JPH085564Y2 - Transistor parallel connection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a parallel connection device of transistors.

(Prior Art) Conventionally, the drain or collector sides of a plurality of transistors Tr1, Tr2, ..., Trn are connected to the heat sink 4 in a line,
The sources or emitters of the plurality of transistors Tr1, Tr2, ..., Trn are connected in parallel with a conductor 3, a source or emitter side terminal 2 is arranged at an end of the conductor 3, and a drain is provided on a side surface of a heat sink 4. Alternatively, the collector side terminal 1 is arranged, and the source or emitter side terminal 2 and the drain or collector side terminal 1 are formed in the same direction.

Further, there is a structure in which two transistors are connected in parallel and a connection terminal is provided at an intermediate position between the two transistors.

(Problems to be solved) In the former structure, an imbalance occurs in the amount of current flowing through each transistor, leading to destruction of the transistor.

 This will be described in detail below.

The device shown in FIG. 3 can be equivalently represented by a circuit as shown in FIG. Resistors R1, R2, ..., Rn and r1, r2 ,. Considering the resistance value, the value is proportional to the distance in the same material. So the following relation holds between R1, R2, ..., Rn and r1, r2, ..., rn.

R1 <R2 <... <Rn- (1) r1 <r2 <... <rn- (2) In addition, if a current flows from the drain or collector side terminal 1 toward the source or emitter side terminal 2, the transistor Trl will Current flows.

Generally the transistor Trn Current flows.

Here, since the relations (5) and (6) hold for the resistors R1, R2 ..., Rn and r1, r2, ..., rn respectively, R1 + r1 <R2 + r2 ... <Rn + rn- (5) Holds.

Therefore, the relation I1> I2> ……> In (7) is established between the currents I1, I2 ... In flowing through Trl, Tr2 ..., Trn.

That is, when the source or emitter side terminal 2 and the drain or collector side terminal 1 are in the same direction, current is concentrated in the transistor closest to them and the transistor is destroyed.

Also, in the latter structure, if there are three or more, the intermediate position cannot be taken, and if it is tried to take it, the shape of the heat sink itself is changed, or the resistance value of the connected resistor is changed in production. There is a drawback that various inconveniences occur in management.

The present invention has been devised to eliminate these drawbacks.

(Means for Solving the Problems) In the present invention, the drain or collector sides of three or more transistors are connected by inserting and fixing them in a row in the longitudinal direction of a rectangular heat sink, and are connected to the above three or more rows. Each of the source or emitter side of the transistor is inserted and connected to a conductor made of one strip plate, and the source or emitter side terminal formed at one end of the conductor is arranged at one end in the longitudinal direction of the heat sink and the heat sink A drain or collector side terminal is arranged at the other end in the longitudinal direction, and the resistance between the drain or collector of each transistor and the drain or collector side terminal, or the resistance between the source or emitter and the source or emitter side terminal With the connection configuration with the same composite value of is there.

(Embodiment) FIG. 1 shows an embodiment of the present invention in which the drain or collector sides of three or more transistors Tr1, Tr2, ..., Trn are fitted and fixed in a row on the heat sink 4 at equal intervals. , Trn, which are connected in one row, are connected to the source or emitter side of each of the transistors Tr1, Tr2, ..., Trn by a single conductor 3 and are formed at one end of the conductor 3. Alternatively, the emitter side terminal 2 is arranged at one end in the longitudinal direction of the heat sink and the drain or collector side terminal 1 is arranged at the other end in the longitudinal direction of the heat sink.

In such a structure, r1, r2, ..., Rn are resistances of conductors on the source or emitter side, that is, copper plates, and R1, R2 ,.

1, l2, ..., ln are the distances from the source or emitter side terminals to the transistors Tr1, Tr2 ,.
1, L2, ... Ln are the distances from the drain or collector side terminals to the transistors Tr1, Tr2 ,.

FIG. 1 can be equivalently represented by a circuit as shown in FIG.

Here, when electric power is supplied from the drain or collector side terminal 1 to the source or emitter side terminal 2, currents expressed by the equation (4) respectively flow through the transistors Tr1, Tr2, ..., Trn. If the resistance value is the same material and the cross-sectional area is constant, it is proportional to the distance. Therefore, the heat sink 4 made of aluminum has a rectangular shape, the cross-sectional area thereof is constant, and the conductor 3 made of a copper plate is used. Is a strip and has a constant cross-sectional area. Furthermore, if the size of the heat sink and the copper plate is determined so that the ratio of the cross-sectional area of the heat sink and the copper plate is 100: 61, therefore, in this circuit, 1 + L1 = l2 + L2 = ... ln + Ln. R1 ＋ r1 ＝ R2 ＋ r2 …… ＝ Rn ＋ rn …… (9)

 Therefore, the relationship of I1 ＝ I2 …… ＝ In …… (10) holds between 11,12 …… In.

(Effects) As described above, by implementing the present invention, it is possible to easily cope with an increase or decrease in the number of connections, without the trouble of production control, and to make the amount of current flowing through each transistor equal. As a result, breakdown of the transistor due to current concentration can be eliminated.

The present invention is not limited to the above embodiment,
Of course, it can be applied to an element such as a thyristor which needs to be fixed in parallel to a heat sink or the like.

[Brief description of drawings]

FIG. 1 shows a basic embodiment of the present invention, and FIG. 2 shows an equivalent circuit thereof. FIG. 3 shows a conventional device, and FIG. 4 shows its equivalent circuit. 1 ... Drain or collector side terminal 2 ... Source or emitter side terminal 3 ... Conductor 4 ... Heat sink

Claims (1)

[Scope of utility model registration request] 1. The drain or collector sides of three or more transistors are connected by inserting and fixing them in a row in the longitudinal direction of a rectangular heat sink, and the source or emitter sides of the transistors connected in one or more rows of three or more are connected. Each of them is inserted and connected to a conductor composed of one strip plate, and a source or emitter side terminal formed at one end of the conductor is arranged at one end in the longitudinal direction of the heat sink and a drain is provided at the other end in the longitudinal direction of the heat sink. Or, the collector side terminal is arranged, and the combined value of the resistance between the drain or collector of each transistor and the drain or collector side terminal is the same as the resistance between the source or emitter and the source or emitter side terminal. A parallel connection device of transistors characterized by the above.