GRRRR part 2

I'm waiting for a sim to run, so may as well whine. It's running at 12
PPM of real time.

LT Spice lets you put the value of a part anywhere on the screen. I
just spent an embarassing amount of time figuring out why my current
limiter didn't work. It's a switching half-bridge with an output
current sensor, and a pair of P+I opamps that sense positive and
negative over-current and clamp the input demand signal appropriately.

(The current limit will be in an FPGA, but I like to do an analog sim
to get the dynamics close.)

I have a couple of BVs as isolators between the PWM generator and the
floating (+ and - 48 volt supplies) LTC4444 mosfet gate driver. The
equations of the BVs were swapped, so my power stage gain was
reversed. Negative feedback wasn't.

Some cad software limits how far a ref designator or a value can be
from the part. Or highlights one if you click on the other.

More fun: if you copy and paste a chunk of circuit, the copy has all
the same node names. So everything is shorted to everything until you
find and change the nodes that matter.

I'll need to get a new PC soon. People say that a screaming CPU and
lots of ram and solid-state C drive would really speed things up.

Hey, it finished. It made a 5.4 Gbyte RAW file.





-- 

If a man will begin with certainties, he shall end with doubts, 
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

On a sunny day (Wed, 01 Jun 2022 15:38:20 -0700) it happened John Larkin
<jlarkin@highland_atwork_technology.com> wrote in
<m2pf9hp44ssn7vu45eftf46jncjo4ppbp5@4ax.com>:

>I'm waiting for a sim to run, so may as well whine. It's running at 12
>PPM of real time.
>
>LT Spice lets you put the value of a part anywhere on the screen. I
>just spent an embarassing amount of time figuring out why my current
>limiter didn't work. It's a switching half-bridge with an output
>current sensor, and a pair of P+I opamps that sense positive and
>negative over-current and clamp the input demand signal appropriately.
>
>(The current limit will be in an FPGA, but I like to do an analog sim
>to get the dynamics close.)
>
>I have a couple of BVs as isolators between the PWM generator and the
>floating (+ and - 48 volt supplies) LTC4444 mosfet gate driver. The
>equations of the BVs were swapped, so my power stage gain was
>reversed. Negative feedback wasn't.
>
>Some cad software limits how far a ref designator or a value can be
>from the part. Or highlights one if you click on the other.
>
>More fun: if you copy and paste a chunk of circuit, the copy has all
>the same node names. So everything is shorted to everything until you
>find and change the nodes that matter.
>
>I'll need to get a new PC soon. People say that a screaming CPU and
>lots of ram and solid-state C drive would really speed things up.
>
>Hey, it finished. It made a 5.4 Gbyte RAW file.

There was a headline in scidaily.com today about if AI designed stuff should be patented and by whom, or something

I know I probably draw fire if I say that all that spice is a dead end road at least for many things.

Neural networks, done some programming with that, we are like that.. could be the future
in electronic design too.
But a NN (Neural Net) is trained by building and testing things.
Even if you spice on a supper computah there is NO guarantee the circuit will even work in reality.

I play with Raspberry Pis these days.. Even those are very much unobtainable due to chip or other shortages..
Would be nice to have LT spice running on ARM processors (maybe there is a port already?)
There must be a break even point between AI an Spice type simulations for electronic design?
Wonder how far that is away.
For the rest I leave the problem solving to my neural net, have not touched spice in years?
It is nice for filters that need a lot of repeated math scribbling, but there are other filter design programs.
Many things do not have a good spice model...

John Larkin wrote: 

> I'll need to get a new PC soon. People say that a screaming CPU and lots
> of ram and solid-state C drive would really speed things up. 

I have had NVMe drives for ages. Get good ones, like from Samsung. Spend
more than you used to spend on hard drives, it's well worth it. Primary
(and secondary) storage is not whizbang fun, but as IBM used to put it, it
affects "throughput" more than anything else. NVMe is what I have always
wanted. 

If you use a secondary drive, the transfer rate between two premium NVMe
drives is OUTRAGEOUS. Transferring movies from your downloads folder to
the secondary drive is quick. Making backups of Windows is also quick. 

On Thu, 02 Jun 2022 06:05:25 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

>On a sunny day (Wed, 01 Jun 2022 15:38:20 -0700) it happened John Larkin
><jlarkin@highland_atwork_technology.com> wrote in
><m2pf9hp44ssn7vu45eftf46jncjo4ppbp5@4ax.com>:
>
>>I'm waiting for a sim to run, so may as well whine. It's running at 12
>>PPM of real time.
>>
>>LT Spice lets you put the value of a part anywhere on the screen. I
>>just spent an embarassing amount of time figuring out why my current
>>limiter didn't work. It's a switching half-bridge with an output
>>current sensor, and a pair of P+I opamps that sense positive and
>>negative over-current and clamp the input demand signal appropriately.
>>
>>(The current limit will be in an FPGA, but I like to do an analog sim
>>to get the dynamics close.)
>>
>>I have a couple of BVs as isolators between the PWM generator and the
>>floating (+ and - 48 volt supplies) LTC4444 mosfet gate driver. The
>>equations of the BVs were swapped, so my power stage gain was
>>reversed. Negative feedback wasn't.
>>
>>Some cad software limits how far a ref designator or a value can be
>>from the part. Or highlights one if you click on the other.
>>
>>More fun: if you copy and paste a chunk of circuit, the copy has all
>>the same node names. So everything is shorted to everything until you
>>find and change the nodes that matter.
>>
>>I'll need to get a new PC soon. People say that a screaming CPU and
>>lots of ram and solid-state C drive would really speed things up.
>>
>>Hey, it finished. It made a 5.4 Gbyte RAW file.
>
>There was a headline in scidaily.com today about if AI designed stuff should be patented and by whom, or something
>
>I know I probably draw fire if I say that all that spice is a dead end road at least for many things.

It's sure not dead for people who design real electronics. What I want
is for Spice to run on an Nvidia parallel compute engine, 200x or so
faster than on an Intel cpu.

>
>Neural networks, done some programming with that, we are like that.. could be the future
>in electronic design too.
>But a NN (Neural Net) is trained by building and testing things.

Are NNs anything but an academic toy?

>Even if you spice on a supper computah there is NO guarantee the circuit will even work in reality.

Sometimes things work exactly as Spiced. Good engineers can usually
expect when the sims aren't to be trusted.

>
>I play with Raspberry Pis these days.. Even those are very much unobtainable due to chip or other shortages..
>Would be nice to have LT spice running on ARM processors (maybe there is a port already?)
>There must be a break even point between AI an Spice type simulations for electronic design?
>Wonder how far that is away.

There have been attempts to use computers to actually design circuits,
or at least to optimize values in a given topology. They tended to be
ludicrous failures.

It's strange that our brains, evolved to be hunter-gatherers, can
design electronics. 

>For the rest I leave the problem solving to my neural net, have not touched spice in years?
>It is nice for filters that need a lot of repeated math scribbling, but there are other filter design programs.
>Many things do not have a good spice model...

That's the main hazard, not having dependable part models. That's a
serious problem when using RF-type parts large-signal time domain.

We finally finished our big laser modulator chassis. The
amplifier/fiducial board got to rev C, and we avoided D by adding a
MiniCircuits SMA DC block in one of the cables. You can't sim this
fast stuff; just guess and etch.

https://www.dropbox.com/s/29ttap9urihhep1/T500_Top_Final.jpg?raw=1

We couldn't get LCD driver chips, but their eval boards are available,
so we used eval boards.



-- 

Anybody can count to one.

- Robert Widlar

On Thu, 2 Jun 2022 09:28:24 -0000 (UTC), John Doe
<always.look@message.header> wrote:

>John Larkin wrote: 
>
>> I'll need to get a new PC soon. People say that a screaming CPU and lots
>> of ram and solid-state C drive would really speed things up. 
>
>I have had NVMe drives for ages. Get good ones, like from Samsung. Spend
>more than you used to spend on hard drives, it's well worth it. Primary
>(and secondary) storage is not whizbang fun, but as IBM used to put it, it
>affects "throughput" more than anything else. NVMe is what I have always
>wanted. 
>
>If you use a secondary drive, the transfer rate between two premium NVMe
>drives is OUTRAGEOUS. Transferring movies from your downloads folder to
>the secondary drive is quick. Making backups of Windows is also quick. 

I guess one can plug an ssd into a PCIe slot. I need new PCs and it
would be cool to have a fast D: drive on them, mostly for Dropbox.



-- 

Anybody can count to one.

- Robert Widlar

jlarkin@highlandsniptechnology.com wrote:
> On Thu, 02 Jun 2022 06:05:25 GMT, Jan Panteltje 
> <pNaonStpealmtje@yahoo.com> wrote:
<snip>

>> 
>> Neural networks, done some programming with that, we are like
>> that.. could be the future in electronic design too. But a NN
>> (Neural Net) is trained by building and testing things.
> 
> Are NNs anything but an academic toy?

They're great for flagging possibilities for later evaluation.  IIRC
they're used in drug discovery for that reason.  For control systems,
not so much.

>> Even if you spice on a supper computah there is NO guarantee the
>> circuit will even work in reality.
> 
> Sometimes things work exactly as Spiced. Good engineers can usually 
> expect when the sims aren't to be trusted.
> 
>> 
>> I play with Raspberry Pis these days.. Even those are very much
>> unobtainable due to chip or other shortages.. Would be nice to have
>> LT spice running on ARM processors (maybe there is a port
>> already?) There must be a break even point between AI an Spice type
>> simulations for electronic design? Wonder how far that is away.
> 
> There have been attempts to use computers to actually design
> circuits, or at least to optimize values in a given topology. They
> tended to be ludicrous failures.
> 
> It's strange that our brains, evolved to be hunter-gatherers, can 
> design electronics.

It's not at all strange that our minds, being made in the image of the
Maker, can do that. ;)

> 
>> For the rest I leave the problem solving to my neural net, have not
>> touched spice in years? It is nice for filters that need a lot of
>> repeated math scribbling, but there are other filter design
>> programs. Many things do not have a good spice model...
> 
> That's the main hazard, not having dependable part models. That's a 
> serious problem when using RF-type parts large-signal time domain.
> 
> We finally finished our big laser modulator chassis. The 
> amplifier/fiducial board got to rev C, and we avoided D by adding a 
> MiniCircuits SMA DC block in one of the cables. You can't sim this 
> fast stuff; just guess and etch.
> 
> https://www.dropbox.com/s/29ttap9urihhep1/T500_Top_Final.jpg?raw=1
> 
> We couldn't get LCD driver chips, but their eval boards are
> available, so we used eval boards.

There's a lot of that going around.

Cheers

Phil Hobbs

(Who is in the middle of a board spin for our nanowatt photoreceiver, 
partly for that reason.)


-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

On 6/2/2022 9:36 AM, jlarkin@highlandsniptechnology.com wrote:
> On Thu, 2 Jun 2022 09:28:24 -0000 (UTC), John Doe
> <always.look@message.header> wrote:
> 
>> John Larkin wrote:
>>
>>> I'll need to get a new PC soon. People say that a screaming CPU and lots
>>> of ram and solid-state C drive would really speed things up.
>>
>> I have had NVMe drives for ages. Get good ones, like from Samsung. Spend
>> more than you used to spend on hard drives, it's well worth it. Primary
>> (and secondary) storage is not whizbang fun, but as IBM used to put it, it
>> affects "throughput" more than anything else. NVMe is what I have always
>> wanted.
>>
>> If you use a secondary drive, the transfer rate between two premium NVMe
>> drives is OUTRAGEOUS. Transferring movies from your downloads folder to
>> the secondary drive is quick. Making backups of Windows is also quick.
> 
> I guess one can plug an ssd into a PCIe slot. I need new PCs and it
> would be cool to have a fast D: drive on them, mostly for Dropbox.
> 

Cross-probing large .raw files even stored on an SSD is still slow cuz 
they use a compressed format, to make it snappy you have to first 
convert the data file:

<https://ltwiki.org/LTspiceHelp/LTspiceHelp/Fast_Access_File_Format.htm>

which is also slow. Or with your new machine you can buy a bunch of RAM 
say 32 or 64 gig and make half of it a RAM drive dedicated to sim data 
which also speeds up probing considerably.

64 gig of DDR5 is about $500 and $250 for 64 gig of DDR4 on Amazon these 
days.

On Thursday, June 2, 2022 at 11:36:51 PM UTC+10, jla...@highlandsniptechnology.com wrote:
> On Thu, 2 Jun 2022 09:28:24 -0000 (UTC), John Doe 
> <alway...@message.header> wrote:  
> >John Larkin wrote: 

<snip>

> I guess one can plug an ssd into a PCIe slot.

Worked for me. Didn't make spice run any faster, but it did make mousing round in the stored waveforms much faster.

> I need new PCs and it  would be cool to have a fast D: drive on them, mostly for Dropbox.

-- 
Bill Sloman, Sydney

On a sunny day (Thu, 02 Jun 2022 06:33:32 -0700) it happened
jlarkin@highlandsniptechnology.com wrote in
<5pdh9htc6l399o9esj9ua3t9p145kd0vmo@4ax.com>:

>On Thu, 02 Jun 2022 06:05:25 GMT, Jan Panteltje
><pNaonStpealmtje@yahoo.com> wrote:

>>I know I probably draw fire if I say that all that spice is a dead end road at least for many things.
>
>It's sure not dead for people who design real electronics. What I want
>is for Spice to run on an Nvidia parallel compute engine, 200x or so
>faster than on an Intel cpu.
>
>>
>>Neural networks, done some programming with that, we are like that.. could be the future
>>in electronic design too.
>>But a NN (Neural Net) is trained by building and testing things.
>
>Are NNs anything but an academic toy?

Many new medicines have been designed by AI now,
it is worth keeping up to date on science by reading sciencedaily.com
But also technical things, like airplane wings, what not.
How did I learn? From looking at circuits, building and trying those.
Big advantage for me is that I had to do fast fault finding in very complex systems
and also simpler ones, so have seen thousands of designs, and HAD to grasp how those worked
to be able to fix those.
So you get an idea of the latest state of the art and what works and what not (when it fails)
This is exactly how AI is trained, say for object recognition for military - or diagnostics for medical applications.


>>Even if you spice on a supper computah there is NO guarantee the circuit will even work in reality.
>
>Sometimes things work exactly as Spiced. Good engineers can usually
>expect when the sims aren't to be trusted.
>
>>
>>I play with Raspberry Pis these days.. Even those are very much unobtainable due to chip or other shortages..
>>Would be nice to have LT spice running on ARM processors (maybe there is a port already?)
>>There must be a break even point between AI an Spice type simulations for electronic design?
>>Wonder how far that is away.
>
>There have been attempts to use computers to actually design circuits,
>or at least to optimize values in a given topology. They tended to be
>ludicrous failures.
>
>It's strange that our brains, evolved to be hunter-gatherers, can
>design electronics. 
>
>>For the rest I leave the problem solving to my neural net, have not touched spice in years?
>>It is nice for filters that need a lot of repeated math scribbling, but there are other filter design programs.
>>Many things do not have a good spice model...
>
>That's the main hazard, not having dependable part models. That's a
>serious problem when using RF-type parts large-signal time domain.
>
>We finally finished our big laser modulator chassis. The
>amplifier/fiducial board got to rev C, and we avoided D by adding a
>MiniCircuits SMA DC block in one of the cables. You can't sim this
>fast stuff; just guess and etch.
>
>https://www.dropbox.com/s/29ttap9urihhep1/T500_Top_Final.jpg?raw=1

Looks neat, what's in that metal box on the right?


>We couldn't get LCD driver chips, but their eval boards are available,
>so we used eval boards.

Yes, I have some eval boards, also lots of small boards from China for cheap.
About triacs.. ever used an ACS108S? Third time one blew up in my Whirlpool washing machine
Does not like spikes on the mains it seems, ordered 10 for 4 $ from ebay..
Very strange if you look at the datasheet it wants a negative drive, so takes plus as ground sort of thing

bitrex <user@example.net> wrote: 

> jlarkin@highlandsniptechnology.com wrote: 
>> John Doe wrote: 
>>> John Larkin wrote: 
>>>
>>>> I'll need to get a new PC soon. People say that a screaming CPU and
>>>> lots of ram and solid-state C drive would really speed things up. 
>>>
>>> I have had NVMe drives for ages. Get good ones, like from Samsung.
>>> Spend more than you used to spend on hard drives, it's well worth it.
>>> Primary (and secondary) storage is not whizbang fun, but as IBM used
>>> to put it, it affects "throughput" more than anything else. NVMe is
>>> what I have always wanted. 
>>>
>>> If you use a secondary drive, the transfer rate between two premium
>>> NVMe drives is OUTRAGEOUS. Transferring movies from your downloads
>>> folder to the secondary drive is quick. Making backups of Windows is
>>> also quick. 
>> 
>> I guess one can plug an ssd into a PCIe slot. I need new PCs and it 
>> would be cool to have a fast D: drive on them, mostly for Dropbox. 

The terminology "NVMe" is critical, and some are better than others.

At one point, before buying a motherboard with 2 NVMe slots, I used a PCIe 
card, like that, for the additional NVMe drive.

As long as you have one NVMe drive on the motherboard and a second NVMe on 
that PCIe card, file transfers are about as (blazing) fast as a motherboard 
with 2 NVMe slots, but only when you are in Windows. For something like 
restoring backups of Windows that might happen outside of Windows, that card 
doesn't provide the same benefit as 2 slots on the motherboard. Probably to 
do with drivers loaded when Windows boots.

I just copied a 2.7 GB file from one Samsung NVMe drive to the other. It took 
less than two seconds. This is my PC's storage configuration. My NVMe drives 
are not state-of-the-art, but they were a HUGE leap, even a big leap over 
"SSD"...

https://www.flickr.com/photos/27532210@N04/?

There is an old picture of file transfer there too, but it's a little
faster than that now. 

> Cross-probing large .raw files even stored on an SSD is still slow cuz 
> they use a compressed format, to make it snappy you have to first 
> convert the data file: 
> 
> <https://ltwiki.org/LTspiceHelp/LTspiceHelp/Fast_Access_File_Format.htm> 
> 
> which is also slow. Or with your new machine you can buy a bunch of RAM 
> say 32 or 64 gig and make half of it a RAM drive dedicated to sim data 
> which also speeds up probing considerably. 
> 
> 64 gig of DDR5 is about $500 and $250 for 64 gig of DDR4 on Amazon these
> days. 

Difficult to believe how out of touch with reality that opinion appears to 
be, on something this plainly technical. Or maybe I'm missing something in 
the translation.

"Cross-probing"?
Something to do with PCB design?
:D