Doubt regarding i.MX95 EVK base board design

[mrnobody]

mrnobody_0-1784709346702.png

This is the schematic of how 12v power input is taken into the imx95 board, i have some doubts regarding this design...

1. why are 2 fuses of 20A connected in parallel, is it done for 40A current rating, is it a good practice to do so?

2. When Q2 is "on" the gate of Q2 is connected to GND, but for turning "off" Q2, the gate is just left in floating state, Is it reliable to do so? should the gate pin be pulled up to source voltage?

[yipingwang · Accepted solution]

Q1. Since the inrush current is higher than 20A, it is a good practice to use 2 pcs of fuses with 20A rating in small size (1206) to provide higher current rating cost-effectively.

Q2. When Q2 is off, its Gate pin is not left floating, but pulled up to the same power rail as its Source pin with 100KOhms resistor (R197) so that it can be turned off completely.

[mrnobody]

why not use a 40A fuse, is it bcos of size constrains

[yipingwang]

If 40A rating small size fuse could be be sourced, the  2pcs 20A fuses could be replaced with it. If fuse protection is not necessary, the fuses can be shorted as well.