How can I tell if my power supply/regulator will accept backfed current?
Synchronous buck regulators are pretty useful at dealing with current in reverse. After all they do it all the time if the current is discontinuous - the lower transistor has to spend a certain amount of time dragging the current backwards through the inductor. OK normally the current is all forward current but in discontinuous mode the average current could be zero.



Added bonus - you are also recovering some of the energy from the motor into the inductor.