Silvio, I can't understand your concerns about the high-side buffer (bootstrap?) cap.
Bogdan uses - as I can see from the photographs - a perfectly suited multi-layer ceramic capacitor.
The only thing which is wrong is the way he wired his high-side gate-discharging resistor.
I also have to correct a statement which I gave.
It is of course necessary to use a high-voltage ultrafast diode and not a simple schottky diode.
The gate-discharge resistors should be >10kOhm.
There may be designs from stone-age, where multi-layer ceramic caps didn't exist.
So your commercial smps-thingies you've seen, may be from designers from this age.
Bogdan uses - as I can see from the photographs - a perfectly suited multi-layer ceramic capacitor.
The only thing which is wrong is the way he wired his high-side gate-discharging resistor.
I also have to correct a statement which I gave.
It is of course necessary to use a high-voltage ultrafast diode and not a simple schottky diode.
The gate-discharge resistors should be >10kOhm.
There may be designs from stone-age, where multi-layer ceramic caps didn't exist.
So your commercial smps-thingies you've seen, may be from designers from this age.