Selecting stepper driver components...

[fyffe555]

I'm looking for a stepper driver chip to build into a home built driver. Want to drive bipolar parallel with motor current control and at least to quarter step capability. Allegro et al have some nice stuff (and Samples!) , such as the a3977 used in xylotex(?) but all their stuff is rated up to 3A and 50v max, but is there anything else able to carry greater than 3A?

I've found many surplus Stepper motors in the >200oz range are available in nema23 or nema34 but rated 5-6A or greater at ~2v. Outside the commonly available drivers spec. I want to build something to drive these motors at ->6A and current limiting at 65v.

Building it is the exercise, not necessarily buying something off the shelf, like Gecko's - good as they are.

Alternatively I thought of putting mosfets after the driver to carry the power but would lose current limiting and I have some concerns about response at the frequencies qtrstepping and the velocities require. Simply put ( for my use only...) looking to step at around 25ksteps per second per axis at max.

tia