we made a non dimmable 28W (70V/400mA) driver with guidance of DER286. It is works good but flickering at 260volts and above. Ckt is having all components same as of der286 except the output rectifier which used MUR460. Transformer used PQ2625 and design spread sheet shows no warning. We put KP = 0.8 and VOR = 116V and switch is LNK419. It is working from 80V to 260V without any issues. Can you gude us to solve the the FLICKERING PROBLEM @260V. Pls note the Feedback pin current is 160uA upto 264V. We added RV2 - 1.4M ohms and found no change in the flickering.
Waiting for your immediate reply