Originally Posted by jeffs555
I just re-read your original post and it says you are using IRF540S. Those are not logic level mosfets and are only spec'd for 10v gate drive. Just because the threshold voltage is below 5v does not make them logic level mosfets. Most logic level mosfets have thresholds of around 2v. You will need logic level mosfets for use with that 5v driver.
PS There is an IRL540 that has the same 100V rating as the IRF540 but is a logic level device.
I switched Mosfets for the second go around because I couldn't solder the D2Pak worth a damn.
These are PSMN3R-430-127
As Kiwi says, their on-resistance between 10V and 4.5V gate is almost the same.
I just can't explain why I get so much voltage droop on the boot capacitor even at very small duty cycles.