It may be scaled up, or several converters may be paralleled, but EMI performance and efficiency is still not good at such high power levels. Voltage and current stress on transistors and diodes is higher, and primary side and secondasry side silicon is not used at the same time, so silicon uitilization is 50% lower than push-pull. Also, the required transformer is considerably bigger and prone to leaking tons of flux...
Also, that 10KW amplifier does not actually use a 10KW flyback but more likely a 1-2KW one with current limiting. The rails should start sagging above a certain continuous power output. Note that tracking amplifiers are not only much more efficient than class AB with music signals but also achieve a considerable reduction in power consumption. Power efficiency of class AB with music seems to be around 10-20% (depending on how heavy the bass content is and how much compression was employed).
Also, that 10KW amplifier does not actually use a 10KW flyback but more likely a 1-2KW one with current limiting. The rails should start sagging above a certain continuous power output. Note that tracking amplifiers are not only much more efficient than class AB with music signals but also achieve a considerable reduction in power consumption. Power efficiency of class AB with music seems to be around 10-20% (depending on how heavy the bass content is and how much compression was employed).
Eva said:
That is the R14 function of published schema (as you know much better than me).
Exactly the same principle is used on the refereed “10Kw” amplifier PSU, but with “R14” value adjusted for cycle by cycle current limiting.
Eva said:
Hhmm.. Eva I appreciate when you are so reasonable and objective in your comments…
Well, I forgot to mention that class D and rail tracking tend to exhibit 80-90% power efficiency regardless of the crest factor of the music signal, that's why those amplifiers can play high power music with a small PSU. Most of the power drwan from mains supply is just delivered to the loudspeaker. Plain class AB playing music tends to waste into heat 80-90% of the power delivered by the PSU.
PS: Get some reasonably sized class D module, like UCD180/400/800, and use it to play your favourite music into a full range speaker at clipping threshold. Then measure average current consumption.You will probably have a hard time believing how much class D music you can get out of, say, 50W PSU power.
PS: Get some reasonably sized class D module, like UCD180/400/800, and use it to play your favourite music into a full range speaker at clipping threshold. Then measure average current consumption.You will probably have a hard time believing how much class D music you can get out of, say, 50W PSU power.
hm... everything is possible, but not everything makes sense...
Does anybody have the link to the full appliction note?
My search at ONSEMI did not show this beast.
I am really wondering about the trafo design. They use 3mm wires at 40kHz? Strange! Even if we consider a single layer winding (no need to consider proximity effect) and ignore that flybacks ussually have airgaps with catastrophic fields (leading to eddy current issues in the winding...) .... even then, just from the skin effect wires above 1mm are a waste of copper. At 40kHz already at 0.32mm below the surface the current density down to 30%. The inner area of the copper doesn't carry much current.
Which core do they use?
Does anybody have the link to the full appliction note?
My search at ONSEMI did not show this beast.
I am really wondering about the trafo design. They use 3mm wires at 40kHz? Strange! Even if we consider a single layer winding (no need to consider proximity effect) and ignore that flybacks ussually have airgaps with catastrophic fields (leading to eddy current issues in the winding...) .... even then, just from the skin effect wires above 1mm are a waste of copper. At 40kHz already at 0.32mm below the surface the current density down to 30%. The inner area of the copper doesn't carry much current.
Which core do they use?
Class D sure is efficient! I have an old 30w Philips amp (USB input) that can play really loud without distortion, while only getting warm in the process.Eva said:
My current amp is 260w, also by Philips. It has S/PDIF input and is very amazing for efficiency. TI PurePath technology is simply amazing. I'm surprised why it's not used more and advertised more as it's environmentally friendly (uses less than half the power of a traditional analog amplifier) and cheaper at high power. With digital sources, the quality is better as the D/A conversion is done at high power levels.
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