USB charging plus boost output circuit

Basic instructions

The function is not complicated, just charging + voltage stabilization, but I am not very satisfied with the design itself. If you have the conditions, I suggest you modify and verify it yourself.

Current version status

1. When the battery is not connected, if the boost chip used is QX2303L33E, the voltage may reach 3.7, which is not safe for the connected device. It must be used with the battery connected.

2. There is no problem if you use QX2303L50E

3. The QX2303LxxE chip is a booster, but it is not a complete stepdown.

4. A relatively high-priced inductor is used in exchange for a very thin thickness. You can make your own choice.

5. The temperature of TP4059 will reach 100 degrees under 600ma, but no problem was found during the test.

Inductor purchase reference

https://item.taobao.com/item.htm?spm=a1z09.2.0.0.43b52e8dpiil4X&id=562929319358&_u=5kdsk4839c6

requires attention

Even if there is no power indicator light, the boost chip used will also consume its own power. Therefore, if possible, it is best to have a hard switch connection between the module and the battery, so that devices that cannot be connected will be useless. It just ran out of power.

Some silk screen instructions are not completely correct. Anyway, I recommend using 5V power supply output, that is, the chip installed is QX2303L50E.