Claiming it and it being so are different things. If the output is analog as we can safely assume it is then any feedback whether or not it is ADC'ed and thereby technically digital after that still is topologically identical to an amplifier with an ADC as the front end before an analog modulator.
I didn't respond to the original question because it was already answered. Just wanted to point out that TPA3116 is not a digital amplifier.
I think you will be very busy then. There are a lot of digital amplifier threads out there
Yes, it is a hopeless battle, but just because a lot of people are wrong doesn't make it right...
I know. back in the old days I did the same. I must admit that I only think of digital amplifier as being amplifiers with the PWM signal made by PCM to PWM conversion. Open loop was the only thing back then, but Saturnus is offcourse correct that closed loop means analog feedback before the digital feedback processor, and then some of the "digital" is gone.
To me the PWM output stage is always analogue. Since I dont use analogue inputs, I just prefer digital PCM to PWM over analogue to PWM conversion.
A good ADC is expensive, but the extra requirements in PSU for open loop amplification is also expensive.
I think you will be very busy then. There are a lot of digital amplifier threads out there
Don't really care. There's very very few actual digital amplifiers, TACT Millennium for example. And then there's a lot of analog amplifiers with digital front ends.
Digital amplifiers carriers no inherent advantages (but a lot of disadvantages) though so it should not be a design goal in itself.
Bruno Putzey describes it better and in more words than I care to here. The Truth About Digital (Class D) Amplifiers | Audioholics
I have read Brunos description. The TI developers have something similar that is also very good reading
http://www.eetasia.com/STATIC/PDF/200909/EEOL_2009SEP04_ACC_TA_01.pdf?SOURCES=DOWNLOAD
since I'm not and engineer, I just read this stuff for fun. In the end I can only trust my ears and my wallet (and my common sence for what that is worth)
http://www.eetasia.com/STATIC/PDF/200909/EEOL_2009SEP04_ACC_TA_01.pdf?SOURCES=DOWNLOAD
since I'm not and engineer, I just read this stuff for fun. In the end I can only trust my ears and my wallet (and my common sence for what that is worth)
Basically that paper just shows that closed loop is better than open loop.
No you can't say that, unless you just look at numbers.
quote from the paper
"Before discussing how to
address the deficiencies of the
PSRR measurement, let’s first
talk about feedback. If you have
had your coffee and are following
along with this argument, it
should come as no surprise that
Class D amplifiers inherently have
problems with supply noise. This
would be a major problem if not
for feedback. (In high-end audio
applications, open-loop amplifiers
sound great, but that is a different
story. They typically have very
stable, high-performing supplies
and much higher cost targets.)"
Basically that paper just shows that closed loop is better than open loop.
Unless you design a power supply with no, or extremely low ripple. It's a case of the different engineering parts of TI not working together because if they had looked into their own portfolio they would have realized that what causes the problem in the first places, supply ripple, can be virtually eliminated with modern multiphase interleaved power converter technologies also available from TI, and at vanishingly low design cost as well.
Yes, that is indeed a different story, as that claim, just thrown in there, is not supported in any way by anything else in that paper.
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