I'm trying to understand how CI HT7A6322 starts up.
Relevant part of the datasheet says:
Control circuit power supply. Also provides a charging current during start up due to a high voltage current source connected to SW. For this purpose, a hysteresis comparator monitors the VCC voltage and provides two thresholds:
VCCON: Voltage value (typically 14.5V) at which the device starts switching and turns off the start up current source.
VCCOFF: Voltage value (typically 8V) at which the device stops switching and turns on the start up current source
When the circuit is connected to mains the internal current source is ON state which is connected together with SW pin.
This current source in winding A induces a voltage in winding B powering the VCC pin. Is my explanation correct?