Power distribution on pcb

I have several very long traces > 18 inches that are approximately parallel and divide up the pcb into sections(this is due to routing between distant components such as proving a clock). Because I'm doing this on a 2-layer board and it has potential for relatively large currents and changes I want to distribute the ground and vcc better across the board.

So think of a board of, say, 19x6 with 3 long traces parallel to the long edge of the pcb separated by about 1.5 inches.

Now what I'm doing is sorta "stitching" across the traces somewhat uniformly long the 3 traces so that the ground currents do not have to flow inward from the sides of the board.

-----++++-----++++----- C

-----++++-----++++----- C

-----++++-----++++-----

Where the +'s are jumpers(through vias on the other layer) to connect the two "sides". The idea is to reduce the impedence of the ground as seen by some components designated by C.

Any problems doing it this way? Please don't bitch/preach to me about using

2 layers or having long parallel traces or whatever... I have reasons for using 2 layers... the most important one being cost and that the circuit is relatively simple enough that it should work fine with 2 layers. I simply want to optimize it before I send it off for fab.

I really doubt I probably even need to do that but, again, it's just an "optimization" that doesn't seem to hurt? May not help much but thats besides the point.

Alternatively I could alternate the long traces to change layers regularly:

-----++++-----++++----- C

-----++++-----++++----- C

-----++++-----++++-----

Where + now means on the "other layer".

This is not really an option though because I actually have several other traces, it creates potential transmission issues, and there are some other traces on the other layer that makes it difficult.

In any case, if it's not clear:

formatting link

A copper pour will eventually be added connecting the two sides to gnd.

Reply to
Jon Slaughter
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Err, so what's the problem if the Red side is going to have copper pour anyway?, nothing usual there at all.

Not nearly enough info provided for any sensible advice. You haven't shown the power traces, what components, what speeds, what current etc.

BTW, the blue traces don't look straight, ugly as. You must have a "any angle" mode on instead of the proper 45/90 only. Snap grid?

Dave.

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Reply to
David L. Jones

I believe I gave all the information needed. You simply want to overanalyze the problem. I asked a simple question and only want a simple answer. Obviously in some extreme cases there are possible pitfalls with doing what I did... but that is the case with just about anything.

As I said, the board will most likely work either way and I'm simply adding those "features" because I believe it can only help barring any obvious reason why it would be disasterous.

Tlue blue traces are not straight and not meant to be. Again, it is irrelevant for the question posed.

Reply to
Jon Slaughter

Really? then why do you think no one has answered your question?

You mention "high current" but don't indicate what that is or where it is flowing.

Your ASCII diagram doesn't really match what your screenshot shows, it's confusing.

From what you have shown, you are simply stiching ground from one side of some long traces to another, and then you said you'd flood it with copper pour anyway. That's standard practice, and if it's copper pour all on the bottom then you dont' need the stiching anyway, so it's hard to actually understand what you actual question is.

Have you got any more of the board to show us?, that might help.

Dave.

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Check out my Electronics Engineering Video Blog & Podcast:
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Reply to
David L. Jones

Well, thats totally different than me not supply enough information. If I wasn't clear on explaining what I actually meant then I'm sorry. But as I said before, all the other details are not important.

Personally, I think the screen shot along with the two pieces of information "2-Layers" and "Copper pour" should have made it clear enough... but thats just me, I obviously know whats going on already...

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Reply to
Jon Slaughter

Right, that last paragraph sums it up, everything else just sounds like confusing gobbledygook.

Just like I thought, you have long traces going right across your board, no big deal, that happens all the time. In that case, like I said in my first post, stiching to either side like this is the normal way to do it, usually uniformly anong the long traces. Basic 2 layer design involves routing your signal and power tracks first (preferably keeping as many as you can on the top layer) and then flood everything on the bottom and top with copper pour at the end and then stitch to your hearts content. That's 2 layer design 101 stuff.

You keep throwing in words like impedance, infinite, trace seperation and reducing effects etc. That's confusing unless you are specifically talking about high frequency signal integrity stuff. For most other general uses you either have electrical net connection that can handle the required currents, or you don't.

Copper pours and lots of stictching along those long traces is standard practice, you are on the right track. If you have other complex issues like analog/digital ground seperations etc, then that's a different story.

So the simple answer to your simple question is NO, it shouldn't be a problem. Show us your finished board and we can tell you more.

Dave.

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Check out my Electronics Engineering Video Blog & Podcast:
http://www.eevblog.com
Reply to
David L. Jones

Ok, I was just making sure because I've never seen such a thing in any board I've ripped for scrap. This might simply be because all the boards were > 2 layer.

As I said, it's a very simple board and will probably work just fine without them. Again, it was just something I figured I could do "Just in case" but since I've never seen it mentioned anywhere I wanted to make sure there wasn't something obivous I was missing.

Reply to
Jon Slaughter

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