Did you know the ratings beforehand?

If you did, why would you connect it up to 120VAC, which is about 169V P-P?

If the MOSFETs both happened to be biased ON (which could easily have happened, since the gates would be "floating" until the uC received power) you would've created a direct short across the supply.

This circuit definitely needs work.

 

I now get it. The circuit needs some serious work. Could you please suggest me some compatible components which i could use in place of the diodes and the power mosfet

 

You're one of the "few good men" sarge, but you may have overlooked the magnitude of the mains in this example, which is 220VAC giving a peak of 311 VDC.

Rather than try to put band aids on a design with manifest deficiencies we might better ask the OP for his requirements since that is where all good designs start. We know they are good designs because we know what done means.

I don't suppose the OP bothered to write a requirements document. Did he?

What do we have to do to stamp out and obliterate this notion among the 90 day wonders that power supplies should be built without transformers. I suggest we make clear in no uncertain terms that this is in the same category as cellphone detonators, shockers, and other assorted deprecated devices.

 

You're one of the "few good men" sarge, but you may have overlooked the magnitude of the mains in this example, which is 220VAC giving a peak of 311 VDC.

Thank you, Papabravo - I did indeed miss that. I still find the OP's schematic very difficult to read; I couldn't make out the "220" when I was posting. My vision isn't what it once was, and when I'm tired, it gets worse.

Rather than try to put band aids on a design with manifest deficiencies we might better ask the OP for his requirements since that is where all good designs start. We know they are good designs because we know what done means.

I don't suppose the OP bothered to write a requirements document. Did he?

What do we have to do to stamp out and obliterate this notion among the 90 day wonders that power supplies should be built without transformers. I suggest we make clear in no uncertain terms that this is in the same category as cellphone detonators, shockers, and other assorted deprecated devices.

I concur with your statements.

Prasanthebenezer,
You really, really must not try to implement your design without a transformer.
Obtain a 220vac to 34vac transformer. This will give you about 48VDC after the output has been rectified and filtered with sufficiently large capacitors.

You can then experiment in comparative safety. There will still be a chance you will receive mild shocks or burns from too-hot components if you are careless, but should not be life-threatening.

From there, you can build a DC-DC "buck" converter if you'd like.

Write down exactly what you want to do - your statement of requirements. How much voltage at what current will you need?
How will you get things started when there is no power to run the microcontroller?

 

did you guys notice he had the bridge connected backwards... so on applying power there would be a direct short through the protection diodes for the fets

 

The schematic is fuzzy because it was saved as a JPG file type that has losses. If it was saved as a GIF or PNG file type then it would be very clear.

I also noticed that the rectifier bridge was wired backwards and that the high side Mosfet dosn't work.

 

well guys thanks....... I will soon get back with the updated ckt if I have any more problems