looking for some help regarding switching regulators for a personal robot project.
I have: two 18v 4.5Ah batteries (which when fully charged are actually more like 21v)
I need: 5v/1A for a USB hub, 12v/2A for a Udoo, and 30v-35v/2A for some stepper controllers.
Ideally, I'd just use three switching regulators to provide the required voltages at 90%ish efficiency, but I'm having trouble finding any that would cope with the 42v of the batteries in series.
What I'd like to do is add something like a 15v regulator to each battery and combine the outputs of the two regulators in series to make 30v. This would power the steppers and I could then add two further regulators to step down from 30v to 12v and 5v for the rest.
My question is: can this be done?!