Tool/software:
Hello,
I implemented the circuit from LM5169FEVM using LM5169FDDAR. The secondary output is non connected in any way to the primary output, not even the ground. Please ignore the IC on the schematic below. The actual chip soldered on the PCB is LM5169FDDAR. 
Input voltage range tested between 20V and 62V
I get this strange behaviour:
If I apply instant input voltage the converter enters in some mode which looks like a protection. Switching frequency drops to about 100kHz, secondary output is around 5V@input voltage 60V and primary output is very low, about 1.5V
If input voltage is applied with some slew rate the converter starts with switching frequency of 750kHz. I see very nice square wave pulses on the SW pin. At this point the primary output voltage is tightly regulated to 10V whilst the secondary voltage vary depending on the input voltage. For example at input voltage 60V the secondary output is 50V at which point the 1k load resistor is starting to smoke. At lower input voltages secondary output voltage goes low - e.g. with input voltage of 21V I get secondary output of about 10V. At the same time the primary voltage is regulated to 10V and I managed to load it to about 300mA without any issues.
Now, if I get the converter to an overcurrent state, the protection kicks in and we get into a permanent protection state as explained at the beginning. This is a latched state - the converter does not attempt to restart. Power cycling with slow climbing input voltage is required to restart it. By "slow" I mean either wind up my bench power supply or set it at a voltage and press the power button - even the bench power supply output ramping is slow enough to restart the circuit.
Would it be possible to advise what am I doing wrong?
