JP2002141452A - Bus bar structure of semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an inductance when a power source side is observed from a switching element. SOLUTION: Additional wirings 10f are provided at a positive side bus bar 10, and additional wirings 12f are provided at a negative side bus bar 12. Thus, the bar 10 and the bar 12 become a shape of corresponding pair to reduce its inductance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a plurality of switching elements, and more particularly to a bus bar structure of a semiconductor element for connecting each switching element to a power supply.

[0002]

2. Description of the Related Art Conventionally, strip-shaped, rod-shaped or strip-shaped conductors, that is, bus bars, have been used for connection between circuit elements in a power circuit or connection between a circuit element and a power supply or a load. For example, a three-phase AC is used to drive a motor, and an inverter is used to obtain a three-layer AC from a DC power supply. This inverter usually has six switching elements (for example, IGBT: Insulated Gate Bipol).
ar Transistors), two of which are arranged between the positive side and the negative side of the DC power supply.

For example, in a hybrid vehicle or an electric vehicle, DC power from a battery is converted into a desired AC by an inverter. Such a hybrid vehicle or an electric vehicle requires high-power driving, and a large current of several hundred A or more is used. Therefore, at the time of switching, a large flyback voltage is generated according to the inductance when the power supply side is viewed from the switching element. Therefore, in order to enable high-speed switching, there is a demand to reduce inductance when a power supply is viewed from a switching element.

Japanese Patent Application Laid-Open No. H11-113244 discloses that, of the power-supply-side bus bars connecting a switching element and a power supply, ends of bus bars having the same polarity, which are opposite to the power supply side, are connected by loop wiring. In this way, by forming the bus bar in a loop shape, a parallel connection of the inductance appears in an equivalent circuit of the inductance as viewed from the power supply side from the switching element. Therefore, the inductance can be reduced, and high-speed switching can be performed.

[0005]

However, when performing high-power switching, it is necessary to increase the size of the switching elements or to connect a plurality of switching elements in parallel. As a result, the length of the bus bar constituting the electrode of the switching element becomes longer.
As a result, the inductance of the bus bar increases, and the flyback voltage increases. Therefore, there is a demand for further reducing the inductance when the power supply side is viewed from the switching element.

[0006] The present invention has been made in view of the above problems, and has as its object to provide a bus bar structure capable of further reducing inductance.

[0007]

According to the present invention, there is provided a semiconductor device having a plurality of switching elements, wherein the semiconductor element has a bus bar structure for connecting each switching element to a power supply. A plurality of positive-side power supply connection wires, a plurality of negative-side power supply connection wires paired with the positive-side power supply connection wire, and connecting a negative-side end of a plurality of switching elements to a power supply; A positive loop wire that connects the power connection wires at a position away from the power source side to form a positive loop; and a negative loop that connects the plurality of negative power connection wires at a position away from the power side. And connected to either the positive loop or the negative loop, and arranged outside the loop and extended to a position close to the outer periphery of the other loop. It has an additional wire that, the, the additional wiring, and the positive loop, by reducing the difference in the arrangement of the negative-loop, characterized in that reducing the inductance when viewed power source side switching element.

Further, additional wiring is provided for each of the positive side loop and the negative side loop, and
It is preferable that the arrangement of the outer portion of the negative side loop be substantially the same.

As described above, according to the present invention, the additional wiring is provided, and the positive side loop and the negative side loop are shaped so as to correspond to each other. As a result, the positive conductive path and the negative conductive path from the switching element to the power supply are arranged relatively close to each other. As a result, the inductance value when the power is viewed from the switching element is small. Become. As a result, the flyback voltage is also reduced, and switching can be performed at a higher speed than before.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a bus bar structure according to an embodiment. The positive bus bar 10 has two electrode portions 10a and 10a.
b. The electrode portions 10a and 10b are connected to a terminal 10d connected to a power supply by a power supply side wiring 10c, and the other end is connected by a loop wiring 10e.

On the other hand, the negative side bus bar 12 has two electrode portions 1.
2a and 12b. These electrode portions 12a, 12b
Is connected to a terminal 12d connected to a power supply via a power supply side wiring 12c, and the other end is connected via a loop wiring 12e.

Here, all of the above-described structure is formed on a semiconductor substrate, and a pair of switching elements (not shown) connected in series is formed at a portion of the semiconductor substrate sandwiched between the electrode portion 10a and the electrode portion 12a. These intermediate points are drawn out by a load (eg, motor U phase) side bus bar (not shown). The electrode section 12a and the electrode section 10
The next pair of switching elements connected in series is formed at the portion sandwiched by b, and the intermediate point between them is drawn out by the load (for example, the V phase of the motor) side bus bar. Further, a pair of next switching elements connected in series is formed in a portion sandwiched between the electrode portion 10b and the electrode portion 12b,
The midpoint between them is drawn by the bus bar (for example, the W phase of the motor). The switching element is, for example, an IGBT.

Further, as shown on the right side of FIG. 1, the positive bus bar 10 and the negative bus bar 12 are arranged so as to have different depths and positions, and detour at the intersection of the two. Insulated from each other by such means.
In this example, the electrode portions 10a, 10b are connected to the electrode portions 12a, 1
2b, the power supply side wiring 10c and the loop wiring 10e are connected to the power supply side wiring 12c and the loop wiring 12e.
It is located outside. Also, the power supply side wiring 10c, 1
2c and the loop-side wirings 10e and 12e are strip-shaped in the depth direction longer than the surface direction, and the electrode portions 10a, 10b, 1
Each of 2a and 12b has a belt shape whose surface direction is longer than the depth direction. As for the additional wirings 10f and 12f, the portions following the power supply wirings 10c and 12c and the loop wirings 10e and 12e have a band shape in which the depth direction is longer than the surface direction and are parallel to the electrode portions 10a, 10b, 12a and 12b. Is a belt-like shape longer than the depth direction in the surface direction.

Here, the positive side bus bar 10 is
Both ends of a and 10b are connected by a power-supply-side wiring 10c and a loop wiring 10e to form a square loop as a whole. The negative bus bar 12 is connected to the electrode 12
Both ends of a and 12b are connected by a power-supply-side wiring 12c and a loop wiring 12e to form a square loop as a whole.

The electrode portion 10a at the left end of the loop of the positive bus bar 10 is shifted to the left by a pair of switching elements from the electrode portion 12a at the left end of the loop of the negative bus bar 12. On the other hand, the electrode portion 12b at the right end of the loop of the negative bus bar 12 is shifted to the right by the pair of switching elements from the electrode portion 10b at the right end of the loop of the positive bus bar 10. That is, the positive side bus bar 10 and the negative side bus bar 12 have substantially the same shape and are arranged shifted by a pair of switching elements.

In the present embodiment, the primary bus bar 10
, A U-shaped additional wiring 1 extending to the right in the drawing
0f is additionally provided, and in the negative side bus bar 12,
In the figure, an inverted U-shaped additional wiring 12f extending to the left is additionally provided.

Thus, the additional wiring 10f is connected to the power supply wiring 12c and the loop wiring 12e of the negative bus bar 12.
And the additional wiring 12f is arranged along the shift part of the power supply side wiring 10c and the loop wiring 10e of the positive side bus bar 10 and the electrode part 10a. Therefore, the loop of the positive bus bar 10 including the additional wiring 10f and the loop of the negative bus bar 12 including the additional wiring 12f have substantially the same outer shape.

By making the loop shapes of the positive side bus bar 10 and the negative side bus bar 12 substantially the same, the distance between both circuits becomes very small. Therefore, the inductance between the positive bus bar 10 and the negative bus bar 12 can be reduced, and the inductance when the power supply side is viewed from the switching element can be reduced.

According to the experiment, the inductance can be reduced by about 30% by providing the additional wirings 10f and 12f.

The positive bus bar 10 and the negative bus bar 12 may be formed integrally, or may be formed by connecting separately formed portions.

FIG. 2 shows the configuration of another embodiment. In this configuration, both outer portions of the positive bus bar 10 and the negative bus bar 12 are formed in a belt shape whose depth direction is longer than the surface direction. Thereby, the additional wirings 10f, 12f
The portion parallel to the electrode f is also in a belt shape whose depth direction is longer than the surface direction.

In such a configuration, the same effect as in the above-described embodiment can be obtained. Further, with this configuration, the wiring can be provided by effectively utilizing the side surface of the semiconductor substrate.

The electrodes, wirings, etc. do not necessarily need to be provided on the side surfaces, but may be all provided on the front surface side.

In the above-described embodiment, the U-phase electrode is shared with the other-phase electrodes in the three-phase inverter, but they may be provided separately.

[0026]

As described above, according to the present invention,
Additional wiring was provided, and the shape was such that the positive side loop and the negative side loop were paired. As a result, the positive conductive path and the negative conductive path from the switching element to the power supply are arranged relatively close to each other. As a result, the inductance value when the power is viewed from the switching element is small. Become. As a result, the flyback voltage is also reduced, and switching can be performed at a higher speed than before.

[Brief description of the drawings]

FIG. 1 is a diagram showing a bus bar arrangement according to an embodiment of the present invention.

FIG. 2 is a diagram showing a bus bar arrangement according to another embodiment of the present invention.

[Explanation of symbols]

10 positive busbar, 12 negative busbar, 10a, 1
0b, 12a, 12b electrode part, 10c, 12c power supply side wiring, 10d, 12d terminal, 10e, 12e loop wiring, 10f, 12f additional wiring.

Claims (2)

[Claims] 1. A semiconductor device having a plurality of switching elements, comprising a bus bar structure of a semiconductor element for connecting each switching element to a power supply, wherein a plurality of positive power supplies connecting a positive end of the plurality of switching elements to a power supply. Connection wiring, a plurality of negative power supply connection wires that are paired with the positive power supply connection wire, and connect the negative ends of the plurality of switching elements and the power supply; and a plurality of the positive power supply connection wires from the power supply side. A positive loop wiring connected at a distant position to form a positive loop; and a negative loop wiring connected to the plurality of negative power supply connection wires at a position distant from the power supply side to form a negative loop. An additional wiring connected to one of the positive loop and the negative loop, arranged outside the loop, and extending to a position close to the outer periphery of the other loop; A bus bar structure for a semiconductor device, wherein additional wiring reduces a difference in arrangement of a positive side loop and a negative side loop to reduce inductance when a power supply side is viewed from a switching element. 2. The bus bar structure of a semiconductor device according to claim 1, wherein additional wirings are provided for both the positive side loop and the negative side loop, and outer portions of the positive side loop and the negative side loop. A bus bar structure of a semiconductor device, wherein the arrangement of the bus bars is substantially the same.