L6470PD Stepper driver - Power dissipation issue

[Jacek Pieczaba]

Hello,

I am designing Stepper driver for NEMA17 motors which going to operate within range of 300RPM max. I am planning to use 42V to supply the motor and torque tests shows that 1A is sufficient to obtain the target.

What I have noticed on the first samples is that the driver get extremely hot after just 30sec of operation.

Since the software on my final application still not ready I am using the PC SW driving my board with L6470PD (https://www.st.com/content/st_com/en/products/evaluation-tools/solution-evaluation-tools/motor-control-solution-eval-boards/steval-pcc009v2.html.

I have set it for microstepping / 1A running current.

I have tried to follow as much as possible to meet the layout recommendation, based on the dev kit (https://www.st.com/content/st_com/en/products/evaluation-tools/solution-evaluation-tools/motor-control-solution-eval-boards/eval6470pd.html)

Regarding layout I am have a board 7x7cm with this driver mounted + other components 4 layer 1oz copper.

Could you kindly suggest what can I do to improve the heat dissipation in the most easiest and economical way?

Thank you in advance

Jacek Pieczaba

[Kurtnelle]

I added a heat sink to my L6470s to get them to perform just a little bit better. You could also turn down the current, or get a motor that has a higher phase resistance. If the package is getting that hot, then the motor may also be melting as well.