If I adopt this circuit if there is a problem,Do I need to further improve or add components? enter image description here

If I were looking to drive a FET at:
Logic voltage drive (5V)
Duty cycle is 0-100%
20A load
How would I determine an appropriate MOSFET and how would I determine the driving requirements?

MIC5018 datasheet

  • \$\begingroup\$ Is there any reason why you can't use the FET on the low side? \$\endgroup\$ – Wesley Lee Jun 24 '19 at 8:50
  • \$\begingroup\$ Add 2 spaces at end of each line to stop them wrapping ||CCt looks OK. Besure FET gate voltage max is NEVER exceeded.Low side drive easier unless load MUST be ground referenced. What speed is PWM (control signal). FET gate capacitaNce matters as speed foes up. \$\endgroup\$ – Russell McMahon Jun 24 '19 at 10:50

You already included all you need to look for.

The gate output voltage of the MIC5018 is specified as min. 11.4V @ V[supply]=4.5V, typically above 15V @ 5V.

You want a FET with V[th] preferredly lower than (11.4V-5V)=6.4V (e.g. logic-level MOSFET), or at least lower than 15V-5V=10V, current capability 20A at given V[gs] of 6.4...10V, min. 48V V[ds] rating.

Besides the requirement to be able to carry 20A at the available V[gs], you want to look for a reasonably low R[ds] at that gate voltage to reduce losses and heat in the FET.


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