Output Waveform

[rjo]

Is the output waveform bipolar like an ET232/312? Anyone got a scope image of it?

[CrashOverride85]

Yes - output waveform is bipolar, and quite similar to the MK312 at least.

This is it outputting 150hz / 150us into a 500Ω resistor at full power:

[rjo]

Awesome! thanks for the quick response.

So I'm thinking about using the output board with my own controller. How does the DAC input signal map to a positive/negative output? I'll dig into the code/design but if there is a quick answer to help me grock it I would appreciate it!

[CrashOverride85]

Essentially it doesn't, the DAC controls the amplitude in both directions - so the positive & negative output must be the same amplitude (and the DAC isn't fast enough to change in between pulses).
However the pulse width of the positive & negative output can be varied separately per pulse (right down to 0), which achieve a similar effect.

The general design (as with the 312) is that per channel, there is 1 PFET that controls amplitude (driven by the DAC via an opamp), and 2x NFETs - for the positive and negative pulse.

[rjo]

Ahh got it. Thank you!