Mosfet gate drive distortion

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usernam

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I've designed a buck converter with a 6V input. It is running at 60% duty cycle & is carrying abt 1.5A current.
I'm using a IRL3103 mosfet as my switch. When I test the gating signal to the switch, seperately when the switch is not in the buck circuit, I get a good switching waveform, however when I set it up in the buck converter the gating waveforms are highly distorted with a lot of noise. However the o/p is still abt 3.3V as expected. I want to eliminate this noise, & figure out why it is coming in the first place.

TIA
 

may be your MOSFET get's unstable or the driving ability of the control circuit is insufficient (gate capacitance is too big), add some resistor/inductor in series.
 

or use a snober (RC) parallel with mosfet
 

I agree with Verba, somwhere around 10 ohms may help.

Also add some additional decoupling capacitance to the gate driver circuitry.

Quinn
 

Take a look at this thread, mighth help you.



Cheers
Powermos
 

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