USB PD Power Suply
USB-PD Based Power Supply to power your non-5V electronics
Total Time Spent: 14 hours
Also spent about 2 hours making the BOM and finalising components
May 23 2025:
Today i will be finding the USB PD negotiation IC. So basically i have the idea of making the smallest(that i can create) power module to power my electronics projects, when i am prototyping.
okay, found the IC, it is AP33772SDKZ-13-FA01, and now i have another idea, let's make a variable power supply, which gives variable power supply if PPS is available, or else it gives constant supply @ 5V, 9V, 12V, 15V or 20V.
i think i am gonna use some microcontroller (probably an rp2040) along with an OLED that displays voltage and current, and also rotary encoders/potentiometers, although i haven't decided on that.
Total Time Spent - 20 Mins
May 24 2025:
Today, i made a block diagram by hand, and i selected the ams1117 3.3v LDO regulator for the RP2040, but then i came to realise that the max input voltage for ams1117 is 15V, while max voltage with PD is 20V, so i chose another regulator(it is so hard to find a proper regulator). the new regulator now is AMS1117S-3.3
I have also decided that instead of using EasyEDA this time, i will be using KICAD - THE DAD OF CIRCUIT DESIGN
(lol). I started working on the schematic. RP2040 is also finalised for now. so 2 USB-C connectors will be on the PCB, one for programming RP2040 and other for POWER
Ok, so let me just write out all the finalised parts here: 1. I2C OLED 2. Rotary Encoders x2, what i chose earlier 3. Microcontroller: RP2040 4. Flash for RP2040 5. USB PD Sink Controller: AP33772SDKZ-13-FA01 6. Push Button 7. Crystal @ 12MHz
Why I chose a 128Mbit chip instead of a smaller one?
I chose a bigger chip rather than the typical 16Mbit because of mainly three reasons:
1. the difference in price is about $0.1.
2. The RP2040 design guide recommends it.
3. I dont know how long is the code gonna be.
ok, so i have finished with the work for the day, today i completed the RP2040 connections, like the bare minimum connections required, and i also finalised the parts, and tomorrow i will be looking into the connections of the USB-PD controller, and i hope to make a 4 layer PCB, although i will try with 2 layers, if it will be possible.
PS: I am changing the rotary encoders as i found out about a new, more popular encoder, the EC11H, which is the one that i will be using...
okay, i had some free time tonight so i worked more on the schematic, i came to realise that i have to LOGIC-SHIFT the I2C communication, so that i dont burn the rp2040, so for logic shifting i found BS138 to be the most common and i went with them. So, for proper logic-shifting, we also need a proper 5V supply, so i chose another LDO regulator😭(it's a pain finding proper regulator). A wise legend once said, choose your components wisely.Btw, i also added a few capacitors to the PD controller.
Things added to schematic:
If i were to rate the experience using Kicad rather than EasyEDA, i would say that it is good, and you get A LOT of customisability, but EasyEDA is much simple.
Total Time Spent today - 2 hours 10 mins
May 25 2025:
Another New day, another new schematic making sesh... Today i will likely complete the schematic
So i have added the rotary encoders in the schematic, and i also added ESD protection on the USB-C ports. worked on the schematic too, and i had a bit of issue with the PD controller, what happened was that there were two voltage pins, VCC and VOUT, and i wasn't sure what to cnnect to what, but now it is fixed, thanks to the application circuit. so the plan is, today i finish the schematic, i start with the PCB at night, and by tomorrow night i start with the cad, and i apply by day after tomorrow night, let's see if i can apply by May 27 night, after that i will start with the code for it.
Yay! the schematic is done!!
Ok, it's evening now, and i completed all the work of assigning footprints to symbols, now i can finally start with pcb designing
Hell Yeah! Most of the placement on my PCB is like done, and tomorrow i will start with the routing and finish it ASAP.
Haha, i will add 3d models tomorrow.
This is the Design till now, i've tried to keep it as small as possible(50mmx70mm) and i will reduce the size even more if needed, but i haven't yet found connectors. People on slack recommened me XT60 connector, but i am not sure what am i gonna use.
Maybe i can integrate multiple kinds of connectors, but this is for tomorrow, i am really really tired today
Total time spent: 6 hours
May 26 2025:
Yup, i started the PCB routing, i added 4 M3 Mounting holes too, here is the current progress:
Time spent this session: 1 hour 45 mins
Time Spent Today: 1 hour 45 mins
May 27 2025
Today was the day i was supposed to complete my project, it is ofcourse delayed, but i will try to complete by tomorrow, i completed the pcb today, got a few errors to deal with:
All the errors are the same, just for different components.
Here is the finished PCB:
Here is the CAD file i started tonight:
(I spent 5 mins only on the CAD)
Time Spent Today: 1 hour 30 mins
May 28 2025
Done with the PCB, rmeoved all the thermal errors by using a bunch of vias and got 0 errors and warnings! I also shifted the barrel jack to the right by 2mm so that it would not be a problem in 3d printed part... Now Working on the 3D Model
Time Spent this session: 20 mins
Completed the CAD, here are the final images:
CAD:
PCB:
Time Spent this session: 1 hour 45 mins
Now time to work on other things like writing README.md and writing total time on top and writing BOM and all that
May 29 2025
Shit, i cant find any DC barrel jack connectors on LCSC and i made a mistake selecting the footprint of the regulator ic, so i got to change some stuff up😭
Finally:
