How do I design a Galvanic Separation Power Supply: Input: 5V to 25V DC Output: 5V 5A DC
I generally use reference design to design power supply or power supply design like TI workbench etc Its needed for IOT gateway project

 

Welcome to AAC.

I can’t understand your question.

”How do I design…” anything is a very ambiguous question.
”I generally use a reference design…” seems like an answer.

What, exactly, is the help you are looking for?

 

Are you saying that without a reference design you have little to no idea how to proceed? If that is the case, you might want to start by understanding the basic requirements. I'm going to guess that English is not your first language and what you are trying to describe is known as:
"galvanic isolation". Maybe you already know the concept by another name in your language but are missing the appropriate search term for English. If that is the case maybe knowing to correct term will be helpful. If not, you are free to ask more questions.

 

How do I design a Galvanic Separation Power Supply: Input: 5V to 25V DC Output: 5V 5A DC
I generally use reference design to design power supply or power supply design like TI workbench etc Its needed for IOT gateway project

When you use TI Power Designer, just turn on the switch labelled "Isolated Output".
TI gave me 13 designs mainly LM5156 based.
The you need to know just how isolated it needs to be? Functional isolation which would withstand about 500V or isolated to 230V mains standards which may need to withstand 4kV. That information is needed by the transformer designer.

 

The beginning of a design is always the requirements, followed by the limitations.
For starters, "galvanic isolation" means no electrical connection between the input and the output. THAT means that there will be a transformer of some kind, with at least a primary and a secondary winding. Then we have the output: 5 volts DC at up to 5 amps. so 25 watts out of the transformer.
Then the power source, from 5 volts DC up to 25 volts DC. So some place there needs to be some sort of regulation.
What is not mentioned is the accuracy of that output: Is it just 5 volts, or must it be 5.00 volts?
The final thing is efficiency. That was not mentioned and so it might not matter so very much. But those are the requirements.
It could be an inverter with a transformer and a linear regulator on the output. OR it could be a switcher inverter with feedback to keep the output constant.
OR it could be an inverter that drives the transformer into saturation so that the output is fairly common. That could provide much of the regulation, like a SOLA CVT system. Then just set the number of turns to provide the desired output voltage at transformer saturation. Not the most efficient but certainly built in regulation.