I desiged P-MOSFET for reverse voltage protection, without gate resistor.

The reason that I tend to use it is protect from reverse DC voltage when someone connects the battery. Do I need a gate resistor? (When someone connects the battery correctly it will be in the ON state, otherwise the PMOS will be OFF.)

Second question:

How does a gate resistor reduce ringing?

  • \$\begingroup\$ Show your schematic design; embed an image so everyone knows exactly what you are talking about. Battery voltage range and output current range values are needed. \$\endgroup\$
    – Andy aka
    Dec 3 '20 at 11:33
  • \$\begingroup\$ its a simple voltage circuit protection with dc input that could connect from ATX Power supply(12v) its okay for datasheet... @Andyaka \$\endgroup\$
    – Knowledge
    Dec 3 '20 at 11:49
  • \$\begingroup\$ Does this answer your question? \$\endgroup\$ Dec 3 '20 at 13:37
  • \$\begingroup\$ electronics.stackexchange.com/questions/287792/… \$\endgroup\$
    – JonRB
    Dec 4 '20 at 10:16

Does a MOSFET gate resistor reduce ringing?
No a MOSFET gate resistor doesn't reduce ringing.

Ringing is an unwanted oscillation of a voltage or current. It happens when an electrical pulse causes the parasitic capacitances and inductances in the circuit to resonate at their characteristic frequency.

Do I need a gate resistor?
It depends on the VGS of your mosfet if the applied voltage and current is higher than it rated for YES you should add a resistor if not you don't have to. With a resistor or without your mosfet is always on.

what you are trying to do is well described here

  • \$\begingroup\$ Gate stopper resistor sometimes helps to dampen the oscillation/ringing. \$\endgroup\$ Dec 3 '20 at 13:38
  • \$\begingroup\$ @RohatKılıç A low pass filter is more promising, but it depends the cause of the ringing. \$\endgroup\$
    – autodidact
    Dec 3 '20 at 13:52
  • 3
    \$\begingroup\$ -1 this answer implies that if you add a gateresistor you can drive the gate with a higher than rated Vgs. Incorrect, of you overvoltage the gate you damage the gate. Could you use a voltage divider ? Yes but there would also be issues. A gate resistor should always be added, at the very least it helps prevent creating a Pearce oscillator. Likewise control the current flowing into the gate \$\endgroup\$
    – JonRB
    Dec 3 '20 at 14:43
  • 2
    \$\begingroup\$ Also a gate resiator can reduce ringing (on Vgs and Vds) \$\endgroup\$
    – JonRB
    Dec 3 '20 at 14:44
  • \$\begingroup\$ As the gate has capacitance, adding a series resistor creates a low pass filter. That's why it can help reduce ringing. \$\endgroup\$
    – Finbarr
    Dec 3 '20 at 14:55

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