JPS622889A - High-density composite semiconductor device and power conversion device using it - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a high-density composite semiconductor device consisting of a plurality of semiconductor chips and a power conversion device using the same, such as a power conversion device used for inverter control, etc. It is particularly effective when used in current source inverters.

[Background of the invention]

Speed control of AC motors using inverter control has become very popular, and there is a demand not only for increased capacity but also for lower noise from motors. Current source inverters are expected to meet this demand, but they have the problem of generating overvoltage when cutting off the circuit current.

The basic means to solve this problem is to reduce the inductance between semiconductor elements.

However, since the transistor, which is an element with a self-extinguishing function, has a very low reverse voltage blocking ability, it is necessary to connect a diode or the like, which is an element with high reverse voltage withstand capability, in series. The conventional device shown in FIG. 1 employs a configuration in which a self-extinguishing function element U67° and a diode element Du are connected in series.

However, with such a configuration, the wiring between elements becomes long, making it difficult to solve the problem of overvoltage.

[Purpose of the invention]

An object of the present invention is to provide a high-density composite semiconductor element with low inter-element inductance, and a power conversion device that can reduce the generated voltage by using this in each arm and can withstand increased capacity and higher frequencies. It is in.

[Summary of the invention]

In order to achieve the above object, the present invention includes a first semiconductor chip on which a first semiconductor element having a self-extinguishing function with a low reverse voltage withstand capacity is formed, and a second semiconductor element with a high reverse voltage withstand capacity. A high-density composite semiconductor device in which a first semiconductor device and a second semiconductor device are connected in series by chip-connecting the formed second semiconductor chip, and a power conversion device using the same in upper and lower Arnaud. It shall be a device.

[Embodiments of the invention]

An embodiment of the present invention will be explained below with reference to FIGS. 1 to 6.

FIG. 1(a) is a connection configuration diagram of a high-density composite semiconductor element in which a chip of a transistor T and a chip of a diode D are chip-connected, and a transistor T and a diode D are connected in series. B, C, and E each indicate a lead-out terminal. FIG. 1(b) shows the voltage/current characteristics of the transistor T and the diode D, the solid line m1 is the reverse blocking voltage characteristic of the transistor T, and the broken line curve 2 shows the voltage/current characteristics of the diode 2.
This is the reverse blocking voltage characteristic of

Although the transistor T has a self-extinguishing function, the reverse blocking voltage characteristic is generally very low as shown by the solid curve 1, so it has the disadvantage that it cannot be used in a circuit where a reverse voltage occurs. On the other hand, the reverse blocking voltage characteristic of diode D can be made high as shown by broken line curve 2.

It has the disadvantage of not having a self-extinguishing function.

In this way, by chip-connecting two chips in which elements with different functions are formed, and connecting the two elements in series, it is possible to achieve a high reverse blocking voltage, as shown in Figure 1(e). Moreover, it has a self-extinguishing function, and a high-density composite semiconductor device that takes advantage of each other's features can be obtained. Because the transistor T and diode D are connected in series by chip connection.

The wiring between the transistor T and the diode 10 can be ideally short, and therefore there is no inductance, which is very advantageous for increasing the frequency of the power converter.

Furthermore, by using a high-speed diode with a small recovery current as the diode D, not only the efficiency of the power conversion device is improved, but also the on-loss of the transistor is reduced, so the heat generation of the high-density composite semiconductor element itself is reduced, and the power This is advantageous for increasing the capacity of the converter.

In constructing a power conversion device, it is necessary to protect the high-density composite semiconductor element shown in FIG. 1(a) from overvoltage and the like. Figure 2 shows a high-density composite semiconductor device with protection in mind. By providing a lead terminal C' from the connection point of transistor T and diode D, an external snubber circuit for overvoltage protection etc. can be added, and a more reliable power conversion device can be constructed.

As shown in FIG. 3, a diode D is connected in series to a transistor T with a diode D1 connected in parallel. In this way, the reverse voltage of the transistor T can be lowered, and a highly reliable high-density composite semiconductor device can be obtained. Diode D.

An element with a small capacitance that allows the recovery current of the diode D to flow is sufficient. By configuring the high-density composite semiconductor element in this manner, the number of external wirings is reduced and the power conversion device can be made smaller.

FIG. 4 is a circuit diagram of a power conversion device using six high-density composite semiconductor elements T1 to T6 having the configuration shown in FIG. 3(a), and a load formed by a resistance R and an inductance L. In this example, the high-density composite semiconductor elements T1 and Ts are turned on from the 5 power supply A to supply the load current I. The state when the high-density composite semiconductor element T1 is turned off from this state is shown in the fifth section.
As shown in the figure.

When T1 is turned off and T2 is turned on, the current flowing through T1 is commutated to T2 during a period t, as shown in FIG. 5(b). , T1. Inductance of each arm of T2 is 0
□9A voltage is generated by QZ and Ic/l. By the way, since T1 and T2 are high-density composite semiconductor elements, the inductances n,, a, are very small, and the generated voltage can be made very small. Therefore, there is an effect that the configuration of a particularly high frequency or large current power conversion device can be easily achieved.

Next, FIG. 6(a) shows the situation when T2 is turned off and T2 is turned on. When T2 is turned off, the current flowing through T2 is commutated as shown in FIG. 6(b). At this time, the current flowing through T□ includes, in addition to the load current ■, a recovery current t of the diode D connected in series with T2. By reducing the recovery current I tt of the high-density composite semiconductor element, the on-loss of the T can be reduced.

This allows the high-density composite semiconductor element to generate less heat, which is advantageous for constructing a large-capacity power conversion device.

In FIG. 4, it has been explained that the present invention is applied to a forward converter having R and L loads, but it is natural that a current source inverter system for driving an AC motor can be constructed by connecting reverse converters of the same type.

〔Effect of the invention〕

According to the present invention, it is possible to provide a composite semiconductor device with small inductance between elements, and when used in a power converter, the voltage generated in each arm can be reduced, and a large capacity, high frequency device can be provided.

[Brief explanation of drawings]

FIG. 1(a) is a connection configuration diagram of an embodiment of the present invention. (b) is a power/current characteristic diagram of each transistor and diode, (c) is a voltage/current characteristic diagram of a composite element, and
The figure is a connection configuration diagram of another embodiment of the present invention. FIG. 3(a) is a connection configuration diagram of still another embodiment of the present invention, FIG. 3(b) is its power/current characteristic diagram, and FIG. Figure 5 (a), (
b) and (c) are explanatory diagrams of the operation when T□ is off and T2 is on in Fig. 4 (a), respectively, and Fig. 6 (a) and (b)
) are explanatory diagrams of operations when T2 is off and T1 is on, respectively. T...Transistor, D...Diode, T-T
6...High-density composite semiconductor element.

Claims (1)

[Claims] 1. In a high-density composite semiconductor device consisting of a plurality of semiconductor chips, a first semiconductor chip on which a first semiconductor device having a self-extinguishing function with low reverse voltage withstand capability is formed, and a reverse A second semiconductor chip formed with a second semiconductor element having a high voltage withstand capacity is chip-connected to the first semiconductor element and the second semiconductor element.
A high-density composite semiconductor device characterized by connecting semiconductor devices in series. 2. The high-density composite semiconductor device according to claim 1, wherein the first semiconductor device is a transistor, and the second semiconductor device is a diode. 3. The high-density composite semiconductor device according to claim 1, wherein the second semiconductor device is a high-speed diode with a small recovery current. 4. A patent characterized in that the connection point between the first semiconductor element and the second semiconductor element is connected to one end of a lead wire, and the other end of the lead wire is connected to an external terminal. A high-density composite semiconductor device according to claim 1. 5. The high-density composite semiconductor according to claim 1, wherein the first semiconductor element is a transistor including diodes connected in antiparallel, and the second semiconductor element is a diode. element. 6. A first semiconductor chip on which a first semiconductor element having a self-extinguishing function with a low reverse voltage withstand capacity is formed, and a second semiconductor chip on which a second semiconductor element with a high reverse voltage withstand capacity is formed. A high-density composite semiconductor element formed by chip-connecting a first semiconductor element and a second semiconductor element in series,
A power conversion device characterized by being provided in each lower arm.