# IGBT Modules - Technologies, Driver and Application (Second Edition) - page 161

149
Gate voltageU
GE
In the datasheet there is usually a gate voltage of U
GE
= 15V specified at which
a certain short circuit current I
SC
or the short circuit SOA diagram is shown.
Due to the IGBT transconductance
, i.e. the dependency of the collector
current on the applied gate voltage, an increase (decrease) of the gate voltage
affects a greater (lesser) short circuit current. This is also the reason why for
anSC1 it is not the peak value of I
C
that is given as the short circuit current I
SC
,
but instead the linear extrapolation for the gate voltage of 15V as depicted in
(left) aswell a
Fig. 3.32
Short circuit current I
SC
in dependency of thegate voltageU
GE
DC-bus voltageU
DC
or Collector-emitter voltageU
CE
In the datasheet the short circuit current I
SC
is quoted for a particular DC-bus
voltage or the collector-emitter voltage in blockingmode or instead by the short
circuit SOA diagram. Because different manufacturers quote different
maximum U
CE
values, the following values for U
CE
result, referenced back to
the IGBT voltage ratin
, as anexample:
-
600V IGBT
U
CE
360...400V
-
1.2kV IGBT
U
CE
800...900V
-
1.7kV IGBT
U
CE
1.0...1.1kV
-
3.3kV IGBT
U
CE
2.5kV
-
6.5kV IGBT
U
CE
4.4kV
Short circuit time t
SC
This time states for how long the short circuit may take effect on the IGBT
(pulse duration t
p
in
. Generally the short circuit time results from the
short circuit energy which is the integer of the product of short circuit current
16
The transconductance g
m
defines the relation between an input voltage and an output current. The term
transconductance is the abbreviated form of ‘transfer conductance’. Conductance is here the effective
conductanceof anelectronic component.
17
These values have tobe takenas reference values only andmay differ from onemanufacturer toanother.
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