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IGBT collector and emitter showing short

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nareshgtr

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igbt collector

HI guys,
In what conditions the IGBT Emitter and Collector or all pins shows short. Is this is due to either high current or high voltage, to avoid this what actions i should take.
Regards
V. Naresh Kumar
 

what is the cause of shorted igbt

nareshgtr said:
HI guys,
In what conditions the IGBT Emitter and Collector or all pins shows short. Is this is due to either high current or high voltage, to avoid this what actions i should take.
Regards
V. Naresh Kumar
Click to expand...
If the device behaved like this while in circuit, it might be due to short circuit in load.
if you observed this while the IGBT is in package , better check again the gate terminated with a 10K to emitter.
Sarma
 

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    nareshgtr

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avoiding igbt gate overvoltage

thanks for reply....... I should have asked the question in this way......
In what condition all IGBT pins become short either in over current or over voltage situation.
 

why igbt fails

It's most likely impossible to detect the primary cause. An IGBT has to be protected against both failure mechanism.
Even a gate overvoltage can possibly cause a catastrophic failure later on.
 

I connected Zener diode across the gate and emitter. I hope it gives the protection from gate over voltage for IGBT, still IGBTs are going bad. Please help me by giving any suggestions.........
Regards
V. Naresh Kumar
 

nareshgtr said:
I connected Zener diode across the gate and emitter. I hope it gives the protection from gate over voltage for IGBT, still IGBTs are going bad. Please help me by giving any suggestions.........
Regards
V. Naresh Kumar
Click to expand...

Hi here, me to had connected a zener diode across gate and emitter, still my igbt failed showing short across all pins, i am thinking of avoiding over voltage at igbt.
if igbt is coupled to inductive load during off state the collapsing magnetic field may generate very high voltage in reverse direction on the igbt and may fail by overvoltage .hence over voltage protecting circuit is required
contact me on sanjuvernekar@yahoo.co.in if you have any developments
i am also trying to develop some protection.
 

There are many reasons why IGBTs can fail this way.

If you can give me some more details such as a schematic or a detailed description of the circuit around the IGBT, I may be able to help out. I have had a lot of experience with IGBTs so I should be able to spot the problem.
 

Hi All,

do you guys know What is the sign of over voltage and over current of the IGBT ? Is that anyway to differentiate it such as base on burn mark?
 

itaig said:
There are many reasons why IGBTs can fail this way.

If you can give me some more details such as a schematic or a detailed description of the circuit around the IGBT, I may be able to help out. I have had a lot of experience with IGBTs so I should be able to spot the problem.
Click to expand...


I am using IGBTs in inverter of DC to 3 ph output. They are failing after working for some period in customer end. Please suggest what could be the reason for IGBT failure
 

I would say the failure is most probably due to overvoltage, or thermal damage (ie excessive VI).
If you have protected against overvoltage (Make sure you have a good gate connection as gate currents can come up to amps), then it's due to thermal.
If you are using a bridge-type topology, you have to ensure there's no shoot-through, ie having some sort of anti-cross conduction circuitry.
 

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