JP2536099B2 - MOS gate type bipolar transistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a MOS gate type bipolar transistor (also referred to as an IGBT, which integrates a MOSFET for supplying its base current to a vertical type bipolar transistor.
Abbreviated as T. ) And a MOS-gate bipolar transistor with a bypass capacitor that suppresses the transient current that flows through it.

[Conventional technology]

In order to speed up the switching speed of a bipolar transistor, when an MBT with the MOS structure of the MOSFET that supplies its base current formed on the surface is used in a power converter, if an accident occurs on the load side, a short circuit of several times the rated current will occur. An electric current flows. In Fig. 2, when the power supply 21 is connected to the emitter-collector of the MBT1 and a voltage is applied to the gate by the gate circuit 22, a current I _C flows between the collector and the emitter, but when a short-circuit current flows, the collector-emitter voltage suddenly increases. A drastic fluctuation, that is, dv / dt becomes large, and a current flowing from the collector to the gate flows as shown by a broken line 23 in FIG. This current causes a problem that the gate potential rises, the peak current at the time of an accident increases, and the element deteriorates. To solve this problem, connect a capacitor 2 between the gate and emitter as shown in Fig. 3, and connect the current 23 due to dv / dt at the time of an accident on the load side with the capacitance between the gate and emitter. The ratio is divided into 24 and 25. As a result, the current flowing into the element 1 is reduced, the peak current can be suppressed, and the loss generated in the element when an accident occurs can be reduced.

[Problems to be Solved by the Invention]

When the bypass capacitor 2 as shown in FIG. 3 is built in the same container as the element, conventionally, using the board wiring,
Or it was common to connect using wire wiring. However, at this time, the inductance depending on the wiring length was increased, the transient impedance was increased, and a sufficient response could not be taken when an accident occurred.

An object of the present invention is to provide a MOS gate type bipolar transistor which eliminates the above-mentioned drawbacks and which prevents an increase in inductance due to the connection of a bypass capacitor for suppressing the peak current at the time of an accident on the load side of the MBT. .

[Means for solving the problem]

In order to solve the above problems, the present invention provides an MBT-type bipolar transistor including a MBT and a bypass capacitor connected between its gate and emitter.
A gate external lead-out terminal conductor connected to the gate electrode of the MOS gate type bipolar transistor via a wire in the vicinity of one side of the semiconductor body, and an emitter external lead-out terminal conductor connected to the emitter electrode via a wire. Are insulated from each other and arranged in parallel, and a bypass capacitor is fixed between the gate external lead-out terminal conductor and the emitter external lead-out terminal conductor.

[Action]

Both electrodes of the bypass capacitor are directly fixed to the gate external lead terminal conductor and the emitter external lead terminal conductor of the MBT, and wiring for connecting the capacitor is not used, so inductance does not occur due to the wiring length and transient impedance increases. Is prevented.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which a gate external lead-out terminal conductor 3 and an emitter external lead-out terminal conductor 4 are arranged in parallel with each other near an MBT chip 1 fixed on a substrate (not shown) with an insulating gap 6 interposed therebetween. Has been done. Of course, both terminal conductors are also insulated from the MBT board. MBT chip 1
The gate electrode 11 is connected to the terminal conductor 3 and the emitter electrode 12 is connected to the terminal conductor 4 by wires 5, respectively. The electrodes of both ends of the capacitor 2 are the terminal conductor 3 and the terminal conductor 4.
Respectively. As a result, the capacitor 2
Bypasses the gate electrode 11 and the emitter electrode 12 of the MBT.
Inductance due to connection for bypass is wire 5
Are limited to those generated by.

FIG. 4 shows another embodiment, in which the gate external lead-out terminal conductor 3 and the emitter external lead-out terminal conductor 4 are vertically stacked with the two insulators 7 interposed therebetween, and the bypass capacitor 2 is located between the two insulators 7. The electrodes on both sides are directly fixed to both the terminal conductors 3 and 4. This structure is the capacitor 2
Is protected by the terminal conductor, and the area occupied by the terminal is reduced as compared with the case of FIG. Further, there is an advantage that the fixing of the capacitor 2 can be performed in the same assembly process as the fixing of the both terminal conductors 3 and 4 via the insulator 7. Further, since the insulator 7 is interposed between the two terminal conductors 3 and 4, a capacitance is formed between the two terminal conductors 3 and 4. The capacitance between the two terminal conductors 3 and 4 forms a parallel connection with the gate-emitter bypass capacitor and performs the same function. Therefore,
Compared with the embodiment shown in FIG. 1, a small capacitor 2 can be used, and not only the terminals but also the occupied area of the capacitor can be reduced.

〔The invention's effect〕

According to the present invention, the wiring for connection can be omitted by directly fixing the gate-emitter bypass capacitor for suppressing the peak current at the time of occurrence of an accident on the load side of the MBT to the gate and emitter external lead-out terminal conductors. In addition, the inductance due to the wiring length is reduced, and transient impedance can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an essential part of an embodiment of the present invention, FIG. 2 is a circuit diagram of an MBT without a bypass capacitor, FIG. 3 is a circuit diagram of an MBT with a bypass capacitor inserted, and FIG. It is a perspective view which shows the principal part of another Example of invention. 1: MOS gate type bipolar transistor (chip), 2:
Bypass capacitor, 3: Gate external lead terminal conductor, 4: Emitter external lead terminal conductor, 7: Insulator.

Claims (1)

(57) [Claims] 1. A MOS gate bipolar transistor comprising a MOS gate bipolar transistor and a bypass capacitor connected between its gate and emitter, the MOS gate bipolar transistor being close to one side of a semiconductor body of the MOS gate bipolar transistor. The gate external lead-out terminal conductor connected to the gate electrode of the above through the wire and the emitter external lead-out terminal conductor connected to the emitter electrode through the wire are arranged in parallel and insulated from each other, and the bypass capacitor is connected to the gate external lead-out terminal. A MOS gate type bipolar transistor characterized in that it is fixed between a conductor and an external lead terminal conductor of the emitter.