So I have a PCB I made and already bought, but it has some issues and I wondered if there are people that know #PCB better than me which would be up to point out the bugs I got here. :D
Both in terms of bugs, but also best practices I did incorrect. The schematic is available at https://cloud.midnightthoughts.space/s/5PYLnAGQFnWtTqs (see licence on the PDF)
Of course nobody is required to review this, but in the Open-Source sense I would love to get a review :)
Note that this is my first real PCB I really worked on :) So I probably did a lot wrong even though this is iteration 4. Iteration 3 only differs that the diodes in the USB-C setup are not there, and that's the version I have physically currently.
Issues I did already confirm IRL:
- The USB-C port at my PC does provide only 100mA, but this board requires 160mA to run. This works with bootloader mode but not in normal mode -> Bootloops/Brownout
- I am unsure about PROG2 on IC1. Should I add a resistor or not? It's not entirely obvious from the Datasheet.
- I am also not sure about CE on IC1. Does it need to be controlled? Does is always stay high?
- IC2 seems not to work. It reads weird data. I am guessing I wired it up incorrectly to the 3 status lines, but I am not entirely sure what exactly is wrong here. (My current working theory is that I wired 5V analog data to ports that can only do 3.3V. I only want to basically have a way to see the LED state while charging on my Homeassistant via it.)
- Touching the frontside of the board (2 layer pcb) seems to sometimes cause the battery charging chip to glitch out and restart. Unsure why. It's like it acts like a capacitor, maybe?
- The software reset of the ESP32 is not reliable.
- Some chargers I had (USB-2 with usb-c cable) seem to cause the charging chip to short and die. Power jumps from the regular 0.4-0.8W to ~1W+ constant.
- The PG LED is changing brightness under load (Not sure if that's normal or not with this chip)
- The battery I use to power it right now does after a while shutoff for unknown reason. It doesn't seem to be time-based. Possibly overcurrent protection? Or something else? Not sure.
I checked the power rails while having the jumpers open and USB power has stable 5V, +5V rail after IC3 has ~4.7-4.8V (I am guessing it needs some load to be stable?) and the +3.3V rail has stable 3.3V. The sense Pad reads 2.0V.
All of this was tested without a battery, actually attached to it.
Thanks to everyone who already read this far!
#electronics #microelectronics #pcb #esp32 #tinkering
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