https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
On 24/05/2025 1:05 am, john larkin wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
Anther one of John Larkin's pencil sketches - no resistances, no
inductances or capacitances and part numbers only for the transistors.
At least with an LTSpice .asc file you get that stuff automatically.
And you get some hint at the switching spikes, which can be nasty.
On Sat, 24 May 2025 02:37:09 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 24/05/2025 1:05 am, john larkin wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
Anther one of John Larkin's pencil sketches - no resistances, no
inductances or capacitances and part numbers only for the transistors.
Uniball Vision ink pen, not pencil.
At least with an LTSpice .asc file you get that stuff automatically.
And you get some hint at the switching spikes, which can be nasty.
It's an idea. If you want a finished design, write me a purchase
order.
On 24/05/2025 3:22 am, john larkin wrote:
On Sat, 24 May 2025 02:37:09 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 24/05/2025 1:05 am, john larkin wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
Anther one of John Larkin's pencil sketches - no resistances, no
inductances or capacitances and part numbers only for the transistors.
Uniball Vision ink pen, not pencil.
At least with an LTSpice .asc file you get that stuff automatically.
And you get some hint at the switching spikes, which can be nasty.
It's an idea. If you want a finished design, write me a purchase
order.
The guy who contacted me already had an idea the Baxandall inverter
would work. I'm still waiting for Infineon to come back to me with the
Spice model of their IMWH170R450M1 so that I can send him a simulation.
I won't charge him for it. If Infineon doesn't come through soon I'll
see if I can bodge an existing MOSFET model to match the SiC datasheet.
Whacky ideas including a Diac aren't going to open anybody sensible's
wallet. The kind of gullible sucker who would vote for Trump might go
for it.
Bill Sloman <bill.sloman@ieee.org> wrote:
On 24/05/2025 3:22 am, john larkin wrote:
On Sat, 24 May 2025 02:37:09 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 24/05/2025 1:05 am, john larkin wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
Anther one of John Larkin's pencil sketches - no resistances, no
inductances or capacitances and part numbers only for the transistors.
Uniball Vision ink pen, not pencil.
At least with an LTSpice .asc file you get that stuff automatically.
And you get some hint at the switching spikes, which can be nasty.
It's an idea. If you want a finished design, write me a purchase
order.
The guy who contacted me already had an idea the Baxandall inverter
would work. I'm still waiting for Infineon to come back to me with the
Spice model of their IMWH170R450M1 so that I can send him a simulation.
I won't charge him for it. If Infineon doesn't come through soon I'll
see if I can bodge an existing MOSFET model to match the SiC datasheet.
Whacky ideas including a Diac aren't going to open anybody sensible's
wallet. The kind of gullible sucker who would vote for Trump might go
for it.
Actually a Diac might make quite a good switch in an inverse Marx style >cascade voltage divider!
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
On Sat, 24 May 2025 08:41:44 -0000 (UTC), piglet
<erichpwagner@hotmail.com> wrote:
Bill Sloman <bill.sloman@ieee.org> wrote:
On 24/05/2025 3:22 am, john larkin wrote:
On Sat, 24 May 2025 02:37:09 +1000, Bill Sloman <bill.sloman@ieee.org> >>>> wrote:
On 24/05/2025 1:05 am, john larkin wrote:Uniball Vision ink pen, not pencil.
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
Anther one of John Larkin's pencil sketches - no resistances, no
inductances or capacitances and part numbers only for the transistors. >>>>
At least with an LTSpice .asc file you get that stuff automatically. >>>>>
And you get some hint at the switching spikes, which can be nasty.
It's an idea. If you want a finished design, write me a purchase
order.
The guy who contacted me already had an idea the Baxandall inverter
would work. I'm still waiting for Infineon to come back to me with the
Spice model of their IMWH170R450M1 so that I can send him a simulation.
I won't charge him for it. If Infineon doesn't come through soon I'll
see if I can bodge an existing MOSFET model to match the SiC datasheet.
Whacky ideas including a Diac aren't going to open anybody sensible's
wallet. The kind of gullible sucker who would vote for Trump might go
for it.
Actually a Diac might make quite a good switch in an inverse Marx style
cascade voltage divider!
Interesting. Gotta think about that one.
Diacs are cool. I don't understand how they work. I've tried
simulating one with transistors but they don't unlatch. Must be some
silicon trick.
I once needed to indicate the presense of high voltage without
dissipating a lot of power. An RC and a diac and an LED made a nice
bright 0.5 Hz flash with low average current.
CCFL transformers usually have two windings with about a 100:1 ratio,
so it should be possible to make a sort of non-saturating blocking oscillator, my buck topology but without the diac. Maybe even rectify
a winding, a forward converter.
Diacs come up to 380 volts and one amp, so one might use a diac as the
actual power switch in a buck or forward converter. Maybe even use two
in series.
https://www.littelfuse.com/assetdocs/discrete-thyristors-kxxx0yh-series-datasheet?assetguid=89c51170-552a-4b3a-a3bd-287d64436e92
You-know-who will hate the idea, as he instantly hates new ideas.
Before there were IGBTs, there were megawatt power switchers,
converters and cycloconverters, that used enormous SCRs. That was
terrifying. At least diacs can turn themselves off.
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com>
wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range.
(think cicada)
RL
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com>
wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range.
(think cicada)
RL
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine
them taking milliseconds to turn off.
Interestingly, sidacs have been used in series strings up to many
kilovolts, which suggets a kilovolt step-down converter with
diacs/sidacs as the only active components.
On 25/05/2025 3:35 am, john larkin wrote:
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com>
wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range.
(think cicada)
RL
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine
them taking milliseconds to turn off.
Step recovery diodes do turn off a lot faster than that, but it does
take while for the stored charge to get swept out of the diode.
Step recovery diode are great for getting a fast edge out of relatively >slowly changing current, but the fast edge only shows up after the
stored charge has been cleared from the diode, so it's hard get it to
show up exactly when you want it.
Interestingly, sidacs have been used in series strings up to many
kilovolts, which suggets a kilovolt step-down converter with
diacs/sidacs as the only active components.
Probably not a step-down converter trying to convert 10uA from a 1kV
source into about a 3mA at 3.3V.
On Sun, 25 May 2025 04:21:16 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 25/05/2025 3:35 am, john larkin wrote:
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com>
wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range.
(think cicada)
RL
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine
them taking milliseconds to turn off.
Step recovery diodes do turn off a lot faster than that, but it does
take while for the stored charge to get swept out of the diode.
Step recovery diode are great for getting a fast edge out of relatively
slowly changing current, but the fast edge only shows up after the
stored charge has been cleared from the diode, so it's hard get it to
show up exactly when you want it.
Interestingly, sidacs have been used in series strings up to many
kilovolts, which suggets a kilovolt step-down converter with
diacs/sidacs as the only active components.
Probably not a step-down converter trying to convert 10uA from a 1kV
source into about a 3mA at 3.3V.
You are right. A diac isn't the best choice to make a 99% efficient converter.
On Sun, 25 May 2025 04:21:16 +1000, Bill Sloman
<bill.sloman@ieee.org> wrote:
On 25/05/2025 3:35 am, john larkin wrote:
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca>
wrote:
On Fri, 23 May 2025 08:05:28 -0700, john larkin
<jl@glen--canyon.com> wrote:
You are right. A diac isn't the best choice to make a 99% efficient converter.
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com> >>wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range.
(think cicada)
RL
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine
them taking milliseconds to turn off.
Interestingly, sidacs have been used in series strings up to many
kilovolts, which suggets a kilovolt step-down converter with
diacs/sidacs as the only active components.
On Sat, 24 May 2025 10:35:21 -0700, john larkin <jl@glen--canyon.com>
wrote:
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:Punch some numbers.
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com> >>>wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range. >>>(think cicada)
RL
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine
them taking milliseconds to turn off.
Interestingly, sidacs have been used in series strings up to many >>kilovolts, which suggets a kilovolt step-down converter with
diacs/sidacs as the only active components.
Cap size - charge rate - dV.
Turn-0ff time is only a small part of it.
Diacs turn off when discharge current < hold current.
They also have significant internal impedance.
RL
On Sun, 25 May 2025 10:40:54 -0400, legg <legg@nospam.magma.ca> wrote:
On Sat, 24 May 2025 10:35:21 -0700, john larkin <jl@glen--canyon.com> >>wrote:
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:Punch some numbers.
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com> >>>>wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range. >>>>(think cicada)
RL
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine >>>them taking milliseconds to turn off.
Interestingly, sidacs have been used in series strings up to many >>>kilovolts, which suggets a kilovolt step-down converter with
diacs/sidacs as the only active components.
Numbers are cheap. 2 nF charged to 1 KV stores a millijoule. Transfer
that at 10 Hz and you get the required 10 mW.
The problem is the circuit.
On Sun, 25 May 2025 09:35:48 -0700, john larkin <jl@glen--canyon.com>
wrote:
On Sun, 25 May 2025 10:40:54 -0400, legg <legg@nospam.magma.ca> wrote:
On Sat, 24 May 2025 10:35:21 -0700, john larkin <jl@glen--canyon.com> >>>wrote:
On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:Punch some numbers.
On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com> >>>>>wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
The highest diac rep rate will likely be in the tens of hertz range. >>>>>(think cicada)
RL
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine >>>>them taking milliseconds to turn off.
Interestingly, sidacs have been used in series strings up to many >>>>kilovolts, which suggets a kilovolt step-down converter with >>>>diacs/sidacs as the only active components.
Numbers are cheap. 2 nF charged to 1 KV stores a millijoule. Transfer
that at 10 Hz and you get the required 10 mW.
The problem is the circuit.
Diac section is pretty simple to breadboard.
RL
Newsgroups: sci.electronics.design
On 24/05/2025 1:05 am, john larkin wrote:
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1
Anther one of John Larkin's pencil sketches - no resistances, no
inductances or capacitances and part numbers only for the transistors.
At least with an LTSpice .asc file you get that stuff automatically.
And you get some hint at the switching spikes, which can be nasty.
--
Bill Sloman, Sydney
Bill - there was some talk here about a power supply I was working on. It used a pnp transistor
driven by 2 capacitors and a diode to switch a solenoid style inductor. Efficiency was about 80%. This
was two or three years ago. Initial starting powrer can be a puzzler.
Newsgroups: sci.electronics.design
On 27/05/2025 10:39 am, Hul Tytus wrote:
Bill - there was some talk here about a power supply I was working on. It used a pnp transistor
driven by 2 capacitors and a diode to switch a solenoid style inductor. Efficiency was about 80%. This
was two or three years ago. Initial starting powrer can be a puzzler.
Hi Hul - getting Baxandall style inverters to start-up cleanly can be a problem. The amplitude can overshoot. The 1959 original would "squeg" is
the feed inductor was too big, and you used bipolar transistor switches, which is something I've never been able to simulate. MOSFET switches apparently aren't susceptible to this problem.
--
Bill Sloman, Sydney
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