Смотри какой кондер идет на 2-ю ногу TNY177PN (С7 по даташиту), он определяет макс. предел тока.
"For design fl exibility the value of C7 can be selected to pick one
of the 3 current limits options in U1. This allows the designer
to select the current limit appropriate for the application.
• Standard current limit (I
LIMIT
) is selected with a 0.1 μF BP/M
pin capacitor and is the normal choice for typical enclosed
adapter applications.
• When a 1 μF BP/M pin capacitor is used, the current
limit is reduced (I
LIMITred
or I
LIMIT
-1) offering reduced RMS
device currents and therefore improved effi ciency, but at
the expense of maximum power capability. This is ideal
for thermally challenging designs where dissipation must
be minimized.
• When a 10 μF BP/M pin capacitor is used, the current
limit is increased (I
LIMITinc
or I
LIMIT
+1), extending the power
capability for applications requiring higher peak power or
continuous power where the thermal conditions allow."
http://dalincom.ru/datasheet/TNY176PN.pdf
