In a previous thread I asked about 15 stepper motor simultaneously. I was able to get the proper items for this purpose with the help of the answers. Now I use A4988 stepper drivers with an Arduino Mega.
Now I will print a PCB with home-made techniques and trying to determine the width of the tracks. I don't have any question about the 12 V supply voltage for the stepper motors. However I don't know how much current VDD pin of the driver draws. As I was told supplying logic current to 15 stepper drivers will not be an issue I believe the current must be less than 20 mA but I just want to confirm. How can I determine the logic current a stepper driver draws from Arduino Mega?
Wawa:
You can find things like that in datasheets.
Google "A4988 datasheet".
Logic input current is defined as <1uA.
Leo..
Thanks for guiding me. I had already checked but it seems I had missed. Now I see the typical value is <1uA and even the max value is 20 uA. I don't really need to worry about the track width for the logic pins then.
Signal traces are typically 10 to 16 mil, supply 40--60 mil or so. Wider supply traces are for low inductance
when suppling a logic chip typically(*). High current traces for power electronics can be checked
against a
trace-width calculator, there are many of these on-line.
(*) Even if the logic supply is microamps, make them wider than signal traces to keep the
inductance low (and don't forget decoupling capacitors for any logic chip, these are
not optional, even if not mentioned in the datasheet).