Electronics > Projects, Designs, and Technical Stuff
Isolated DC/DC converters "unregulated"?
(1/4) > >>
Simon:
I'm looking at some isolated power converters so that I can power an isolated coms bus. But all I see on the datasheets is "unregulated". Not much of a deal is made and i fear a burying of the detail. So do these converters simply work at a fixed ratio to the input supply and will follow any error in the supply input. Usually they are specified at +/- 10% input like 4.5V to 5.5V, does this mean that the output would also be in this range for a 5V output model?

This converter does not talk of "unregulated", does this mean it is regulated or did they just forget to tell me that?: https://www.xppower.com/portals/0/pdfs/SF_ITB.pdf
Siwastaja:

--- Quote from: Simon on December 25, 2019, 02:08:51 pm ---This converter does not talk of "unregulated", does this mean it is regulated or did they just forget to tell me that?: https://www.xppower.com/portals/0/pdfs/SF_ITB.pdf

--- End quote ---

If you look at numbers beyond the headlines, both line and load regulation is specified on page 2. Yes, it sucks.

AFAIK, at least some of these regulators include input voltage feedforward, i.e., some line regulation, because it's easy to implement in their topology; but poor load regulation, because it would require isolating the feedback signal from the output, which is expensive.

The simplest have poor line regulation, though, as well.

Actual "proper" isolated DC/DC modules that are properly regulated and protected can be horribly expensive and hard to find.

These cheaper modules are often indeed used to supply power to isolated communication transceivers, where the exact voltage, regulation and ripple tend not to matter too much. The efficiency tends to suck, as well.

Also note they are built to a price and certain footprint, and often require extra capacitance and possibly an EMI filter.
Simon:
Ah another screw you datasheet. Are there any regulated ones? maybe the parametric search on digikey is better, mouser don't even offer a temperature selection.

Yes this is for isolated comms.
Siwastaja:

--- Quote from: Simon on December 25, 2019, 02:48:12 pm ---Ah another screw you datasheet. Are there any regulated ones? maybe the parametric search on digikey is better, mouser don't even offer a temperature selection.

Yes this is for isolated comms.

--- End quote ---

If regulation is important, it's the cheapest and simplest to choose one with a higher voltage, then use a $0.10 linear regulator after it.

The regulated ones are much more expensive so you can sort by price.
Simon:
Yea I guess so. It's not much of a problem but I will have to make sure my main 5V converter is regulated or I will have a chain of inaccuracies.
Navigation
Message Index
Next page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod