Tripath?
In message , Arny Krueger
writes
Snipped...
The problem I saw was that ignoring your first nasty bit of news, the amps
had a lot of nonlinear distortion related to the switching, well below
clipping. I mean like 2-3 dB below clipping. They also had a relatively
high output impedance in the top half of the audio band.
The Tripath design took its NFB from before the output filter, so the
rising impedance of the output inductor became important.
The UCD design is one of the few that take the NFB after the output
filter and use the phase shift of the filter (together with other
components) to set the self-oscillating frequency.
For those who are interested, it's worth reading the paper that Bruno
Putzeys (then of Philips) presented at an AES conference a few years
ago. It details the background behind the UCD design.
--
Chris Morriss
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