Hi Everyone ,

I need some opinion regarding Voltage conversion.

I need 48 V,5A; 24V,1A; 12V,2A and 5V,2A DC .

Which is the efficient way to get these voltages .
Buy a AC DC converter that converts 230V AC to 48V DC and then step down from 48V DC to 24V,12V and 5V

or

Buy 2 AC DC converters that converts 230V AC to 48V DC and 230V AC to 24V DC and then step down from 24 V DC to 12V and 5V respectively.

NOTE: All the DC voltages has to be galvanically isolated.

thank you in advance.

 

I'd simply buy 4 AC/DC converters. Probably cheaper than trying to drop the volts down at those currents.

 

1. Galvanically isolated from each other, or just from the AC source?

2. All purchased modules, grow from scratch, of some combo of both?

IF AC isolation only and all purchased, I vote for only one fully-isolated AC/DC for 48 V at 350 W, followed by three DC/DC buck regulators from ebay. If you need better vendor control, TI, XP Power, Artesyn, etc. all have POL (Point Of Load) product lines. How are you packaging this? High density bricks or shoe-box industrials?

ak

 

1. Galvanically isolated from each other, or just from the AC source?

Galvanically isolated from each other too...

2. All purchased modules, grow from scratch, of some combo of both?

Everything from the scratch is too much time consuming.
So , What I thought was to buy a AC DC converter for 48 V, 7.5A and then to build a PCB with 3 DC DC converter modules for 24V , 12 V or 5V.
Is this a good option??

IF AC isolation only and all purchased, I vote for only one fully-isolated AC/DC for 48 V at 350 W, followed by three DC/DC buck regulators from ebay. If you need better vendor control, TI, XP Power, Artesyn, etc. all have POL (Point Of Load) product lines. How are you packaging this? High density bricks or shoe-box industrials?

Packaging :The 48 V DC module would be used as a laptop charger module( external ) and the remaining voltages will be enclosed in a metal housing with heatsinks or fans..

Sorry :Answers for questions 1 and 2 are inside the quote...

 

And what is your opinion on using the TExas instruments WEBENCH design tool for such DC DC convertes ?? ( 48 V to 24 V , 12V , 5V DC)

 

Nothing wrong with your plan; I've done it a few times. When time or money are short, nothing beats buying your AC isolation pedigree off the shelf.
While you don't owe us an explanation, I'd like to know what it is about your application that needs 6-way galvanic isolation.
Note that most low voltage DC/DC converters, such as 48V to 5V, do not have the same isolation specs as AC/DC converters that are built for UL or MIL compliance.
Laptop chargers don't run up to 350 W; the most I've seen is under 200 W. 350 W industrial supplies are available with a perf metal cover for safety if your location can't tolerate an open frame supply.
If you don't have forced air cooling, you will have to oversize the +48 supply.
Four separate fully isolated converters will be relatively expansive, but just about any major power supply vendor will have all the parts.
Astrodyne, XP Power, Lambda, Artesyn, Autec, Cherokee, Power One...
Also, many surplus stores and ebay have these kinds of devices if you don't need big name vendors.

ak