JP2744675B2 - Transistor module - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a structure of a transistor module used for an inverter or the like that drives an AC motor at a variable speed.

(Prior art) In recent years, there has been an increasing demand for higher integration and higher reliability of inverter devices that drive an AC motor at a variable speed, and a transistor module incorporating a plurality of transistors has been put into practical use to meet such needs. Have been.

FIG. 3 is a perspective view showing an external appearance of an example of a transistor module currently in practical use. This transistor module 1 is a module in which all six transistors constituting an inverter are modularized into one package.
This is convenient because an inverter can be constituted by one module. And, by arranging all the terminals on the upper surface and on the same plane, connection to each terminal can be made using a printed circuit board, and by using connection terminals by screwing, wiring of the device is achieved. The number of work steps can be reduced. FIG. 4 is an internal circuit diagram of the transistor module 1. The collectors of the transistors TR1, TR3 and TR5, the emitters of the transistors TR2, TR4 and TR6,
Each emitter of transistors TR1, TR3, TR5 and output terminals U, V, W
And by using a common terminal to reduce the number of terminals,
The cost has been reduced.

(Problem to be Solved by the Invention) The transistor module 1 described above is a transistor TR
Since the emitters of TR2 and TR4 and TR6 are shared and shared as one terminal (N), there are the following problems. For example, taking the transistor TR2 shown in FIG. 5 as an example, the output of the base drive circuit 6B that drives the transistor TR2 is connected to the B2 terminal and the N terminal of the transistor module 1, and the N terminal is connected to the DC power supply of the main circuit. Because it is shared as an input terminal, the wiring from the N terminal to the emitter of the transistor TR2 is connected to the transistor T
A large current with a high rate of change (di / dt) flows with the ON / OFF of R2. For example, transistors
A voltage e generated as indicated by the following equation (1) to the ON state across the internal inductance l ₄ of TR2.

Since this voltage e has a polarity that cancels the output voltage of the base drive circuit 6B, the voltage actually applied between the base and the emitter of the transistor TR2 becomes small, and the switching speed of the transistor TR2 becomes slow.

Such adverse effects are caused by IGBTs with higher di / dt than transistor modules using conventional bipolar transistors.
This is an important issue for transistor modules using such devices. Furthermore, the size of the module itself is large for a plurality of built-in transistors, therefore (such as l ₄₎ internal inductance becomes large, and the adverse effect occurs more remarkably. In addition, the current having a high di / dt as described above also flows through the internal inductance l ₁ , and particularly when the transistor is turned off, a high surge voltage (e = l ₁ .di / d
t) occurs, causing a problem that the transistor is easily broken by an overvoltage.

That is, in such a transistor module, the emitters and the like connected to each other are shared as one terminal in order to reduce the number of terminals. However, by sharing the terminals in this manner, the inductance of the emitter line and the like of each transistor is reduced to the operating characteristics. And the disadvantage that the intrinsic performance of the transistor cannot be exhibited.

The present invention has been made under the circumstances described above,
An object of the present invention is to provide a transistor module which can share an emitter terminal and the like without deteriorating the characteristics of the transistor and can obtain good characteristics with a minimum number of terminals.

(Means for Solving the Problems) The present invention has a plurality of built-in transistor chips, is commonly connected to each emitter of the transistor chips, supplies a main current to the transistor chips, and supplies the transistor chips. Transistor module having one common emitter terminal commonly used as a common terminal of a base drive circuit connected between the base and the emitter and eliminating an auxiliary emitter terminal for connecting the base drive circuit. And
The object of the present invention is to provide a first conductor that connects the emitters of the transistor chip to each other and connects the common emitter terminal, and a first conductor that is arranged in parallel with and close to the first conductor, This is achieved by providing a plurality of conductors connecting each base and a plurality of base terminals respectively corresponding to the base.

(Operation) The transistor module of the present invention uses the voltage generated in the internal inductance of the conductor (emitter wiring) connecting the emitter of the transistor and the common emitter terminal,
Mutual induction between the conductor and a base wiring disposed in parallel with and close to the conductor acts to induce the conductor toward the base wiring. The induced voltage acts so as to cancel the voltage generated on the emitter wiring side, so that a desired voltage applied between the base terminal and the common emitter terminal is applied between the base and the emitter of the transistor. Is applied, and the switching characteristic delay as described above does not occur. A first conductor connecting each emitter of the first transistor group to a common emitter terminal and a second conductor connecting each collector of the second transistor group to a common collector terminal are parallel and close to each other. Since the currents flowing through these two conductors have opposite polarities, they act to cancel each other out, and as a result, the internal inductance itself can be suppressed to a small value.

(Embodiment) FIG. 1 is a perspective view showing an example of an internal wiring structure of a transistor module according to the present invention, wherein transistors TR2, TR4,
TR6 is connected to a common emitter terminal (N terminal) by conductor 2, and base wirings 3a, 3b, 3c are connected to transistors TR2, TR
4, in the section from TR6 to the vicinity of the N terminal, it is arranged parallel and close to the conductor 2; Therefore, depending on the inductance of the conductor 2, each transistor TR2, TR
4. The voltage generated in the section from TR6 to the N terminal is induced in the base wires 3a, 3b, 3c by mutual induction.

FIG. 2 is a perspective view showing another example of the internal wiring structure of the transistor module of the present invention, in which a printed wiring board 4 is used for internal wiring, and transistors TR2, TR4,
The conductor 21 connecting each emitter of TR6 is printed wiring board 4
Printed or pasted on the back of the transistor TR
A conductor 22 connecting the collectors of TR1, TR5 and TR5 is arranged parallel to and close to the conductor. So these conductors
The inductance between 21 and 22 is realized very small. Also, base wirings 3a, 3b, which connect each base of the transistors TR2, TR4, TR6 and each base terminal B2, B4, B6,
3c is printed on the surface of the printed wiring board 4 so as to be parallel to the conductor 21. Thus, the base wiring 3a, 3b, 3c and the conductor
21 are disposed close to each other on the front and back sides of the printed wiring board 4, so that the inductive coupling between the base wires 3a, 3b, 3c and the conductor 21 can be made sufficiently dense. The voltage (ldi / dt) due to the inductance is reliably induced in the base wires 3a, 3b, 3c. As a result, despite the fact that the voltage generated on the conductor 21 acts on the base signal applied to the transistor in the opposite polarity, a voltage that offsets this voltage is induced on the base wiring, and the desired voltage is applied to the base of the transistor. Is applied, and good characteristics can be obtained.

(Effects of the Invention) As described above, according to the present invention, in a transistor module having a plurality of built-in transistors, a transistor module having a minimum number of terminals by sharing terminals has an effect on the operating characteristics of the transistors. It can be realized without giving. As a result, it is possible to realize an inverter device which achieves miniaturization and high reliability by high integration and ensures performance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of the internal wiring structure of the transistor module of the present invention, FIG. 2 is a perspective view showing another example of the internal wiring structure of the transistor module of the present invention, and FIG. FIG. 4 is a perspective view showing an appearance of an example of a transistor module, FIG. 4 is an internal circuit diagram thereof, and FIG. 5 is a circuit diagram for explaining a problem to be solved by the present invention. 1 ... transistor module, 21,22 ... conductor, 3a, 3
b, 3c …… Base wiring, 4 …… Printed wiring board, 6A, 6B…
... Base drive circuit.

Claims (1)

(57) [Claims] 1. A plurality of transistor chips are built-in, are commonly connected to respective emitters of the transistor chips, supply a main current to the transistor chips, and are connected between a base and an emitter of the transistor chips. In a transistor module in which one common emitter terminal commonly used as a common terminal of a base drive circuit is provided to eliminate an auxiliary emitter terminal for connecting the base drive circuit, each emitter of the transistor chip is connected to each other. A first conductor for connecting and connecting the common emitter terminal;
And a plurality of conductors arranged in parallel with and close to the conductors of the transistor chip and connecting each base of the transistor chip and a plurality of base terminals respectively corresponding to the bases.