More OSMMU* details

* Open Source Multi Measure Unit

This title is a reference to Keithleys elusive source measure units. I have tried to get another one forever and now I'm just making my own, much better version instead :)

Keithleys regular SMUs are precision power supplies with pA resolution and 4-quadrant capability meaning they can be programmed to source and measure +/- voltages and +/- currents. Almost nobody needs pA resolution, so I wont include that initially, but a 4-quadrant supply is very useful. Three 4-quadrant supplies are even more useful!

And that's what I want to make: A digitally controlled 4-quadrant PSU with 3 isolated channels. Here are some of the possibilities of such a device:

• A single channel can be a normal adjustable psu
• With the current sink capability it can discharge and analyze batteries and capacitors
• It can analyze other 2 pin components and act as a curve tracer
• I'm trying to use HF components, maybe it can even be an antenna analyzer, transmitter etc? Low priority for now ...

• A second channel enhances the possibilities greatly:
• Channels can be stacked to get a higher voltage output channel
• Now even transistors and thyristors can be analyzed
• 2 Phase stepper motors can be driven and tested with clean current waveforms
• Can analyze a 2s pack or 2 batteries at the same time
• Can output waveforms on one channel and measure result on the other channel. Is that what's called a network analyzer?
• I-V characterization of solar cells

• Diminishing returns for the third channel:
• Analysis and driving of 3-Phase brushless motors
• Classic 3-output PSU arrangement

It is a complicated design for sure and I haven't even started to think about the software that controls it all. But then again there is afaik no other product like it, so it is worth it. The more I think about it, the more application ideas appear ... Please comment if you have any :)