transformer coupled logic isolator...

On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman
<bill.sloman@ieee.org> wrote:

On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time
and effort.

Getting the real thing to act like the model is probably
delusional.

RL
 
On 30/12/2021 15:22, Phil Hobbs wrote:
legg wrote:
On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jlarkin@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sylvia.

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

RL


Or very fast edges are needed, as in the examples JL and I posted in the
\"CML-CML level shifter\" thread.  Logic isolators don\'t go much faster
than 40 ns AFAICT.

Cheers

Phil Hobbs

NVE GMR isolators do rather better, eg...

https://uk.farnell.com/nve/il712-1e/isolators-digital-standard-msop/dp/2125082

....but their WebSite is down ATM.

--
Cheers
Clive
 
On Fri, 31 Dec 2021 16:52:25 +0000, Clive Arthur
<clive@nowaytoday.co.uk> wrote:

On 30/12/2021 15:22, Phil Hobbs wrote:
legg wrote:
On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jlarkin@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sylvia.

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

RL


Or very fast edges are needed, as in the examples JL and I posted in the
\"CML-CML level shifter\" thread.  Logic isolators don\'t go much faster
than 40 ns AFAICT.

Cheers

Phil Hobbs


NVE GMR isolators do rather better, eg...

https://uk.farnell.com/nve/il712-1e/isolators-digital-standard-msop/dp/2125082

...but their WebSite is down ATM.

Interesting. Quiescent power is low and dynamic power is high. They
must be making a high current driver coil shot on every data edge.

18 ns max at 3.3 volts. It\'s expensive!



--

I yam what I yam - Popeye
 
On Fri, 31 Dec 2021 11:38:25 -0500, legg <legg@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman
bill.sloman@ieee.org> wrote:

On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time
and effort.

Getting the real thing to act like the model is probably
delusional.

RL

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.



--

I yam what I yam - Popeye
 
Clive Arthur wrote:
On 30/12/2021 15:22, Phil Hobbs wrote:
legg wrote:
On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jlarkin@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sylvia.

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

RL


Or very fast edges are needed, as in the examples JL and I posted in
the \"CML-CML level shifter\" thread.  Logic isolators don\'t go much
faster than 40 ns AFAICT.

Cheers

Phil Hobbs


NVE GMR isolators do rather better, eg...

https://uk.farnell.com/nve/il712-1e/isolators-digital-standard-msop/dp/2125082


...but their WebSite is down ATM.

Interesting, thanks. 10 ns prop delay eats my whole (aspirational)
recovery time budget, but it\'s much better than 40 ns.

Cheers

Phil Hobbs

--
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 Fri, 31 Dec 2021 09:23:48 -0800, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 31 Dec 2021 11:38:25 -0500, legg <legg@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman
bill.sloman@ieee.org> wrote:

On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time
and effort.

Getting the real thing to act like the model is probably
delusional.

RL

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

RL
 
On Saturday, January 1, 2022 at 4:24:04 AM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman
bill....@ieee.org> wrote:

On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time
and effort.

Getting the real thing to act like the model is probably
delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and too risky.

Anybody else would being intentionally satirical, but since John Larkin doesn\'t design electronics but rather evolves his circuits by making lots of small changes and seeing what effect they have, which may be tedious but doesn\'t seem to be difficult or all that expensive (if you can do it by hacking existing board) he may be posting with a straight face.

For the record, designing novel circuits is hard and risky, but it can pay off.

--
Bil Sloman, Sydney
 
On Fri, 31 Dec 2021 20:21:16 -0500, legg <legg@nospam.magma.ca> wrote:

On Fri, 31 Dec 2021 09:23:48 -0800, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 31 Dec 2021 11:38:25 -0500, legg <legg@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman
bill.sloman@ieee.org> wrote:

On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time
and effort.

Getting the real thing to act like the model is probably
delusional.

RL

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

RL

Do you mean Sloman? He\'s the group leader on never actually doing
anything. So naturally he finds reasons why nothing will work.



--

I yam what I yam - Popeye
 
On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

> He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

> So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

--
Bill Sloman, Sydney
 
On 12/31/21 1:32 PM, John Larkin wrote:
This would work too:

https://www.dropbox.com/s/vmuusyllo9fo2qe/XFMR_Isolator_RSFF.jpg?raw=1

Lots of pulse transformers have center taps, I tried to think of
something that utilized a CT in some way maybe driving from the not-Q
output but nothing that seemed a particular improvement on the original
circuit came to mind.
 
On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
<bill.sloman@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.
An integrated magnetic component has been used in some places,
though the isolation tended to be compromised.

Semiconductor \'pulse stretchers\' go back to the mid 70\'s. Physical
iteration may still be the fastest way to implimentation for a
practical app, though a pencil and paper can cut this work down.
The simulation just eats man-hours.

RL
 
On Sat, 01 Jan 2022 13:45:00 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
bill.sloman@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.
An integrated magnetic component has been used in some places,
though the isolation tended to be compromised.

Semiconductor \'pulse stretchers\' go back to the mid 70\'s. Physical
iteration may still be the fastest way to implimentation for a
practical app, though a pencil and paper can cut this work down.
The simulation just eats man-hours.

RL

Spice is great. It lets a person play with ideas quickly, explore
hunches, get quantitative with the things that look promising.
Sometimes I design a circuit and understand it later, if ever.

https://www.youtube.com/watch?v=x6TrbD7-IwU

\"Intuition is the most important part of engineering.\"

\"The function of a simulator is to train your instincts.\"



--

I yam what I yam - Popeye
 
On Sunday, January 2, 2022 at 7:45:52 AM UTC+11, jla...@highlandsniptechnology.com wrote:
On Sat, 01 Jan 2022 13:45:00 -0500, legg <le...@nospam.magma.ca> wrote:

On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
bill....@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.

When I cam up with my version of the circuit in 1979 this did strike me as the useful feature. I wasn\'t tempted to try and get it patented.

> >An integrated magnetic component has been used in some places, though the isolation tended to be compromised.

Integrating anything means realising it within very limited dimensions, and high voltage isolation needs big gaps.

> >Semiconductor \'pulse stretchers\' go back to the mid 70\'s.

Valve-based equivalents go back quite a bit further. WW2 Radar used them.

Physical iteration may still be the fastest way to implimentation for a practical app, though a pencil and paper can cut this work down.
The simulation just eats man-hours.

A lot less than building the hardware. It\'s good for getting rid of ideas that can\'t work, but it isn\'t a reliable way of working out whether real hardware will work.

Spice is great. It lets a person play with ideas quickly, explore
hunches, get quantitative with the things that look promising.

But only to the extent to which the simulation is realisitic. An inductor winding without any parallel capacitance isn\'t. For a single layer winding 1pF of parallel capacitance is sort of realistic. Multilayer winding need more.

> Sometimes I design a circuit and understand it later, if ever.

Obviously true.

https://www.youtube.com/watch?v=x6TrbD7-IwU

\"Intuition is the most important part of engineering.\"

Engineering means getting stuff to work that can keep on working reliably. Intuition may be useful in getting to a circuit that might work, but there\'s no way that it can the most important factor in the whole process.

> \"The function of a simulator is to train your instincts.\"

And to do that it has to be more or less realistic. Transformer windings without parallel capacitance aren\'t.

--
Bill Sloman, Sydney
 
02.01.22 02:38, Anthony William Sloman wrote:
On Sunday, January 2, 2022 at 7:45:52 AM UTC+11, jla...@highlandsniptechnology.com wrote:
On Sat, 01 Jan 2022 13:45:00 -0500, legg <le...@nospam.magma.ca> wrote:

On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
bill....@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.

When I cam up with my version of the circuit in 1979 this did strike me as the useful feature. I wasn\'t tempted to try and get it patented.

An integrated magnetic component has been used in some places, though the isolation tended to be compromised.

Integrating anything means realising it within very limited dimensions, and high voltage isolation needs big gaps.

Not really. Just needs to be solid. 0.4mm FR4 is approved reinforced. So spiral coils on either side of the PCB could work. In practical size, leakage inductance is high


--
Klaus
 
jlarkin@highlandsniptechnology.com wrote:
On Sat, 01 Jan 2022 13:45:00 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
bill.sloman@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.
An integrated magnetic component has been used in some places,
though the isolation tended to be compromised.

Semiconductor \'pulse stretchers\' go back to the mid 70\'s. Physical
iteration may still be the fastest way to implimentation for a
practical app, though a pencil and paper can cut this work down.
The simulation just eats man-hours.

RL

Spice is great. It lets a person play with ideas quickly, explore
hunches, get quantitative with the things that look promising.
Sometimes I design a circuit and understand it later, if ever.

https://www.youtube.com/watch?v=x6TrbD7-IwU

\"Intuition is the most important part of engineering.\"

It\'s a _sine qua non_ of building new circuit forms, for sure. For
doing bridge abutments and oil wells, not so much. ;)

\"The function of a simulator is to train your instincts.\"

At board level, I mostly agree. Due to crappy models, board-level
simulations generally bear only an impressionistic resemblance to actual
circuit performance, so intuition is about all it\'s good for, apart from
catching gross blunders such as biasing errors or running out of GBW.

Foundry models are usually much better, because otherwise they wouldn\'t
turn out many functioning chips.

Interestingly I\'m currently dealing with an exception: the Xfab 180 nm
process with APDs and SPADs and such. One gathers that they haven\'t
actually fabbed many APD-based chips lately. (This is the first time
I\'ve actually collaborated closely on an IC design, apart from my
silicon photonics work.)

Cheers

Phil Hobbs

--
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 Sun, 02 Jan 2022 10:09:25 +0100, Klaus Kragelund
<klauskvik@hotmail.com> wrote:

02.01.22 02:38, Anthony William Sloman wrote:
On Sunday, January 2, 2022 at 7:45:52 AM UTC+11, jla...@highlandsniptechnology.com wrote:
On Sat, 01 Jan 2022 13:45:00 -0500, legg <le...@nospam.magma.ca> wrote:

On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
bill....@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.

When I cam up with my version of the circuit in 1979 this did strike me as the useful feature. I wasn\'t tempted to try and get it patented.

An integrated magnetic component has been used in some places, though the isolation tended to be compromised.

Integrating anything means realising it within very limited dimensions, and high voltage isolation needs big gaps.

Not really. Just needs to be solid. 0.4mm FR4 is approved reinforced. So spiral coils on either side of the PCB could work. In practical size, leakage inductance is high

There are down-firing surface-mount leds and photodiodes. One could
couple light through a board.

Or e-fields, an FR4 capacitor based signal or power coupler.



--

I yam what I yam - Popeye
 
On Sun, 2 Jan 2022 09:39:30 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

jlarkin@highlandsniptechnology.com wrote:
On Sat, 01 Jan 2022 13:45:00 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
bill.sloman@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.
An integrated magnetic component has been used in some places,
though the isolation tended to be compromised.

Semiconductor \'pulse stretchers\' go back to the mid 70\'s. Physical
iteration may still be the fastest way to implimentation for a
practical app, though a pencil and paper can cut this work down.
The simulation just eats man-hours.

RL

Spice is great. It lets a person play with ideas quickly, explore
hunches, get quantitative with the things that look promising.
Sometimes I design a circuit and understand it later, if ever.

https://www.youtube.com/watch?v=x6TrbD7-IwU

\"Intuition is the most important part of engineering.\"

It\'s a _sine qua non_ of building new circuit forms, for sure. For
doing bridge abutments and oil wells, not so much. ;)

It\'s good that our designs seldom kill people if they fail.

\"The function of a simulator is to train your instincts.\"

At board level, I mostly agree. Due to crappy models, board-level
simulations generally bear only an impressionistic resemblance to actual
circuit performance, so intuition is about all it\'s good for, apart from
catching gross blunders such as biasing errors or running out of GBW.

I disagree with Mike about the utility of Spice. We do go directly
from subcircuit sims to PCB layout of final products, and it usually
works. Why build a breadboard when you can build a sellable thing? We
only breadboard enough to understand new components that don\'t have
trustable models.


Foundry models are usually much better, because otherwise they wouldn\'t
turn out many functioning chips.

Interestingly I\'m currently dealing with an exception: the Xfab 180 nm
process with APDs and SPADs and such. One gathers that they haven\'t
actually fabbed many APD-based chips lately. (This is the first time
I\'ve actually collaborated closely on an IC design, apart from my
silicon photonics work.)

Mike is in the IC business, so his perspective on simulation is a
little differerent from people who solder parts to boards. But then,
Spice won\'t help much with semiconductor physics problems.

Can you make test chips? Maybe in the corners of a production wafer?



--

I yam what I yam - Popeye
 
02.01.22 16:29, jlarkin@highlandsniptechnology.com wrote:
On Sun, 02 Jan 2022 10:09:25 +0100, Klaus Kragelund
klauskvik@hotmail.com> wrote:

02.01.22 02:38, Anthony William Sloman wrote:
On Sunday, January 2, 2022 at 7:45:52 AM UTC+11, jla...@highlandsniptechnology.com wrote:
On Sat, 01 Jan 2022 13:45:00 -0500, legg <le...@nospam.magma.ca> wrote:

On Sat, 1 Jan 2022 04:01:57 -0800 (PST), Anthony William Sloman
bill....@ieee.org> wrote:

On Saturday, January 1, 2022 at 12:43:32 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 20:21:16 -0500, legg <le...@nospam.magma.ca> wrote:
On Fri, 31 Dec 2021 09:23:48 -0800, jla...@highlandsniptechnology.com wrote:
On Fri, 31 Dec 2021 11:38:25 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 30 Dec 2021 19:05:06 -0800 (PST), Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, December 31, 2021 at 5:21:07 AM UTC+11, John Larkin wrote:
On Thu, 30 Dec 2021 09:08:03 -0500, legg <le...@nospam.magma.ca> wrote:

On Thu, 30 Dec 2021 19:04:22 +1100, Sylvia Else <syl...@email.invalid
wrote:

On 30-Dec-21 4:11 pm, jla...@highlandsniptechnology.com wrote:
Version 4

snip

What is the use-case for this that a conventional digital isolator
wouldn\'t be suitable for?

Sometimes used in lower frequency isolated gate drive, when minimal
magnetics cost is the aim.

It\'s faster than most isolators, and is DC-coupled, after a power-up
priming shot.

Not a claim that\'s worth making for a purely theoretical transformer driving an LT Spice generic Schmitt trigger.

No parallel capacitance across either inductor, and no current induced in the transformer core - it\'s a little too theoretical too swank about.

It worked fine when I did it in 1979, but I wasn\'t around to see it go into production (if it did).

Getting the model to act like the real thing takes time and effort.

Getting the real thing to act like the model is probably delusional.

Right, it\'s best to avoid designing any electronics. It\'s too hard and
too risky.

Hey! The model works! What\'s HIS problem . . . ?

Do you mean Sloman?

Legg was responding to one of your posts, not mine.

He\'s the group leader on never actually doing anything.

I\'d got what you posted working with real parts back in 1979 - I\'d already done it, so why would I need to do it again?

So naturally he finds reasons why nothing will work.

I didn\'t say it wouldn\'t work - I just pointed out that the transformer model wasn\'t all that realistic, and neither was the Schmitt trigger.

You could have done quite a bit better, and telling us what you had in mind to use for your transformer would have been a good start.

Simulationss are useful in that they suggest what should or
could work.

If you limit it to a specific application, you can introduce
realistic strays and likely operating conditions with increasingly
more accurate models.

The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.

When I cam up with my version of the circuit in 1979 this did strike me as the useful feature. I wasn\'t tempted to try and get it patented.

An integrated magnetic component has been used in some places, though the isolation tended to be compromised.

Integrating anything means realising it within very limited dimensions, and high voltage isolation needs big gaps.

Not really. Just needs to be solid. 0.4mm FR4 is approved reinforced. So spiral coils on either side of the PCB could work. In practical size, leakage inductance is high

There are down-firing surface-mount leds and photodiodes. One could
couple light through a board.

Or e-fields, an FR4 capacitor based signal or power coupler.



I have done both the AM modulated transformer and the E field. Both tend to emit a lot of radiated noise, so you need to keep it to only transitions transmission

Also, they can be subceptible to EMC burst

LED method is clean, but slow


--
Klaus
 
On Sun, 02 Jan 2022 10:09:25 +0100, Klaus Kragelund
<klauskvik@hotmail.com> wrote:

<snip>
The \'party trick\' aspect of this circuit was the miniscule magnetic
component that was possible - though reduction in actual cost shows
diminishing and even reversing returns as you get carried away.

When I cam up with my version of the circuit in 1979 this did strike me as the useful feature. I wasn\'t tempted to try and get it patented.

An integrated magnetic component has been used in some places, though the isolation tended to be compromised.

Integrating anything means realising it within very limited dimensions, and high voltage isolation needs big gaps.

Not really. Just needs to be solid. 0.4mm FR4 is approved reinforced. So spiral coils on either side of the PCB could work. In practical size, leakage inductance is high

These guys were electrodepositing core material.

RL
 
On Sat, 1 Jan 2022 17:38:31 -0800 (PST), Anthony William Sloman
<bill.sloman@ieee.org> wrote:

<snip>
Physical iteration may still be the fastest way to implimentation for a practical app, though a pencil and paper can cut this work down.
The simulation just eats man-hours.

A lot less than building the hardware. It\'s good for getting rid of ideas that can\'t work, but it isn\'t a reliable way of working out whether real hardware will work.

Spice is great. It lets a person play with ideas quickly, explore
hunches, get quantitative with the things that look promising.

But only to the extent to which the simulation is realisitic. An inductor winding without any parallel capacitance isn\'t. For a single layer winding 1pF of parallel capacitance is sort of realistic. Multilayer winding need more.

Unless it\'s a saturating core model, miniaturization and
minimalization efforts will be misleading.

As L values reduce, inductive strays also become important,
as do recovery times in the semiconductors of the transmitting
and receiving structures, when impressed with below-ground
or above rail transients or reflected emf.

The physical dimensions of beads and insulated wire create
clusters of performance features that have sometimes been
spelled out quite effectively, in millimeters, in patents.

I expect it\'s much the same for the integrated case, given
the limited types of core matl and dimensional constraints
present.

Even more so, if there\'s no core material.

RL
 

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