Hello everyone. I am a beginner in pcb design and I am trying to design a power electronics circuit. This pcb design was printed with jlcpcb but my printed circuit does not perform the step down from 5 volts to 3.3 volts. I do not know if the problem is with Kicad’s gerber output or if Kicad’s own AMS1117-3.3 component has the wrong footprint or if the problem is on my end. I would appreciate it if you could examine the pcb design, examine my mistakes and give me feedback, thank you.
https://drive.google.com/drive/folders/1DRvsIcgOIRfzKHXpwHsaWWUDOZkQEiZU?usp=sharing
I had a quick look at your .rar and saw no schematic file. I think we all would need to have that. Was your pcb designed by doing a schematic first?
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It is a bad idea to try to design a pcb without doing the schematic first.
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If you are truly a newbie in electronics (???) switching power conversion is not the place to start.
I drew the schematic in Proteus. I thought KiCAD was more comfortable so I drew the PCB directly without transferring the schematic. I will add the schematic to the rar file. I am an electrical-electronics engineer and I just started working on embedded systems.
Rule #1: In any engineering discipline, if it doesn’t work it’s almost guaranteed to be your own fault.
You ask if the Gerber generation is bad. Did you look at the Gerber files with KiCad’s Gerber viewer? If you don’t trust it, try another like Gerbv. Do they match what you expect? Does an ohmmeter show the connections to be correct?
You ask if the KiCad footprint is wrong. You can (and should) verify the footprint matches the component datasheet before you send a board out for fabrication. It’s a simple 4-pin device, and took me all of 30 seconds to verify.
I guess Rule #1 applies here.
Rule #2: When asking for help, explain what behavior you expect and what behavior you’re actually getting.
“Does not perform” doesn’t do that. What have you done to diagnose the problem?
Does the input voltage match what you expect? Is it +5V or something else? Is it stable?
What are you seeing on the +3.3V line? 0V? +5V? Is it stable or does it oscillate?
Random comments:
- A schematic is critical. Without them we can’t see how your circuit is intended to function. I wasted far too much time just trying to identify your AMD1117-3.3.
- Component placement is often critical. PCB traces introduce inductance and impedance and pick up noise from other circuits. Input and output capacitors should be mounted close to the regulator. I looked for caps next to the regulator and couldn’t find any.
- Component values must be listed. The capacitors elsewhere on the +5V and +3.3V tracks have no values listed.
I’ll leave you with this hint: look at CR1 and CR2.
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I added the proteus schematic to the rar file. I did not edit the component values in the schematic. The value of each part was calculated on paper. Please do not get hung up on the values. Thanks for the feedback.
This is my first work, I am trying to make an MPPT boost converter. I am open to all criticism and advice.
First you say you are making a 5V to 3.3V step down converter. Fine, the AMS1117-3.3 is a linear regulator for that. Now you say you are trying to make a boost converter.
I think you are confused.
I think the +3.3V regulator he’s worrying about is just an internal part of the Maximum Power Point Tracking (MPPT) controller he’s trying to build.
From a relevant IEEE paper:
Comprehensive Analysis of MPPT Techniques using Boost Converter for Solar PV System
An efficient maximum power point tracking (MPPT) controller is a crucial part of solar photovoltaic (PV) system, which can handle the non-linear characteristics of a solar PV array. In this study, a proposed solar PV system with boost converter and dc load is modeled and compared according to the operating characteristics (i.e. voltage, current, power and efficiency under varying solar irradiance and cell temperature) using five conventional and modern MPPT techniques. The proposed solar PV system and MPPT controllers are modeled and simulated in MATLAB Simulink platform. Among these five MPPT controllers, artificial neural network (ANN) MPPT controller provides the highest efficiency of 97.55% and produces less voltage and power fluctuations. The novelty of this paper is that it focuses on the key characteristics and simulated results of the five MPPT techniques to make a comparison between them.
I think skipping drawing a KiCad schematic is a penny wise pound foolish decision.
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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.
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.
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.
Your schematic contains an error that is likely the cause of your problem. Look closely at U5 and U6.
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.
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.
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.
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.
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!)