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This is an ESP32 circuit I've designed with battery charging and protection. I'm a complete beginner in circuit board designing, and this is my first time designing a PCB from scratch. I'm wondering if the board/schematic has flaws; any suggestion would be greatly appreciated.

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    \$\begingroup\$ General schematic comment: please draw all negative (and ground) voltages pointing down and positive ones pointing up. Wherever possible, inputs to the left and outputs to the right and the overall signal/power flow in the same way. \$\endgroup\$
    – winny
    Commented Sep 22, 2022 at 13:46
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    \$\begingroup\$ Do you have a ground plane on bottom layer? \$\endgroup\$
    – winny
    Commented Sep 22, 2022 at 13:46
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    \$\begingroup\$ Read the espressif document on pcb layout for the esp32 module. You’ve violated a number of requirements. The layout of U3 is inadequate, as is the power distribution and specification of the capacitors. You have not considered dc bias in your choice of capacitors. For example, the 22uF caps in 0805 will most likely perform nowhere near 22uF. You’ll need ones that are larger and higher voltage. You layout looks random and you’ve probably used the auto router. Spend some time arranging the components and route the tracks by hand. And use a ground plane on the bottom layer. \$\endgroup\$
    – Kartman
    Commented Sep 22, 2022 at 13:59
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    \$\begingroup\$ First I want to say I like it that you want to try this yourself and you’re willing to open yourself by discussing your work so far. Don’t give up! But … there has to be done a lot of work before you make this board. What is your experience with breadboards so far? And if you want to have a jumpstart, I recommend you Robert Feranec. He has a paid (low price) course about designing a buck converter board. You will learn a lot of basics, like grounding. And on youtube check for his Eric Bogatin videos. \$\endgroup\$
    – RemyHx
    Commented Sep 25, 2022 at 4:16
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    \$\begingroup\$ Some things to catch up: grounding/ground plane (better said: return plane). Capacitance and inductance (impedance) of tracks and planes. Decoupling capacitors. Proper way to connect a USB-C port (or try USB micro of A first). Pull up and pull down resistors. Switching node buck and boost converters. Inductors. ESP32 design rules, your antenna is covering tracks now, move to outside board. Crosstalk. Ground bounce. Shared returns. It’s a lot: but worth it. You can do it. \$\endgroup\$
    – RemyHx
    Commented Sep 25, 2022 at 4:23

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In addition to all the good advises already in the comments, I'd like to provide a few general directions when designing a custom board.

  1. every MCU or SOC chip manufacturer publish some sort of hardware design guide or even reference design, read them. ESP32 is no exception, there is a ESP32 hardware design guidelines available.

  2. every IC manufacturer publish datasheet for every chip they sell, there is always a section about PCB design do and don't in related to the chip.

  3. Add part number of each component in your schematic in addition to the chip reference number (U1, U2, etc.), this allows others to figure out what is the chip and the function easily, even they are not familiar with your schematic, they could check against the datasheet based on part number. For example, I could figure out that U1 is a charging IC out of familiarity, but I have hard time to know what is U5.

  4. For PCB design, as the beginning, I would recommend to read PCB Design Tutorial by David L. Jones or watch his youtube videos.

  5. You seems trying to implement a charger with load sharing (that is, charging while with load drawing current at the same time), for that, I would suggest you read this application note from Microchip.

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