output circuit diagram according to the second embodiment. FIG. 10 is a configuration diagram of a main part of a sustain output circuit module according to a second embodiment. FIG. 10 is a sustain output circuit diagram according to the third embodiment. FIG. 10 is a configuration diagram of a main part of a sustain output circuit module according to a third embodiment. FIG. 10 is a sustain output circuit diagram according to the fourth embodiment. FIG. 10 is a configuration diagram of a main part of a sustain output circuit module according to a fourth embodiment. FIG. 10 is a sustain output circuit diagram according to the fifth embodiment. FIG. 10 is a configuration diagram of a main part of a sustain output circuit module according to a fifth embodiment. FIG. 10 is a sustain output circuit diagram according to the sixth embodiment. FIG. 10 is a configuration diagram of a main part of a sustain output circuit module according to a sixth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... 1st metal base board, 102 ... 2nd metal base board, 112 ... 3rd metal base board, 130 ... Metal fine wire, 140 ... Hole, 141 ... 1st metal base board, 143 ... 2nd metal base board, 144 ... 3rd metal base plate, 151 ... 1st metal base plate, 153 ... 2nd metal base plate, 161 ... 1st metal base plate, 163 ... 2nd metal base plate, 172 ... 1st metal base plate, 173 ... 1st 2 metal base plate, 182 ... 1st metal base plate, 184 ... 2nd metal base plate, Di1 ... 1st diode, Di2 ... 2nd diode, Di3 ... 3rd diode, Di4 ... 4th diode, Di5 ... diode, SW1 ... Switch, Q1 ... Semiconductor switch, Q41, Q42, Q51, Q52 ... Semiconductor switch, Di41, Di42, Di51, Di52 ... Diode, Du, Dd ... Die N1, N2, N12, N34, N41, N42, N43, N44, N45, N51, N52, N53, N54, N61, N62, N63, N64, N71, N72, N73, N74, N81, N82, N83 , N84, N85 ... nodes,

Claims (7)

A semiconductor module that constitutes a predetermined circuit by combining a plurality of semiconductor elements,
A first metal base plate and a second metal base plate;
The first metal base plate is mounted with a first semiconductor element having a junction electrode connected to the first node of the circuit and having the same potential as the first metal base plate,
The second metal base plate is mounted with a second semiconductor element having a junction electrode connected to the second node of the circuit and having the same potential as the second metal base plate,
The semiconductor module according to claim 1, wherein the first and second metal base plates and the non-joining electrodes of the first and second semiconductor elements are connected by metal thin wires, respectively. The semiconductor module according to claim 1,
The predetermined circuit is a bridge-type bidirectional switch that allows current to pass in both directions. One end of the bridge-type bidirectional switch is the first node, and the other end is the second node. A first diode array in which a first diode connected to the first node and a second diode connected to the second node are connected in reverse series between the node and the second node;
A third diode connected in parallel to the first diode row, having a polarity different from that of the first diode row, connected to the first node, and a fourth diode connected to the second node is anti-series. A second diode string connected at
A third node, which is a connection point between the first diode and the second diode in the first diode row, and a connection point between the third diode and the fourth diode in the second diode row. A semiconductor switch connected between the four nodes;
A semiconductor module comprising: The semiconductor module according to claim 2,
The third node of the first diode row corresponds to the cathode electrode side of the first diode and the second diode, and the fourth node of the second diode row is the anode electrode side of the third diode and the fourth diode. Corresponds to
The semiconductor switch is characterized in that the third node side is a drain electrode or a collector electrode, and the fourth node side is a source electrode or an emitter electrode. The semiconductor module according to claim 2 or 3,
A third metal base plate having a potential corresponding to the third node;
The semiconductor module, wherein the first metal base plate has a potential corresponding to the first node, and the second metal base plate has a potential corresponding to the second node. The semiconductor module according to claim 4,
The third diode as the first semiconductor element is placed on the first metal base plate, and the cathode electrode of the third diode is used as the junction electrode.
The fourth diode as the second semiconductor element is placed on the second metal base plate, and the cathode electrode of the fourth diode is used as the junction electrode.
The semiconductor switch and the first diode are connected to the third node using the drain electrode surface or collector electrode of the semiconductor switch as a junction electrode and the cathode electrodes of the first diode and the second diode as junction electrodes. And a semiconductor module, wherein the second diode is mounted on the third metal plate.   The semiconductor module according to claim 5, wherein the semiconductor switch is a MOSFET, an IGBT, or a bipolar transistor. In a plasma display device having a power recovery circuit composed of a bridge-type bidirectional switch including a plurality of diodes,
The power recovery circuit includes a first metal base plate and a second metal base plate,
The first metal base plate has a first diode element mounted thereon, and an anode electrode of the first diode element is connected to a first node of the bridge type bidirectional switch,
The second metal base plate has a second diode element mounted thereon, and a cathode electrode of the second diode element is connected to a first node of the bridge type bidirectional switch,
The first node and the junction electrode of the first diode element are set to the same potential, and the second node and the junction electrode of the second diode element are set to the same potential.
A plasma display apparatus having a power recovery circuit, wherein the first and second metal plates are connected to a cathode electrode of the first diode element and an anode electrode of the second diode element by a thin metal wire, respectively.

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