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Re: LF: RE: 73kHz tests tonight

To: [email protected]
Subject: Re: LF: RE: 73kHz tests tonight
From: "Tom Boucher" <[email protected]>
Date: Wed, 13 Jun 2001 10:58:59 +0100
In-reply-to: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
In message <[email protected]>, James Moritz
<[email protected]> writes
Only real problem so far was getting the gate driver to work - even with both sections of a TC4427 driver IC in parallel, the drive waveform had rather slow edges when feeding the 4 large- geometry FETs in parallel, so I ended up adding a "booster" with a complementary pair of discrete MOSFETs in a circuit adapted from one of IR's application notes. The driver transformer now seems to be the limiting factor, but is OK for the time being.
Jim, Andy and group

My 136KHz full bridge PA uses one section of a TC4426 ac coupled to a
quintifilar (?) wound driver transformer and, like yours, the waveform
is rather rounded. My theory is that is not such a bad thing because it
provides some switch-on delay which prevents all 4 PA FETS being on
together.

I did try a single FET driver per Decca which took a lot of supply
current and although the drive waveform was better, the PA appeared to
be showing some instability tendency.

73, Tom



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