u/Various_Area_3002

Hi all, I am designing a PCB for a soldering fume extractor. I plan on using a 4 pin noctua fan, and a 4S battery to power all this.

I am using a 555 timer to generate pwm for the fan, 20V usbc to a PMIC for charging the battery. The comparator/resistor battery gauge uses tested values that seem to work. The potentiometer has a switch, so when enabled will make the mosfet trigger the fan on, while still adjusting the speed with the 555 timer. I would really like to also know about my layout as this is something I am working on. This is also my first USBC design. Also, this uses Vcuts to make two circuit boards, the plan is to use the 3 pin connectors from the two boards to connect them together to get the battery gauge. Anyways, let me know what you think!

My PCB schematic and layout: https://imgur.com/a/aa5a78q

PMIC 4S Charger IC Monolithic MP26124GR-Z
USB-C PD Chip TI TPS25730DREFR (20V 3A output in the design)
STmicro 4 Comparator IC TSX3704IYPT
NCH MOSFET VISHAY SIS406DN-T1-GE3
5V VOLTAGE REGULATOR LDO AS78L05RTR-E1
TI ADJ BUCK CONVERTER (12V output in the design) LMR51450SDRRR

Hi, I’m hoping someone might be able to help. I bought this switch cheap, and am trying to fix it. The first thing I noticed was it was charging with 5V, and pulled a very low current. The battery was also completely dead after tearing it apart and measuring with a multimeter, it read 0V.

I initially replaced the USBC port since using my cheap USBC multimeter it showed it only working on one side only. After that it “worked” with both sides showing something was being turned on. Before the PD chip replacement, it showed 5V being negotiated and about .06-0.19A it varied with 0.19A happening only like once or twice for a few seconds and stabilising around 0.06. After replacing, it only shows 5V with 0A. I should also mention one capacitor was shorting, which made me suspect the PD chip was the issue, and now that short is gone after replacing the chip (capacitor in question shown in pics).

Now I don’t know if having no current is normal for something like this since nothing is hooked up (ram, screen, etc is disconnected, just the raw motherboard) or being turned on. So, I also tried measuring the charging battery connectors, with also 0V. If anyone has any ideas let me know!

https://imgur.com/a/IX2aAnF