If you actually plan to use that FTDI while device is plugged into mains, then it is a horrible idea. You will end up killing USB ports, or yourself in the worst case.
Thanks alex.
The reason would be because the power supply is grounded and......what else
You will have potentially live voltage with minimal to no isolation exposed on the USB connector. It is just a bad idea all around.
You can use switching power supply, and small transformers are pretty cheap. You can probably even find complete sub-assembly at a decent price.
Your other option would be to power all low-voltage part from USB +5V, if device is constantly plugged in.
Or power FTDI from USB and use optocouplers to decouple it from the high-voltage part. Although this one also depends on what else on that board is accessible by the user. You don't want to have mains on encoder knobs either.
you will have potentially live voltage with minimal to no isolation exposed on the USB connector. It is just a bad idea all around.
yea, i will just stick to the existing.
@anishkgt,
regarding the TRIAC driving. From where you got that schematic ? What was the main purpose or what was the main load ?
The load is an MOT. The TRIAC driver schematic is in the data sheet of the driver itself. It's a dual SCR back to back.
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