Original question:
Hello,
I have not heard of customers having any issues designing with this device that follow the layout guidelines in the data sheet and follow the design procedure in application note slua560.
https://www.ti.com/lit/pdf/slua560
If the design has a poor layout it could be susceptible to noise. The following link will bring you to a 600 W reference design using the UCC28950. There is a schematic, BOM and layout capture in the User's guide. You might want to use the reference design layout as a reference and compare it to yours. If there are see any major differences between your layout and reference design, then your layout might be the issue.
https://www.ti.com/lit/pdf/sluu421
The other thing that may be causing your issue is that the design does not have enough phase margin or gain margin. You can check the voltage compensation with application note SLUA560. You should also check the loop compensation with a network analyzer as well.
https://www.ti.com/lit/pdf/slua560
I would also double check your CS transformer setup. If this was setup incorrectly your design could be going into Over Current hiccup mode protection.
You can check this setup with application note SLUA560. Please note if the CS signal is noisy due to poor layout it could could the control to misbehave.
You also might want to order this reference design to evaluate from ti.com. It was design with application note slua560 and the design is quite stable and does not exhibit any of the behavior that you describe.
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Regards,
