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Need to replace an old power supply

Flyback

Well-Known Member
Hi,

Need to replace an offline 240VAC power supply that had outputs +13.5V, 6A and -13.5V, 1A.
Size is 140mm x 230mm x 55mm. In metal case with vent holes for fans.

Do you off the top of your head know of any quick, cheap off the shelf way of doing this?
 

danadak

Active Member
I would take this to the leading manufacturers and post the requirements, along with
datasheet for old supply. That way they can confirm it meets the same standards, as
well as the application HW.


Regards, Dana.
 

Flyback

Well-Known Member
Thanks, i think two 15v open frame SMPS's which can be trimmed down to 13.5V woudl do the job...then we can knock them into a case and voila.

Thinking about one of these for the 13.5V at 6A:
LM25-23B15

and one of these for the -13.5V at 1.5A:
LCS100US15

in a metal enclosure, and add some fans in there.

And add some diodes across each output, this will give 13.5v-0-(-13.5v)


And even though its >75W, we will not have to worry about PFC?...because each PSU passes regulations on their own......so even though we have mounted them in a single box, the overall PFC drawn by that box does not matter?
 
Last edited:

ChrisP58

Well-Known Member
Most Helpful Member
Thanks, i think two 15v open frame SMPS's which can be trimmed down to 13.5V woudl do the job...then we can knock them into a case and voila.

Thinking about one of these for the 13.5V at 6A:
LM25-23B15

and one of these for the -13.5V at 1.5A:
LCS100US15

in a metal enclosure, and add some fans in there.

And add some diodes across each output, this will give 13.5v-0-(-13.5v)


And even though its >75W, we will not have to worry about PFC?...because each PSU passes regulations on their own......so even though we have mounted them in a single box, the overall PFC drawn by that box does not matter?
I expect that a certification agency would look at your box as a single system, and view the PFC requirement as one item.
 

Pommie

Well-Known Member
Most Helpful Member
If you get a 13.5 (12V or 15V tweeked) >7A PSU that is certified, you can produce the negative supply with an inverting DC-DC converter.

Mike.
 

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