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The internals of a Semikron SKM400GB124D

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Mads Barnkob

Mon Aug 01 2016, 06:26AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

GrantX wrote ...

Mads Barnkob wrote ...

Ill be sure to take some macro shots of the CM600s I have to open up to cut out the current limiter :)

Forgive me for going off topic, but I'm struggling to find solid information through google. I've heard someone mention modifying the innards
of an IGBT brick before, but I'm not sure what the current limiting circuit is?

Which modules include the current limiting? I assume the part number indicates whether an IGBT is equipped with it, but I've never seen one or found a datasheet including details about it.

Just curious :)

They are not that common, which is also why I have them saved in my own archive :)

H-series Mitsubish/Powerex CMXXX IGBTs does not have a current limiter, but the F-series does, see datasheets here:

Alex Yuan

Fri Aug 05 2016, 03:48AM

Registered Member #9614 Joined: Mon Jan 14 2013, 10:00PM
Location:
Posts: 44

Apparently the goo turns into a liquid if you heat it up, but it's flammable? I think Eric Goodchild might have written about it. Then again, that doesn't make sense since it's thermal goop and will end up heating up.

Here's a shot of a CM200:

Instead of cutting the RTC out with some sidecutters I found it better and cleaner to just use sharp tweezers and wiggle the bond wire back and forth until it breaks off completely. It's slightly unnerving to cut them and leave the two ends of the bond wire dangling. Also, with some sharp tweezers you'll barely disturb the thermal goop.

Edit: sorry for the double post, accidentally clicked quote and not edit.

Mads Barnkob

Fri Aug 05 2016, 05:53AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Alex Yuan wrote ...

Instead of cutting the RTC out with some sidecutters I found it better and cleaner to just use sharp tweezers and wiggle the bond wire back and forth until it breaks off completely. It's slightly unnerving to cut them and leave the two ends of the bond wire dangling. Also, with some sharp tweezers you'll barely disturb the thermal goop.

Edit: sorry for the double post, accidentally clicked quote and not edit.

Do we agree that the RTC wires are the set of two wires(or just one of them?, could be two gate connections since there is two small pads on main die) from the main dies to the small rectangular piece where the gate signal is routed in over? So that too much current draw makes some kind of voltage drop through the RTC to drain all gate drive current into the main die instead of gate.

It is pretty much identical to my CM600s, but I will post a high res picture of that later in my drsstc thread.

Alex Yuan

Fri Aug 05 2016, 04:50PM

Registered Member #9614 Joined: Mon Jan 14 2013, 10:00PM
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Posts: 44

The RTC is that little island of die where the gate bond wire goes through. IIRC in the datasheet it says it will just pull the gate signal low and shut off the IGBT.

Courtesy of GGY:

Mads Barnkob

Fri Aug 05 2016, 07:48PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Alex Yuan wrote ...

The RTC is that little island of die where the gate bond wire goes through. IIRC in the datasheet it says it will just pull the gate signal low and shut off the IGBT.

Courtesy of GGY:

Just as I described, if anyone could understand it ;)

Alex Yuan

Sat Aug 06 2016, 03:32AM

Registered Member #9614 Joined: Mon Jan 14 2013, 10:00PM
Location:
Posts: 44

Mads Barnkob wrote ...

Just as I described, if anyone could understand it ;)

Haha didn't mean to repeat what you wrote, I thought you were asking for clarification :)

Mads Barnkob

Sat Aug 06 2016, 01:52PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Alex Yuan wrote ...

Mads Barnkob wrote ...

Just as I described, if anyone could understand it ;)

Haha didn't mean to repeat what you wrote, I thought you were asking for clarification :)

I was, sarcasm isn't so good in text :)

Now the tricky question, why is there wire to the first die and a second wire to the terminal? So that it works even if it looses a die?

Alex Yuan

Sun Aug 07 2016, 05:40PM

Registered Member #9614 Joined: Mon Jan 14 2013, 10:00PM
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It's connected to the gate and the output; the second output is a current mirror.

Under "4.0 RTC Description and Behavior":

Alex Yuan

Sun Aug 07 2016, 05:44PM

Registered Member #9614 Joined: Mon Jan 14 2013, 10:00PM
Location:
Posts: 44

Alex Yuan wrote ...

It's connected to the gate and the output; the second output is a current mirror.

Under "4.0 RTC Description and Behavior":

Actually, further down it says it actually doesn't completely shut off the IGBT, it just reduces the gate voltage to limit current only.

Mads Barnkob

Tue Aug 23 2016, 07:06PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

So here is my CM600DU-24FA bricks with marked wires, these are what I would cut to disable the RTC, can I get confirmation on this before I go into surgery? :)

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