Bootstrap capacitor capacitance selection

[steve13579]

Hey all I'm working on a buck converter for 300mA to 1A constant current operation and I am having a hard time fully understanding the process on choosing a bootstrap capacitor value for the high side driver portion. Specifically the quiescent current of the bootstrap current. Looking at the FAN7382 mosfet gate driver with bootstrap circuit it lists I_QBS or quiescent V_BS supply current to have a maximum value of 120uA. Is that the maximum average current per duty cycle that can be sourced from the bootstrap capacitor to operate the high side gate of an N channel mosfet? Here is a calculator I found online and it uses IDDO which I believe is the 120uA rating I saw in the datasheet: https://www.silabs.com/support/Pages/bootstrap-calculator.aspx

Also if I can throw this in here too; I am working on my EE degree and wanted to know an example of a project with a complexity level that would put me ahead of other graduates, I fear I am behind at the moment, but I still have over a year left.
 
Thanks to everyone who reads this

[Simon]

It could be the average current once the gate capacitance has been charged you shouldn't actually need any current but it does limit the size of mosfet and frequency. The higher the rating of the mosfet the larger the gate capacitance usually.

[steve13579]

I was looking at NTR4503N; it has a total gate charge of 3.6nC typically and 7.0nC max. This is probably the largest demand as leakage current I believe would be small, should I consider these occurring from the diode leakage, gate leakage, etc? Edit: Your first sentence helped significantly, should of thought of that knowing the definition of quiescent.