I am building a project that I would like to power off of a single 2.5A USB power supply. I would like to power both a microcontroller (ESP32) and the stepper motor controller using this power supply. My schematic currently has a 100uF cap across VMOT and GND as specified in the DRV8834 reference diagram. Can I use the same 5V power supply for both the ESP32 AND the stepper motor controller? This will be driving one NEMA17 stepper motor at ~1.4A current limited. Will I need to do further decoupling or even have separate regulated power supplies?
With a quick search, it looks like the ESP32 microcontroller’s operating range is between 2.2 V and 3.6 V, so you probably will need to power the chip separately from the DRV8834 or consider using an appropriate step-down voltage regulator.
I am using an ESP32 devkit board with a voltage regulator on it (regulator ams1117). Will I still need to protect it from back EMF if it is tied to the same 5V supply as the DRV8834?
We recommend adding a capacitor across VMOT and GND (as shown on the DRV8834’s product page), which should help with any noise or spikes on the input voltage line. With that I would not expect most applications to need more protection, but if you have a specific reason to worry about back-EMF damaging your microcontroller, powering the two boards separately is better.
Sounds good. We have a 100uF cap across VMOT and GND but the VIN for the microcontroller is after the the CAP (see photo)
Just put the pieces together and it looks like things are working fine so far.