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I had a problem with some IGBT models....

Discussion in 'Electronic Design' started by Genome, Nov 12, 2006.

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  1. Genome

    Genome Guest

    ______________________________________________________________
    Reference :R7621707218970340
    Title :Big Dildo
    Requester :
    Question : I could have been nice about this. I might have spent some time
    defining the problem as I see it and providing more detailed information.
    However in order to inform you about a problem I had to register. The
    information in my registration details is like your spice models for IGBTs.
    CRAP!!!! I will be informing my company that under no circumstances should
    they use your IGBTs in the product because they are not suitably rated for
    RBSOA. That might be a lie but I'm sure they won't argue too much. Have a
    nice day.
    ______________________________________________________________
    Dear User,
    Please find here below latest information concerning the request
    R7621707218970340
    Dear Sir,

    You seem to be a little bit upset? This is a new system that we are just
    getting up and running and you may have had an unsatisfactory service for
    which we apologies. However, I am sure that your company needs a competitve
    source of products now and in the future and to dismiss one of the major
    supplies of components for a technical issue with our support hotline does
    seem a little short sighted if I may be so bold!

    If you regain your composure in the near or far future, please do not
    hesitate to contact us again.

    With our very best regards,
    _____________________________________________________________
     
  2. Genome

    Genome Guest

    Silly thing is that after that response I feel the need to explain further
    but I've forgotten my log in details and wouldn't be able to send in
    pictures to show the problem anyway.

    Well... there you go. I'll bollox it......

    If you are into spice....

    Go to SGS Thompson ST or whatever........ download some of their IGBT
    models.

    Go to IRF and grab hold of some of theirs.

    Stick them up circuits....... compare them.....

    IRF seems to mess up the turn on characteritics but the turn off is close.

    ST seriously fucks the bollocks on turn off.

    I'm no expert, but comparing things in the models I might take a
    guess.........

    ST got shafted by the model provider.

    I'd ask Jim Thompson to take a look at things and give them some advice but,
    apart from the name, they are a bunch of Frenchies.

    DNA
     
  3. legg

    legg Guest

    Many a slip between cup and lip. Seldom pays to go ballistic.

    RL
     
  4. Jim Thompson

    Jim Thompson Guest

    I've had inquiries about making models, but was informed that I was
    too expensive ;-)

    I guess crap models are OK with the manufacturer.

    ...Jim Thompson
     
  5. Fred Bartoli

    Fred Bartoli Guest

    Jim Thompson a écrit :
    Not even. I've seen worse...
     
  6. Guest

    See I keep telling you you have to be an EXPERT to get anything useful
    out of spice, maybe now you'll believe me but then again....
     
  7. Genome

    Genome Guest

    Yes....... of course.

    I presume that, by the same reasoning, when you have built one of your
    'real' circuits and it is misbehaving you give up. I suppose you will claim
    that you actually investigate the problem and find a cause and a solution.

    In this case the 'problem' was a result of some bad models, hence my disgust
    with ST. Of course that will be a reason for you to bounce up and down with
    glee saying 'told you so'.........

    Sigh, it must be the shrapnel.

    DNA
     
  8. Guest

    Why would I do that?

    I suppose you will claim
    No not really. You've been working on this for weeks, you could have
    built it long ago and it would most likely be working. My point is
    you're still going to have to build it and it's very unlikely to work
    like the simulation so you will still have to get it working the "old
    fasioned way" and so your simulation has achieved very little.
     
  9. Fred Bartoli

    Fred Bartoli Guest

    a écrit :
    How do you know that (since you're such a spice expert)?

    so you will still have to get it working the "old
     
  10. Guest

    How do you know that (since you're such a spice expert)?

    Because he can't model the transformer acurately, for a start it
    probably doesn't exist as yet. Then there are all the other unmodeled
    parasitics.
     
  11. Joerg

    Joerg Guest

    Hello Jim,
    Sounds familiar over here as well. Some don't want to pay the consultant
    and try it on their own, thinking this would save money. Then a couple
    of years down the road major problems start to unfold and the phone
    rings. By that time the required changes will typically be painful.
    Relayouts, major architectural changes, new agency approvals,
    significant inventory write-off and so on.

    What really surprises me is that most companies have no qualms about
    paying their attorneys several hundred per hour. Sometimes even for
    rather mundane work such as checking a standard consulting agreement.
    But competent technical help often seems not to be valued much. Until
    the comeuppance, that is...
     
  12. Jim Thompson

    Jim Thompson Guest

    Yep. The only smile is when they come back a year or two later and I
    stick it to 'em ;-)

    ...Jim Thompson
     
  13. Joel Kolstad

    Joel Kolstad Guest

    Pointy-haired bosses at least somewhat understand what it is that attorneys do
    for them, whereas they really don't even begin to understand all this stuff
    about "models" and "SPICE" and "simulation?"
     
  14. Joerg

    Joerg Guest

    Hello Jim,
    I don't. I'll help them but sometimes I am booked up and can't. The
    really sad cases are when it's too late. Like with a European company
    that had to shut down. It was clearly avoidable but they could not do it
    on their own.
     
  15. Joerg

    Joerg Guest

    Hello Joel,

    The successful ones surround themselves with engineers who tell them
    when it's time to call in an expert. However, some of them won't listen.
     
  16. Ha! As if you don't have a hearing problem, and rethinking DOS as
    the ultimate OS for your PC's. Hahaha....
     
  17. Rich Grise

    Rich Grise Guest

    This is particularly frustrating when the expert that needs to be called
    in is oneself. ;-)

    Cheers!
    Rich
     
  18. Joerg

    Joerg Guest

    Hello Frank,
    Oh, I use Windows. Right now, actually. But without any doubt in my mind
    DOS is more reliable and sometimes you just need that. Also, there is
    stuff that simply doesn't exist without DOS. Or have you ever heard of a
    program to calculate wave digital filters that doesn't run under DOS?
    And here I don't mean some wild and skimpily documented collection of
    routines and snippets but the real stuff, where you key in the passband
    values and it spits out the coefficients in proper CSD representation.
     
  19. Yes, you once told us about your favorite filter program. But even so,
    it may be time to throw it out of the window now, together with the
    warped 5.25 floppies. I'm not in the digital filter business, but I would
    expect that your compadres in this area use Mathlab or something.

    http://www.amazon.com/Digital-Signal-Processing-Theory-Practice/dp/981238216X
     
  20. Joerg

    Joerg Guest

    Hello Frank,
    My compadres in academia use Matlab. The ones in industry mostly don't.
    Too many version changes, incompatibilities, etc. That's only what I
    hear, I do not use Matlab myself.

    Throw out the filter program? And then? Of course I could tell my
    clients that they can't have that new gizmo to be "really" portable
    anymore because now I need a fat DSP that requires four big D-cells to
    run for a few hours. Or a car battery :)

    BTW Texas just came out with a new filter routine that is a little more
    comfortable than the one I had, no need to crank the CSD conversions by
    hand anymore. However, this one is sans graphical interface. Strictly
    DOS command line. If a company that size does that I guess there has to
    be a reason...

    Thanks, but I already got about 2ft of DSP books on my shelf here.

    It's not that I find Windows less useful. This afternoon I had to do a
    final presentation after completing a consulting task. In that one I had
    to show the achieved noise reduction and the only way to do that was to
    run three independent video loops in parallel via a projector. Now way
    that I could ever do that under DOS. But there are situations where DOS
    is simply better.
     
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