1000v p-p class AB

[Enzo]

I found this little article in EDN, I found it interesting.

http://www.edn.com/article/CA6643367...dustryid=44217

[unparalleled]

I found this little article in EDN, I found it interesting.

http://www.edn.com/article/CA6643367...dustryid=44217

Power supply would be cheap, microwave oven transformers 1Kv 1Amp.

[cbarrow7625]

That is really interesting. Simple yet powerful. I wonder how it sounds since those Mosfets aren't designed for Audio. Not that THD is a bad thing in a guitare amp. It might actually sound better than the typical "audio" devices that get stuc in SS guitar power amps. I suppose it would be cool to use the amplifer as a welder and guitar amp at the same time! It would make for a great stage show.

Seriously though, I'd love to hear feedback if anyone decides to build it.

[defaced]

You'll get sparks, but you won't get a welder out of that - voltage is too high. You need something that's at the opposite end of the range, more like 12-24 volts and 200 amps.

Pardon my ignorance, but would this need an output transformer to drive a speaker? The high voltage output makes me think that it would, but it's solid state which usually doesn't need one.

[cbarrow7625]

I was joking. Just referencing one of the spec sheet intended uses.

It shouldn't need an OT if the +/- 600 volt rails are held symmetrical. I think some tweaking of values would be necessary on each amp to ensure that the two sides sum to 0VDC at the output.

You have a good point though. With +/- 60 volt rails an offset of 0.1VDC might not be a big deal but up that by 10 x and your offset could go up by 10x as well to 1VDC. I can see where that might be a problem.

I'm no expert on high power SS power amps. Maybe someone else can give us a more informed take on your question.

[Enzo]

The article mentions current limiting of 125ma if I recall. Can't drive a speaker very hard with that, so as drawn I'd be thinking it needed an OT. I'm not sure what the intended application was. I don;t know why one couldn't scale it differently. Driving the output stages from optos isn;t new. A number of Behringer amps are designed that way.

[Steve Conner]

Yes, at 1kV and 125mA it most definitely needs an OT, I'd say! That corresponds to a "speaker" impedance of 8k ohms and a power of about 60 watts RMS. Maybe you could make a huge cabinet with 1,000 transistor radio speakers all in series.

It was probably intended as a driver for piezo transducers. They're used for micro-positioning in the semiconductor and laser industry. I used to work for a company that had a high voltage piezo driver in their product line, and they kept blowing up all the time. I tried to convince them to redesign it with tubes (and I was only half joking!) but no luck.

Of course you can design a lower voltage, higher current version. I'm sure the circuit would work just as well off +/- 50 or 100V, and you wouldn't need the series cascoded MOSFETs.

Or again, it might be useful as a HV regulator for power scaling, just feed a DC voltage from a "B+ adjuster" pot into it. You only need to build the top half.

Anyway, nice circuit, I'll remember this one