ground consideration of PCB design with multi power and high current

hi, guys

I'm designing a voice coil motor driver with DRV8412, this device require 12V for logic regulators and gate drive circuit; one the H bridge which drive the motor, a PVDD up to 50V DC is supplied, the operating current of the output is about 8-9A. In addition, this driver is controlled by a microcontroller which is powered by 5VDC.

Right now I plan to use two power supply to this board, 12V and 50V; a voltage regulator is used to get 5V for microcontroller from 12V.50V power supply goes directly to the H bridge.

I think I should use polygon pour to make different Ground for these three power. But I don't really know how to do that, can somebody give me some advice or recommend me some books or material?

Another thing about the high current, how can I make the track for that? I used some calculator online which says the thickness of the track should be .075 inch for 10A. Is that all?

hope somebody could help me out

The trick is to use wide tracks for High current paths, in PC SMPS they cover the tracks with thick solder layer to increase the conducting path thickness. Keep high current track length as short as possible. Leave enough gap between other tracks to avoid stray pickup. Take care to avoid ground loops and common mode.

Hi,ark
I used some calculator which shows that if I use 2 oz. copper, I need 7 mm. That would be too wide. If I used even thicker copper, I'm afraid that I would be not good for other trace, or unless we could design the thickness of copper for certain trace?

would it be a good idea to use 2 oz. copper with 1mm width and cover it with solder layer? I'm afraid that it's hard to do that, because it seems to me that it's difficult to put solder on the trace of PCB, they just won't touch together.

ark5230 said:

The trick is to use wide tracks for High current paths, in PC SMPS they cover the tracks with thick solder layer to increase the conducting path thickness. Keep high current track length as short as possible. Leave enough gap between other tracks to avoid stray pickup. Take care to avoid ground loops and common mode.

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That is obvious, one has to strike upon a suitable compromise, else design or search for copper clad to suit your requirement using higher copper layer thickness.