Fun And Games With Spice

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Mike H
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#76

Post by Mike H »

O right, thanks, I figured a different way but try that...


Back in a min...


.
 
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Mike H
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#77

Post by Mike H »

Whooo ... Image

Ta chaps

Well dunno what you chaps think but to me looks pretty close to the datasheet ~
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Datasheet PDF:
Datasheet PDF:
new-triode-ECC82-graph.gif
 
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#78

Post by Andrew »

Well done that man....what next?
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Mike H
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#79

Post by Mike H »

What indeed...
 
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Nick
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#80

Post by Nick »

Mike H wrote:What indeed...
How about push pull composite curves?
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Mike H
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#81

Post by Mike H »

What about them? :D

Think I saw some recently, made no sense whatsoever

Anyway ...

Currently making an ECC81 copy.

It seems to work like this:

Code: Select all

.subckt ECC81_12AT7 A G K
XV1 A G K TRIODE
+PARAMS: MU=65 EX=1.3 KG1=460 KG2=0 KP=260 KVB=300 CCG=2.3P CPG=1.6P CCP=0.2P RGI=2k
.ends
1. get some existing triode model that's close.
2. get the datasheet graph.
3. Set up the .dc sim so's it makes graph with exactly same ref points / lines as the datasheet.

'KG1' seems to mostly affect the left-most side of the bias lines.

'KP' seems to mostly affect the right-most lines.

Basically keep fiddling with KG1 & KP until the 0 bias line crosses same points as datasheet, and extreme right bias line ditto.

As a hint KP also sets the points where anode current cuts off to 0mA at some Voltage for each bias line, so it seems like getting that in the ball park first might be a good start. Probs still needs modifying later though.

The 'bible' is of course the datasheet graph. Just try to get it to look like that. Keep flicking between LTspice and Adobe acrobat. lib file in notepad, edit, save, re-run ad nauseum...
 
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Mike H
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#82

Post by Mike H »

Want a play?

.
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New Triodes.zip
(4.33 KiB) Downloaded 432 times
 
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#83

Post by Nick »

Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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Mike H
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#84

Post by Mike H »

There's a cryptic message :D

Ta Nick

Is there a tetrodes one as well?

.
 
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Nick
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#85

Post by Nick »

No, I don't think so.
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#86

Post by Andrew »

That looks handy.

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Mike H
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#87

Post by Mike H »

Did you know ..?


Hold down Ctrl + Alt + Shift + R will renumber all the components in the schematic consecutively.

I.e. if you've deleted some so there are gaps, like R7 is now missing, all will be renumbered from 1.

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Mike H
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#88

Post by Mike H »

Did you know ..?


LTspice can export net lists for PCB design software.

I.e. you can use it as your schematic editor as well.

Including ExpressPCB and FreePCB (PADS2000)

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Mike H
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#89

Post by Mike H »

Still trying to simulate the IXCP10M45S, did get a JugFET to do it except the current goes way off if the Voltage is changed substantially. Which, given that the range is 10V to 450V, can a lot. Plus can't make it develop the max. current of 100mA unless the Voltage is very large, but then the botom end is all over the shop as well.

Then tried a G variable current source by feeding it a table of the correct different values relative to gate Voltage, this works but can't figure how to make the current variable with Vds, which is has to be as a CCS is never actually absolutely constant. So the exact opposite problem to the jugFET experiment.

However the IXCP10M45 data sheet (this is the fixed 10mA non-adjustable version) show a very interesting block diagram supposedly of its internals:
Attachments
ixcp10m45.gif
ixcp10m45.gif (7.79 KiB) Viewed 4392 times
Last edited by Mike H on Tue Apr 27, 2010 2:32 pm, edited 1 time in total.
 
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Nick
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#90

Post by Nick »

Would a current source with a parallel resistance not be close enough for most purposes?

There are pspice models of the 900v item.
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