MT6M15962a
© Fuji Electric Co., Ltd. All rights reserved.
5.6 IGBT chips over heating protection (
T
jOH
) operation
: When the ON/OFF state of
V
in
affects the protection operation
• If the IGBT chip surface temperature
T
vj
is higher than
T
jOH
continuously for a period exceeding 1ms,
an alarm signal is output and the IGBT is turned off softly
※
1
. (1)
• The protection operation continues during the period of
t
ALM(TjOH)
even if
T
vj
drops below
T
jOH
-
T
jH
before the elapse of
t
ALM(TjOH)
. Normal operation resumes if
V
in
is in OFF-state after the elapse of
t
ALM(TjOH)
. (2)
• The protection operation continues if
V
in
is in ON-state, even if
T
vj
drops below
T
jOH
-
T
jH
after the
elapse of
t
ALM(TjOH)
. (3)
• The protection operation continues after the elapse of
t
ALM(TjOH)
even when
V
in
is in OFF-state if
T
vj
exceeds
T
jOH
-
T
jH
. Even if the protection operating duration is sufficiently longer than
t
ALM(TjOH)
, the
alarm signal is output only once. (4)
※
1 Soft turn off: This means a slower than normal turn-off.
3-19
Fig.3-13
T
jOH
protection operation (1)
V
in
: Input signal voltage
V
ALM
: Alarm signal voltage
t
ALM(TjOH)
: Alarm signal hold time
T
jOH
: IGBT chips over heating protection temperature level
T
jH
: Over heating protection hysteresis
the IGBT
chip surface
temperature
