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The internals of a Semikron SKM400GB124D

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Finn Hammer

Fri Jul 22 2016, 10:30AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

All,
Poking around with these IGBT modules from Semikron, I noticed that there was access to the internal cavity through the nuts below the mounting tabs, and looking trough these holes I realized that there seemed to be not very much silicon in there.
I bought a whole pack of these modules some 6-7 years back, thinking they'd come in handy some time, and haven't used any of them until now, so paranoia crept into my mind, and the dreaded thought "Chinese Counterfeit" flashed in bright neon.
I could do nothing to calm my mind, but to take one of them apart, and as you all see, there is plenty of dies in these baby's.
Jut thought you'd like to know that that there is lots of die area in the Semikrons, nothing beats an autopsy.

Cheers, Finn Hammer

Sulaiman

Fri Jul 22 2016, 03:30PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Odd ... most of the units that I've opened have big black areas

Mads Barnkob

Fri Jul 22 2016, 07:03PM

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

Sulaiman wrote ...

Odd ... most of the units that I've opened have big black areas

It looks like there is plenty of silicon in that picture, notice how small the gate pad is, in the middle is, compared to the size of just one of those silicon chips and there is four of them in parallel to a transistor.

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

Finn Hammer

Fri Jul 22 2016, 08:51PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

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 :)

Mads,

Do you know of a way to get rid of the goo, any solvents available for that?

Cheers, Finn Hammer

Sulaiman

Sat Jul 23 2016, 12:53AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

the jelly-like silicone rubber keeps air and especially moisture away from the silicon dies
and the bonding wires are weak.

You can however probe through the silicone.

Conundrum

Sat Jul 23 2016, 05:12AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Interesting.
An amusing tip, back in ye olden dayz people used to centrifuge germanium transistors to get the black compound added to lightproof the (immersed in gel) transistor away from the die so it could be turned into a phototransistor.
The move to metal cans rendered that pointless but sometimes a tiny hole in the can over the die will work here if done carefully.

I have a few similar modules here which are dual series IGBTs so maybe these can be modified into motor drivers?

Mads Barnkob

Sat Jul 23 2016, 01:15PM

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

Finn Hammer 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 :)

Mads,

Do you know of a way to get rid of the goo, any solvents available for that?

Cheers, Finn Hammer

I never tried to, so I do not know of any.

I will just cut the wires through the goo and try to keep it as intact as possible to ensure it stays protected from dirt :)

Patrick

Mon Jul 25 2016, 04:29AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

This may be me being crazy. but since inductance is a function of loop area and current and other things, having the case open, could you add TVS's or other safety devices super close to the active silicon ?

My TO-247 transistors give small inductance when i solder directly to its leads for this reason. I have pics here on the forum some where.

Finn Hammer

Mon Jul 25 2016, 09:59AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

Patrick wrote ...

This may be me being crazy. but since inductance is a function of loop area and current and other things, having the case open, could you add TVS's or other safety devices super close to the active silicon ?

My TO-247 transistors give small inductance when i solder directly to its leads for this reason. I have pics here on the forum some where.

Patrick,

Perhaps, I am not sure how the goo reacts to undergoo soldering, but Since these Semicron equipped coils appear to function just fine withouut these safety measures, I would prefer to leave them unopened and instead benefit from the features of the casing, being stable buss and exit points, as well as fixed gate attachment points, not to mention the exclusion of dirt and the likes.

Cheers, Finn Hammer

GrantX

Mon Jul 25 2016, 10:58AM

Registered Member #4074 Joined: Mon Aug 29 2011, 06:58AM
Location: Australia
Posts: 335

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 :)

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