MT6M15962a
© Fuji Electric Co., Ltd. All rights reserved.
2.5 Over current protection function (OC)
The collector current of IGBTs is detected by the current sense IGBT built into the IGBT chip. If the
collector current reaches the over current protection level (
I
OC
) and continues for more than the over
current protection delay time (
t
dOC
), it is determined as being in the OC status and the IGBT is turned
off to prevent destruction due to over current.
When the OC status is detected, the protection function is activated and an alarm signal is output.
The OC status alarm signal output period (
t
ALM
) is approximately 2ms.
• Protection operation is reset after 2ms (
t
ALM
) and normal operation is resumed if the current level is
lower than the
I
OC
level and the control input signal is OFF.
• Even if the alarm factor is resolved within 2ms (
t
ALM
), the protection operation continues until the
period of 2ms (
t
ALM
) elapses. During this period, the IGBT will not be turned on.
2.6 Short circuit protection function (SC)
The SC protection function prevents the IPM from being damaged by the peak current during load
short circuit and arm short circuit. If the IGBT collector current exceeds the protection level (
I
SC
) and
continues for more than the short circuit protection delay time (
t
sc
), it is determined as being in the SC
status and the IGBT is turned off softly to prevent destruction due to short circuit.
When the SC status is detected, the protection function is activated and an alarm signal is output.
The SC status alarm signal output period (
t
ALM
) is approximately 2ms.
• Protection operation is reset after 2ms (
t
ALM
) and normal operation is resumed if the current level is
lower than the
I
SC
level and the input signal is OFF.
• Even if the alarm factor is resolved within 2ms (
t
ALM
), the protection operation continues until the
period of 2ms (
t
ALM
) elapses. During this period, the IGBT will not be turned on.
2.7 Control power supply under voltage protection function (UV)
The UV protection function prevents malfunction of the control IC caused by voltage drop of the
control power supply voltage (
V
CC
), and protects the IGBT from thermal destruction caused by increase
of
V
CE(sat)
loss. When
V
CC
is continuously below the under voltage protection level (
V
UV
) for
about 20μs,
it is determined as being in the UV status and the IGBTs are turned off softly to prevent malfunction
and thermal destruction due to control power supply voltage drop.
When the UV status is detected, the protection function is activated and an alarm signal is output.
The UV status alarm signal output period (
t
ALM
) is approximately 4ms.
• As hysteresis
V
H
is provided, protection operation is reset after 4ms (
t
ALM
) and normal operation is
resumed if
V
CC
is higher than (
V
UV
+
V
H
) and the input signal is OFF.
• Even if the alarm factor is resolved within 4ms (
t
ALM
), the protection operation continues until the
period of 4ms (
t
ALM
) elapses. During this period, the IGBT will not be turned on.
Furthermore, an alarm signal to determine the UV status is provided at the time of startup and
shutdown of the control power supply
V
CC
.
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