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usernam
Joined: 09 Mar 2004
Posts: 634
Helped: 101
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 04 Oct 2006 20:39 Mosfet gate drive distortion |
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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
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Verba
Joined: 12 Apr 2003
Posts: 97
Helped: 7
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| 05 Oct 2006 23:03 Mosfet gate drive distortion |
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| 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.
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sabeti_1990
Joined: 16 Nov 2007
Posts: 65
Helped: 4
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| 02 Jul 2008 11:03 Re: Mosfet gate drive distortion |
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| or use a snober (RC) parallel with mosfet
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quinn
Joined: 03 Jul 2008
Posts: 6
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| 03 Jul 2008 11:51 Re: Mosfet gate drive distortion |
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I agree with Verba, somwhere around 10 ohms may help.
Also add some additional decoupling capacitance to the gate driver circuitry.
Quinn
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TekUT
Joined: 17 Jun 2008
Posts: 209
Helped: 12
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A.Anand Srinivasan
Joined: 15 Oct 2005
Posts: 1728
Helped: 205
Location: India
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| 06 Jul 2008 18:25 Mosfet gate drive distortion |
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| can you post a rough sketch of the waveforms....
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