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Thanks for this great article
Thanks for your comment Ralph Arciniega, have a nice day.
- Steve Adil, Staff Member
hi now there were quite a lot of people who wanted me to take them through my PCB layout of this power supply board and that's exactly what I'm going to do here while I was laying out this board I did actually capture it in real time so what I plan to do here is actually play that back the complete recording of laying out the board at times ten speed and adding some commentary on top of that of how I was laying it out what I was thinking and the processes and things like that so let's get onto it now before anybody asked the package I'm using here is Altium Designer okay so no more that's the package I'm using yes it's very expensive I'm aware of that but that's the tool I've used for 20 years so here we go now the board itself when I'm actually setting this up I've already done the outline of the board that is actually the first step I'm going to do when I start laying out a board is to do the outline of it and this is based on the box I know I haven't done a video outline the system design and the case it's actually going into but the template of the PCB that you'll see here in black the the black background that is already defined as the outline of my board with the little cutouts required and things like that so that's the first step you're going to want to do to a board as well as setting up your placement grids now I've already done this because this is a through-hole design instead of surface mount most of my components are on an imperial naught point 1 inch grid so what I'm going to do is set my grids of both a component grid and a snap grid as well I'm going to set the snap grid to 50 mil or 50 foul it's the same thing fail means mil I'll probably use these sort of terms interchangeably throughout the video I do tend to use both so mil is not millimeters mil is thou one thousandth of an inch so because the components are things like dip package is our on a 100,000 or 0.1 inch grid I'm going to set my snap grid to half that value when I'm routing maybe drop that snap grid down to 25 fail or something like that and the reason you want a multiple of this is so that your tracks when you take them between pins of your IC go smack bang through the center and if you try and layout an imperial board like this a instead of a metric ball which is what new surface mount components use if you use the metric grid with imperial components you're going to end up with the tracks not quite going through the sentence or going to get a bit messy but I went on designing and laying out a board like this I you have to you're forced to use both Imperial and metric dimensions because I will use metric for things like whole sizes I'll use not point eight millimeter hole instead of X amount of thou so I'll also use metric for the dimensions of the board and possibly are placing components and the center of components and things like that so when I'm dragging around my components I will actually I might switch to a metric grid instead of my imperial grid so that a lot of the components and cells especially on the front panel components when you're lining them up they will be on a metric grid so I've already set these things up in the background and I've dumped all my components down because it's a very important step to get your schematic and all your footprints correct in your libraries as a first step and then dump them all onto your board so that's what you'll see here I've started off I didn't capture this process on video unfortunately but what you'll see when I start out here I've got a blank board that has the outline already done I've placed some of the components around the edges because it's in very important the first thing you want to do is place those fixed components that poke out your front panel on the edges your board your connectors your switches you you know all sorts of things like that you want those to be exactly where you want them on the edge of the board and then you fix them you lock them in place and then your components can that's when you start to get to the art of PCB designers where do you put your components how do you lay them out how do you which area the board do you put them in and so on so I've already done that I've place the components around the outside so let's get into it all right here we are we've got our main schematic of course and I've dumped down all the components as I've said and you'll see the menus are flash up sorry I can't actually slow this thing down as I'm actually recording this audio narration on top of it but as you can see what I'm doing around at the top of the screen there as I'm moving the heatsink around now I'm playing and at the moment I'm getting that power connector there's that 2.5 millimeter sorry 5 millimeter a DC power jack and I'm just mucking around that top area of the board there just to make sure I've got that power connector on the side I want and I'm also thinking about the system design at this point because I still don't have a a complete idea in my mind about where everything's going to go and how it's all going to work and this will actually evolve as I lay out the board because a lot of this might be dependent upon you know things I see when I'm laying out so what I'm doing now is I'm placing down the power traces there from the there I think close to 100,000 the DC input jack and you'll notice all these art wires actually connecting all the components that I've dumped down there the Altium Designer the programs just done this for me it's it's dumped all the components down and they're actually net wires accord from twos in Altium speaking other packages they might be called you know a rubber Nets rubber banded nets highlights like that now what I'm doing here this is a key part of laying out a board you'll notice that I started to group together functional components our functional block and if you've got the schematic and you playing along at home here you'll you'll see that I've divided the schematic into these functional blocks and that stuff started laying out here as I started laying out just that functional block I've moved in the components I'm doing this outside of the area of the board that's another key thing I'm doing this out in the dead area and when I've laid out this little subsection of the circuit I then I will take that highlight at all and then drag it into the board somewhere as a little module so I'm developing this thing as a module you'll notice that the one I'm laying out now is actually there's the MOSFET that's this is the micro current part of the circuit so that's its own little module and there's the drive transistor and there's the base resistor for the other pull-up resistor or whatever for that that little micro current part of the circuit and if your circuit is modular like this and that's what you're going to want to do and here are the current are shunt resistors all ten of them in parallel there and once again you'll notice that the location of those ten parallel resistors will change later as the board evolved zand I move things around but that's where I put them for our starters because it was it seemed like a convenient locatio
Thanks drygfydH your participation is very much appreciated
- Steve Adil
About the author
I've studied computer communications (networks) at University of West Georgia in Carrollton and I am an expert in ancient chinese history (outline). I usually feel angry. My previous job was transportation attendants I held this position for 28 years, I love talking about watching movies and wind surfing. Huge fan of Alfred Molina I practice squash and collect chemical elements.