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Subject: Re: Choosing the right transformer
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Date: Sun, 19 Jan 2003 13:48:03 -0500
NNTP-Posting-Date: Sun, 19 Jan 2003 13:48:06 EST
I am not quite sure i get the whole feedback idea... Why would we try to
close the loop around the modulator? That does not make any sense to me.
The actual "amplifier" is the class D analog circuit (the H bridge), if
there are any feedback to be put in this design, shouldn't it be between the
output of the H bridge and the input of the H bridge, NOT the input of the
modulator. Or am i just missing something?
"Greg" wrote in message
> Here's the block diagram of the system
> CD player -->digital out-->(DSP or FPGA)-->one-bit
> I really don't see how you could feed back the output of the Hbridge in
> DSP to correct the power supply irregularities.
> "Chuck Simmons" wrote in message
> > Greg wrote:
> > >
> > > > Ripple voltage on the supply will only be modulated onto the output
> > > > you design the amplifier with no negative feedback. You aren't
> > > make
> > > > an "open loop" class D amp, are you?
> > >
> > > What does everyone has against ''open loop'' class D amp. TI does it
> > > don't see how closing the loop could be done if the modulator is
> > > in DSP.
> > > Any ideas?
> > As pointed out, power supply regulation becomes a problem.
> > Why cannot the loop be closed in a DSP? Most DSP applications I know of
> > are closed loop and some involve PWM. Can you explain what you mean?
> > Chuck
> > --
> > ... The times have been,
> > That, when the brains were out,
> > the man would die. ... Macbeth
> > Chuck Simmons firstname.lastname@example.org
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