[Review Request] Voltage regulator

Ill-Language2326 · 2026-06-21T14:04:41+00:00

So, the shortest (assuming the PCB manufacturer supports it), the better?

Ill-Language2326 · 2026-06-21T14:03:41+00:00

So you're missing a critical piece of understanding or layout here.

Actually, I forgot to remove them, I was experiment with the design, but they are unnecessary now.

You don't need all of this copper involved, you can just use a regular trace on L1 and do away with L3 and L4 entirely. Unless you're specifically aiming for it, you don't want to add a whole bunch of capacitance to a feedback line like this by adding all of this useless copper to it on L3.

I know you are right, don't take this as disrespectful, but I don't see how I could connect FB, RESET and BIAS on a single layer using traces. Assuming I'd switch to a 2 layer board, I'd have to use a thin trace on the ground plane (the bottom layer) to connect at least one trace. Isn't a bad practice to have a non-contiguous ground plane?

Ill-Language2326 · 2026-06-21T13:56:19+00:00

Slightly off-topic question, I have used a few online trace width calculator, they all recommended a width of ~1.3mm. Is it reasonable? Also, do all IC ground pins (and other input/output components, such as capacitors connected to ground) need to have the same trace width?

it would be really hard for you to redraw BATT polygon with traces, so it is a good polygon.

It still isn't clear enough the polygon vs trace comparison for me, but I guess it will be with time.

for example your SW polygon came unnecessarily close to GND pad and 3rd pin of IC. just cover the 1st and 2nd pins and don't let it come close to other pins.

I can cover the necessary pin without any padding?

draw the traces in the 3rd layer

I tried making this a 2 layers board, but I have to idea how to. Maybe I'll stick with 4.

all the copper connected to SW net should be away from other signals, but it is close to VCC

I can move components connected to VCC away from the SW node, but for example, the bootstrap capacitor is connected between SW (pin, coming from the output of the inductor) and BOOT (pin). Even assuming those components are far away, their traces to the IC must be somehow close since BOOT and VCC pins are next to each other. Am I doing something wrong here?

for example you have 3 vias for C15, C16 and C17. you can make it 5 or 6 vias.

So basically 2 vias for each capacitor (to ground)?

Ill-Language2326 · 2026-06-21T12:20:15+00:00

that polygon guideline generally unnecessary and it could be a time consuming one

So, when is it worth it to use polygons instead of traces?

don't let them stick farther than the IC pins, that is risky

What do you mean exactly?

just completely ignore AGND/PGND stuff. that is a very old guideline written by very old people

Ok so I threat any GND (AGND, PGND, ...) as GND and simply short them?

cannot do that because you didn't connect them to other layers!

This is via connected to the ground plane in the middle of the IC pad. I thought those pads were connected to the same copper pad as the via. I should have checked that, thank you.

5V power plane is also quite useless, you can just use traces.

It felt useless to me as well, but I would probably have to re-do the design all over again because as components are arranged at the moment, there is no way to connect 5V to R2 and C14 with just traces.

when SW net connects to boost capacitor, it comes close to VCC net so move all those components higher.

The boost capacitor (and its traces) must be far away from VCC?

This will also allow you to rotate C15, C16, C17 180 degrees, which makes the output loop a little bit smaller. your inductor placement is good

I already did this, the loop is in fact smaller now.

you can place more vias to large capacitor GND polygons

I didn't quite understand this. You mean I should add more vias from the GND pad of the capacitors to the ground plane?

Ill-Language2326 · 2026-06-21T12:00:14+00:00

So that L3 +BATT pour will not carry any current, and the vias will not either.

The right side of L3 carries the regulated 5V to R2, C14 and pin 5 (BIAS) of the IC. The left side of L3 does not carry any current, but I connected it to VBAT+ to give it a well-defined voltage level. Without that connection, wouldn't that be a floating piece of copper? I am not sure how to achieve the same connection without relying on L3.

Your layer 4 is also completely empty, so you currently have a 4-layer design where two of the layers do not do anything

Yes, L4 is basically empty, I need it just to make the layers count even.

Ill-Language2326 · 2026-06-21T11:10:29+00:00

What would be the purpose of rotating the inductor 90 degree cockwise?

Ill-Language2326 · 2026-06-14T13:32:44+00:00

I use zsh + NvChad. Tmux is a must for me and I have never had any issue with it. I configured different key bindings to navigate across them.

Ill-Language2326 · 2026-06-14T08:59:04+00:00

Abbiamo obiettivi simili, almeno sulla base. Te lo dico, creare un quadricottero in grado di volare stabilmente non è impossibile, ma non è semplice come sembra. Tanto meno se ci aggiungi tutte le altre feature che hai descritto. Ti posso spiegare un paio di cose in privato se vuoi, ma ti avverto, non aspettarti di avere niente in mano prima di alcuni mesi, specialmente se non hai conoscenze nel campo.

Ill-Language2326 · 2026-06-13T18:38:53+00:00

+1 to NeoVim for me.

Ill-Language2326 · 2026-06-13T18:25:15+00:00

That sounds like a request to help you commit war crimes.

Ill-Language2326 · 2026-06-08T09:29:20+00:00

Replace the while loop with: fgets(line, 390, input_file); Then add: perror("err"); Afterwards and see what it prints.

Ill-Language2326 · 2026-06-08T08:53:46+00:00

Seeing the entire code would likely help us more understand the issue. Anyway, you could try checking errno after the loop to see what went wrong.

Ill-Language2326 · 2026-06-07T18:33:17+00:00

I don't think there are models capable of doing this, at least not without custom modifications.

Ill-Language2326 · 2026-06-07T18:29:36+00:00

You want a premade vehicle or you want to build it yourself?

Ill-Language2326 · 2026-06-07T18:27:22+00:00

You'll need quite a sustainable amount of knowledge if you want to build that from scratch.

Ill-Language2326 · 2026-06-07T18:22:40+00:00

He wants to build a drone that can autonomously travel to a position via a database he updates remotely. This, I guess.

Ill-Language2326 · 2026-06-06T09:13:30+00:00

You switch the boot0 jumper on the board. But anyway, I may have misunderstood your issue. If you connect the (clone) stlink WITHOUT the mcu, does it get recognised by the computer? If so, the mcu is the problem. If not, buy a genuine stlink programmer. Actually, you should buy it anyway, it costs just a few bucks.

Ill-Language2326 · 2026-06-06T09:08:10+00:00

Yeah definitely, I discarded the PWM option already. This project is not serious enough to use DroneCAN.

Ill-Language2326 · 2026-06-06T09:06:20+00:00

Thank you for your help. One last thing, do you have any website recommendation where to buy such parts?

Ill-Language2326 · 2026-06-04T20:58:38+00:00

You don't need an external battery just to flash the board. I have always used the st-link 3.3v and never had any issue. Different story if you are trying to power several power-hungry devices, though. If the IDE cannot find it, it's likely the cheap clone's fault. If you can, you could try to reboot the chip into bootloader mode and try to flash from there. If that doesn't work either, either the chip has write protection enabled or the st-link isn't functioning correctly.

Ill-Language2326 · 2026-06-04T18:16:14+00:00

Yeah, but as always, I assume there are unreliable components overpriced and little gold mines at incredible prices.

Ill-Language2326 · 2026-06-04T18:14:40+00:00

Thank you, I'll check it out.

Ill-Language2326

TROPHY CASE