Feedback for 220VDC SMPS

[vimalkhanna]

Trying to use a TL431A to stablize my SMPS design of 220VDC output .
Long tailed bleeders used ,dropped the output but the 431punctured .

 

[Orson Cart]

you need a different resistive divider system as when the 431 turns off (light to no load) it will see the full applied volts...
i.e. make sure the worst case applied volts (usually no load) to the 431 are below the rating for the particular device you are using - not all are 40V.
Regards, Orson Cart.

 

[vimalkhanna]

I divided thru re.sistor networks to give 18-24VDC at the cathode of 431A but they still blew for no reason...

 

[Orson Cart]

You need to make sure you are not trying to pull too much current in the TL431 - can you post the complete circuit please? Regards, Orson Cart.

 

[vimalkhanna]

I was trying to go for bipolar transorbs at the cathode of the 431A ...any help?

 

[leo_o2]

Currently, primary side feedback is more popular for AC-DC. You can find many this kind of IC thru websites.
No 431 needed. It is cheaper and easier for design.

 

[Orson Cart]

a linear opto, e.g. IL300 can be used to transfer the Vout to the pri side if you have a 12V say, aux supply on the sec to power the IL300 ckt. Or you can post the current circuit and we can then see the problem. Regards, Orson Cart.

 

[leo_o2]

Even some RCC structure don't need 431 too.