LR8 high volltage linear regulators...

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[Jeremy Morgan]

On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:

Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win

Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

 

[Phil Hobbs]

On 2023-03-09 07:25, Jeremy Morgan wrote:

On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win

Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

Welcome to Usenet, which has been around since 1979. This group
(sci.electronics.design) is older than Google. The short answer is,
\"You can\'t do it on the Google Groups web interface.\"

Unfortunately Google collapses multiple space characters into one, which
destroys schematics and other ASCII art.

Ditch Google Groups and use a real newsreader such as Thunderbird or
Seamonkey.

You can get a free Usenet account from eternal-september.com. Setting
it up is pretty simple--you\'ll be on the air in half an hour.

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

 

[Carlos E.R.]

On 2023-03-09 13:25, Jeremy Morgan wrote:

On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win

Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

From a post made in 2006? No, I can\'t. I don\'t have access to it, I am
not using Google Groups as you do.

You need to display them in a terminal using fixed width fonts, as I do.
Not a web browser. And download them from an Usenet server that contains
that old thread, not from Google Groups. I don\'t know any that has that
old content.


For those on Usenet, it is this thread:

https://groups.google.com/g/sci.electronics.design/c/MM5_wQtm0ds




--
Cheers, Carlos.

 

[Carlos E.R.]

On 2023-03-09 13:37, Phil Hobbs wrote:

On 2023-03-09 07:25, Jeremy Morgan wrote:
On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
.......................****

Please can anyone explain to me how to read the ASCII schematics in
this post? Thanks


Welcome to Usenet, which has been around since 1979.  This group
(sci.electronics.design) is older than Google.  The short answer is,
\"You can\'t do it on the Google Groups web interface.\"

Unfortunately Google collapses multiple space characters into one, which
destroys schematics and other ASCII art.

Ditch Google Groups and use a real newsreader such as Thunderbird or
Seamonkey.

You can get a free Usenet account from eternal-september.com.  Setting
it up is pretty simple--you\'ll be on the air in half an hour.

Yes, but the other problem is getting that ancient post. Most Usenet
servers probably don\'t.

Mine doesn\'t, or my client expired it.

--
Cheers, Carlos.

 

[Phil Hobbs]

On 2023-03-09 07:52, Carlos E.R. wrote:> On 2023-03-09 13:37, Phil Hobbs
wrote:

On 2023-03-09 07:25, Jeremy Morgan wrote:
On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
......................****

Please can anyone explain to me how to read the ASCII schematics in
this post? Thanks


Welcome to Usenet, which has been around since 1979. This group
(sci.electronics.design) is older than Google. The short answer is,
\"You can\'t do it on the Google Groups web interface.\"

Unfortunately Google collapses multiple space characters into one,
which destroys schematics and other ASCII art.

Ditch Google Groups and use a real newsreader such as Thunderbird or
Seamonkey.

You can get a free Usenet account from eternal-september.com. Setting
it up is pretty simple--you\'ll be on the air in half an hour.

Yes, but the other problem is getting that ancient post. Most Usenet
servers probably don\'t.

Mine doesn\'t, or my client expired it.

You can get 20G for $10 of downloading from astraweb, which goes back to
2003. (I splurged and got 180G for $25, so I should be reading SED till
about 2523 AD.

Supernews also has stuff back to 2003.

The Internet Archive has mbox files of a number of groups going back
about that far, including this one.

At the moment I have some Seamonkey config problem that I haven\'t
bothered tracking down, that prevents me from _posting_ via Astraweb,
but it works fine via Supernews or ES.

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

 

[Fred Bloggs]

On Thursday, March 9, 2023 at 7:37:25 AM UTC-5, Phil Hobbs wrote:

On 2023-03-09 07:25, Jeremy Morgan wrote:
On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win

Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

Welcome to Usenet, which has been around since 1979. This group
(sci.electronics.design) is older than Google. The short answer is,
\"You can\'t do it on the Google Groups web interface.\"

Unfortunately Google collapses multiple space characters into one, which
destroys schematics and other ASCII art.

I used to be able to read the ascii schematic by swiping the text block, copy, and paste into notepad. It would come out perfectly every time.

Haven\'t done it in a while because all the traffic is verbiage, so I can\'t really say it still works.

Ditch Google Groups and use a real newsreader such as Thunderbird or
Seamonkey.

You can get a free Usenet account from eternal-september.com. Setting
it up is pretty simple--you\'ll be on the air in half an hour.

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

 

[John May]

On Thursday, March 9, 2023 at 12:25:36 PM UTC, Jeremy Morgan wrote:

On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win
Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

If you\'re prepared to faff-about highlight the ascii schematic lines and (if using firefox) right click and select view source. Copy to vim and replace the <br> with returns (%s/<br>/\\r/g).

 

[Jeremy Morgan]

On Thursday, 9 March 2023 at 13:23:15 UTC, John May wrote:

On Thursday, March 9, 2023 at 12:25:36 PM UTC, Jeremy Morgan wrote:
On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win
Please can anyone explain to me how to read the ASCII schematics in this post? Thanks
If you\'re prepared to faff-about highlight the ascii schematic lines and (if using firefox) right click and select view source. Copy to vim and replace the <br> with returns (%s/<br>/\\r/g).

Thanks for your responses and suggestions.

@JohnMay Your suggestion re: View source worked a treat thanks. I was able to paste it into a text editor in Windows. Using a monospaced font (Courier) made everything line up OK and I was able to make sense of the schematics..

 

[John Larkin]

On Thu, 9 Mar 2023 04:25:32 -0800 (PST), Jeremy Morgan
<jeremy.robert.morgan@gmail.com> wrote:

On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win

Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

It would be readable in a fixed-pitch font, with some line wraps
fixed.

That circuit is probably the one on page 609 of Win\'s book, AoE 3rd
Edition Improved. Everyone should have that book, and the X-chapter
supplement (to which Phil and I made modest contributions.)

Given your requirements, we could play with HV regulator ideas here.

 

[Jan Panteltje]

On a sunny day (Thu, 9 Mar 2023 13:52:19 +0100) it happened \"Carlos E.R.\"
<robin_listas@es.invalid> wrote in <3d1pdjxduu.ln2@Telcontar.valinor>:

On 2023-03-09 13:37, Phil Hobbs wrote:
On 2023-03-09 07:25, Jeremy Morgan wrote:
On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
......................****

Please can anyone explain to me how to read the ASCII schematics in
this post? Thanks


Welcome to Usenet, which has been around since 1979.  This group
(sci.electronics.design) is older than Google.  The short answer is,
\"You can\'t do it on the Google Groups web interface.\"

Unfortunately Google collapses multiple space characters into one, which
destroys schematics and other ASCII art.

Ditch Google Groups and use a real newsreader such as Thunderbird or
Seamonkey.

You can get a free Usenet account from eternal-september.com.  Setting
it up is pretty simple--you\'ll be on the air in half an hour.

Yes, but the other problem is getting that ancient post. Most Usenet
servers probably don\'t.

Mine doesn\'t, or my client expired it.

My newsreader keeps its own database, goes back to Feb 2006..
but only of articles and postings I found interesting.
I wrote it around year 1998 as Linux replacement for Free Agent,
https://panteltje.nl/panteltje/newsflex/index.html
Version 1.5.5 is from 2002...
Some older code and data got lost, or maybe on that old PC in the attic?
Anyways its still going strong.

 

[Don]

John Larkin wrote:
> Jeremy Morgan wrote:

Readable version of Win\'s followup:

<https://crcomp.net/misc/lr8.php>

<snip>

It would be readable in a fixed-pitch font, with some line wraps
fixed.

That circuit is probably the one on page 609 of Win\'s book, AoE 3rd
Edition Improved. Everyone should have that book, and the X-chapter
supplement (to which Phil and I made modest contributions.)

Given your requirements, we could play with HV regulator ideas here.

Close, but no cigar. Although Win apparently cooked up the above circuit
with ideas presented on page 608 - 609.
What! Wait. Win\'s circuit went to pot as they say. So it\'s no good,
right John? LOL.
Regardless, this thread illustrates the virtues of hosting your own
usenet archive instead of outsourcing it to the slop served by Big Tech.

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[John Larkin]

On Thu, 9 Mar 2023 16:17:59 -0000 (UTC), \"Don\" <g@crcomp.net> wrote:

John Larkin wrote:
Jeremy Morgan wrote:

Readable version of Win\'s followup:

https://crcomp.net/misc/lr8.php

snip

It would be readable in a fixed-pitch font, with some line wraps
fixed.

That circuit is probably the one on page 609 of Win\'s book, AoE 3rd
Edition Improved. Everyone should have that book, and the X-chapter
supplement (to which Phil and I made modest contributions.)

Given your requirements, we could play with HV regulator ideas here.

Close, but no cigar. Although Win apparently cooked up the above circuit
with ideas presented on page 608 - 609.
What! Wait. Win\'s circuit went to pot as they say. So it\'s no good,
right John? LOL.

English translation, please?

 

[Carlos E.R.]

On 2023-03-09 14:23, John May wrote:

On Thursday, March 9, 2023 at 12:25:36 PM UTC, Jeremy Morgan wrote:
On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:

....

Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

If you\'re prepared to faff-about highlight the ascii schematic lines and (if using firefox) right click and select view source. Copy to vim and replace the <br> with returns (%s/<br>/\\r/g).

Wow :-o

--
Cheers, Carlos.

 

[Don]

John Larkin wrote:

Don wrote:
John Larkin wrote:
Jeremy Morgan wrote:

Readable version of Win\'s followup:

https://crcomp.net/misc/lr8.php

snip

It would be readable in a fixed-pitch font, with some line wraps
fixed.

That circuit is probably the one on page 609 of Win\'s book, AoE 3rd
Edition Improved. Everyone should have that book, and the X-chapter
supplement (to which Phil and I made modest contributions.)

Given your requirements, we could play with HV regulator ideas here.

Close, but no cigar. Although Win apparently cooked up the above circuit
with ideas presented on page 608 - 609.
What! Wait. Win\'s circuit went to pot as they say. So it\'s no good,
right John? LOL.

English translation, please?

You preach potentiometer perdition, no?

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[ehsjr]

On 3/9/2023 11:17 AM, Don wrote:

John Larkin wrote:
Jeremy Morgan wrote:

Readable version of Win\'s followup:

https://crcomp.net/misc/lr8.php

+1

(It deserves more than a plus 1, maybe a
plus 1 times the number of characters in
Win\'s schematic. )
Ed

 

[Phil Hobbs]

On 2023-03-09 18:43, ehsjr wrote:

On 3/9/2023 11:17 AM, Don wrote:
John Larkin wrote:
Jeremy Morgan wrote:

Readable version of Win\'s followup:

https://crcomp.net/misc/lr8.php


+1

(It deserves more than a plus 1, maybe a
plus 1 times the number of characters in
Win\'s schematic. )
Ed

Yikes. The poor pot is going to have to dissipate 500 mW and drop 500V.
That\'s your unobtainium Allen Bradley carbon unit there.

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

 

[Anthony William Sloman]

On Friday, March 10, 2023 at 11:57:54 AM UTC+11, Phil Hobbs wrote:

On 2023-03-09 18:43, ehsjr wrote:
On 3/9/2023 11:17 AM, Don wrote:
John Larkin wrote:
Jeremy Morgan wrote:

<snip>

Yikes. The poor pot is going to have to dissipate 500 mW and drop 500V.
That\'s your unobtainium Allen Bradley carbon unit there.

Nobody sane would use a carbon film to dissipate 500mW.

A cermet part would work fine. The trouble with carbon film is the negative temperature coefficient of resistance. Treat them wrong and you can form a low resistance hot channel in the film. I\'ve seen it done with a 10k carbon film resistor, and - worryingly - the resistor still measured 10k afterwards, though there was a thin dark line in the paint over where the hot channel had been.

--
Bill Sloman, Sydney

 

[ehsjr]

On 3/9/2023 7:57 PM, Phil Hobbs wrote:

On 2023-03-09 18:43, ehsjr wrote:
On 3/9/2023 11:17 AM, Don wrote:
John Larkin wrote:
Jeremy Morgan wrote:

Readable version of Win\'s followup:

https://crcomp.net/misc/lr8.php


+1

(It deserves more than a plus 1, maybe a
plus 1 times the number of characters in
Win\'s schematic. )
Ed


Yikes.  The poor pot is going to have to dissipate 500 mW and drop 500V.
 That\'s your unobtainium Allen Bradley carbon unit there.

Cheers

Phil Hobbs

Right. I was giving the +1\'s to Don\'s post with the
link that contained the schematic, not the circuit.
But I sure didn\'t make that clear.

Ed

 

[John Larkin]

On Thu, 9 Mar 2023 04:25:32 -0800 (PST), Jeremy Morgan
<jeremy.robert.morgan@gmail.com> wrote:

On Monday, 31 July 2006 at 00:57:28 UTC+1, Winfield Hill wrote:
Piglit wrote...

Winfield Hill wrote:
Are you aware of the inherent difficulty in stabilizing high-
side current-amplification circuits? The regulator has an
internal high-gain feedback loop, whose gain drops 20dB/decade
with frequency, with an associated 90-degrees phase shift.
(snip comprehensive reply)

Great answer (kinda restores faith in usenet), thanks Win.
cheers
As you can see, I compared two ways of enhancing high-voltage
low-current three-terminal programmable regulators, one with
excess gain inside the feedback loop, and a second without but
with hopefully-modest output voltage errors. There\'s a third
attractive approach using low-voltage high-current regulators,
like the LM317 or LM317L, and cascoded series voltage-dropping
MOSFET(s) that always present the low-voltage LM317 with about
7V more than its output, for safe cool operation. I, and others,
have written about these in earlier s.e.d. posts, complete with
ASCII drawings. Here\'s an example from January 7th, 2002,
From: Winfield Hill (hi...@rowland.org)
Subject: Re: regulated power supply 50 volt to 400 100mA
Date: 2002-01-07 15:27:16 PST
Radioman wrote:

I am looking for a schematic for a regulated power supply
50 volt to 400 volt that can deliver 100mA or more.
The ST VB408 etc., parts that Xenos suggests are nice, but
they may be hard to get. You may be interested in a simple
high-voltage regulator that uses standard LM317 or LM317L
chips plus an easy-to-get reliable high-voltage MOSFET.
600V FET _____ LM317L 5 to 500V
IN o----+----, ,-+-----+--| |--+---+----+---o OUT
| | | | s | | | | | | to 100mA
| _|_V_|_ | |_adj_| 1.2k | |
2.2M ----, | | | | | 0.47uF
1/2 W | \'-||--+-----+ | ===
| | , 68pF | | | 630V
\'--------+---|<|-----------|---\' |
\' 10V zener | 2.7 ohms
500k |
pot gnd
|
gnd
The FET needs a very serious heat sink, because 450V at
100mA is 45 watts, and under a short circuit condition the
LM317L may allow even more current to flow. You can add
a single-transistor foldback current limit if you want.
Add a 1n4002 diode backwards across the LM317 if you plan
on ever shorting out the input filter-storage capacitor.
(Always use drain resistors with high-voltage capacitors.
And always approach the open circuit with one hand behind
your back.)
The LM317L needs as much as 2.5mA to operate, and the 1.2k
resistor only takes 1mA, so this sets a 1.5mA minimum load
requirement. (BTW, the VB408 has a 1.2mA minimum load spec.
Note, you could use 470-ohms instead of 1.2k, but this would
require a 200k pot with up to 1W of dissipation, instead of
the 0.4W maximum dissipated in the 500k pot when its set to
about 400k for +400V out.)
---------
(Looking forward to the next edition of \"The Art..\")
Groan.

--
Thanks,
- Win

Please can anyone explain to me how to read the ASCII schematics in this post? Thanks

Here\'s a classic HV regulator. There are lots of variations.

https://www.dropbox.com/s/ak7lvemwbd4sj48/HV_Pos_Reg.jpg?raw=1