1EDS20I12SV Datasheet, PDF (19/33 Pages) Infineon Technologies AG – Single-channel isolated IGBT Driver

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1EDS - slew rate control IGBT driver IC
The second voltage level is set in a way that turn-off losses are the same as during normal turn-off for nominal
current values. The turn-on signal is delayed by the duration of the two-level turn-off in order to achieve identical
pulse lengths.
The duration of the plateau is set by the capacitor connected between terminals CZ and VEE2.
The IC starts charging the capacitance on CZ for obtaining the two-level set time T_TLSET, when a turn-on signal is
given. The IC starts the turn-on sequence and resets the capacitor at terminal CZ as soon as the voltage at
terminal CZ exceeds 3 V.
The IC activates additionally a soft turn-off sequence, if a turn-off is initiated due to a desaturation condition on
terminal DESAT.
4.8.7
Desaturation shut down protection
Desaturation protection ensures the protection of the IGBT in case of a short. When the desaturation voltage on
terminal DESAT rises and reaches 9 V, the output is driven low by soft turn-off and the /FLT output terminal is
activated. The blanking time is determined by the combination of the highly precise internal current source and
an external capacitor. Desaturation protection is only set active 400ns after the preboost phase.
4.8.8
IGBT overcurrent detection
The IGBT overcurrent detection is a protection feature that senses the emitter current on current-sense IGBTs
or standard IGBTs via using an emitter shunt resistor. The voltage is measured by a comparator that triggers at
0.35 V. The current sense signal at terminal CS is ignored while the IGBT is off. An external blanking circuit is
necessary to prevent false tripping during turn-on. With non-sensing IGBT types, a low resistance shunt is used
to sense the emitter current. When a short is detected, the IGBT is switched off by a soft turn-off. Both the
desaturation and the current sense features can be used at the same time. The fault status is signaled on
terminal /FLT. The fault status has to be reset via terminal EN. IGBT overcurrent detection is only active 400ns
after the preboost phase.
4.8.9
Overcurrent protection ON/OFF
If terminal OCOFF is connected to GND2 or left unconnected, the IGBT is switched off via a soft turn-off in case
of a CS or DESAT event. If terminal OCOFF is connected to VCC2, the IGBT is not switched off in such cases.
The IGBT can be turned off externally instead, e.g. via control input EN. However, the signaling of CS or DESAT
events to output /FLT is done in any case.
4.8.10 Soft turn-off
The IGBT can be turned off smoothly via an external higher-ohmic gate resistor attached to terminal SOFF. The
soft turn-off speed can be adjusted by selecting the appropriate resistor value. The soft turn-off reduces the
voltage overshoot considerably and may be used in combination with the two-level turn-off function of the IC.
The regular turn-off function at terminal OFF supports the soft turn-off as soon as the voltage between terminals
GATE and VEE2 drops below 3 V. An additional safety feature is installed by means of a watchdog timer, which
starts at the same time the soft turn-off is triggered. The watchdog turns off the IGBT in any case via terminal
OFF after 5 µs. If the soft-off function is not used, both the terminals SOFF and OFF can be combined to
increase the turn-off current capability of the IC.
Trigger conditions for a soft turn-off:
 Desaturation condition at terminal DESAT
 Overcurrent condition at terminal CS
 Driver Enable OFF (EN equals GND1)
 UVLO1 of the input side supply VCC1
 UVLO of the input side logic reference PADP
 Internal signal transmission error
Target datasheet
19
<Revision 0.73>, 05.06.2014