Dear Sir ,
How are you ? I hope you are good also your work .
we use LM3447 to make 50 watt led driver . when connect the power .out put go up and down from 30 v to 40 v
i measured the volt on Vcc it go up and down from 11.5-18 v . when I connect the load cob 1.5 A 32 V
it turn on & off but I do not Know the reason . the attached files contain the design Example& schematic
Hint :- I remove resistor R2 it absorb a lot of current also D1 is too hot i replace it by part number of D3