Other Parts Discussed in Thread: LM5155, LM5155EVM-FLY
Hello
We are designing with the LM51551 in a flyback configuration and have a question the on soft start calculation.
We have 2.2uF connected to SS pin, then going to a BJT gate connected to COMP_PRI (image below).
Normally we would have expected a soft start time of about 0.22usec, however we're seeing only 0.03 seconds.
The calculation in the datasheet is tss = Css / Iss with Iss = 10uA.
Could you please let us know? Thank you, Keith