I am from Kolkata, India.
Using PI products regularly.
I have assembled circuit of figure-4 of DER-286. Transformer design is attached.
I have reduced R10 to 54K as to drive 2X(1WX9 nos) LED strings. OP- 27V, 650mA.
But, PF is as poor as 0.65.
Middle portion of input current wave form is having high spikes and not at all matching with the image of DER-286.
PLEASE HELP, so that PF is 0.9 +.
Your prompt reply will be much appreciated.