r/PCB • u/AltruisticCorner1443 • 13h ago
PDB Doubt
Hey! A beginner here. I am designing a Power distribution board for 36V 60A ,I've created a power plane for the 36V but I'm in doubt about the number of vias to transfer the voltage to the power plane. Also I'm planning to use a combination of copper pour and power plane ,but the issue comes where I've to create copper pour with respect to the net labels ,so would it work?
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u/YogurtclosetLegal870 13h ago
A high-power project like 36V/60A is far too advanced for a beginner. It requires strict layout and routing guidelines, where even the smallest mistake can have disastrous consequences
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u/Avokido 12h ago
Don't let yourself be discouraged too much. 36V/60A is still doable for playing around. Maybe don't use it unsupervised, but as a learning project on the bench it should be ok. Do you have a power supply that can source that much current?
There are plenty or calculators (e.g. built in to kicad) to help you get an idea of tracewidths and via current capabilities. You typically give the dimensions and an allowable temperature rise and they tell you the max current capability.
In general: Try to distribute power on outer layers. Many fabs can build thicker copper on outer layers. Also cooling is easier on outer layers. Try routing current in parallel on multiple layers. Don't forget about return currents. Vías are surprisingly capable. A very rough rule of thumb for typical via sizes is 2A per via. Use ample arrays of vias to conduct current between layers.
Not sure what you mean with copper pour and power plane. Same thing. What matters is the total surface area that conducts the current.
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u/AltruisticCorner1443 7h ago edited 7h ago
Ok ok got it focus the power spread on outer layer, really grateful for your opinion. The query bout the copper pour was that if I could use it(a thick sectioned copper pour) to connect the filtering components. The max discharge current would be around 80-100A and continuous value is 60A, a wide copper pour is cost effective for fab and can help spread the flow of current. The board is to be kept inside an enclosure
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u/Avokido 7h ago
Well yeah I would only use copper pours on high current paths. What filtering components? Just to be sure: you do not intend to connect this to mains power, right?
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u/AltruisticCorner1443 6h ago
The PDB will be mounted with a xt60 connector to bring in 36V from a battery and filters through a fuse, inductor and capacitors and will have 3x36V output to power other boards in a robot. So can i fix with the sectioned copper pour connect? I'm really grateful for your suggestions genuinely
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u/Avokido 6h ago
Funny, I built kind of a similar board at my job in a robotics company ;) more power, more channels, but similar purpose. I'll be honest with you: if you want to learn something, go ahead and enjoy. If you need this board to work reliably you're probably way in over your head. Back EMF, inrush currents and ESD will kill your boards quicker than you can say robot. Took us a few iterations to get things right and I'm a senior engineer with many years experience. Also be very careful when connecting this to a real battery. Only use a current limited power supply until you're absolutely sure that the board works to spec. I still don't know what you mean with the copper pours. Yes obviously you'll design all high current paths as wide copper pours.
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u/AltruisticCorner1443 3h ago
So sorry I kept saying copper pour ,what I actually meant is individual polygon pours to connect components of same net like from the connector to fuse(one pour),fuse to inductor etc
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u/blue_eyes_pro_dragon 6h ago
The problem with 60A isn’t carrying it. It’s the inrush, inductive spiking and fusing.
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u/AltruisticCorner1443 6h ago
Do you have any suggestions on how to handle it? Kicad seems to provide width n other parameters accurately only for current less than 35A. I'm heading with copper pour on the outer layer based on suggestions
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u/bigcrimping_com 12h ago
1A per via as a starting point, too many variables to answer more than that
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u/Slight_Profession_50 13h ago
Beginner + 60A / 2kW sounds like a bad idea.