On Mon, 24 Jul 2023 20:04:56 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
>tirsdag den 25. juli 2023 kl. 04.24.47 UTC+2 skrev John Larkin:
>> On Mon, 24 Jul 2023 18:59:58 -0700 (PDT), Lasse Langwadt Christensen
>> <lang...@fonz.dk> wrote:
>>
>> >tirsdag den 25. juli 2023 kl. 03.16.00 UTC+2 skrev John Larkin:
>> >> On Mon, 24 Jul 2023 23:25:47 -0000 (UTC), Phil Hobbs
>> >> <pcdhSpamM...@electrooptical.net> wrote:
>> >>
>> >> >John Larkin <jla...@highlandSNIPMEtechnology.com> wrote:
>> >> >>
>> >> >> https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>> >> >>
>> >> >> I like C1, with just a high-enough-voltage mosfet that it survives the
>> >> >> max flyback voltage.
>> >> >>
>> >> >> C2 would use some exotic avalanche-rated thing.
>> >> >>
>> >> >> Everthing else needs more parts.
>> >> >>
>> >> >> Any more?
>> >> >>
>> >> >>
>> >> >
>> >> >TVS across the coil. That sometimes helps a bit with keeping the rail
>> >> >clean, and (unlike the shunt rectifier approach) lets the contacts open at
>> >> >full speed.
>> >> >
>> >> >Cheers
>> >> >
>> >> >Phil Hobbs
>> >> I'd like to use a sot-23 fet and nothing else. I'll brickwall 120
>> >> 7x20mm relays and have to put the drivers between the pins on the
>> >> bottom side of the board and I need room for hundreds of fat traces
>> >> too.
>> >>
>> >> It's tough to get a flyback boost of 10:1, and I'm hoping that a relay
>> >> coil can't do that. I could use a 100 or 150 volt fet and the spike
>> >> voltage might not get that high.
>> >
>> >literally what the SSM3K357R is made for as shown in the datasheet
>> We can probably do a footprint that allows the SSM or some other part.
>> We're paranoid about availability and sole-source lately.
>>
>> The SSM is a slightly unusual package but it looks like it will work
>> in a standard SOT23 footprint. I'll get some and try them.
>
>afaict it uses the same footprint, the legs are just flat with the bottom instead of gullwing
>
>
On Thu, 27 Jul 2023 21:02:47 -0700, boB <boB@K7IQ.com> wrote:
>On Thu, 27 Jul 2023 07:02:40 -0700, John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote:
>
>>On Thu, 27 Jul 2023 05:16:20 GMT, Jan Panteltje <alien@comet.invalid>
>>wrote:
>>
>>>On a sunny day (Wed, 26 Jul 2023 12:28:30 -0700) it happened John Larkin
>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>><68s2cihg5o9vsu5lmjj7e3nv0io1u9vf7d@4ax.com>:
>>>
>>>>On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <alien@comet.invalid>
>>>>wrote:
>>>>
>>>>>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>><vh82ci91224q6qmmj9bcs2uuu4dsb24ago@4ax.com>:
>>>>>
>>>>>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <alien@comet.invalid>
>>>>>>wrote:
>>>>>>
>>>>>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>>>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>>><hcsvbi5qh32b4fm3go7mlkitktphr2qr8c@4ax.com>:
>>>>>>>
>>>>>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <alien@comet.invalid>
>>>>>>>>wrote:
>>>>>>>>
>>>>>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>>>>>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>>>>><m9vtbidjnfs514s4s26nhj59m1ojp8q2m1@4ax.com>:
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>>>>>>>>>>
>>>>>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>>>>>>>>>>max flyback voltage.
>>>>>>>>>>
>>>>>>>>>>C2 would use some exotic avalanche-rated thing.
>>>>>>>>>>
>>>>>>>>>>Everthing else needs more parts.
>>>>>>>>>>
>>>>>>>>>>Any more?
>>>>>>>>>
>>>>>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>>>>>>>>
>>>>>>>>That's no fun. Everybody does that.
>>>>>>>>
>>>>>>>>The stored energy is dissipated in the diode and the coil resistance.
>>>>>>>
>>>>>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>>>>>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>>>>>>>Driving on the right side of the road may seem dull but it is safer.
>>>>>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>>>>>>
>>>>>>Adding 120+ diodes might cost another PCB layer.
>>>>>
>>>>>You have 120 relays on one board???
>>>>
>>>>Yes. Brickwalled. And we need to get a lot of very fat traces deep
>>>>into the array.
>>>>
>>>>If I add the 48 polyfuses, so the customer doesn't fry my traces,
>>>>there's even less room.
>>>>
>>>>https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
>>>
>>>Impressive!
>>>
>>>
>>>>The mosfet relay drivers can go on the bottom, between the thru-hole
>>>>relay pins, but will block traces. Diodes would block more.
>>>>
>>>>My customer designed a box to do this function, many years ago, back
>>>>when aerospace companies designed their own test gear. Nowadays, the
>>>>old engineers and techs retire and aren't replaced, and they can't
>>>>build or maintain their stuff any more. This is our version.
>>>
>>>What about relay wear out, is it possible to replace one?
>>
>>Only by soldering. The box will have BIST, self-test, to check
>>everything. The customer's original didn't, and that was a problem.
>
>We stress to our PCB layer outers that they need to make sure there is
>enough copper pad area around the holes so that rework can be done.
>
>Sometimes this doesn't get through to them.
>
>boB
We don't have many rework problems. We do have a bunch of the right
equipment, like fancy IR and hot air things. We can heat an area on
the bottom of a board and lift a relay out with no stress. Solder
suckers and wicking can damage pads and thru-hole plating.
We do enforce a minimum annular ring on pads and vias. I've seen
boards with zero annular ring... a trace just disappears into a hole.
Creepy.
Reply by boB●July 28, 20232023-07-28
On Thu, 27 Jul 2023 07:02:40 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:
>On Thu, 27 Jul 2023 05:16:20 GMT, Jan Panteltje <alien@comet.invalid>
>wrote:
>
>>On a sunny day (Wed, 26 Jul 2023 12:28:30 -0700) it happened John Larkin
>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>><68s2cihg5o9vsu5lmjj7e3nv0io1u9vf7d@4ax.com>:
>>
>>>On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <alien@comet.invalid>
>>>wrote:
>>>
>>>>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>><vh82ci91224q6qmmj9bcs2uuu4dsb24ago@4ax.com>:
>>>>
>>>>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <alien@comet.invalid>
>>>>>wrote:
>>>>>
>>>>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>><hcsvbi5qh32b4fm3go7mlkitktphr2qr8c@4ax.com>:
>>>>>>
>>>>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <alien@comet.invalid>
>>>>>>>wrote:
>>>>>>>
>>>>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>>>>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>>>><m9vtbidjnfs514s4s26nhj59m1ojp8q2m1@4ax.com>:
>>>>>>>>
>>>>>>>>>
>>>>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>>>>>>>>>
>>>>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>>>>>>>>>max flyback voltage.
>>>>>>>>>
>>>>>>>>>C2 would use some exotic avalanche-rated thing.
>>>>>>>>>
>>>>>>>>>Everthing else needs more parts.
>>>>>>>>>
>>>>>>>>>Any more?
>>>>>>>>
>>>>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>>>>>>>
>>>>>>>That's no fun. Everybody does that.
>>>>>>>
>>>>>>>The stored energy is dissipated in the diode and the coil resistance.
>>>>>>
>>>>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>>>>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>>>>>>Driving on the right side of the road may seem dull but it is safer.
>>>>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>>>>>
>>>>>Adding 120+ diodes might cost another PCB layer.
>>>>
>>>>You have 120 relays on one board???
>>>
>>>Yes. Brickwalled. And we need to get a lot of very fat traces deep
>>>into the array.
>>>
>>>If I add the 48 polyfuses, so the customer doesn't fry my traces,
>>>there's even less room.
>>>
>>>https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
>>
>>Impressive!
>>
>>
>>>The mosfet relay drivers can go on the bottom, between the thru-hole
>>>relay pins, but will block traces. Diodes would block more.
>>>
>>>My customer designed a box to do this function, many years ago, back
>>>when aerospace companies designed their own test gear. Nowadays, the
>>>old engineers and techs retire and aren't replaced, and they can't
>>>build or maintain their stuff any more. This is our version.
>>
>>What about relay wear out, is it possible to replace one?
>
>Only by soldering. The box will have BIST, self-test, to check
>everything. The customer's original didn't, and that was a problem.
We stress to our PCB layer outers that they need to make sure there is
enough copper pad area around the holes so that rework can be done.
Sometimes this doesn't get through to them.
boB
Reply by John Larkin●July 27, 20232023-07-27
On Thu, 27 Jul 2023 05:16:20 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
>On a sunny day (Wed, 26 Jul 2023 12:28:30 -0700) it happened John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote in
><68s2cihg5o9vsu5lmjj7e3nv0io1u9vf7d@4ax.com>:
>
>>On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <alien@comet.invalid>
>>wrote:
>>
>>>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>><vh82ci91224q6qmmj9bcs2uuu4dsb24ago@4ax.com>:
>>>
>>>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <alien@comet.invalid>
>>>>wrote:
>>>>
>>>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>><hcsvbi5qh32b4fm3go7mlkitktphr2qr8c@4ax.com>:
>>>>>
>>>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <alien@comet.invalid>
>>>>>>wrote:
>>>>>>
>>>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>>>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>>><m9vtbidjnfs514s4s26nhj59m1ojp8q2m1@4ax.com>:
>>>>>>>
>>>>>>>>
>>>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>>>>>>>>
>>>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>>>>>>>>max flyback voltage.
>>>>>>>>
>>>>>>>>C2 would use some exotic avalanche-rated thing.
>>>>>>>>
>>>>>>>>Everthing else needs more parts.
>>>>>>>>
>>>>>>>>Any more?
>>>>>>>
>>>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>>>>>>
>>>>>>That's no fun. Everybody does that.
>>>>>>
>>>>>>The stored energy is dissipated in the diode and the coil resistance.
>>>>>
>>>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>>>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>>>>>Driving on the right side of the road may seem dull but it is safer.
>>>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>>>>
>>>>Adding 120+ diodes might cost another PCB layer.
>>>
>>>You have 120 relays on one board???
>>
>>Yes. Brickwalled. And we need to get a lot of very fat traces deep
>>into the array.
>>
>>If I add the 48 polyfuses, so the customer doesn't fry my traces,
>>there's even less room.
>>
>>https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
>
>Impressive!
>
>
>>The mosfet relay drivers can go on the bottom, between the thru-hole
>>relay pins, but will block traces. Diodes would block more.
>>
>>My customer designed a box to do this function, many years ago, back
>>when aerospace companies designed their own test gear. Nowadays, the
>>old engineers and techs retire and aren't replaced, and they can't
>>build or maintain their stuff any more. This is our version.
>
>What about relay wear out, is it possible to replace one?
Only by soldering. The box will have BIST, self-test, to check
everything. The customer's original didn't, and that was a problem.
Reply by John Larkin●July 27, 20232023-07-27
On Wed, 26 Jul 2023 20:22:17 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
>torsdag den 27. juli 2023 kl. 05.10.38 UTC+2 skrev boB:
>> On Wed, 26 Jul 2023 12:28:30 -0700, John Larkin
>> <jla...@highlandSNIPMEtechnology.com> wrote:
>>
>> >On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <al...@comet.invalid>
>> >wrote:
>> >
>> >>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
>> >><jla...@highlandSNIPMEtechnology.com> wrote in
>> >><vh82ci91224q6qmmj...@4ax.com>:
>> >>
>> >>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <al...@comet.invalid>
>> >>>wrote:
>> >>>
>> >>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>> >>>><jla...@highlandSNIPMEtechnology.com> wrote in
>> >>>><hcsvbi5qh32b4fm3g...@4ax.com>:
>> >>>>
>> >>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <al...@comet.invalid>
>> >>>>>wrote:
>> >>>>>
>> >>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>> >>>>>><jla...@highlandSNIPMEtechnology.com> wrote in
>> >>>>>><m9vtbidjnfs514s4s...@4ax.com>:
>> >>>>>>
>> >>>>>>>
>> >>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>> >>>>>>>
>> >>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>> >>>>>>>max flyback voltage.
>> >>>>>>>
>> >>>>>>>C2 would use some exotic avalanche-rated thing.
>> >>>>>>>
>> >>>>>>>Everthing else needs more parts.
>> >>>>>>>
>> >>>>>>>Any more?
>> >>>>>>
>> >>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>> >>>>>
>> >>>>>That's no fun. Everybody does that.
>> >>>>>
>> >>>>>The stored energy is dissipated in the diode and the coil resistance.
>> >>>>
>> >>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>> >>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>> >>>>Driving on the right side of the road may seem dull but it is safer.
>> >>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>> >>>
>> >>>Adding 120+ diodes might cost another PCB layer.
>> >>
>> >>You have 120 relays on one board???
>> >
>> >Yes. Brickwalled. And we need to get a lot of very fat traces deep
>> >into the array.
>> >
>> >If I add the 48 polyfuses, so the customer doesn't fry my traces,
>> >there's even less room.
>> >
>> >https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
>> >
>> >The mosfet relay drivers can go on the bottom, between the thru-hole
>> >relay pins, but will block traces. Diodes would block more.
>> >
>> >My customer designed a box to do this function, many years ago, back
>> >when aerospace companies designed their own test gear. Nowadays, the
>> >old engineers and techs retire and aren't replaced, and they can't
>> >build or maintain their stuff any more. This is our version.
>> Looks great !
>>
>> BUT I hope that those are Through-Hole and not SMT in case you need to
>> change one.
>
>SMD would take up quite a bit more space
>
Yes. There are many drop-in sources for the 7x20mm SPST relay. We'll
selective-solder the pins and we need to dance around the
surface-mount mosfet drivers on the bottom, between the relay pins.
Another reason to avoid catch diodes.
We'll probably have to hand-load the relays. We might see if our
pick-and-place can do it but I suspect not.
Reply by Jan Panteltje●July 27, 20232023-07-27
On a sunny day (Wed, 26 Jul 2023 12:28:30 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<68s2cihg5o9vsu5lmjj7e3nv0io1u9vf7d@4ax.com>:
>On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <alien@comet.invalid>
>wrote:
>
>>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>><vh82ci91224q6qmmj9bcs2uuu4dsb24ago@4ax.com>:
>>
>>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <alien@comet.invalid>
>>>wrote:
>>>
>>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>><hcsvbi5qh32b4fm3go7mlkitktphr2qr8c@4ax.com>:
>>>>
>>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <alien@comet.invalid>
>>>>>wrote:
>>>>>
>>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>><m9vtbidjnfs514s4s26nhj59m1ojp8q2m1@4ax.com>:
>>>>>>
>>>>>>>
>>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>>>>>>>
>>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>>>>>>>max flyback voltage.
>>>>>>>
>>>>>>>C2 would use some exotic avalanche-rated thing.
>>>>>>>
>>>>>>>Everthing else needs more parts.
>>>>>>>
>>>>>>>Any more?
>>>>>>
>>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>>>>>
>>>>>That's no fun. Everybody does that.
>>>>>
>>>>>The stored energy is dissipated in the diode and the coil resistance.
>>>>
>>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>>>>Driving on the right side of the road may seem dull but it is safer.
>>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>>>
>>>Adding 120+ diodes might cost another PCB layer.
>>
>>You have 120 relays on one board???
>
>Yes. Brickwalled. And we need to get a lot of very fat traces deep
>into the array.
>
>If I add the 48 polyfuses, so the customer doesn't fry my traces,
>there's even less room.
>
>https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
Impressive!
>The mosfet relay drivers can go on the bottom, between the thru-hole
>relay pins, but will block traces. Diodes would block more.
>
>My customer designed a box to do this function, many years ago, back
>when aerospace companies designed their own test gear. Nowadays, the
>old engineers and techs retire and aren't replaced, and they can't
>build or maintain their stuff any more. This is our version.
What about relay wear out, is it possible to replace one?
Reply by Lasse Langwadt Christensen●July 27, 20232023-07-27
torsdag den 27. juli 2023 kl. 05.10.38 UTC+2 skrev boB:
> On Wed, 26 Jul 2023 12:28:30 -0700, John Larkin
> <jla...@highlandSNIPMEtechnology.com> wrote:
>
> >On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <al...@comet.invalid>
> >wrote:
> >
> >>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
> >><jla...@highlandSNIPMEtechnology.com> wrote in
> >><vh82ci91224q6qmmj...@4ax.com>:
> >>
> >>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <al...@comet.invalid>
> >>>wrote:
> >>>
> >>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
> >>>><jla...@highlandSNIPMEtechnology.com> wrote in
> >>>><hcsvbi5qh32b4fm3g...@4ax.com>:
> >>>>
> >>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <al...@comet.invalid>
> >>>>>wrote:
> >>>>>
> >>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
> >>>>>><jla...@highlandSNIPMEtechnology.com> wrote in
> >>>>>><m9vtbidjnfs514s4s...@4ax.com>:
> >>>>>>
> >>>>>>>
> >>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
> >>>>>>>
> >>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
> >>>>>>>max flyback voltage.
> >>>>>>>
> >>>>>>>C2 would use some exotic avalanche-rated thing.
> >>>>>>>
> >>>>>>>Everthing else needs more parts.
> >>>>>>>
> >>>>>>>Any more?
> >>>>>>
> >>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
> >>>>>
> >>>>>That's no fun. Everybody does that.
> >>>>>
> >>>>>The stored energy is dissipated in the diode and the coil resistance.
> >>>>
> >>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
> >>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
> >>>>Driving on the right side of the road may seem dull but it is safer.
> >>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
> >>>
> >>>Adding 120+ diodes might cost another PCB layer.
> >>
> >>You have 120 relays on one board???
> >
> >Yes. Brickwalled. And we need to get a lot of very fat traces deep
> >into the array.
> >
> >If I add the 48 polyfuses, so the customer doesn't fry my traces,
> >there's even less room.
> >
> >https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
> >
> >The mosfet relay drivers can go on the bottom, between the thru-hole
> >relay pins, but will block traces. Diodes would block more.
> >
> >My customer designed a box to do this function, many years ago, back
> >when aerospace companies designed their own test gear. Nowadays, the
> >old engineers and techs retire and aren't replaced, and they can't
> >build or maintain their stuff any more. This is our version.
> Looks great !
>
> BUT I hope that those are Through-Hole and not SMT in case you need to
> change one.
SMD would take up quite a bit more space
Reply by boB●July 27, 20232023-07-27
On Wed, 26 Jul 2023 12:28:30 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:
>On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <alien@comet.invalid>
>wrote:
>
>>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>><vh82ci91224q6qmmj9bcs2uuu4dsb24ago@4ax.com>:
>>
>>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <alien@comet.invalid>
>>>wrote:
>>>
>>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>><hcsvbi5qh32b4fm3go7mlkitktphr2qr8c@4ax.com>:
>>>>
>>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <alien@comet.invalid>
>>>>>wrote:
>>>>>
>>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>><m9vtbidjnfs514s4s26nhj59m1ojp8q2m1@4ax.com>:
>>>>>>
>>>>>>>
>>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>>>>>>>
>>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>>>>>>>max flyback voltage.
>>>>>>>
>>>>>>>C2 would use some exotic avalanche-rated thing.
>>>>>>>
>>>>>>>Everthing else needs more parts.
>>>>>>>
>>>>>>>Any more?
>>>>>>
>>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>>>>>
>>>>>That's no fun. Everybody does that.
>>>>>
>>>>>The stored energy is dissipated in the diode and the coil resistance.
>>>>
>>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>>>>Driving on the right side of the road may seem dull but it is safer.
>>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>>>
>>>Adding 120+ diodes might cost another PCB layer.
>>
>>You have 120 relays on one board???
>
>Yes. Brickwalled. And we need to get a lot of very fat traces deep
>into the array.
>
>If I add the 48 polyfuses, so the customer doesn't fry my traces,
>there's even less room.
>
>https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
>
>The mosfet relay drivers can go on the bottom, between the thru-hole
>relay pins, but will block traces. Diodes would block more.
>
>My customer designed a box to do this function, many years ago, back
>when aerospace companies designed their own test gear. Nowadays, the
>old engineers and techs retire and aren't replaced, and they can't
>build or maintain their stuff any more. This is our version.
Looks great !
BUT I hope that those are Through-Hole and not SMT in case you need to
change one.
boB
Reply by John Larkin●July 26, 20232023-07-26
On Wed, 26 Jul 2023 15:43:38 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
>On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote in
><vh82ci91224q6qmmj9bcs2uuu4dsb24ago@4ax.com>:
>
>>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <alien@comet.invalid>
>>wrote:
>>
>>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>><hcsvbi5qh32b4fm3go7mlkitktphr2qr8c@4ax.com>:
>>>
>>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <alien@comet.invalid>
>>>>wrote:
>>>>
>>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>><m9vtbidjnfs514s4s26nhj59m1ojp8q2m1@4ax.com>:
>>>>>
>>>>>>
>>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>>>>>>
>>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>>>>>>max flyback voltage.
>>>>>>
>>>>>>C2 would use some exotic avalanche-rated thing.
>>>>>>
>>>>>>Everthing else needs more parts.
>>>>>>
>>>>>>Any more?
>>>>>
>>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>>>>
>>>>That's no fun. Everybody does that.
>>>>
>>>>The stored energy is dissipated in the diode and the coil resistance.
>>>
>>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>>>Driving on the right side of the road may seem dull but it is safer.
>>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>>
>>Adding 120+ diodes might cost another PCB layer.
>
>You have 120 relays on one board???
Yes. Brickwalled. And we need to get a lot of very fat traces deep
into the array.
If I add the 48 polyfuses, so the customer doesn't fry my traces,
there's even less room.
https://www.dropbox.com/scl/fi/x8ily46c4igji6tlkjnrg/P948_polyfuses_5.jpg?rlkey=fot52eisaxq9g8l0hbmbt2gsc&raw=1
The mosfet relay drivers can go on the bottom, between the thru-hole
relay pins, but will block traces. Diodes would block more.
My customer designed a box to do this function, many years ago, back
when aerospace companies designed their own test gear. Nowadays, the
old engineers and techs retire and aren't replaced, and they can't
build or maintain their stuff any more. This is our version.
Reply by Jan Panteltje●July 26, 20232023-07-26
On a sunny day (Wed, 26 Jul 2023 06:42:07 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<vh82ci91224q6qmmj9bcs2uuu4dsb24ago@4ax.com>:
>On Wed, 26 Jul 2023 05:03:17 GMT, Jan Panteltje <alien@comet.invalid>
>wrote:
>
>>On a sunny day (Tue, 25 Jul 2023 09:01:31 -0700) it happened John Larkin
>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>><hcsvbi5qh32b4fm3go7mlkitktphr2qr8c@4ax.com>:
>>
>>>On Tue, 25 Jul 2023 05:20:21 GMT, Jan Panteltje <alien@comet.invalid>
>>>wrote:
>>>
>>>>On a sunny day (Mon, 24 Jul 2023 15:41:16 -0700) it happened John Larkin
>>>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>><m9vtbidjnfs514s4s26nhj59m1ojp8q2m1@4ax.com>:
>>>>
>>>>>
>>>>>https://www.dropbox.com/scl/fi/40slcbgbngggdcwwt95vi/Relay_Drivers.jpg?rlkey=gfai2trx0n6bnja2yl4hber7i&raw=1
>>>>>
>>>>>I like C1, with just a high-enough-voltage mosfet that it survives the
>>>>>max flyback voltage.
>>>>>
>>>>>C2 would use some exotic avalanche-rated thing.
>>>>>
>>>>>Everthing else needs more parts.
>>>>>
>>>>>Any more?
>>>>
>>>>I would use A to be safe, pevents RF oscillations and delivers power back into the supply ;-)
>>>
>>>That's no fun. Everybody does that.
>>>
>>>The stored energy is dissipated in the diode and the coil resistance.
>>
>>You could use it to make some high voltage rail on the flyback if the relays work often enough... :-)
>>As to no fun: No lack of RF noise is important (you may need to pass some standards perhaps).
>>Driving on the right side of the road may seem dull but it is safer.
>>The diode thing has worked OK in millions of equipment for as long as there have been relay drivers.
>
>Adding 120+ diodes might cost another PCB layer.
You have 120 relays on one board???
>I don't think a once-a-minute ringy thing would even show up on a
>spectrum analyzer.
No but it would screw up your radio's music perhaps.
Things happen, strange things..
'Arte' TV channel had 'The Blues brothers' a movie last Sunday
I watched it.
Then I thought: 'should have recorded it (was in HD I have the lower resolution).
So looked and repeat was next day during day time, set a timer.
Thing started but aborted with 'USB error' after about 2 GB...
sigh, buttons on remote no longer worked either...
So.. well, finally unplugged it and all worked again....
Many GB in HD... all in 4 GB sections, but now I am missing a part.
Looks like it was a mains dip.. 128 GB USB stick is behaving normal..
Now that movie, and driving on the wrong side of the road, ..
I guess many here have seen it..
reminded me of that night with Jerry, he was driving, road with barrier in the middle for the other way
he switched lanes and drove against the traffic .. now you have to know Jerry,
there is a stones song 'paint it black' he was my neighbor and had his room painted black..
He asked me (while driving the wrong way) 'are you not afraid?
Well not really, but told him survival chances were better if we moved back to the right side of the road, which he eventually did,
pointed out the funeral place next to his parents house, did that make him do it?
Jerry was OK, met an old friend of him years later (he had moved), he told me Jerry had become very aggressive.
No idea if he is still around.
But a nice movie, good music... no silly effects, real stuff..
Those days...