We are looking for technique or device that can detect ac line with some logic-out voltage without the need of VCC digital voltage.
Googling it, I found the MID400 device of fairchild, but it need VCC as output voltage stage, and we looking for device that can operate from the same AC line in its input stage.
We have an isolating transformer such that its primary consist with 2 seperate coils, and so its secondary.
The system is powered with 220VAC, and the input can be 110VAC or 220VAC.
If the input is 110VAC than the pins should connect parrallelly. If 220VAC it should connect serially.
I am looking for technique (ac relays, triacs and so) such that it can detect the presence of the 220VAC and switch the coils pins properly.
This won't work with a single relays. The switches must be operated break-before-make with sufficient deadtime to avoid shorting of the mains voltage by contact arcing. I can't imagine a simple implementation.