I forgot to mention, the FET switches in the TX circuit are just place holders. I have not selected the actual devices, still looking at options.
Also, based on feedback in the TX thread, there are pending changes to the TX sampling circuitry for tilt correction. See this post for details.
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AMX Schematics & Layout
Here is an initial try at a more-or-less complete schematic. I still need to add some provisions for connecting to a micro. I believe the AFE is pretty much the same as I posted before. The TX schematic is close to what I've discussed, I had to make some minor changes to the integration loop to accommodate the eventual use of an ADC & DAC for digital control. At real high level, the TX looks like this:
The power circuitry is as discussed before. Here's a block diagram:
The positive boost is an option if I decide to pursue a single-cell lithium battery like a 26650. Right now I'm leaning toward (2) 18650 which makes the positive boost unnecessary. An identical boost has been added to drive the TX switches. Since 2 switches will likely be 1200V SiC MOSFETs they usually require a higher drive; I'm expecting 12-15V.
Overall, including a micro and audio, I think I can get this whole design under 2 watts. Either (2) 18650 or (1) 26650 has ~20W-hrs of energy so this will be 10hrs of run time on a charge.
[ATTACH]n411290[/ATTACH]
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