Audiom | 100-W audio amp is 20 times more efficient than Class D chips

[peranders]

I'm sure Mr. Bruno can explain what this is all about.

[phase_accurate]

To me it seems to be targeted at cheap boom boxes. The title 25 times more efficient than class-d is just marketing ** used as eyecatcher. What they do is achieving less IDLE losses than class-d. Which can not be neglected in battery powered applications that are just used for background listening.
On the circuit board pictured one doesn't see an output filter. Maybe it is a linear amp with a highly efficient PSU. Maybe it is a filterless class-d amp - in this case it is definitley targeted at cheap crappy products.

Regards

Charles

[Saturnus]

I think it's a mix of several technologies. Feed forward switching supply, filterless output, probably also some sound processing to filter out less dominant frequncies and emphasize dominant frequencies.

Definitely targeted at ultra-low end sound (think integrated speakers in mobile phones here). But still "20 times more effecient than class-D"? Load of **! The Tripath 2020 uses ~55mA in idle, or about twice as much a normal power LED, so if you include one you have raised the power consumption by 50%.

[phase_accurate]

For something that is (almost) idle more than 98% of the time there are definitley solutions that offer additional reduction of wasted power than ordinary class-d.

I don't think this chip is targeted at lowest-power applications like mobile phone but at boom boxes.

BTW: Really LOW power applications like mobile-phones and hearing aids are the areas that are mainly class-d nowadays. I was attending a class-d conference recently. A lot of topics covered small integrated class-d amps for mobile phones etc.

Regards

Charles

[coloradosound]

Defineatly cheap aps. Maybe integrated on board PC sound, iPods, etc.
Rather interesting claims, though, and I agree that it is probably some
combinations of various technologies and may be indeed a bit more
efficient than Class D (but nowhere near the claims). I don't want to
buy any yet. But if somebody else wants to experiment in small amps,
it would be nice to have them give us results.

[star882]

I'm not going to believe it at all until I can get the datasheets. And I won't fully believe it until I actually have one to play with. I'll power it with some supercaps and solar cells for the ultimate smug experience.
Actually, I'll power it with some CoolChips ( http://www.coolchips.gi/ ) running in reverse. (Unlike solar cells, a custom machined copper rod thermal collector will work indoors in total darkness, but would be very awkward to use outdoors. So solar cells for outdoors, thermal collector for indoors.)

[Iain McNeill]

That could be the perfect application. If you can charge some VERY LOW ESR caps with solar cells, and do a good job with the power device PCB layout you could have a winner.

Very interesting.

[MOER]

Class D amplifiers are NOT 70% efficient or anything close.

A class D amplifier at idle is 0% efficient.

A class d amplifier at clip into a load which does not push the RDs on to its limits is 90%+ efficient BUT with a sine wave....last time I looked nobody was actually listening to sine waves.

So the typical efficiency of a class D amplifier with average music into a reasonable load with the musical peaks just at clipping is well below 70%

Drive your class D with pink noise at 1/8 of rated power = typical program material with occasional clipping and then measure the efficiency and post that result

[Iain McNeill]

agreed, the efficiency spec is pure bunkum.

[Hurtig]

Originally Posted by DSP_Geek

20 times more efficient? Gee, worst-case class-D is 70% efficient, so this thing must be 1400% efficient! Call the Nobel Prize committee, we've discovered the secret of endless power!

That's what happens when you let the marketing pukes put out a press release before the engineers fact-check it.

Read all the info, before trashing the chip. The 20 times more efficient is at low levels.
I do NOT know any class-D with 70% efficiency at low levels, since the "household-consumption" in the amp typiclly consumes some watt's. And at ex 0,1 watt output, the efficiency is very low.