I am new to circuit design and not sure how to arrange the components in the layout

Layout
#1

As I already said I’m new to KiCat and have never used it before. I have to use it for university now and want to better understand on how to arrange the elements. I created my circuit how the professor wants it to be but now I dont know excactly whats the best way to arrange them on the pcb layout. Is there a possibility to upload the file so I can show you? The issue is the control via a half bridge
The specifications are:
Arrange the components on the board in such a way that there are no line crossings later. A two-layer board in 1.5mm FR4 is to be created, with the fully metallized backside serving as the
back side serves as reference ground.
Wire the components on the layer “F.Cu”.

  • The +12 V supply voltage should also be realized on the layer F.Cu. Leave
    the +12 V connections unwired at first. After the layout is done, the F.Cu residual area ¨
    is filled with the +12 V net “Insert” → “Add Filled Area”.
  • The minimum trace width and the minimum trace spacing are 0, 5 mm. Larger values for the width are necessary depending on the current flow. For this, check the simulated ¨
    current values especially in the supply and output lines. Set these for at least
    I = 7.5 A, ∆T = 60◦.
  • All lines should be kept as short as possible, but without pushing the components too close together.
  • Through-platings to the (full-surface) rear ground (layer “B.Cu”) should be realized with a hole of 1.1 mm (via hole) and with a via cover of 2 mm diameter (via diameter).
    shall be realized.

Thanks for your help!

#3

@Jonas1893 I have promoted you one level, so that you can upload.
I also moved this thread to “Projects”

#4

Hello and welcome @Jonas1893

That is the most difficult part of creating a PCB!
The rest is joining the dots and filling in the spaces.
Looking forward to reading your file.
Welcome to our world :slightly_smiling_face:

Just curious,
Is the whole class required to use Kicad?

#5

There are some “rules of thumb” which may help, but knowing proper layout is the “secret sauce” of circuit design. Long story, but I was involved with a switching power converter board which had no schematic errors but no engineering input to the pcb layout process. This board had zero 0.00 functionality. No detectable output. The real story is that you need to learn what is important. And to learn what is important, you need to learn circuit design; how the circuit works. For some circuits which are less critical, the rules of thumb might be good enough. But I have seen the most basic voltage regulator circuit work poorly due to poor pcb layout.

The first rule of thumb: Use a solid ground plane most of the time.

The second rule of thumb: After placing ICs, the next thing to place is power supply bypass capacitors as close as possible to the power pins of each IC.

#10

A lot of the posts I read in this topic are not very on topic, nor friendly towards a beginner with KiCad.

We are willing to help, but we are also not going to do your homework for you.

Learning to do a simple PCB design is not very difficult, but it does take some time to learn a program such as KiCad, because it has quite some functions. There is a “Getting started with KiCad” built into KiCad’s main menu, but it’s an old version. There is another document (with the same name) but written specifically for KiCad V6 on the KiCad website.

Getting Started in KiCad | 6.0 | English | Documentation | KiCad

Designing a PCB is also a bit of a puzzle to do it “properly”.
For example, if you have 3 or more parts which have 3 (or more) pins that have to connected, then they simply can not be routed to on a single layer without drawing copper tracks under the parts (footrpints in PCB speak). When you have bigger parts such as QFN or QFP this can be a real puzzle, and it takes practice to learn to do this effectively.

2 Likes
#11

That often happens with certain posters. Good you speak up.

Btw. jokes about nationalities (“Polish passengers…”) should have no place here. Nor anywhere. It’s called inclusion and diversity.

2 Likes
#14

Hey, Jason1893. I’ll give you some general advice:

  1. I assume your class provided some dimensions for the PCB? If not, just draw a square in the edge-cuts layer that’s kinda big enough for all the parts.
  2. All your parts will go on the top of this board in layer F.Cu (the front copper layer). The copper ground plane will go on the B.Cu layer (the back copper layer).
  3. Place any connectors that bring signals/power in and out along the edges of the board. For example, you might put the power input along the left edge and the output on the right edge.
  4. Pick up components in the layout and wiggle them around. That lets you see how the “airwires” (unrouted connections) are connected to other components. Maybe start with the in/out connections and see what is connected to them and then move those parts toward the connectors.
  5. Keep doing step #2 with the components, moving unplaced parts near to parts you’ve already placed. You’ll probably find that parts close to each other on your schematic will wind up close to each other on the board.
  6. Go through the placed parts and make adjustments like rotating them. Your goal is to make the airwires look “nice” so that they aren’t too long and don’t cross over too many other airwires or components. This is a fiddly process. There’s no real science to it. If you like games like Tetris, you will probably like doing this.
  7. At this point, the placement is done. Now you have to click on each airwire and do the routing. If you’ve arranged the components well, you’ll find the wire routes won’t cross over each other very often. If not, go back and rearrange components to lessen the crossings.
  8. The lengths of your wire routes (traces) will determine their resistance along with their width. You can adjust the trace width to lessen the resistance and reduce the temperature rise caused by the current.
  9. After the traces are routed, you can draw a 12V power plane on the F.Cu layer. That should make connections with the 12V input pins of your devices. Or it may not if those pins are blocked by other wires. In that case, fiddle some more with the placement until you unblock those pins. Once again, it’s like Tetris. Enjoy.

That’s a pretty simple, basic outline. As you gain more experience, you’ll get a lot better at it and realize there’s a lot more to it than what I’ve said. But you’ve got to start somewhere.

3 Likes
#15

OK. I just cleaned up some posts that were either off topic or not very helpful or just too long.

@Jonas1893 If you can upload the schematic then we can help. This is one of those things that will make way more sense once you see what is happening and why.

3 Likes
#16

I agree with this. For me, gamifying the process helps to make it enjoyable. I think like Tetris when placing parts, and like connect-the-dots (with really strict rules) when running the traces. It can get quite absorbing and I can easily loose track of time (my ADHD doesn’t help). One thing that I have to watch out for (your mileage may vary) is I need to sometimes stop myself from trying to completely optimize the placement and routing to achieve “perfection” when “good enough” is sufficient. Learning where that fine line is gets better with experience.

#17

Hi guys! Thank you so much for your replies! I will try to solve it as far as I get and if there occur any problems I will post my circuit here.

1 Like
#18

I have one question: I used screw_terminal_01x02 but I see it as with 3 terminals. What did I do wrong there?

#19

Screw_Terminal_01x02 definately has two screw connections:

image
image965×555 73.9 KB

I don’t know what you did.
Maybe you used a Screw_Terminal_01x03 and then later changed the “value” field in the schematic to xxx01_02. Or did you assign a footprint and has it tree pads on the PCB?

#20

Thank you very much! I accidently assigned a wrong footprint to it. Now it works

2 Likes
#21

I thought maybe we scared you off. :wink:

You might want to post your circuit at some point regardless. The jump from university to job market can be jarring. It’s good that your instructor even has you doing this. That said, some pointers early on from people that have done this on real world circuits could prove useful. Good luck with your project.

#22

BLDC_Ansteuerung.kicad_pcb (144.1 KB)
BLDC_Ansteuerung.kicad_prl (1.1 KB)
BLDC_Ansteuerung.kicad_pro (9.1 KB)
BLDC_Ansteuerung.kicad_sch (102.8 KB)
fp-info-cache (1.6 KB)
Mod Edit: From the project screen you can ‘archive’ the project. Also useful for just zipping it up into one work.
BLDC_Ansteuerung.zip (49.6 KB)

Hi guys, sorry for the late response! I have now tried to wire all the components. I hope that it is ok like this. It’s my first design, please don’t be too hard on me :slight_smile: feel free to improve my layout :wink:
Now I have a few questions: How do I add vias? I have not considered these in my uploads yet. Also, the professor has specified that the supply and output lines should be wider so that more current can flow. I should design them for at least I=7.5A and delta T = 60°. Can someone do this for me in the layout and explain how it works?

#23

Yes, we use it for a project work. I understand it much better now that I have familiarized myself with it :slight_smile: thank you so much for your help!

#24

you were right, thanks for your advice. I tried my best. Hope it is ok

#25

Thank you very much for your advices!! how can I draw the 12V power plane?

#26

That is explained in this chapter of the document I already linked to earlier in this post.

There are also beginner tutorials on youtube for KiCad, if that format suits you better.

1 Like
#27

He left out copper thickness but assume the default of 1 oz/ft^2?

File>Board Setup>Netclass is what you want. Damned not intuitive until you understand it though. :wink: