# Picking a power supply for a TMC2130 stepper driver and motor

I'm trying to pick a power supply and need a little more guidance before I'm comfortable spending money on one.

This site explains how to calculate your figures for power supplies but isn't too descriptive. https://learn.watterott.com/silentstepstick/faq/

Their example:

What power supply do I need?
A power supply (Psup) with a few times higher voltage than the motor phase
voltage and a current of roughly the power of the motor (Pmot) plus the
mechanical output power (Pout) is at least needed.

For example 3 stepper motors with 2 coils/phases and every phase has
3.3 Ohm with a 1.2A current rating and a voltage of 4V.

Pmot = 2 coils * 4V * 1.2A = 9.6W (standstill power without load)
Pout = 0.20Nm * (2pi * 1000rpm / 60) = 20.9W (mechanical power)
Psup = 3 * (Pmot + Pout) = 91.5W (electrical input power)

At 24V this is a current of 3.8A (I=91.5W/24V).


I'm using a single 3.2V stepper motor with 2.0A/phase

Here's my calculations using their formulas:

Pmot = 2 coils * 3.2V * 2A = 12.8W
Pout = 1.2Nm * (2pi * 1000rpm/60) = 125.7W
Psup = 12.8W + 125.7W = 138.5W
Vsup = 24V
Isup = 5.77A


I just kinda assumed I should use a 24V supply and got the current from that and the power. I have seen other people use a 12V, but wasn't sure what would be best. At 12V I would need a supply that's 11.5A!! Right?

So assuming I go with a 24V supply, would I try to find one that's 24V and as close to 5.77A without going over? Or is it ok if I use one that's 6A. I couldn't find anything in the TMC2130 datasheet about max input current limits.

Any advice is greatly appreciated.