Linear regulated 150V supply

R

Rene Tschaggelar

Guest
Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
 
On Sun, 21 Nov 2004 22:31:49 +0100, Rene Tschaggelar <none@none.net>
wrote:

Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?
Click to expand...
---
How about something like this?


4W
////////
+170>--+------+------D S--------+----------+---->+150
| | G | |
| [R] | [R] [R]
| | | | |
| +--------+ +---+-----+ |
| | | | | |
|+ | | [R] | |
[BFC] | | | +| |
| D /-|--+ [C] |
| G--+--[R]---< | | | |
| S | \+|--|-----|----+
| | | | |+ | |
| | [C] | [REF] | [R]
| | | | | | |
GND>---+------+----+----------+---+-----+----+---->GND

--
John Fields
 
Rene Tschaggelar wrote:

Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene
Click to expand...
I don't think you're going to find anything that does a better job than
the '723 in the same package. I seriously doubt that you'll find
anything that can stand a supply voltage above 40V or so, which means
you'll need an external pass transistor and a voltage shifter to drive
it. If you needed more precision you could take Mr. Field's suggestion;
just make sure to use a reference and op-amp that are good enough.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
Rene Tschaggelar wrote:
Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene
Click to expand...
You should be able to adapt this:
http://focus.ti.com/docs/prod/folders/print/tl783.html
It's cheap enough- but not a lot of stock out there.
 
On Sun, 21 Nov 2004 15:36:53 -0800, Tim Wescott <tim@wescottnospamdesign.com>
wrote:

Rene Tschaggelar wrote:

Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene

I don't think you're going to find anything that does a better job than
the '723 in the same package. I seriously doubt that you'll find
anything that can stand a supply voltage above 40V or so, which means
you'll need an external pass transistor and a voltage shifter to drive
it. If you needed more precision you could take Mr. Field's suggestion;
just make sure to use a reference and op-amp that are good enough.
Click to expand...
The humble/ubiquitous LM317 will quite happily meet the requirement subject to
the Vin/Vout differential being within specs. It is quite happy to float up
there at 150Vout.
 
artie wrote:
In article <41a10a09$0$28028$5402220f@news.sunrise.ch>, Rene
Tschaggelar <none@none.net> wrote:

Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene

VR150?

--
Namaste--
Click to expand...
Such a GAS!
 
On Mon, 22 Nov 2004 01:40:45 GMT, the renowned Robert Baer
<robertbaer@earthlink.net> wrote:

John Fields wrote:

On Sun, 21 Nov 2004 22:31:49 +0100, Rene Tschaggelar <none@none.net
wrote:

Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

---
How about something like this?


4W
////////
+170>--+------+------D S--------+----------+---->+150
| | G | |
| [R] | [R] [R]
| | | | |
| +--------+ +---+-----+ |
| | | | | |
|+ | | [R] | |
[BFC] | | | +| |
| D /-|--+ [C] |
| G--+--[R]---< | | | |
| S | \+|--|-----|----+
| | | | |+ | |
| | [C] | [REF] | [R]
| | | | | | |
GND>---+------+----+----------+---+-----+----+---->GND

--
John Fields

Oh, my! No consideration for all that extra gain (and likely
oscillation)!
Click to expand...
It'll stop when the gate punctures on the pass transistor.

He did say "something like this".


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
budgie wrote...
The humble/ubiquitous LM317 will quite happily meet the
requirement subject to the Vin/Vout differential being within
specs. It is quite happy to float up there at 150Vout.
Click to expand...
Until there's a momentary output fault. :>)


--
Thanks,
- Win
 
artie (artie.m@gmail.com) writes:
In article <41a10a09$0$28028$5402220f@news.sunrise.ch>, Rene
Tschaggelar <none@none.net> wrote:

Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene

VR150?

That's bound to go over a few people's heads.
Click to expand...

It certainly was the regulator of choice, and likely is still
as useful as it ever was in the application.

Michael
 
On 22 Nov 2004 03:51:20 GMT, et472@FreeNet.Carleton.CA (Michael Black) wrote:

That's bound to go over a few people's heads.

It certainly was the regulator of choice, and likely is still
as useful as it ever was in the application.
Click to expand...
I remember them. Used one, when I was ... younger. I think I may still have
two of them in a box, pulled from a WWII radar scope commissioned in 1944.

Jon
 
budgie wrote:

On Sun, 21 Nov 2004 15:36:53 -0800, Tim Wescott <tim@wescottnospamdesign.com
wrote:


Rene Tschaggelar wrote:


Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene

I don't think you're going to find anything that does a better job than
the '723 in the same package. I seriously doubt that you'll find
anything that can stand a supply voltage above 40V or so, which means
you'll need an external pass transistor and a voltage shifter to drive
it. If you needed more precision you could take Mr. Field's suggestion;
just make sure to use a reference and op-amp that are good enough.


The humble/ubiquitous LM317 will quite happily meet the requirement subject to
the Vin/Vout differential being within specs. It is quite happy to float up
there at 150Vout.
Click to expand...
Keeping that Vin/Vout differential within what -- 40V? -- is a pretty
tall order in this case -- I suppose you could protect it with a zener,
but after accounting for line variations you'd have to filter your input
pretty thoroughly to keep everything working well.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
On Sun, 21 Nov 2004 18:22:00 -0800, Winfield Hill wrote:

budgie wrote...

The humble/ubiquitous LM317 will quite happily meet the
requirement subject to the Vin/Vout differential being within
specs. It is quite happy to float up there at 150Vout.

Until there's a momentary output fault. :>)
Click to expand...
Just for the sake of contrariness, I could bring up the OP's spec of
"up to 200 mA", and can't help but wonder - wouldn't a current limit
or even crowbar help out here?

Thanks,
Rich
 
budgie wrote...
I guess it depends where you'd reather spend your time and money -
in the regulator or before it. I personally gave up 723's when
I first had occasion to use a 317.
Click to expand...
In giving up the 723 you gave up the ability to set a reasonable
current limit, and to use foldback current limiting (yes, thermal
limiting is nice, but often one would rather prevent the power
element from overheating rather than simply limit the overheating
to a rather high temperature). You also gave up the quiet voltage
zener reference, and the ability to further filter the reference.
And you gave up the superior output voltage stability that comes
from separating the reference from the power element, keeping the
high pass-transistor die temperature away from the reference zener.



--
Thanks,
- Win
 
"Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> schreef in
bericht news:cnsis20139d@drn.newsguy.com...
Spehro Pefhany wrote...

Robert Baer wrote:

John Fields wrote:

Rene Tschaggelar wrote:

Is the LM723 still the regulator of choice for a regulated
150V supply driven by a line transformer? The current to
be supplied is moderate, say up too 200mA. Or are there
any alternatives with an external pass transistor / FET ?

How about something like this?

4W
////////
+170>--+------+------D S--------+----------+---->+150
| | G | |
| [R] | [R] [R]
| | | | |
| +--------+ +---+-----+ |
| | | | | |
|+ | | [R] | |
[BFC] | | | +| |
| D /-|--+ [C] |
| G--+--[R]---< | | | |
| S | \+|--|-----|----+
| | | | |+ | |
| | [C] | [REF] | [R]
| | | | | | |
GND>---+------+----+----------+---+-----+----+---->GND

Oh, my! No consideration for all that extra gain (and
likely oscillation)!

Likely? Guaranteed. Three poles in the feedback loop, no zeros.
Click to expand...
Being simple minded, I would have thought that the R-C network
at the opamp's output would prevent oscillation.

BTW, what are 'poles' and 'zeros'? I tried to find an
explanation of the meaning (in context of amplifiers etc),
but I can't seem to find any. All texts seem to assume
it is known to the reader. (blush).

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)
 
Frank Bemelman wrote:

BTW, what are 'poles' and 'zeros'? I tried to find an
explanation of the meaning (in context of amplifiers etc),
but I can't seem to find any. All texts seem to assume
it is known to the reader. (blush).
Click to expand...
Simplistically, a pole is a lag* that goes from 0 at low frequency to 90
degrees at high frequency. A zero is a lead that behaves similarly. If
you end up with a significant gain when the overall lag (that is, the
sum of all the poles minus the sum of all the zeroes) you will get
underdamped (ringing) transients, and if the gain is 1 or above it will
oscillate continuously.

If you make the RC large enough to prevent oscillation or ringing, you
will probably end up with a very poor transient response because the
loop is so slow.

Paul Burke

*this is not intended to reflect in any way on Polish people.
 
Rene Tschaggelar wrote:
Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene
Click to expand...
You can float any of the three terminal regulators, add external
foldback current limiting, and improve the stability with an external
reference that swamps the internal reference:
http://wwwd.national.com/national/PowerMB.nsf/0/8585d691b0c1f68888256ed100202072/$FILE/lm317.pdf
 
On Mon, 22 Nov 2004 15:18:11 GMT, "Genome" <dna@nothere.net> wrote:

"Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:cnsrui01tu4@drn.newsguy.com...
Frank Bemelman wrote...

Winfield Hill wrote...
Spehro Pefhany wrote...
Robert Baer wrote:
John Fields wrote:
Rene Tschaggelar wrote:

Is the LM723 still the regulator of choice for a regulated
150V supply driven by a line transformer? The current to
be supplied is moderate, say up too 200mA. Or are there
any alternatives with an external pass transistor / FET ?

How about something like this?

4W
////////
+170>--+------+------D S--------+----------+---->+150
| | G | |
| [R] | [R] [R]
| | | | |
| +--------+ +---+-----+ |
| | | | | |
|+ | | [R] | |
[BFC] | | | +| |
| D /-|--+ [C] |
| G--+--[R]---< | | | |
| S | \+|--|-----|----+
| | | | |+ | |
| | [C] | [REF] | [R]
| | | | | | |
GND>---+------+----+----------+---+-----+----+---->GND

Oh, my! No consideration for all that extra gain (and
likely oscillation)!

Likely? Guaranteed. Three poles in the feedback loop, no zeros.

Being simple minded, I would have thought that the R-C network
at the opamp's output would prevent oscillation.

BTW, what are 'poles' and 'zeros'? I tried to find an explanation
of the meaning (in context of amplifiers etc), but I can't seem to
find any. All texts seem to assume it is known to the reader.

The breakpoint associated with a high frequency-response rolloff
is called a pole, and at the pole the signal path experiences a
45-degree phase lag. At higher frequencies this pole's phase lag
increases to 90 degrees. A negative feedback loop is already at
-180 degrees (hence the negative feedback), and an additional 90
makes -270. Add another full 90 degrees and the loop will become
unstable with -360 degrees of phase shift, which is the equivalent
of 0 degrees or no shift at all, reinforcing the signal endlessly,
making an oscillation. Now add a third 90 degree pole...

Let's look at the pole-zero loop compensation in my design.

. 20W
. ///////
. +170>--+---+---+--+-R1--+--S D----+-----+----+---> +150V
. | | | | | G | | | 200mA
. | | | E R2 | | | |
. + | | R4 B---+----|--R3--' | _|_+
. BFC | | C | | --- C3
. | R10 +--+----------' | | large
. | | | ,-----+ |
. gnd +---|-----------, C2 | | gnd
. | | ,--R6--|-||-, R7 R8
. Z1 | | |_ | | |
. | C | / -|--+---|-----+
. gnd B--+----< | | |
. E \_+|------+ R9
. | | |+ |
. R5 | REF gnd
. | gnd |
. gnd gnd






Estimating the gain going around the loop, we'll start with the R9/R8
divider, which will have a gain of about 5/150 = 1/30.

Thanks,
- Win

Oh come on Win!

The junction of R9/R8 is at the summing node of the Op-Amp. You're doing a
small signal AC analysis.


DNA
Click to expand...
ROTFLMAO!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
Jim Thompson wrote...
Genome wrote:
Winfield Hill wrote ...

Estimating the gain going around the loop, we'll start with the
R9/R8 divider, which will have a gain of about 5/150 = 1/30.

Oh come on Win!

The junction of R9/R8 is at the summing node of the Op-Amp.
You're doing a small signal AC analysis.

ROTFLMAO!
Click to expand...
Not, so silly at all. To simplify for Frank, who professed some
intimidation, I broke the circuit up into a bunch of small pieces,
one of which is those two resistors NOT connected to the opamp.

My point was that together they represent a substantial loss of
signal, rather than a gain (to be compared to the high gain of
the power MOSFET stage moments later). Well, perhaps that point
and its significance was lost on my readers. Genome would prefer
to skip that and advance straight to saying the small-signal gain
is the impedance of R6 and C2, divided by R8. Fine, that's OK too.


--
Thanks,
- Win
 
In article <cnsis20139d@drn.newsguy.com>,
Winfield Hill <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

. 20W
. ///////
. +170>--+---+---+--+-R1--+--S D----+-----+----+---->+150
. | | | | | G | | |
. | | | E R2 | | | |
. + | | R4 B---+----|--R3--' | _|_+
. BFC | | C | | --- C3
. | R10 +--+----------' | | large
. | | | ,-----+ |
. gnd +---|-----------, C2 | | gnd
. | | ,--R6--|-||-, R7 R8
. Z1 | | |_ | | |
. | C | / -|--+---|-----+
. gnd B--+----< | | |
. E \_+|------+ R9
. | | |+ |
. R5 | REF gnd
. | gnd |
. gnd gnd

Startup opamp voltage regulator.
Click to expand...
There's a nag of suspicion about regulators who derive
the REF current from Vout. There's always the question
of will it, won't it. Maybe have a small amount of seed
current into REF, from the top of Z1.

--
Tony Williams.
 
On Sun, 21 Nov 2004 23:12:53 +0000, artie wrote:

In article <41a10a09$0$28028$5402220f@news.sunrise.ch>, Rene
Tschaggelar <none@none.net> wrote:

Is the LM723 still the regulator of choice for a
regulated 150V supply driven by a line transformer ?
The current to be supplied is moderate, say up too
200mA.
Or are there any alternatives with an external pass
transistor / FET ?

Rene

VR150?
Click to expand...
1N4761A x 2

:)
Rich
 
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