Spice Diode Modeling of Forward Overshoot & Reverse Recovery

How do we know if _your_ scope photos weren't rigged ?>:-}

Nope. I'm in the business of making money, just as you are... I only give away the "free home demos" shown on the Device Models & Subcircuits page of my website. ...Jim Thompson

Show us how that is done >:-} ...Jim Thompson

Zip it with a password. Then I could pull a Thompson: "I have 1N914 forward recovery data, and you can't see it."

There have been a lot of Spice diode models which account for charge storage developed. Most if not all of them concentrate on PIN diodes but I'm sure the same modeling techniques would apply to non PIN diodes. Search in the IEEE journals related to power electronics if you're interested (an example is

Because I am known to share stuff like this.

Hey, if I did fake it, then your model is crap. OK, I did fake it. All your time has been wasted.

Papers aren't _my_ problem... I have several dozen on the subject. I have developed a fairly simple modeling method that seems robust. All I need is data from specific devices to test my method. ...Jim Thompson

You shared photos, I shared screenshots. What's the difference?

No, my time wasn't wasted. That work was set aside last August because I wasn't quite happy with it... so I pursued other items.

I find that approach often refreshes my mind, because, when I went back to it, I realized a major simplification that escaped me previously.

So I'm happy. Someone will provide data so I can compare measured versus model, then I will publish; but I feel quite certain I've cracked the nut. ...Jim Thompson

Here's some data courtesy of Bob Pease

Thanks! ...Jim Thompson

Which isn't of much use - just shows turn on.

I shared all the info I had, and you are hiding and encripting what you claim to know.

I never claim anything I'm not sure of. And you're a horse's ass >:-} ...Jim Thompson

Well, helping you sure turns out to be a stupid thing to do.

We aren't the ones doing the bragging at the moment, though, and an encrypted model wouldn't prove anything, any more than the silly screen shots do.

If your IP is that valuable, why take it to your grave?

And if money is your real reason for not posting the model, you have your business plan all wrong. I published a major fraction of everything I know about technology in a book that has been the foundation of my consulting business.

If you were to write the H&H of modelling, you wouldn't have to be looking for work, believe me. Folks would be better able to do the routine jobs in house, but they'd send you the interesting ones.

Cheers

Phil Hobbs

I agree. And anyway, Jim makes his $$ and most enjoys designing ICs. Nobody will be able to match his skills at that, simply because he might teach people how to model better. And as you say, giving away secrets increases business. Jim is getting along in years, and he should start creating a serious legacy.

Running the encrypted model in LTspice and seeing the results wouldn't prove anything ?? ...Jim Thompson

No, it wouldn't. Let me refresh your memory of what I actually wrote in the "is there something wrong with PMOS" thread (with snippage restored):

Which you eventually agreed with, and apparently have built such a model for the simple step-excitation case.

I can't use it for anything because I don't use glass-package 1N914s any more except in crufty breadboards, and can't adjust it to fit other diodes.

And since it doesn't model actual diffusion behaviour, I have no reason to suppose that it would work in more complicated and realistic situations such as tone bursts in wideband noise.

If it were human-readable, I'd certainly read it, and might learn something.

But it isn't, which makes it entirely uninteresting.

You see here that what I'm disagreeing with is your blanket statement, "Pretty much as long as you can write an equation for it Spice can solve it." Which is provably false, as I said (and then proved).

Hacking together a subcircuit model that produces a similar curve is not solving the actual 1-D transport equation.

Cheers

Phil Hobbs

Sorry. It's behavior is that of diffusion. ...Jim Thompson

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Thinking outside the box... producing elegant solutions.

I just love following these pissing contests