This post is a continuation of Trace width for PCB motor driver board, with a few follow-ups and questions.

Firstly, I'd like to mention again that the motors I want to use have a maximum current of 7 A for when they stall, but their operating current is around 0.35 A. I'm concerned that for my application the motors might stall at some point the driver board might overheat even if I'll be adding heatsinks. I've widened the VCC 12 V trace which provides current to the motors from 2 mm to 3.5 mm. Since the pins of the MOSFETs I will use are quite close to each other, I've routed the power trace into them with 2 mm traces. Does this have any negative effect or is it standard practice?. From there, the rest of the power traces between the MOSFETs and to the motor connectors are 2 mm to 3 mm. The distance between the MOSFETs is quite short and so in theory there shouldn't be much heat generated if the motors stall, right?

I've also added a significant number of vias to stitch the ground planes from both sides of the board, which I believe will help with current and heat dissipation.

So the first question is whether the power traces seem acceptable now considering that the nominal current draw is less than 1 A for these motors in the case that they don't stall.

My second question is about whether the signal traces to my motor drivers are alright. Unfortunately, I had to make them quite long, and I want to use PWM signals to control the motor speed. Will my signal be affected by the length and width of the traces (longest trace is about 78 mm and their width is 0.4 mm).

The third question relates to whether the signal integrity for the motor encoder lines will be affected by the length and width of the trace or other factors (longest line is ~117.3 mm with a width of 0.5 mm).

Signal traces to motor drivers

Signal traces to motor drivers - bottom

Signal traces to motor drivers - top

Overall PCB

  • \$\begingroup\$ There's no supply bypass capacitor? \$\endgroup\$ Commented Jul 5 at 7:54
  • \$\begingroup\$ What about stall detection? If you don‘t do that, then you need 7A capable traces. \$\endgroup\$ Commented Jul 5 at 9:37
  • \$\begingroup\$ Again, have you considered 2 oz copper? \$\endgroup\$
    – Hearth
    Commented Jul 5 at 14:20
  • \$\begingroup\$ @Hearth, I have but it's very expensive with JLCPCB for some reason. \$\endgroup\$
    – hdaniu
    Commented Jul 5 at 15:51
  • \$\begingroup\$ @StefanWyss I'll look into stall detection. I didn't even know that such measures could be implemented. \$\endgroup\$
    – hdaniu
    Commented Jul 5 at 15:51


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