DRV8825: Design Help with Out of Spec Motor

TI-CSC

Part Number: DRV8825

Hello E2E Experts,

Good day.

I'm doing a custom PCB for a stepper motor and I´ll be using a drv8825. I have followed the typical application of the IC but the motor I have doesn´t match the design requirements. I´m new to electronics, and don´t understand much yet, saying this, what I´ll need to change to match the following motor?

E Series Nema 17 Bipolar 0.9deg 30Ncm(42.48oz.in) 1.5A 42x42x38mm 4 Wires - 17ME15-1504S|STEPPERONLINE (omc-stepperonline.com)

Thank you in advance for your support.

Regards,

CSC

over 2 years ago

0 Ryan Kehr over 2 years ago

TI__Guru 55605 points

Hello,

If the design is not complete, please use an updated part that will make your life much easier.

https://www.ti.com/product/DRV8434

This device has integrated current sensing (no external shunt resistors required) and has "smart tune" technology to automatically tune parameters to your motor.

https://www.ti.com/lit/wp/slyy099a/slyy099a.pdf

Regards,

Ryan

0 TI-CSC over 2 years ago in reply to Ryan Kehr

TI__Genius 12865 points

Hello Ryan,

Good day.

Thanks, I will look into it for the v2 but for now I will use the drv8825 since I have a bunch of them laying around, so can you tell me what I need to change please?

Attached herein is my schematic.

schematic.zip

Regards,

CSC

0 Ryan Kehr over 2 years ago in reply to TI-CSC

TI__Guru 55605 points

Hello,

Schematic looks OK in general. One question and a suggestion.

1) The sense resistors are 2x 100ohm in series? Or are those 0.1 ohms. 100 ohms would be way to large. Please check calculations in the datasheet for the desired full scale current.

2) I would add a few resistor "stuff" options for DECAY. A zero ohm to V3p3OUT and a zero ohm to GND. You can leave these uninstalled for now. This will give you flexibility to tune decay as needed later on.

Regards,

Ryan

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DRV8825: Design Help with Out of Spec Motor