Quince
Well-known member
I'm hoping someone would explain how this works; on the left end looks like a regular amplifier, on the right a floating regulated supply, and in the middle, I don't get it
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- Thread starter Quince
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What is it?
It looks like a low-offset, FET-input OPAMP, driving a power FET device, pushing out quite a lot of current..
Jakob E.
It looks like a low-offset, FET-input OPAMP, driving a power FET device, pushing out quite a lot of current..
Jakob E.
ebartlet
Well-known member
What are "E102"?
Quince
Well-known member
It's from here:
http://www.ne.jp/asahi/evo/amp/2sk1380/report.htm
It's definitely a power amp, the site (http://www.ne.jp/asahi/evo/amp/index.htm) seems full or related circuits.
He doesn't have English version of the pates, just descriptions of the index. For this specific amplifier, all it says is "Because Cascode stage is class B SEPP, a big output can be efficiently taken out. And, because VDS is extremely low though output stage is class A single ended which operates by a big idling current, the channel dissipation is small."
http://www.ne.jp/asahi/evo/amp/2sk1380/report.htm
It's definitely a power amp, the site (http://www.ne.jp/asahi/evo/amp/index.htm) seems full or related circuits.
He doesn't have English version of the pates, just descriptions of the index. For this specific amplifier, all it says is "Because Cascode stage is class B SEPP, a big output can be efficiently taken out. And, because VDS is extremely low though output stage is class A single ended which operates by a big idling current, the channel dissipation is small."
[quote author="ebartlet"]What are "E102"?[/quote]
Constant-current generators.
And yes, looks like trouble.. :grin:
Constant-current generators.
And yes, looks like trouble.. :grin:
Quince
Well-known member
right... that cleared it up for me, thanks!
[Edit]
Ah, I think I understand it now, in light of US patent 5,343,166 and the prior art patents it lists.
The 2SK1529/2SJ200 is class B and also sets the reference for the floating supply; the 2SK1380 operates in class A within that. Since the bias current of the 2SK1380 doesn't go through the high voltage supplies, dissipation is minimized (efficiency increased). The patent is similar but uses cascoded output stages.
So what's the trouble then? Specifically, what are the downsides of such approaches?
[Edit]
Ah, I think I understand it now, in light of US patent 5,343,166 and the prior art patents it lists.
The 2SK1529/2SJ200 is class B and also sets the reference for the floating supply; the 2SK1380 operates in class A within that. Since the bias current of the 2SK1380 doesn't go through the high voltage supplies, dissipation is minimized (efficiency increased). The patent is similar but uses cascoded output stages.
So what's the trouble then? Specifically, what are the downsides of such approaches?
