Power semiconductor module

1 . A power semiconductor module having at least an upper arm, comprising:

a Zener diode connected between a gate terminal and a reference potential terminal and provided on the outside of a semiconductor chip of a switching element and provided on an insulating substrate;

a casing which houses the insulating substrate; and

a plurality of external electrodes provided to the casing and connected to the gate terminal and the reference potential terminal,

wherein

the switching element includes a first switching element and a second switching element,

a first insulating substrate on which the first switching element as a component of the upper arm is mounted, and a second insulating substrate on which the second switching element as a component of the upper arm is mounted are included,

the insulating substrate is a third insulating substrate having: the gate terminal supplying a gate signal to the first and second insulating substrates; and the reference potential terminal for detecting reference potential of each of the first and second insulating substrates, and

the Zener diode is provided for the third insulating substrate.

2 . The power semiconductor module according to claim 1 , further comprising a switching element as a component of the upper arm, wherein

Zener voltage of the Zener diode is set to a voltage value obtained by adding predetermined voltage to gate voltage which makes the switching element enter an on state.

3 . A power semiconductor module comprising:

a casing;

a first gate electrode which is led to an outside of the casing;

a first reference potential electrode which is led to an outside of the casing;

a first switching element provided on the inside of the casing and configured by a first semiconductor chip having a first gate terminal and a first emitter terminal;

a first Zener diode provided on an inside of the casing;

a first signal path provided between the first gate electrode and the first gate terminal;

a second signal path provided between the first reference potential electrode and the first emitter terminal;

a third insulating substrate having a first wiring pattern that constitutes a part of the first signal path and a second wiring pattern that constitutes a part of the second signal path;

a first insulating substrate to which the first semiconductor chip is joined;

a second switching element provided on the inside of the casing and configured by a second semiconductor chip having a second gate terminal and a second emitter terminal;

a second insulating substrate to which the second semiconductor chip is joined;

a third signal path provided between the first gate electrode and the second gate terminal via the first wiring pattern; and

a fourth signal path provided between the first reference potential electrode and the second emitter terminal via the second wiring pattern, wherein

the first Zener diode is joined between the first wiring pattern and the second wiring pattern.

4 . The power semiconductor module according to claim 3 , further comprising:

a second gate electrode which is led to the outside of the casing;

a second reference potential electrode which is led to the outside of the casing;

a third switching element provided on the inside of the casing and configured by a third semiconductor chip having a third gate terminal and a third emitter terminal;

a fourth insulating substrate to which the third semiconductor chip is joined;

a fourth switching element provided on the inside of the casing and configured by a fourth semiconductor chip having a fourth gate terminal and a fourth emitter terminal;

a fifth insulating substrate to which the fourth semiconductor chip is joined; and

a sixth insulating substrate,

the power semiconductor module further comprising:

a second Zener diode provided on the inside of the casing;

a fifth signal path provided between the second gate electrode and the third gate terminal;

a sixth signal path provided between the second reference potential electrode and the third emitter terminal;

a seventh signal path provided between the second gate electrode and the fourth gate terminal; and

an eighth signal path provided between the second reference potential electrode and the fourth emitter terminal, wherein

the sixth insulating substrate has: a third wiring pattern that constitutes a part of the fifth signal path and the seventh signal path; and a fourth wiring pattern that constitutes a part of the sixth signal path and the eighth signal path, and

the second Zener diode is joined between the third wiring pattern and the fourth wiring pattern.

5 . The power semiconductor module according to claim 4 , further comprising:

a positive-electrode main terminal which is led to the outside of the casing;

a negative-electrode main terminal which is led to the outside of the casing; and

an AC main terminal which is led to the outside of the casing, wherein

a collector terminal of each of the first and second semiconductor chips is connected to the positive-electrode main terminal,

an emitter terminal of each of the first and second semiconductor chips and a collector terminal of each of the third and fourth semiconductor chips are connected to the AC main terminal, and

an emitter terminal of each of the third and fourth semiconductor chips is connected to the negative-electrode main terminal.

6 . The power semiconductor module according to claim 3 , wherein

the Zener voltage of the first Zener diode is set to a voltage value obtained by adding a predetermined voltage to a gate voltage which makes the first switching element enter an on state.

7 . The power semiconductor module according to claim 4 , wherein

the Zener voltage of each of the first Zener diode and the second Zener diode is set to a voltage value obtained by adding a predetermined voltage to a gate voltage which makes the first to fourth switching elements enter an on state.