CROSS-REFERENCE TO RELATED APPLICATION

This application is the U.S. national phase of PCT Application No. PCT/JP2018/022009, filed on Jun. 8, 2018, the entire disclosure of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to semiconductor modules.

BACKGROUND ART

A semiconductor module that converts DC power inputted from a DC power supply to AC power has conventionally been known as one kind of semiconductor devices.

Such a semiconductor module is used to convert a DC voltage to a three-phase AC voltage to drive a three-phase motor, for example (JP 6062565 B).

The conventional semiconductor module (FIGS. 3 and 4) has an L-shaped ground line that is common to the three phases in order to reduce the wiring resistance.

However, since the ground line pattern is common to the three phases in the semiconductor module, the area of the ground line is large (FIG. 3).

As a result, the inductance of the ground line becomes large and the switching noise caused by the switches of the half bridges included in the semiconductor module is increased.

In order to reduce the switching noise, a filter including a resistor and a capacitor (snubber), for example, needs to be provided.

DISCLOSURE OF THE INVENTION

Problem to be Solved by the Invention

Under the circumstance, it is an object of the present invention to provide a semiconductor module capable of reducing the inductance of the ground line to reduce the switching noise caused by the switches of the half bridges included in the semiconductor module.

Solution to Problem

A semiconductor module according to an embodiment in an aspect of the present invention is a semiconductor module configured to convert a direct current to a three-phase alternating current, and to supply the three-phase alternating current to a three-phase motor to drive the three-phase motor, the semiconductor module comprising:

a substrate;

a power supply line disposed along a first side on the substrate;

a power supply terminal connected to the power supply line;

a first ground line, a second ground line, and a third ground line disposed on the substrate along a second side that faces the first side of the substrate;

a first ground terminal connected to the first ground line;

a second ground terminal connected to the second ground line;

a third ground terminal connected to the third ground line;

first to third motor terminals connected to coils of the three-phase motor;

first to third half bridges each including a high side switch and a low side switch connected in series between the power supply line and a corresponding one of the first to the third ground lines, a junction point of the high side switch and the low side switch being connected to a corresponding one of the first to the third motor terminals, and the junction points of the first to third half bridges being connected in parallel with one another; and

first to sixth control signal terminals, to which control signals for controlling operations of the high side switches and the low side switches of the first to the third half bridges are inputted,

wherein the first ground terminal, the second ground terminal, and the third ground terminal are arranged along the second side to be separated from one another and electrically isolated from one another.

In the semiconductor module,

wherein an area of each of the first to the third ground line is smaller than an area of the power supply line.

In the semiconductor module,

wherein one end of the first ground terminal is connected to one end of the first ground line that is in the vicinity of a third side of the substrate, which intersects with the first side and the second side,

wherein one end the second ground terminal is connected to one end of the second ground line in the vicinity of the second side, and

wherein one end of the third ground terminal is connected to one end of the third ground line in the vicinity of a fourth side that faces the third side of the substrate.

In the semiconductor module,

wherein a fourth control bonding wire that connects a control electrode of a first low side switch of the first half bridge and the fourth control signal terminal extends over the first ground line,

wherein a fifth control bonding wire that connects a control electrode of a second low side switch of the second half bridge and the fifth control signal terminal extends over the second ground line, and

wherein a sixth control bonding wire that connects a control electrode of a third low side switch of the third half bridge and the sixth control signal terminal extends over the third ground line.

In the semiconductor module, the semiconductor module further comprising a thermistor disposed between the first ground line and the second ground line or between the second ground line and the third ground line on the substrate, in the vicinity of the second side of the substrate, to detect a temperature.

In the semiconductor module,

wherein the thermistor is disposed between the second ground line and the third ground line in the vicinity of the second side of the substrate,

wherein the semiconductor module further comprises:

a first temperature detection signal terminal electrically connected to one end of the thermistor; and

a second temperature detection signal terminal electrically connected to another end of the thermistor, and

wherein the first and the second temperature detection signal terminals are disposed between the fifth control signal terminal and the sixth control signal terminal.

In the semiconductor module, the semiconductor module further comprising:

a first support dummy line disposed on a first corner portion of the substrate where the first side and the third side intersect each other;

a second support dummy line disposed on a second corner portion of the substrate where the first side and the fourth side intersect each other;

a third support dummy line disposed on a third corner portion of the substrate where the second side and the third side intersect each other; and

a fourth support dummy line disposed on a fourth corner portion of the substrate where the second side and the fourth side intersect each other,

wherein the first to the fourth support dummy lines are pressed by a support member during a wire bonding process in order to press the substrate by the support member.

In the semiconductor module,

wherein the first ground line is connected to a second electrode of the first low side switch via a bonding wire,

wherein the second ground line is connected to a second electrode of the second low side switch via a bonding wire, and

wherein the third ground line is connected to a second electrode of the third low side switch via a bonding wire.

In the semiconductor module,

wherein the power supply terminal is disposed so as not to cover the first support dummy line,

wherein the third motor terminal is disposed so as not to cover the second support dummy line,

wherein the first ground terminal is disposed so as not to cover the third support dummy line, and

wherein the third ground terminal is disposed so as not to cover the fourth support dummy line.

In the semiconductor module,

wherein the first to the third control signal terminals are arranged in a direction along which the first side extends so that one ends of the first to the third control signal terminals are in the vicinity of the first side of the substrate, and

wherein the fourth to the sixth control signal terminals are arranged in a direction along which the second side extends so that one ends of the fourth to the sixth control signal terminals are in the vicinity of the second side of the substrate.

In the semiconductor module,

wherein the first control signal terminal is disposed between the power supply terminal and the first motor terminal,

wherein the second control signal terminal is disposed between the first motor terminal and the second motor terminal, and

wherein the third control signal terminal is disposed between the second motor terminal and the third motor terminal.

In the semiconductor module,

wherein the fourth control signal terminal is disposed between the first ground terminal and the second ground terminal, and

wherein the fifth and the sixth control signal terminals are disposed between the second ground terminal and the third ground terminal.

In the semiconductor module,

wherein other ends of the first to the third control signal terminals, which are connected to a mounting substrate, are disposed to be closer to the first side of the substrate than another end of the power supply terminal and other ends of the first to the third motor terminals connected to the mounting substrate, and

wherein other ends of the fourth to the sixth control signal terminals, which are connected to the mounting substrate, are disposed to be close to the second side of the substrate than other ends of the first to the third ground terminals connected to the mounting substrate.

In the semiconductor module,

wherein the first half bridge includes a first high side switch disposed on one end of the power supply line, a first electrode of the first high side switch being electrically connected to the power supply line,

wherein the third half bridge includes a third high side switch disposed on another end of the power supply line, a first electrode of the first high side switch being electrically connected to the power supply line, and

wherein the second half bridge has a second high side switch disposed on the power supply line between the first high side switch and the third high side switch, a first electrode of the second high side switch being electrically connected to the power supply line.

In the semiconductor module, the semiconductor module further comprising:

a first central wiring line disposed on a top surface of the substrate between the one end of the power supply line and the first ground line, and electrically connected to another end of the first high side switch and the first motor terminal, the first low side switch being disposed on a top surface of the first central wiring line;

a third central wiring line disposed on the top surface of the substrate between the other end of the power supply line and the third ground line, and electrically connected to another end of the third high side switch and the third motor terminal, the third low side switch being disposed on a top surface of the third central wiring line; and

a second central wiring line disposed on the top surface of the substrate between the power supply line and the second ground line and between the first central wiring line and the third central wiring line, and electrically connected to another end of the second high side switch and the second motor terminal, the second low side switch being disposed on a top surface of the second central wiring line.

Effects of the Invention

The semiconductor module according to an embodiment in an aspect of the present invention is a semiconductor module configured to convert a direct current to a three-phase alternating current, and to supply the three-phase alternating current to a three-phase motor to drive the three-phase motor, the semiconductor module comprising: a substrate; a power supply line disposed along a first side on the substrate; a power supply terminal connected to the power supply line; a first ground line, a second ground line, and a third ground line disposed on the substrate along a second side that faces the first side of the substrate; a first ground terminal connected to the first ground line; a second ground terminal connected to the second ground line; a third ground terminal connected to the third ground line; first to third motor terminals connected to coils of the three-phase motor; first to third half bridges each including a high side switch and a low side switch connected in series between the power supply line and a corresponding one of the first to the third ground lines, a junction point of the high side switch and the low side switch being connected to a corresponding one of the first to the third motor terminals, and the junction points of the first to third half bridges being connected in parallel with one another; and first to sixth control signal terminals, to which control signals for controlling operations of the high side switches and the low side switches of the first to the third half bridges are inputted.

Furthermore, the first ground terminal, the second ground terminal, and the third ground terminal are arranged along the second side to be separated from one another and electrically isolated from one another.

Thus, the semiconductor module according to the present invention is capable of reducing the inductance of the ground line to reduce the switching noise caused by the switches of the half bridges included in the semiconductor module.

