Ultrasonic, high current amp?


2010-02-16 7:23 pm
Noob here. Hi.

I'm needing an amplifier to propagate barely ultrasonic frequency (24 kHz or more) across modest distances (a couple dozen meters), rectifying it at the other end to deliver between one and five amps (project's scale isn't determined yet) at about 5.2 VDC. The AC power must share the line with other, very low frequency power (for all practical purposes it's simply varying DC). The load needs to be ground-referenced (shared with the DC). I don't need to build the DC; it's a given.

I have a proof-of-concept working using an inadequate amplifier -- inadequate mostly in terms of frequency response.

I've been looking at the LM1875 with interest. I'm also wondering if a fairly stock circuit using this amp could be easily pinned down to oscillate at the frequency of interest.

Anyone worked with this chip enough to give some advice, or perhaps with one better suited to this purpose?
wireless power

do a search in the forums for susan parker she has built a very diffrent amplifier it uses zero feedback and very few components and im thinking she has or does work in sonar and may well be able to push you in the right direction.
Regards Ian
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Just had another thought . maybe a switch mode psu with the rectifier relocated to the far end.
But then you state you need an amplifier so that is no good.
You Dont give much detail on what you are doing. Propogate Ac and then rectifiy at far end im guessing some sort of variable dc supply is a part of your aim. The lm 3886 could do 24Khz no problem as it can get into the low Mghz range as i guess lots of other power opamps do too.
As it is not audio signal fidelity you are after im sure there would be a much better way using a few discrete components to do this job
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