Need help understanding a circuit

[tomy983]

Hi, I found this instructable https://www.instructables.com/id/Multichannel-Wireless-Light-Dimmer/ with a circuit for a trailing edge dimmer. I would like to replicate it but instead of two channels I would like to go for 12. I am far from decent so I intend also to post my modified schematics and pcb layout, once about finished.
I understood all the working principle, but since I will have 12 channels I would like to optimize a little.
This is the original schematic. https://cdn.instructables.com/ORIG/FP6/5RF8/J2MAORX6/FP65RF8J2MAORX6.pdf

In the instructable description the author states that each channel must have its own 12V supply to trigger the mosfets. I can't understand why.
Is there a way to have a single 12 or something volts (the mosfets I plan to use hame max Vgs of 25V) supply for all of them?

[Zero999]

Each MOSFETs must have an isolated 12V supply for the driver, because their sources float at different voltages. A pair of switched off MOSFETs will float at the mains voltage, whilst a pair of switched on MOSFETs will be closed to 0V.

[tomy983]

Each MOSFETs must have an isolated 12V supply for the driver, because their sources float at different voltages. A pair of switched off MOSFETs will float at the mains voltage, whilst a pair of switched on MOSFETs will be closed to 0V.

Thank you, it took a while but I understood what was wrong and also looked for a solution. I learnt something about mosfet drivers and also the insulated ones.
I finally put down a schematic that I think might work. I also tried to simulate it and looks ok to me.

I would like if possible your opinion on drivers http://www.vishay.com/docs/83469/vom1271t.pdf and  mosfets https://www.infineon.com/dgdl/Infineon-IPD50R380CE-DS-v02_03-EN.pdf?fileId=db3a30433ecb86d4013ed0a2ef580f38

I don't know what to watch out for and read in several places that matching might not be as straightforward..
Also I am not sure whether I should put a resistor across the gate driver output or not...

To switch the leds of the gate driver I thought I might use a 16 channel constant current led driver, of which I set the current to 30mA

Does it look ok?
Thank you