2SC0435T and gate to collector IGBT shortcircuit
Hello,
I'm interested whether it is common for the 2SC0435T driver to fail (blow up) if a short circuit occurs between the IGBT gate and collector. This short circuit is a result of the blown IGBT.
I am questioning because we were previously using the IHD660NC1(obsolete) and it survived under the same conditions.
Comments
Thank you for your answer!
Yes, I am referring to a scenario where a DC link voltage is applied.
The recommended circuit for the IHD660NC1 included two Zener diodes between the GATE and EMITTER, ensuring that the maximum voltage V_ge stays within the range of ±15V. I assume that in a scenario where the IGBT collector was shorted to the gate due to some fatal IGBT failure, these two diodes ensured that the V_ge was within allowed range.
Of course this "non wanted" IGBT turn on created a short circuit on the same leg of the inverter, but the short circuit is detected and the DC link is turned off, while the IGBT driver remains undamaged (only the Zener diodes were usually destroyed).
As far as I know 2SC0435T ensures that the maximum voltage V_ge stays within the range of ±15V internally, hence the recommended scheme doesn't include GE didoes . Can we add those two Zener diodes (between GATE and EMITTER) to the secondary circuit of 2SC0435T?
Thanks for your feedback .
2SC0435 has gate voltage of +15V and -10V, it is ok to add TVS diode between the gate and emitter.
following has to be checked if you do so
1 the parasitic capacitor of TVS will then become the load of the driver. as an additional gate capacitance --> double-check the actual power of gate dirver
2 please note the maximum sink/source capability of VEx is limited to ±2.5mA, as mentioned in AN-1101, --> make sure the leakage current of added components respect this value
3 the layout position of the TVS should be close to IGBT as much as possible.
So it is not OK to add ZENER diodes (that was my question), but we can add TVS diodes?
TVS is good for transient overvoltage protection
ZENER diode is good for voltage regulation
in your scenario , TVS is a better choice
Thank you for your answers :D
Dear GasperHribar
Thanks for the question
If we are talking about the short-circuit between gate and collector of gate driver when a high voltage is applied (e.g DC link voltage).
It is definitely that the gate driver is running out of its specification, since the gate part of gate driver is not allowed to have high voltages, which will destroy the isolation design of the board.
The faliure mode of isolation failure is hard to predict, the blow up you mentioned is one possibliity.
Meanwhile, the peripheral circuits of a core also have an influence on the result, which is different between 2SC0435T and IHD660NC1
please check my feedback above and let me know if you have furthre questions
IGBT Gate Driver Support