SMPS with PFC

res_smps

Member
I think I have to correct this statement
Sorry Silvio,
With the presence of PFC, capacitor requirements can be smaller, I attach an excel file for PFC calculations (I downloaded from onsemi website) in post # 5
I thought the PFC frequency determined the size of the capacitor, I was wrong
from the worksheet, capacitor requirements are not determined by the PFC frequency, please check this formula (pic) below
cbulk.jpg

*for the same power, the higher the output voltage the smaller the capacitor needs
 
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res_smps

Member
*for the same power, the higher the output voltage the smaller the capacitor needs

In the pfc circuit to my believe the value of the capacitor determines the hold time at load.

Check this ( I sent you mail)

View attachment 7127
Dear Silvio,

yes, that also true. Thank you for the file, I also previously shared it here (zip files) in post #2

please ignore the picture in post #41, there was an error
cbulk.jpg
cbulk value is determined from the highest results from the following 2 formulas :
1) 10000*Pout/(0.01*Vripple*2*pi*Fac*Vout^2
or
2) 2000*Pout*Thold/(Vout^2-Voutmin^2)
from the formula this parameter determines the cbulk
1. Line frequency (Fac) 50/60Hz
2. Pout
3. Tholdup
4. Vout
5. Vripple
Pout and Vout appear in both formula
 
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Marshall

New member
About this project , i checked separately every stage , NCP1653 in Data Sheet has same conections as on this schematic only inductor everywhere is 600uH, UC3845 is simple power supply, i share schematic here, connections are good , power stage with SG3525 is also ok , but, things that i dont understand, as i know , this configuration in half bridge main transformer has 13+13 turns in primary , same number of turns also here, i know that full bridge have less windings than half brigde , maybe 2 X 7.. that its not clear, also inductor 380uH vs. 600uH !? , number of turns on transformer on aux supply !? and windings on GDT !?.. PHOTO.jpg
 

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stewin

Member
hi andrew . did you manage to make your smps work succesful with the pfc? please post photos and your experience on its power.
 
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