Pcb design mistakes - feedback

Projects
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I think the issue concerns an understanding of Electronic Design Automation (EDA). There was a time when I did not understand it either, but I am almost certain that EDA was a new thing after I was a new engineer.

Anyway having the schematic and the pcb in one EDA system (such as KiCad or probably Proteus…not familiar with it) gives you a proven way to assure that the pcb agrees with the schematic, via the netlist. But if you use a schematic from one system and design the pcb in the other, you probably do not get that unless there is a way to import the netlist.

At least, try using KiCad in the way it was intended, before trying the work-around.

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Around 1988 OrCad was good schematic editor but without PCB design. RacalRedac was PCB design program with not so good schematic. So I was drawing schematic in OrCad, and in RacalRedac imported netlist obtained from OrCad to be able to design PCB.
Did you imported in KiCad netlist from proteus?
Read:

to find how to promote yourself to be able to include files in your posts.

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My teachable moment was about 25 years ago. The pcb agreed perfectly with the schematic but the pcb designer worked without engineering guidance. The switching buck regulator did not work AT ALL. No output. Nothing. Zip. Nada.

And I do not really understand what is the “Discourse” program, but I like the way this forum works MUCH better than the others I can think of, such as EEVBlog or Electrotech.

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Your schematic contains an error that is likely the cause of your problem. Look closely at U5 and U6.

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I see what you mean. But with only human attention to link the schematic and the pcb, how do we know that the pcb has the same error, or that it does not have an additional one?

As I look again at the schematic of U5 and U6: First I thought I knew what problem @RRPollack was discussing. And yes, that first one is there, but now I catch something else:

What are components R11, R12, C13, and D2 supposed to do? I believe they will do nothing useful, although the first problem may affect what they actually do. (Imagine for example that a resistor might do nothing in a circuit but a second error might cause it to smoke. In one case it does something, in the other case it does nothing, but neither case is useful.)

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sir, I reduce the energy coming from the pv panel to 5 volts with lm2576. After feeding acs712 with 5 volts, I reduce it to 3.3 volts with ams1117-3.3 since stm32 requires 3.3 volts for its operating voltage. Evaluate the power part and the processor part separately.

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I’ll leave it to others to evaluate your project. As I have said, using two tools in the chain increases the chance of errors slipping in. At least with KiCad for both schematics and layout, you can be sure that the layout corresponds to the schematic if the DRC partity check is turned on. And for what, a saving of maybe ½ hour drawing the schematic.

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U5 and U6 op amp voltage follower r12 for voltage divider c13 filter d2 to protect the system in case of reverse voltage. I measure voltage via the processor with this structure. I got results using Arduino with this scheme.

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If you do decide to redraw the schematic in Kicad, I’d suggest drawing one complete schematic instead of eight small parts scattered over the page.

The schematic, the way you have drawn, may be easy for you to follow because you have spent much time developing it, but for new people to try to read it requires a lot of wasted time trying to work out which pieces go where.

The normal convention for drawing schematics is (where possible) have the inputs on the left and the outputs on the right, V+ supplies above and Gnds underneath.

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The first problem with the op amp connection is that the supply rails are reversed. Vcc should be positive and Vdd should be ground. That is likely to destroy the op amps unless the +5V source has a low current limit. This triangle symbol and labeling from the old National datasheet is much more clear and would help avoid mistakes.

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My question about those passive components is another issue: With one exception, they need some current drawing load impedance to work against. The input to the op amp will normally draw only nanoamps or less. Your diode might conduct that much in reverse, and the resistors will not drop significant voltage. The only situation I can think of where it is reasonable to have a resistor in series with an op amp input (and nothing else loading that resistor) is if you are balancing the op amp input bias current so as to minimize offset voltage. You are clearly not doing that. I would call all of this at least a second circuit design error.

Thirdly I notice that C16= 1 nF looks like the output filter capacitor for the switcher at U7. I suggest that even 10 uF is probably too low so your value there is too low by at least a factor of 10,000x.

With these three errors obvious to a quick and casual view, the question becomes more of what is correct (probably not much) rather than what is wrong.

Consider that I have > 45 years of circuit design experience behind my opinion here.

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Hi.

Regarding rule 1. Errors are not always one’s own fault, there are plenty of examples where component data sheets have been wrong, but certainly self inflicted trouble is all too common. We’ve all been there!

The problem is as the author of some work with such an error, you can’t see it yourself, but someone walking past see’s it stick out like a sore thumb!..

We’ve all been there! Anyway, hope you resolve it.

Regarding MPPT converters. Please (speaking as a user of the RF spectrum) pay attention to EMC aspects and include effective filters to the input and output ports! The rules are changing, and soon you’ll need them to pass EMC compliance tests. Get ahead of the curve while you can!

Also, the design of switching converters for minimal EM disturbance is another discipline again. Being simplistic, keep the switching converter circulating currents to as small a physical area as you can. Not only does that reduce EMI emissions, but helps efficiency too.

All the best with your project, as with most things, the learning curve can be steep at times.

Best Regards…

Dave B.
(Who still hasn’t figured out how to get the circuit simulator to work, even with simple passive circuits!)

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It is very good rule, but even more important is: keep difference between converter circulating currents as small as possible.

With KiCad V7 I just checked that Spice works. With passives I didn’t noticed problems but when trying to insert diode model ended with it being reversed. I have added my 3 cents to:

I have made separate configuration for Spice (Spice only libraries) if I ever will need to use it. In normal configuration I don’t have Spice library.

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Ah, I didn’t mean to imply that the simulator in KiCad has errors. (Though I’d be suprised if any such complex software was truly “perfect”…)

What I should have said, is that I have not yet figured out how to use it!

There are too many conflicting (and out of date) tutorials etc online, and as yet I’ve not found the definitive and importantly “Up To Date” noob’s guide do circuit simulation with worked examples for KiCad. If, such a thing actually exists these days.

I can create schematics just fine, but how to make the simulator work with them has escaped me.

Any pointers? I used to use Qucs, but that seems to have fallen out of favor and sort of abandoned. Plus, the current offering is not available sadly for Linux systems.

Hence, I was looking at using KiCad’s simulator, but fell at the first fence, and don’t know why.

Regards to All.

Dave. (Happier with real hardware and high power RF, than software models and simulation.)

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I didn’t understood it that way.

I understood that you tried and failed. As didn’t know in what you had a problem I just wanted to say that there should be no very big problem as I trying it only once got it working.

I don’t remember, but I fortunatelly did it :slight_smile:

I don’t know what you are saying about.

Few days ago I switched for a moment to Spice in KiCad, but I used there only resistor while your text about ‘passive’ I understand wider than only resistors.

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Hi.

“Qucs” – Quite Universal Circuit Simulator. Fairly highly regarded and very easy to use, handles static and dynamic situations etc.

I’m not sure what it uses behind the user interface, but it worked really well, with good correlation to the real world, and was cross platform. Now it seems, non Windoze users have been left behind.

If there is a good and “up to date” tutorial for KiCad’s simulation facilities, I’d really love to know where it is please, as all I ever find are old tutorials where what they show, doesn’t tie into how it would appear to work now.

Anyway, this is hijacking the original thread. I’ll start this anew sometime when I’m ready to dive in again. Needing too, to re-install KiCad too, after something related to an OS update did the dirty on me… The Flatpack version of KiCad I had, was bricked as a result.

Oh, how do you logout of this forum? That facility seems to be missing, short of exiting the browser and expunging all cookies…

Regards.

Dave B.

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Please have a look at https://www.youtube.com/watch?v=nvtybUhoTOQ and other videos of my channel https://www.youtube.com/@holger8105/videos . There is also a tutorial at KiCad Eeschema as GUI for ngspice, tutorial for setting up the simulation .

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When I joined forum in 2017 it was easy, but later they improved forum software.
You need to click at your avatar at the right side, then the Profile icon (last one) and then you will see.

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Click on your icon at the top right to get a dropdown panel, then on the profile icon at the bottom of the column, then Logout is the bottom option.

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This is not a short cut.

Do not do work this way. To do so is to tell us that it is not important enough for it to work.

Here is my template email for beginners to KiCad:
The four best KiCad tutorials I have found to date 20241202.

First:

For a mostly complete overview of a very simple Schematic, PCB (and the symbol and footprint editors), start here:
Robert Feranec What is KiCad about? Starting with KiCad … https://youtu.be/maaBkw7IRUc

This tutorial is for an older version, 5, but still very very good to start.

Second:

For Version 7.0 here is a well done but much longer tutorial of a complete schematic and an abbreviated PCB project for an ESP32 project.

made by morten KiCad 7 ESP32 PCB Design Full Tutorial

Note: I found that I could listen to this video at 2X speed with good intelligibility.

The following two are part of longer series and will each teach you things the other does not (Or else I may not have watched the full series on either)

Third:

This is the older version 5 but for Hierarchical schematics the best I found.

John’s Basement on KiCad 5 #17 Hierarchical Labels & Pins https://youtu.be/m_HTBurAJn4

This tutorial on Hierarchical (multi page) schematics which (multi page) are very essential for complex is about version 5 KiCad but still works.

Fourth:

Much more elaborate project(s)

KiCad 6 STM32 PCB Design Full Tutorial - Phil’s Lab #65 https://youtu.be/aVUqaB0IMh4

Phil’s schematics and PCB are attractive and electrically well thought out.

Here is the “BananaSchplit” a useful design:

Design Review

To understand that there are many more requirements to keep in mind on a schematic and PCB design, I encourage you to read this design review guide.

While it is written by people using a similar professional software, Altium, the requirements it identifies are VERY much the same because they are requirements for a good schematic and PCB which is largely not specific to the software in which you do the design. I am going to guess this will introduce you to a lot of requirements which are all worth while learning.

Fabricator Requirements

If you will be fabricating PCB and assemblies from, for example, JLCPCB you need to read and understand the fabricator’s requirements.

See: PCB Manufacturing & Assembly Capabilities - JLCPCB

Getting Help

Finally, help us help you. When asking for help DO NOT make us guess.

Share the exact file with the problem. Share your entire project or a simplified version which reproduces the exact problem(s) you have.

Hope this helps.

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