SMPS +/-5V about +50V supply.

[Clive Arthur]

I want a switch mode PSU which will give me two ~2A outputs at 5V above
and below a nominal +50V (say +40V to +60V) DC supply, ie +55V and +45V
from +50V.

I can probably work out some fairly clunky ways of doing this, but it
seems possible that there's some topology particularly suited to this
type of thing.

Any thoughts?

Cheers
--
Clive

 

[Winfield Hill]

Clive Arthur wrote...

I want a switch mode PSU which will give me two ~2A
outputs at 5V above and below a nominal +50V (say
+40V to +60V) DC supply, ie +55V and +45V from +50V.

I'm a big fan of DC-DC converter modules; two isolated
10-watt regulated 5V modules would do the job. If you
want to roll your own dc-dc converter, use a standard
transformer type, rather than something inductor based.



--
Thanks,
- Win

 

On Wed, 9 Oct 2019 14:48:36 +0100, Clive Arthur
<cliveta@nowaytoday.co.uk> wrote:

On 09/10/2019 13:38, Winfield Hill wrote:
Clive Arthur wrote...

I want a switch mode PSU which will give me two ~2A
outputs at 5V above and below a nominal +50V (say
+40V to +60V) DC supply, ie +55V and +45V from +50V.

I'm a big fan of DC-DC converter modules; two isolated
10-watt regulated 5V modules would do the job. If you
want to roll your own dc-dc converter, use a standard
transformer type, rather than something inductor based.

Thanks, Win.

I like the COTS modules too, but this has to be hand-rolled to work at
180'C. I should have mentioned that.

Cheers

Do the 5 volt offsets need to be regulated?

Here are some old open-loop rail boosters.

https://www.dropbox.com/sh/qc9dim5h5k4x6f6/AABGpa6X0xQJfNB_H3lkVIUXa?dl=0



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

You signed up to work in a oil drilling hole? I hope you are getting paid by the hour

 

[Clive Arthur]

On 09/10/2019 13:38, Winfield Hill wrote:

Clive Arthur wrote...

I want a switch mode PSU which will give me two ~2A
outputs at 5V above and below a nominal +50V (say
+40V to +60V) DC supply, ie +55V and +45V from +50V.

I'm a big fan of DC-DC converter modules; two isolated
10-watt regulated 5V modules would do the job. If you
want to roll your own dc-dc converter, use a standard
transformer type, rather than something inductor based.

Thanks, Win.

I like the COTS modules too, but this has to be hand-rolled to work at
180'C. I should have mentioned that.

Cheers
--
Clive

 

[Winfield Hill]

jlarkin@highlandsniptechnology.com wrote...

On Wed, 9 Oct 2019, Clive Arthur wrote:
Clive Arthur wrote...

I want a switch mode PSU which will give me two ~2A
outputs at 5V above and below a nominal +50V (say
+40V to +60V) DC supply, ie +55V and +45V from +50V.

Do the 5 volt offsets need to be regulated?

I like to use coupled inductors. They're available
in triple and quad-winding versions. You regulate
the output of one secondary, and the other two can
go along for the ride, good to maybe 5%, or 10% if
there are extremely unbalanced currents. I'd buck
a 5-volt supply from 50V to start the process; and
run transformer near 50% for good 20W efficiency.


--
Thanks,
- Win

 

[Clive Arthur]

On 09/10/2019 16:27, Winfield Hill wrote:

jlarkin@highlandsniptechnology.com wrote...

On Wed, 9 Oct 2019, Clive Arthur wrote:
Clive Arthur wrote...

I want a switch mode PSU which will give me two ~2A
outputs at 5V above and below a nominal +50V (say
+40V to +60V) DC supply, ie +55V and +45V from +50V.

Do the 5 volt offsets need to be regulated?

I like to use coupled inductors. They're available
in triple and quad-winding versions. You regulate
the output of one secondary, and the other two can
go along for the ride, good to maybe 5%, or 10% if
there are extremely unbalanced currents. I'd buck
a 5-volt supply from 50V to start the process; and
run transformer near 50% for good 20W efficiency.


Thanks.

I could use a ground referenced 5V too, so that sounds like a buck
converter with two extra 5V windings for the 50V +/-5V supplies.
Regulation on those isn't critical, so that looks like a winner.

The cheque's in the post.

Cheers
--
Clive

 

[Winfield Hill]

Clive Arthur wrote...

On 09/10/2019 16:27, Winfield Hill wrote:
jlarkin@highlandsniptechnology.com wrote...

On Wed, 9 Oct 2019, Clive Arthur wrote:
Clive Arthur wrote...

I want a switch mode PSU which will give me two ~2A
outputs at 5V above and below a nominal +50V (say
+40V to +60V) DC supply, ie +55V and +45V from +50V.

Do the 5 volt offsets need to be regulated?

I like to use coupled inductors. They're available
in triple and quad-winding versions. You regulate
the output of one secondary, and the other two can
go along for the ride, good to maybe 5%, or 10% if
there are extremely unbalanced currents. I'd buck
a 5-volt supply from 50V to start the process; and
run transformer near 50% for good 20W efficiency.

I could use a ground referenced 5V too, so that sounds
like a buck converter with two extra 5V windings ...

I didn't suggest a single stage converter, because you
wanted 10W from each extra 5V output. A 20W 50V to 5V
buck is a bit of a beast on its own, needing 4A output,
and hence it's switching 4A at 50V for 10% of the time.
It needs its own special inductor, especially at 180C.
Then you can use a standard coupled inductor, running
at 50% to make an efficient isolated dual 5V 2A outputs.


--
Thanks,
- Win