I have a trouble with correct soft start of the PFC module based on UCC28019.
I used the standard schematic and here is my calculation table:
All components that I actually used specified in this table (there few deviations, but no one in compensation circuits).
Choke made using Sendust ring (33x20x11mm, ue=125). Inductance is 2.1mH. Designed operating current is 2 Amps at approx 0.4T.
In all tests power source used - an isolated AC source, 220V 50 Hz. Load - ITECH IT8512B electronic load in Constant Wattage mode (110W). Current measurement - Agilent N2782A current probe. Oscilloscope - Rigol DS1102D. DC BIAS supply - an ATX computer power source, 12V line.
And here is my problem (1V == 1A):
There is no core saturation. In more close view I see nice current ramp with correctly limited current at the peak.
But it seems PCL is acting. Not a SOC. Why?
After startup PFC works fine at the maximum load and in full input voltage range (90..265VAC) with PF=0.99
I tried to change almost all components in the board, but none change has not led to positive results.
Also, I tried to use more powerful choke and decrease Rsense to 0.1 Ohm.
Please, tell me, what can I do to solve this problem...