Hi,
In other places you used symbols for power supply. Why not here. It´s almost invisible.
In other places you used meaningful lables like "24V". Why not here?
So to validate your schematic we have to do an internet search for the datsheet of the "DB02S2415A" device. (no link)
It tells it´s a DCDC converter (impossible to see this from the schematic symbol).
It says
* nominally15V output
* nominally 24V input.
While you have 24V available you use +24V and -12V which makes 36V in total. This is the absolute maximum specified. Why?
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however what i have inner logical conflict when on one hand we put "floating" Ground.
In electronic circuits the name "GROUND" is a synonym for "(supply) voltage reference".
In a real circuit this is where you connect the black wire of your DVM.
Other names for GROUND are "GND", "0V", "COM" ... there is no perfect name.
In your case you have an isolated system, thus you have a "reference node" at each side of the isolation.
When you use a voltmeter to check the output voltage of the DCDC converter you connect the black wire to "-OUT" or wht you call "GIZ" (whatever that means):
In your circuit this is the HIGH_SIDE_DRIVER_SUPPLY_VOLTAGE_REFERENCE. Not a nice name for a node .. and rather lengthy.
More suitable names would be "HS_GND" for high side ground. or "HS_0V".
And for sure VIZ could then be replaced with "HS_15V" ...
VIZ and GIZ are technically not wrong. You will have you reason why you´ve chosen this names ... but when posting in an international forum we miss some information.
And yes, GIZ is not GND in your case. But the point is it is used to control the MOSFET. And the MOSFET is controlled by V_GS (not by V_G!).
V_GS means the voltage of GATE referenced to SOURCE. SOURCE is the voltage reference. And a voltage reference - as said earlier - is often named "GROUND".
Indeed this [15V_supply, the gate driver, the MOSFET and the according resistors and capacitors] has to be seen as "an isolated unit". Not involved in this unit is what in your schematic is called "GND".
Klaus