Output begins "Flashing" when input voltage is >175VAC

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This is a linkswitch CV design that I have referenced in this post previously: https://ac-dc.power.com/forum/low-power-design/2019/lnk625dg-dual-output-12vdc-04a-33vdc-04a-output-regulation-33v

I previously was running it at 120VAC for initial testing. I recently tried 240VAC and found that it is not working. The output "Flashes" on and off when the DC bus is above 250VDC. Can you tell me what causes this and how to resolve it? I have attached oscilliscope captures to give a better idea of what it looks like. It does not matter what the load is, the operation is basically the same.

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175VAC_problems.pdf1.21 MB

The problem appears to be the current limit kicking in. What would be causing the current limit to kick in even at light to no load conditions?

Attached is a o-scope capture. CH1 is Drain pin on LNK625DG. Using x500 probe, so 50V/Div. Measurment cursor shows 2.737V... x5 for probe = 13.7V on drian. Assuming 16 ohm Rds, that is 0.855A. Well over the current limit.

I determined the cause of the problem. I had used a 40V schottky diode on the output side of the circuit. When the input voltage was higher, the reverse voltage on the output diode was too high, and it was allowing reverse conductance. Switching that diode out fixed the problem.