[SOLVED] Merging three AC to DC power supply.

[papaisou11]

Hi...
I have designed three smps using tinyswi tch - 4 family with different output power rating.

Each smps consits pi filters after the bridge diode. The pi filter consist two bulk capacitors and a single choke.

Now, I want to mege these three smps using a single bridge diode, and single pi filter.

Thus the connection will be bridge diode after that an electrolytic capacitor after that a choke after that agin a capacitor and the high voltage dc will be divided into three smps.


My question is, how can I choose the pi filter capacitors and the choke value?

 

[D.A.(Tony)Stewart]

Start by defining the Zin to each SMPS on startup and range of power use and the spectrum of input currents. The Pi filter Zout(f) needs to be as low as possible to reduce source regulation error and aliasing effects between each load spectrum. So make best estimates of all conditions and parameters in the frequency domain then use Faltad's filter designer with RLC parts and pulse gen's to verify the interactions or Bode plots to see attenuation. Add ESR to real parts. https://www.falstad.com/circuit/e-filt-lopass-l.html BEware of resonances. https://www.falstad.com/afilter/circuitjs.html?cct=$+1+0.000005+5+50+5+50 %+0+28853.998118144256 170+64+112+32+112+3+20+1000+5+0.1 g+192+144+192+160+0 g+144+144+144+160+0 c+192+112+192+144+0+0.0001+4.624691084937425 c+144+112+144+144+0+0.000047000000000000004+4.983533709056215 l+144+112+192+112+0+0.0001+0.03119230076136272 w+112+112+144+112+0 O+192+112+240+112+0 r+112+112+64+112+0+100 o+0+32+0+34+5+0.00009765625+0+-1

random cct https://tinyurl.com/yxuaoypm

 

[papaisou11]

Thanks a lot. It did work. I have designed a pi filter according to it.