Fun And Games With Spice
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#77
Whooo ...
Ta chaps
Well dunno what you chaps think but to me looks pretty close to the datasheet ~
Ta chaps
Well dunno what you chaps think but to me looks pretty close to the datasheet ~
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#81
What about them?
Think I saw some recently, made no sense whatsoever
Anyway ...
Currently making an ECC81 copy.
It seems to work like this:
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...
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
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...
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#82
Want a play?
.
.
- Attachments
-
- New Triodes.zip
- (4.33 KiB) Downloaded 433 times
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
#83
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#87
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.
.
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.
.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#88
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)
.
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)
.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#89
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:
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 (7.79 KiB) Viewed 4452 times
Last edited by Mike H on Tue Apr 27, 2010 2:32 pm, edited 1 time in total.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
#90
Would a current source with a parallel resistance not be close enough for most purposes?
There are pspice models of the 900v item.
There are pspice models of the 900v item.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.