Bootstrap Capacitor value STDRIVEG600

[256QAM]

Im not sure how to figure out the value of the bootstrap cap. Because I want to drive mosfet with 400kHz (I want to use it in a audio application) and the bootstrap diode is rated with typically 140ohm in datasheet. Problem: I see the mosfet charge is to large to use small caps but larger caps donts be charched about hte diode. Is it possible to support the diode externally? Maybe because the controller is designed to drive gan-fet or something.

Thanks!

[Andrea Francesco MERELLO]

It is possible to use an external bootstrap diode. Consider to use a low capacitive diode, due to the high frequency requirements you have, and good ceramic capacitors on both sides with low ESR/L.

Remember to pre-charge the bootstrap capacitor, depending on your system design.

You might need anyway a small resistor in series with the bootstrap diode, to limit inrush startup current and/or injected noise due to dV/dt commutations.