The PCB Design Professionals

Power Planes – 11 Part 2

So, continuing from where we left off,  we better talk about positive planes.

Positive Planes

So far we have drawn our negative plane and added a split to it, after all that hard work you’ll probably want to switch it off now to make it easier to see the positive plane. You can do this by going to “Design” then “Board Layers & Colours” or hit “L” for short, then there is a internal planes column in the middle you can un-check the tick box to hide our internal plane.

Now we can see what we are doing you can add a polygon pour (positive plane) by going to “Place” then “Polygon Pour” or hit “P” then “G” you will be presented with a dialogue box like this.

In here there are a number of different options (I’ll let you discover most of them). The basic ones are Name, Layer, and Connect to Net. Name is just an identifier (can be a life saver on boards with many polygons), layer is fairly straightforward the layer you would like your polygon to be on and Connect to net is also an easy one the net you would like to connect with your polygon. If you set all of these things and press OK.

You should now have a cursor on the end of your mouse that you can use draw your polygon any shape you like. The polygon draw tool is much the same as the tracking tool in that you can press shift and space to change the line style between – Right Angle, Any Angle, 45, Arcs and curves. with a combination of these you can draw a fairly complex shape.

If you would like to edit the polygon after placed you need to right click on it go to polygon actions then move vertices’s this will give you a number of pick point to modify the corners. If you want to stretch a certain section you need to click the line in between the pick points.

Polygon pours do not automatically re-pour so should you need to re pour your polygon you can either double click on it to bring up the dialogue box then click OK to close it you will then get the option to re-pour your polygon. You can also right click and as before go to polygon actions but this time go to re-pour this will re-pour the polygon you right clicked on. There is also the Tools menu, go to “Tool” then “Polygon Pours”  there are few re-pour options there. Then there is the Polygon Manager but we’ll cover that in another post.

What else do you need to know about polygon pours -

One fairly important one I should probably mention is that if you draw a smaller polygon inside a larger one, two things will happen.

1. The clearance between the two will be your minimum whole board clearance unless you set another rule specifically for the polygons.

2. Depending on the order you draw the polygons in the larger poly may pour right over the smaller. To avoid this you will have to use the Polygon Manager to set the pour order (auto generate usually works out fine).

Pros

• Can be use on layers with tracks.
• Dead copper can be removed.
• Easily understandable (WSYWIG).

Cons

• Sometime slow to re-pour.
• Does not auto generate.
• Can take up quite a bit of system resource.

Well I hope that’s given you a start into power planes in Altium if you have any questions or you would like us to do a tips and tricks on a specific topic, post a comment or email us at blog@blackstick.co.uk