12/25/2025 - Journal

Breadboard USB PD Power Supply

I saw a post on r/electronics a few weeks ago about a USB breadboard power supply and I was very interested and thought what if I made one myself but add a PD chip to negotiate different voltages.

So I started out with searching for PD chips, I was initially going to use the STUSB4500 but It was too big and overkill for me; All I really wanted was an IC capable of negotiating voltages, so after some more seraching I found the CH224 by WCH, it's a really good chip and just what I needed.
You can easily configure the negotiated voltage with 3 config pins by pulling them low or high, and the chip has a DFN package which is just 2x2mm!!

It's entire datasheet was originally in Chinese though so I had to first translate that.

The datasheet was very helpful and straightforward, It gave specific example designs so schematics were pretty easy for me.

The schematics were relatively simple; just a simple USB-C receptacle, CH224, a LED and a pin header!! Thats it!

Now the PCB is where things started becoming more difficult; firstly easyeda2kicad kept throwing errors for getting the DFN-10(2x2) footprint, I spent like half an hour solving that; I decided to make my own footprint but wasn't satisfied so I was basically searching for a way to get the correct footprint. That's when a I found a reddit post where I read that you can actually download footprints from easyeda and import them into kicad, so that's what I ended up doing in the end.

I wanted my PCB to be as small as possible and basically just take up the space on the breadboard power rail and not like go outside it!?! (if that makes sense)

The picture below was my first layout revision, It was alright but the PCB was massive and it was basically gonna extend over the power rails of the breadboard.

I measured the breadboard power rail section with my calipers and measured it be be around 9mm wide. Based off the I decided that I should keep my board 8.5mm wide at max; it's length could still be longer if needed (as it will still be inside the power rail section; if you get what i'm saying; Its kinda hard to describe it). While doing rev 2 of the layout I also assigned net classes to the nets and color coded them (it's fun to see the pads with color).

I decided to place the ch224 chip on the bottom; and I gotta tell you I had to really like squeeze it down there. There was basically no space on the board for it

I wasn't really happy with this placement as it just wasn't going to work out and it would probably be a routing nightmare; I ended up adding some more breathing room on the right side of the USB connected and moved the chip there. This was how my layout look at the end:

All that was left to do was to route everything out! It probably took me about an hour or so of just routing traces out, deleting them to make room for other traces and then just trying to find the best way to route things. Here's some progress pictures and the final result-

I initially just routed everything on 2 layers and then wanted to see if there was still space to route out power; unfortunately there just wasn't a way to route out power on 2 layers without making the board chopped, so I switched to 4 layers, filled the inner two with ground and vbus.

After finishing up the PCB I spent some time creating a BOM and a repository. It turns out that the CH224 in DFN package was actually out of stock on lcsc which I somehow did not notice :C ; but no worries I just sourced it from aliexpress for now, It's a tad bit more expensive compared to LCSC but it's the only option as I don't want to switch and use a different footprint (DFN was the smallest one!)

Oh and I spent some time in fusion to get a render for the README!!

Time Spent: 5 Hours