MT6M15962a
3. 第7世代RC-IGBTチップの特徴
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3.2.3 Ground fault
(1)Ground fault protection and alarm signal output of upper arm IGBT
• When the ground fault current flows through the IGBT of the upper phase more than
t
dOC
or
t
dSC
, the
OC (SC) protection is activated, but the alarm signal differs depending on the package.
P629, P639 : The upper arm are protected by the OC (SC) function, but does not output the alarm
signal.
P626, P630, P631, P636, P638, P644 : The upper arm are protected by the OC (SC) function and the
alarm signal is output.
(2)Ground fault protection and alarm signal output of lower arm IGBT
• When the ground fault current flows through the IGBT of the lower arm more than
t
dOC
or
t
dSC
, the OC
(SC) protection is activated and the alarm signal is output for all packages.
6-6
3.2.2 Short-circuit (SC)
• If the short-circuit current continues for more than
t
dSC
, the IGBT is judged to be in SC state and the
is turned off slowly. At the same time, an alarm signal is output.
If the short-circuit current drops below the protection level within the
t
dSC
period, the SC protection is
not activated and the IGBT is turned-off normally.
• There is no alarm signal output in the upper arm of P629 and P639, but SC protection works and the
IGBT is turned off slowly.
3.2.4 Start up under short circuit or ground fault status
• The protection is not activated in case of the input signal pulse width that is less than the dead time
because the OC/SC protection has a dead time(
t
dOC
,
t
dSC
). Especially, if the IPM starts up under a
load short-circuit condition, and the input signal pulse width is shorter than the dead time for a long
time (tens of mill seconds), the chip temperature rises rapidly because the protection function does
not work. In this case, even if the IGBT chip over heating protection (
T
jOH
) operates against a rise in
chip temperature, the protection does not work in time because the
T
jOH
dead time is about 1 ms, and
the chip may be damaged by over heating. In addition, when the power is turned on, the FWD chip
may be destroyed because the charging current of an electrolytic capacitor flows in the path of AC
power → ground → output terminal → FWD chip → electrolytic capacitor.
3.3 IGBT chips over heating protection
• IGBT chip over heating protection (
T
jOH
) is built into all IGBTs including the brake IGBT.
T
jOH
works
when the IGBT chip is over heated abnormally. Not building in a case over heating protection, the X-
IPM is not protected against the case over heating. Please implement the protection for case over
heating if necessary.
3.4 Protection of FWD
• FWDs have no protection functions.
