I understand this circuit for the most part, but I am still confused on something.
So lets say that the bootstrap capacitor is already charged from the bottom MOSFET being on previously. Then, a logic level signal is applied to HI (pin 2) which initiates the capacitor to unload on the gate through the path highlighted in red. This turns the gate of the MOSFET on and because the negative terminal of the bootstrap capacitor is connected to the source of the top MOSFET, the Vgs stays high enough to keep the gate on.
I know that this works, I just don't understand how one part of it works.
The part I don't understand is how the high voltage is getting to the gate. It seems that the only possible way would be from the source of the top MOSFET and through the bootstrap capacitor, which could make sense because the source of the MOSFET is emitting square waves. I see in many circuit designs that the bootstrap capacitor is polarized. Wouldn't that mean that the high voltage coming from the source of the MOSFET would get blocked by the bootstrap capacitor? If that were true then the MOSFET gate wouldn't stay open.
That's my issue, I just don't get how the high voltage is getting to the gate if the bootstrap capacitor is polarized.