i a using an isolated DC DC converter..i wanna know if i don't short the -ve output and input ground annd want to use the -ve output as gnd for the rest of circuitry, how would i do it actually?

 

If the converter is truly isolated then you can connect the input ground and output ground wherever you want.
The only restriction would be the isolation voltage limit between the input and output (which is usually stated in the spec sheet).

 

What is the model number of the converter, or circuit diagram?

 

you mean that if i am using 24 to 12v converter i will connect 24V and GND to input + & - pins and can get 12V and gnd at out + & - pins. And i can connect the rest circuitry to these output pins! it will work correctly?

 

i am using vicor VI-j00

 

24Vin between 1 and 4; 12Vout between 5 and 9. You can tie 4 to 5 or 4 to 9, or not tie input to anything on the output.

 

That is a cranky old part. Any reason you are not using their 2nd gen (Maxi, Midi, Mini) bricks? I've found them to be still a bit Vicor-weird, but not as weird as the VI-J.

ak

 

24Vin between 1 and 4; 12Vout between 5 and 9. You can tie 4 to 5 or 4 to 9, or not tie input to anything on the output.

View attachment 95336

if i don't tie any input to -output, can i still use -output as gnd to drive the rest circuitry?

 

Yes, you can do what you like.

 

if i don't tie any input to -output, can i still use -output as gnd to drive the rest circuitry?

Yes. But dont call that electrical node "Gnd" unless is connected to a metallic rod driven into the earth. A better name is oV or Com.

 

for emi reduction, how will i connect emi filter before dc dc converter and what about grounding?