Hi Vitali,
Yes that is true. During startup, the device can either go into current limit or power limit, depending on which mechanism has a lower current limit. If the power limit is set to 50W, and VIN = 25V, then at startup the device will limit the current to 2A, but if the current limit is set to lower than 2A it will limit at the current limit. As VOUT goes up, the power limit will allow more current to satisfy the constant power across the FET.
During power limit or current limit, the timer pin will begin to ramp until it hits 4V, after which it shuts off the FET. The timer cap. will determine how long this time is.
Let's continue this discussion after Christmas- happy holidays.
Best Regards,
Mike