On Tuesday, January 4, 2022 at 6:53:42 PM UTC+11, Klaus Kragelund wrote:
> On 04/01/2022 03.06, Anthony William Sloman wrote:
> > On Tuesday, January 4, 2022 at 7:22:13 AM UTC+11, Klaus Kragelund wrote:
> >> On 02/01/2022 13.05, Anthony William Sloman wrote:
> >>> On Sunday, January 2, 2022 at 8:09:33 PM UTC+11, Klaus Kragelund 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
> >>>
> >>> Integration is usually taken to be putting stuff together on a silicon substrate (or GaAs or some other kind of semi-conductor). Anything that gets soldered onto FR4 creates an assembled device, not an integrated part.
> >>>
> >> That's your definition. If I integrate a coil into a PCB with no added
> >> components, I would call that.... integrated ;-)
> >>> Alumina would probably be a better high voltage substrate than FR4-epoxy bonded fibre-glass, but arcs have a nasty way of tracking across insulators.
> >>
> >> Not practical for a PCB. Mixing alumina and FR4 makes it very expensive.
> >
> > You used to be able to get thick film hybrids made on alumina. They might have been described as the rich man's printed circuit, through the conductors were silk-screened onto the alumina, along with the resistors and the solder paste. I've no idea whether anybody still does this, but FR4-expoxy-glass substrates are just one of many available substrates.
> >
> You can get cheap alumina PCBs, but then it's single layer traces, and that can only be used for very simple designs.
"Cheap" does exclude some schemes for doing better. Putting a via through an alumina substrate isn't cheap, but it can be done.
--
Bill Sloman, Sydney