Hello.
I have used our carrier board for ON Semiconductor’s AMIS-30543 to do current control in a pair of brushed DC motors (these plastic gearmotors) before. That driver has an SPI interface that allows the current to be changed dynamically. I didn’t do a lot of experiments with alternate configurations, but in general, that seemed to work pretty well for making a sprinting robot with differential drive that accelerated rapidly in a straight line without any feedback. In theory, it should be possible to do the same sort of thing with a any of our Tics, but we haven’t actually tried that here.
The current control algorithms in the various stepper drivers we carry vary quite a bit and low resistance, low inductance coils (and high supply voltages) can cause problems for some drivers. I have a summary here that details some problems commonly encountered with that using the DRV8825. It’s not clear to me whether your issue is a similar current control issue, but if it is, the DRV8825 might not be a good choice for you application.
-Nathan