I have a DC-DC boost converter:
where the mosfet is driven by PWM signal generated with a PIC18F4550.
So, basically we have "3 grounds":
Opto supply GND (supply of 15 [V])
Converter supply (5 [V])
In the practice, the supply is a dual supply one feeding 15 [V] and the other 5 [V] and the PIC is being powered from USB (computer).
The first ground (PIC GND) isn't the same as the last two grounds. The latter two grounds are CONNECTED and the same point in the real circuit. My question: is that ok? should 3 of them be connected? all of them separated?