Cheap FOCer 3 (Open-source, Low-cost, VESC 6 based ESC) (In Development)

I love everything about this. Thank you @shaman for the work you’re doing.

The fact that the Cheap FOCer is still a continuing project speaks volumes of not only your skill, but steadfastness in the industry. Cheers sir.

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There are not other providers? I was asking for that for the Little Focer v3.1 too… is much better than just soldered cables

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The project is centered around JLCPCB and what it can do.

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Sure, but I was talking about little focer, flagship model, expecting the best :wink:

The noise for the current sense signals is coming from the 5V buck converter inductor. I routed some signals just a tad too close to it. Looking at the waveforms and seeing the 150khz noise that matched the switching freq of the 5V buck converter was pretty much a dead give away. I also replaced the 5V supply with an LDO to verify. The noise disappeared. I wanna keep the 5V supply as a buck converter though since people want 1A+ from it. An LDO will burn up under that load with a 15V input voltage.

I can fix this in the design by rerouting some stuff and maybe switching to a higher frequency buck converter. The prototypes can be fixed by some typical bodges and PCB surgery.

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So I was able to boost the drive strength for turnoff and get what I wanted. I added a PNP transistor to assist turnoff similar to the schematic below.


https://www.ti.com/lit/ml/slua618a/slua618a.pdf?ts=1656342568066&ref_url=https%3A%2F%2Fwww.google.com%2F

I did this in the CFOC2 but not effectively. I used it with the intent to mitigate parasitic miller self turnon but it turned out to be too aggressive. Here though I’ve done a much better job implementing it and dialing in it’s strength.

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If you’re working on small tweaks like this ATM is it mostly in simulation or are you paying for fast shipping from JLC or what’s the workflow like? Just curiosity for us playing along at home

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No simulation. Real deal prototyping with hardware. Simulation is ok for small portions of a complete design but i’ve found to be lacking when trying to account for all elements of the total design. Parasitics, EMF noise, and other non-ideal qualities are generally hard to account for in simulation. So I just go for a quick batch of prototypes from JLCPCB and start analyzing them in the land of the real.

Right now the prototype unit I’m working on is fraught with all kinds of stuff I’ve done to it so far. But I’m knocking out one challenge after another. Still able to apply these changes to the other units and move on with beta testing when ready.

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Could you snap a quick picture of this prototype just to see how it looks like? I’m also very curious, as that’s what scares me the most about HW prototyping. What I do (but my projects are basically toys in comparison!) is jerry rig discrete components and mutilate my PCBs beyond recognition.

Also doesn’t help that my day job is software. Just soooo much easier and I’m spoiled :joy:

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