18650 power module

1. The protection circuit in this design uses DW01 and 8205A (dual MOS tube) chips as the protection circuit. It has overcharge and over-discharge protection functions. There is no charging circuit designed in this design, so it only has over-discharge protection. When the voltage of the lithium battery When it drops to the protection voltage, the 8205A chip disconnects GND, unable to form a loop, and the circuit stops working.
2. The 3.3V output circuit uses the AMS1117-3.3 chip, which has stable output and high reliability.
3. The 5V output circuit uses the MT3608 chip. Two fixed feedback resistors are used to stabilize the voltage at 5V. R3 can be replaced with an adjustable resistor, then Become an output adjustable circuit. Vout=Vfb (0.6)*[1+(R3/R4)] R3 and R4 use K-class resistors. The recommended inductor value range is 3.3uH to 22uH. Inductor selection mainly considers smaller DCR resistance to ensure higher efficiency. The input capacitor and output capacitor are recommended to have a capacitance of 22uF or more. In order to obtain smaller output ripple, it is recommended to use ceramic capacitors for the output.
MT3608 has the following features
• 93% efficiency • Internal integrated 80mΩ power MOS • 1.2MHz fixed frequency • 2V-24V input voltage • Adjustable output voltage • Internal 4A current limit • Internal compensation • Output voltage up to 28V
(in my production, I bought the wrong side dial switch, short-circuit the test first, and temporarily replace the power inductor with 2.2UH)