IGBT Modules - Technologies, Driver and Application (Second Edition) - page 163

Other application relevant aspects of the short circuit can be found in chapte
Fig. 3.33
Short circuit current I
in dependency on the junction temperature T
(identical scaling of all measurements and no use of gate or collector clamping)
3.7 Blockingbehaviour
The IGBT blocking behaviour is usually only specified in forward direction, while the
reverse blocking capability is not defined in the datasheet. Generally it can be assumed
that the IGBT reverse blocking capability is significantly less than the forward blocking
capability. In practically all applications this is of no significance as a freewheeling diode
is connected anti-parallel to the IGBT. This means that a reverse blocking capability is
not required except for the reverse voltage overshoot caused by the diode commutation
as described in chapter
In those cases, however, where a specific
reverse blocking capability is required, a combination of IGBT and serial diode is
The forward blocking capability of an IGBTwill usually define its voltage class or rating,
i.e. a 600V IGBT has a forward blocking capability of U
= 600V. This value U
quoted in the datasheet may not be exceeded in the application, not in static nor in
dynamic operation; even though U
at T
= 25°C is usually below the breakdown
voltage U
, as the manufacturers work with a sufficient safety margin in the
datasheet value.
A small cut-off current I
flows during the blocking phase of the IGBT due to the
externally supplied thermal energy. Yet the value I
quoted in the datasheet does not
necessarily turn out to be the value that can be expected in reality. Instead it is usually a
value which poses the lower limit of detection during the final test in the manufacturing
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