MT5F33743
© Fuji Electric Co., Ltd. All rights reserved.
3.4 Dynamic avalanche phenomenon
It is explained in previous section that
V
CE
is increased when turn-off operation is performed. And if
V
CE
is excessed certain voltage,
V
CE
voltage is suppressed. One of typical example of this
phenomenon is shown in Fig. 5-6. This phenomenon is called Dynamic avalanche.
If this dynamic avalanche is happened, spike voltage of
V
CE
is suppressed by the decreased turn-off
current. The certain operating conditions which happen dynamic avalanche shall not be applied
because there is possibility of IGBT destruction by turn-off loss increase and latch-up phenomenon.
There are many causes of dynamic avalanche like long wiring of main circuit. To prevent this dynamic
avalanche, IGBT module shall be used within RBSOA condition, at least.
5-5
Fig. 5-6 An example of dynamic avalanche waveform
150
℃
,
V
CC
=500V
I
C
=2000A
V
GE
=+15V/ -0V
R
Gon/off
=+2.7/ -
1.8Ω
C
GE
=56nF
L
S
=30nH
0
100
200
300
400
500
600
700
800
900
1000
0
400
800
1200
1600
2000
2400
2800
3200
3600
4000
0
250
500
750
1000 1250 1500 1750 2000
V
CE
(V
)
Col
lec
tor
c
urr
en
t
(A
)
time (ns)
I
C
(A)
V
CE
(V)
150
℃
,
V
CC
= 500V,
I
C
= 2000A
V
GE
= +15V/-0V
R
G
= +2.7/-1.8
Ω
C
GE
= 56nF
L
S
= 60nH
