Question
L6563 gate pulses happen only at the crest of Vac, for Vac>220Vrms and load <25%
Nice 3mSec string of gate pulses as Vac rounds the top of the AC wave, then the gate pulses stop for 5.3mSec until the next 60Hz crest comes along. Voltage waveforms on all the other pins look normal as expected. Schematic and complete set of scope shots are available to send to ST Tech support.
