What causes oscillation when a MOSFET gate is driven in an SMPS?

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eem2am

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Hello,

When a MOSFET gate is driven in an SMPS, there is often a series gate resistor included (say 10 Ohms or so).

This resistor is used to stop the gate voltage from oscillating.

What is it that causes this oscillation?

Is it the MOSFET’s Drain_Gate Capacitance and the parasitic inductance of the gate drive trace ?
 

fet gate

Yes you are right its the parasitic inductance(Track + body lead) & gate capacitor (Miller + GS)+ parasitic capacitor around gate can resonate & cause the oscillations on the gate. :arrowlease refer Infenion application notes for more details
 
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