I modified the LNK408 reference dimming circuit to work at 277 volts. (Scaled dampening components and increased voltage ratings.) It runs fine (months continuously) in full output but when I connect a 277V dimmer it fails. It dims beautifully at 120 volts. Also, the current waveform at 277 is pretty ugly, is this normal? Is dimming at 277 volts even possible with this IC?