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
transformer coupled logic isolator
Started by ●December 30, 2021
Reply by ●December 31, 20212021-12-31
Reply by ●December 31, 20212021-12-31
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
Reply by ●December 31, 20212021-12-31
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
Reply by ●December 31, 20212021-12-31
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. > >RLRight, it's best to avoid designing any electronics. It's too hard and too risky. -- I yam what I yam - Popeye
Reply by ●December 31, 20212021-12-31
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
Reply by ●December 31, 20212021-12-31
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
Reply by ●December 31, 20212021-12-31
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
Reply by ●December 31, 20212021-12-31
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 . . . ? > >RLDo 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
Reply by ●January 1, 20222022-01-01
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
Reply by ●January 1, 20222022-01-01
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.
