Parrallel diode for efficiency improvement ?

[jalinei]

Hello everyone,

I was looking at the MPPT-2420 layout today, and I was thinking maybe it would be useful to add a small shottky diode between the switching node and ground.

From the transistor datasheet we get that the body diode recovery charge is about 135nC (this is not helping much because it heavily depends on the A/us slope rate), but from that info we can estimate the added switching loss that would be about

Qrr x fs x VIn = 0.5W approx. loss for a diF/dt of 100A/µs

Do you know if this diF/dt is somewhere near the actual switching characteristics ?
Maybe it's worth added a 100V diode ?

Here is an application note from TI I found quite interesting that covers the topic quite well IMO.
https://training.ti.com/sites/default/files/docs/not-all-regulators-are-created-equal-synchronous-v-non-synchronous-presentation.pdf

According to this document, it would also improve the transient by lowering the voltage spikes amplitude.