AoE x-Chapters, floating high-voltage current sources

W

Winfield Hill

Guest
Here's another section from our new soon-to-printed AoE
x-Chapters book: Floating high-voltage current sources.

https://www.dropbox.com/s/458d9vuxv8w2ua5/3x.6_HV-current-sources_DRAFT-2.pdf?dl=1

This one is 12 pages long, and rather detailed. Paul
complained that I was going on and on, but agreed, and
helped in the end. Here's my defense, from the text,
midway though the saga,

"Why all the fuss? At this point the reader can be excused
for wondering why they are being dragged through so many
circuits? Why not just show the best HV current-source
circuit, and leave it at that? Well, as in engineering
generally, there is no overall “best” circuit. Many
applications will be fine with simple circuits, but others
require more effort. The story of improving HV current-
source performance is the story of adding more and more
parts. But there’s no point in using a complex part-laden
design for a non-critical application. We do hope you’ll
enjoy exploring the options (as we did, designing them!) as
we continue with higher-voltage, higher-current versions."

That gave us leave to add five more pages of intense detail.

Floating current source circuits are much more complex than
ones that operate off a rail, but they have the advantage
they can be used from either end, either as a current source,
or as a sink. And available HV parts are not well suited
for making non-floating circuits, tied to the HV rail.

Our new x-Chapters book is filled with Pearls of Electronics,
as our editor likes to say; a wide assortment of detailed
discussions of esoteric engineering circuit-design topics.
Not everyone will want to read it straight through, but
when you are confronted with a tough design problem, we may
have already explored it. Others will read it as an idea
generator. Some will enjoy the circuit-design exploration.
It's filled with detailed advanced material, not available
elsewhere. This 12-page section can serve as an example.



--
Thanks,
- Win
 
On 7/26/19 2:15 PM, Winfield Hill wrote:
Here's another section from our new soon-to-printed AoE
x-Chapters book: Floating high-voltage current sources.

https://www.dropbox.com/s/458d9vuxv8w2ua5/3x.6_HV-current-sources_DRAFT-2.pdf?dl=1

This one is 12 pages long, and rather detailed. Paul
complained that I was going on and on, but agreed, and
helped in the end. Here's my defense, from the text,
midway though the saga,

"Why all the fuss? At this point the reader can be excused
for wondering why they are being dragged through so many
circuits? Why not just show the best HV current-source
circuit, and leave it at that? Well, as in engineering
generally, there is no overall “best” circuit. Many
applications will be fine with simple circuits, but others
require more effort. The story of improving HV current-
source performance is the story of adding more and more
parts. But there’s no point in using a complex part-laden
design for a non-critical application. We do hope you’ll
enjoy exploring the options (as we did, designing them!) as
we continue with higher-voltage, higher-current versions."

That gave us leave to add five more pages of intense detail.

Floating current source circuits are much more complex than
ones that operate off a rail, but they have the advantage
they can be used from either end, either as a current source,
or as a sink. And available HV parts are not well suited
for making non-floating circuits, tied to the HV rail.

Our new x-Chapters book is filled with Pearls of Electronics,
as our editor likes to say; a wide assortment of detailed
discussions of esoteric engineering circuit-design topics.
Not everyone will want to read it straight through, but
when you are confronted with a tough design problem, we may
have already explored it. Others will read it as an idea
generator. Some will enjoy the circuit-design exploration.
It's filled with detailed advanced material, not available
elsewhere. This 12-page section can serve as an example.
Click to expand...

I believe you can make a variation of the sources on p. 202 with a tube,
with the right triode you can have supplies up to a couple kV with the
SS regulator safely wrapped up in the grid -> cathode differential.

Might be amusing to add for, ah, "completeness"
 
On 26 Jul 2019 11:15:59 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Here's another section from our new soon-to-printed AoE
x-Chapters book: Floating high-voltage current sources.

https://www.dropbox.com/s/458d9vuxv8w2ua5/3x.6_HV-current-sources_DRAFT-2.pdf?dl=1

This one is 12 pages long, and rather detailed. Paul
complained that I was going on and on, but agreed, and
helped in the end. Here's my defense, from the text,
midway though the saga,

"Why all the fuss? At this point the reader can be excused
for wondering why they are being dragged through so many
circuits? Why not just show the best HV current-source
circuit, and leave it at that? Well, as in engineering
generally, there is no overall “best” circuit. Many
applications will be fine with simple circuits, but others
require more effort. The story of improving HV current-
source performance is the story of adding more and more
parts. But there’s no point in using a complex part-laden
design for a non-critical application. We do hope you’ll
enjoy exploring the options (as we did, designing them!) as
we continue with higher-voltage, higher-current versions."

That gave us leave to add five more pages of intense detail.

Floating current source circuits are much more complex than
ones that operate off a rail, but they have the advantage
they can be used from either end, either as a current source,
or as a sink. And available HV parts are not well suited
for making non-floating circuits, tied to the HV rail.
Click to expand...

For a truly floating true current source, I'm fond of PV optocouplers.
Only good for 10s of uA. PVs and mosfets can be interesting together.



Our new x-Chapters book is filled with Pearls of Electronics,
as our editor likes to say; a wide assortment of detailed
discussions of esoteric engineering circuit-design topics.
Not everyone will want to read it straight through, but
when you are confronted with a tough design problem, we may
have already explored it. Others will read it as an idea
generator. Some will enjoy the circuit-design exploration.
It's filled with detailed advanced material, not available
elsewhere. This 12-page section can serve as an example.
Click to expand...

I'll read it straight through!


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
John Larkin wrote...
For a truly floating true current source, I'm fond of
PV optocouplers. Only good for 10s of uA. PVs and
mosfets can be interesting together.
Click to expand...

Yes, I thought about that, remembering your and other's
proclivity. But we had to draw the line someplace. We
used PVs for a floating switch, Figure 3.107, page 205.

> I'll read it straight through!

Have fun, and don't choke!


--
Thanks,
- Win
 
bitrex wrote...
I believe you can make a variation of the sources on
p. 202 with a tube, with the right triode you can have
supplies up to a couple kV with the SS regulator safely
wrapped up in the grid -> cathode differential.

Might be amusing to add for, ah, "completeness"
Click to expand...

Yes, or up to 20kV, 15A (pulsed) with a 5D21 tube.


--
Thanks,
- Win
 
On Friday, July 26, 2019 at 11:16:21 AM UTC-7, Winfield Hill wrote:
Here's another section from our new soon-to-printed AoE
x-Chapters book: Floating high-voltage current sources.
Click to expand...

Maybe I'm missing something, but in figure 3x.61D, wouldn't U1
be better used with the adjust pin connected to
the Q1 emitter, rather than the base?
 
On 26/07/2019 7:15 pm, Winfield Hill wrote:
Here's another section from our new soon-to-printed AoE
x-Chapters book: Floating high-voltage current sources.

https://www.dropbox.com/s/458d9vuxv8w2ua5/3x.6_HV-current-sources_DRAFT-2.pdf?dl=1
Click to expand...

All the mosfets in that chapter are drawn using a non-standard symbol.
In other chapters you have used the interanationally recognized symbol
of 50+ years which shows the channel diode on the substrate opposing the
gate.

The non-standard symbol can cause confusion as it appears to show a
bjt-like emitter structure in the source connection.

piglet
 
whit3rd wrote...
On Friday, July 26, 2019, Winfield Hill wrote:

Here's another section from our new soon-to-printed AoE
x-Chapters book: Floating high-voltage current sources.

Maybe I'm missing something, but in figure 3x.61D,
wouldn't U1 be better used with the adjust pin
connected to the Q1 emitter, rather than the base?
Click to expand...

Yes, excellent observation. I'll add this text:

"____ suggested moving U1's adjust pin to Q1's
emitter, in Figure 3x.61D. This is a good idea
(although U1 is a slow part, Q1's cascode response
is fast), possibly as good or better than 3x.61E."


--
Thanks,
- Win
 
Winfield Hill wrote...
whit3rd wrote...

On Friday, July 26, 2019, Winfield Hill wrote:

Here's another section from our new soon-to-printed AoE
x-Chapters book: Floating high-voltage current sources.

Maybe I'm missing something, but in figure 3x.61D,
wouldn't U1 be better used with the adjust pin
connected to the Q1 emitter, rather than the base?

Yes, excellent observation. I'll add this text:

"____ suggested moving U1's adjust pin to Q1's
emitter, in Figure 3x.61D. This is a good idea
(although U1 is a slow part, Q1's cascode response
is fast), possibly as good or better than 3x.61F."
Click to expand...

Corrected this to, "better than 3x.61F"


--
Thanks,
- Win
 
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