I have been working on a non-isolated 15V supply using the LNK3205. I am having trouble with the turn off behavior of the supply. When I cut the AC power to the circuit the 15V output starts to drop as I would expect, but then it behaves as though it is trying to start up again a couple of times. After about 800mS it finally gives up and the output slowly decays as the energy stored in the output caps is drained. I've included a waveform of the output as well as schematic of my circuit. Note that I have a full wave bridge rectifier elsewhere in the design that supplies the rectified AC to this circuit.
My primary goal is to keep the output below 5V after I cut AC power to the circuit. I've added a cap around the feedback resistor (Cnew in the SCH) to improve the turn on performance but it hasn't had an effect on the turn off behavior.