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Re: LF: DC restoration

To: [email protected]
Subject: Re: LF: DC restoration
From: DK7FC <[email protected]>
Date: Wed, 17 Jul 2019 20:22:55 +0200
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Hi Chris,

Maybe it helps to show a concrete schematic together with your question.
I find reverse diodes quite useless, at least when MOSFETs are used. It may be a different thing with bipolar transistors...

73, Stefan

Am 17.07.2019 15:38, schrieb Chris Wilson:

Hello  rsgb,

   Some Class D LF / MF amps use a diode to DC restore the waveform
   after the FET driver chip to the gates. Why do they do this, I am
   thinking the negative part of the waveform would turn OFF the gate
   harder, assuming the positive part is adequate to turn the gates ON
   hard enough? Is there any point in using the modern FET's designed
   to have a negative rail to turn the gates off hard? Cree do the
   Wolfspeed ones with this feature. I have also noticed that with amps
   where the input to the driver is capacitively coupled adding a DC
   restoration diode makes the waveform pretty much exactly 50 / 50
   mark  space,  whereas without one this is not the case. Good idea to
   use these restoration diodes there? Thanks.


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