Desat after few minutes in IR2214

hello everyone i have build a desat detection with IGBT driver , i am using this circuit to drive IGBT of 1200v 100A to switch 160 dc to 160 ac.
the circuit works fine till approx 5 minutes.after 5 minutes if the dc supply is on then it unnecessary detects as desaturation.
but if the same circuit is kept as it is except without applying DC supply then it works fine.

so in my opinion it is getting some noise back when it is connected to DC supply,i tried many methods still it detects as fault/sd and that led glows indicating fault condition.
i have used RC combination to gate to emitter in IGBT it doesnt work.

need help if anyone have suggestion...
below is the pdf of my circuit diagram.
i have attached only 3rd page because rest two page contains only power supply and driving high/low signal.

View attachment Schematic - IR2214-DRIVER Page 3 of 3.pdf

5 minutes sounds like a thermal problem to me. Have
you monitored IGBT and driver case temps?

dick_freebird said:

5 minutes sounds like a thermal problem to me. Have
you monitored IGBT and driver case temps?

Click to expand...

I have not checked the temperature but if I don’t apply the DC supply across the IGBT it works and don’t give desat condition for long time but as soon as I apply DC supply after few time it gets error after few minutes

This problem is solved as I increased bootstrap capacitor
Ty for help.

Hi,

I hope you recognize that we never had a chance to detect this because
* there are a lot part values missing
* there are the IGBTs missing
* we don't know about switching frequency

Thus .. for the next time .. please try to give complete informations.

Your solution: I wonder, because I never needed larger than 470nF as bootstrap capacitors. Are there any GE resistors?
What's the value of R9 and what is it good for? It slows down charging of the bootstrap capacitor.

Klaus

No other resistor used apart from the schematic above and value of R9 is 10Ohm.

The OP declared the problem being solved, so we don't need to think further about the circuit.

The schematic parameters don't seem to fit the real circuit anyway, we see 60V rated MBR160 used for 160 V switcher, hardly possible. Thus I won't give credit to other schematic details.