Author Topic: can vias improve current carrying capacity in a two layer PCB?  (Read 666 times)

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Offline iontodirel

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can vias improve current carrying capacity in a two layer PCB?
« on: October 18, 2017, 06:10:23 am »
Can vias improve current carrying capacity in a two layer PCB? I have a 2 layer PCB, the top layer and the bottom layer carry high currents and it's the same path. If I add vias that connect the two layers, can that improve the current carrying capacity relative to not having any vias? Could the current carrying capacity improve with more vias?
 

Offline samnmax

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Re: can vias improve current carrying capacity in a two layer PCB?
« Reply #1 on: October 18, 2017, 06:50:13 am »
Provided the current can reach both layers easily in their entry/exit points, additional vias spread through the track will not increase the current capacity. Instead, via holes will reduce the longitudinal cross-section of the tracks, reducing their capacity. Think of it this way: you want current to go through the X and Y axes, not Z.

However, if your entry/exit points are too narrow, some vias around them may help with carrying current to/from top and bottom layers.
 

Offline T3sl4co1l

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Re: can vias improve current carrying capacity in a two layer PCB?
« Reply #2 on: October 18, 2017, 09:05:46 am »
Better to open up soldermask and add big globs of solder, or tack on extra copper wire/strip.

Tim
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Offline iontodirel

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Re: can vias improve current carrying capacity in a two layer PCB?
« Reply #3 on: October 18, 2017, 09:32:44 pm »
so this is what I have
 

Offline katzohki

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Re: can vias improve current carrying capacity in a two layer PCB?
« Reply #4 on: October 18, 2017, 11:08:18 pm »
Google "Saturn PCB Tool" to help you make some calculations. Basically current capacity translates to "how much will my trace heat up?". Obviously at a certain point the trace will fail when it heats up too much (or fuses, if you happen to try forcing 200A through a 5 mil trace). Via stitching helps to move current from one layer to another by increasing the surface area and volume of the connection. This can be used for heat sinking, but I think the points others made about adding it in the manner you're suggesting are valid. I would consider an imbalance between the two paths and see if that could also cause trouble. You may need to increase the copper pour thickness.
 

Offline iontodirel

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Re: can vias improve current carrying capacity in a two layer PCB?
« Reply #5 on: October 19, 2017, 09:14:33 am »
thanks, fixed it
 


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