Re: gEDA-user: [OFF] high current amplifier

[John Griessen <john@xxxxxxxxxxxxxx>]

Levente wrote:
> Hi,
> 
> 
> I have to design an audio amplifier that can deliver 100Amps. It should 
> work around 50Hz, and the maximum output power shall be 500W. I am 
> currently reading articles about this topic, but it is very hard to find 
> things like this. If someone has some experience with, or some 
> documentation of high current amplifiers, please share it.

Sounds like a fog horn driver.  Your best bet will be a "digital amp",
or in other words a sigma delta DAC with the speaker coil and some capacitance
in the feedback loop.  An example would be: a train of 2-bit plus sign data is converted into
analog levels 0 +1 +2 -1 -2 Volts and the analog level on the speaker coil and cap. is
fed back into the DAC to a fast ADC stage so it can combine with the datastream
inside the sigma delta converter.  The low pass filter that loses all the choppy
back and forth of the drive data levels is the cap. and speaker coil itself.

This is the highest efficiency type of driver since it's driving transistors are
never in active region -- always full on or off. High efficiency is what you need
to put out 500W.

John
-- 
Ecosensory   Austin TX


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