Here's a plausibly-interesting and tangentially-related finding:

"Transient Voltage Suppressor" arrays, apparently often found in ethernet to protect against things like ESD and whatnot, might just do the job for fast-switching high-current freewheeling diodes...

E.G. http://media.digikey.com/pdf/Data Sheets/Bourns PDFs/CDNBS08-PLC03-3.3.pdf

There's also a 7400-series chip that does-so for data-buses, claims 200mA max at some pulse-duration, plausibly if the pulses are short (with fast PWM?) then maybe they could handle even the surges from a motor driven at 2A...?

So, I might be checking my old ethernet cards for these things, as individual Schottky diodes might be somewhat harder to locate on my old PCBs in quantities.

Though, I've thoughts on whether freewheeling diodes are actually necessary with a linear-amp (and my system's expected loads)... more on that in a bit.

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I bought the 4-channel audio-amps mentioned/linked in a previous log. Sale Ends Today! $5 for *14* 4-channel audio-amps! Throw in that set of rotary-tool PCB bits I've been eyeing, for $4-off, and it's a pretty good order... kinda like [plausibly] 14 4-motor driver-chips for $1 ;)

For motor-driving, these TA8251AH's may be a little bit more difficult to interface than the TDA1510's I've been experimenting with... The TDA1510's have inverting AND non-inverting inputs, typical of op-amps, and used (so far) as more like a comparator. The TA8251AH's have a single input for each channel, which might mean the bias-point needs more consideration. Both chips are single-supply, and I don't (yet) know what the input to the TA8251AH is expecting... It might be biased at 1/2 V+, so at 12V (for the motors) that'd mean they'd need something like 7V for "on" and 5V for "off" (in the PWM-sense). From a uC...? I've got a few ideas... Maybe a buffer chip with Open-Collector outputs inbetween... Or a simple transistor+pull-up resistor... Maybe a voltage-divider between the uC output and V+ (and a diode?) could do something... haven't worked that out yet. It's also *plausible* these are biased around an entirely different voltage, being that they're most-likely *intended* to be AC-coupled... We'll see when they get here. Here's some other plausibilities: *maybe* the "standby" pin could be used for PWM, all channels tied together for one high-current output...? Another plausibility is use of the AUX amplifier, which claims it can be directly connected to a uC (though, still, likely through an AC-coupling capacitor, right? Documentation's sparse...).

Also the TA8251AH uses *one* input for *both* outputs, much more like a typical H-bridge chip used for motor-driving... This could be a blessing, few pins to control, but as far as I can think it requires locked-antiphase (where 50% PWM would result in no motion). Not a problem, but a consideration.

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Gotta get back to experimenting!