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
transformer coupled logic isolator
Started by ●December 30, 2021
Reply by ●January 1, 20222022-01-01
Reply by ●January 1, 20222022-01-01
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. > >RLSpice 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
Reply by ●January 1, 20222022-01-01
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
Reply by ●January 2, 20222022-01-02
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
Reply by ●January 2, 20222022-01-02
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
Reply by ●January 2, 20222022-01-02
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 highThere 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
Reply by ●January 2, 20222022-01-02
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
Reply by ●January 2, 20222022-01-02
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
Reply by ●January 2, 20222022-01-02
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 highThese guys were electrodepositing core material. RL
Reply by ●January 2, 20222022-01-02
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
