Single power supply for DRV8834 & microcontroller

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?

Thanks!
TW

Hello, TW.

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.

- Amanda

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.

- Amanda

Sounds good. We have a 100uF cap across VMOT and GND but the VIN for the microcontroller is after the the CAP (see photo)

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Just put the pieces together and it looks like things are working fine so far.

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