DIY Gecko type...

[WilliamD]

I've seen a lot of the DIY controllers out there for steppers, and they are great, but none of them seem to be like the Gecko's. Why is that? What is it that makes them capable of 70 volts and 7 amps? Is this a whole different way of doing things?

[pminmo]

Most of the DIY stuff is using off the shelf controller chips which are mostly self contained. That typically limits voltage and current rating. I have a couple of designs in work that use discrete components, and will come closer to the Gecko's, but it won't be as good as a Gecko. Personally I don't have the time and and equipment to verify a design. What I am shooting for is G201 like ratings, but, but will be limited to full/half/quarter and hopefully 1/8th step. No mid band compensation.
Unipolar 100+ volts similar amperage to above. Same step options.

Gecko's are awfully good drives for the price. They are proven designs, and have the support structure in place.


postscript: I'm still a couple of months away form having something, I just don't code software like I used to be able to :-(

[joecnc2006]

Most of the DIY stuff is using off the shelf controller chips which are mostly self contained. That typically limits voltage and current rating. I have a couple of designs in work that use discrete components, and will come closer to the Gecko's, but it won't be as good as a Gecko. Personally I don't have the time and and equipment to verify a design. What I am shooting for is G201 like ratings, but, but will be limited to full/half/quarter and hopefully 1/8th step. No mid band compensation.
Unipolar 100+ volts similar amperage to above. Same step options.

Gecko's are awfully good drives for the price. They are proven designs, and have the support structure in place.

I believe you will take us there someday, I'm hopping to start building some of your boards real soon.

[WilliamD]

Thanks a lot for your replies! I've already started ordering parts for the some boards on Pminmo's site. Really some great work there, and a true contribution to the hobby.

[pminmo]

Thanks guys,
WilliamD make sure you match boards to motors. I think the biggest dissapointment I run into is people building some great looking boards of my site, then turn out not to be able to use them or the motors because they aren't compatible.

[rklosinski]

What makes 70v hard to do is the engineering behind it. 70v switching silicon is harder to deal with, and dumping that much emf can be a chore. I finished my own cnc conversion using a custom driver that I designed. My driver runs off of about 50v (36v torroid output), 1/8 step and move my steppers just fine. I was thinking of comercializing it, but need input as to what else needs to be on the pcb (e.g. isolated, x number of inputs and thier type, x number of outputs and their type). Anyway, what I would consider doing is build the ultimate cnc card with the forums help, then make x number of the cards available to the members at cost.

Anyway, its just an idea.

Rich