Krill - The Next Generation

[Steve Dunlap]

Hi Andy,

Perhaps I posted the wrong file. I exported it both ways. One of the files is exactly as you describe. The other opens correctly for me. The file is too large to post here. May I send it to you in an E-mail?

I'm off for the night now. I will follow up tomorrow.

[andy_c]

Originally Posted by Steve Dunlap

Hi Andy,

Perhaps I posted the wrong file. I exported it both ways. One of the files is exactly as you describe. The other opens correctly for me. The file is too large to post here. May I send it to you in an E-mail?

I'm off for the night now. I will follow up tomorrow.

Okay, it may be my error. I'll look back through the thread again.

[GK]

Originally Posted by andy_c

If you look at the Vbe of just the output device by itself though, it ends up being forward-biased when one might expect reverse bias. But its base when in that state is essentially open-circuited (except for strays), since the Vbe of its corresponding driver has a hard reverse bias. So the output device is kind of hanging in the breeze there. Its Vbe is forward biased, but only due to stored charge.

Yes, I know - the output devices turn off slowly. I'm just sticking to the point I made back in post #8

[andy_c]

Sounds like we're on the same page then . I'm hoping that, with the models from Steve's sim, I can replicate his results. Intusoft has a weird way of modeling power output devices. They are subcircuits with two individual devices, plus a resistor. One of them has an external base spreading resistor, the other not. I'll have to look in their manuals to see why they do that. Maybe they don't support XCJC and this is how they work around that?

.SUBCKT QSC3281 1 2 3
* TERMINALS: C B E
* 200 Volt 15 Amp SiNPN Power Transistor 12-03-1991
Q1 1 2 3 QPWR .67
Q2 1 4 3 QPWR .33
RBS 2 4 9.5
.MODEL QPWR NPN (IS=1.63P NF=1 BF=150 VAF=254 IKF=12 ISE=1.34N NE=2
+ BR=4 NR=1 VAR=20 IKR=16.5 RE=22.1M RB=4 RBM=.4 IRB=5.556U RC=4.84M
+ CJE=481P VJE=.6 MJE=.3 CJC=312P VJC=.22 MJC=.2 TF=5.33N TR=204N)
+ XTB=1.5 PTF=120 XTF=1 ITF=9.6)
.ENDS

[GK]

Probably a silly question, but is there a parameter in a BJT's spice model for leakage current?

[andy_c]

Not directly. That's a really good thing to look at in the models though. It could explain the differences we're seeing.

Edit: The more I think about this, the more I think that could be the explanation. There's some reverse parameters, that can't be obtained from the data sheets, that may hold the key.

[stinius]

andy_c and GK
It’s not possible to send you PM’s

[andy_c]

Stinius,

Email is fine - preferred actually.

[scott wurcer]

Originally Posted by AKSA

Steve:

'Progress can only depend on the unreasonable man' - GB Shaw, 1904

Fashions and trends abound in science and technology, just like the fashion industry. The conventionalists control proceedings with high priesthoods and ridicule. Galileo and Copernicus come to mind. But it's hard to forget that Nikola Tesla was regarded as an eccentric fringe dweller, yet he gave us many high voltage techniques, the AC power grid, the AC induction motor, and many other inventions.

When I was a kid I thought that Meadowlark Lemon and the Harlem Globe Trotters could beat any NBA team hands down. We all have our own view on reality.

Nicola Tesla WAS eccentric and on some fronts totally wacked.

[juma]

Originally Posted by scott wurcer

....
Nicola Tesla WAS eccentric and on some fronts totally wacked.

It might be true (depending on state of development of local cultural standards), but it's for sure completely irrelevant in full awareness of his incomparable contribution to well-being of the mankind. AC (not to mention his other achievements) is still fundamental to modern civilization.