We are working on Two switch forward family of PI Part # TFS7708H without PFC ,
I/P AC range : 180VAC to 285VAC
O/P : 30V 10A and 60V 5A
Sample reference design we are following is DER - 472 (61V 4.59A ) and
Design Example: 12 V / 15 A Main Output, 12 V, 0.83 A Standby
Now the standby converter is working fine (12V / 1A ) transformer EF20
Problem is with Main Converter, upon injecting current on by-Pass(BP) of TFS7708H
the whole converter with standby converter switches off and the then takes several minutes
for the standby converter to start again, meanwhile the primary bias of standby converter drops to 3V ~ 5V.
Hereby, i am attaching PI design excel file containing our exact design .
Please suggest how can we address this issue.