Any electronic product can be easily modified to a charging module

1. Material Description
There are many models of charging IC that are completely compatible with replacement. Search "4054" in LiChuang Mall, then click the "Power Management" label, click Apply, and you can find a lot. The setting on my schematic is the cheapest, and the input withstand voltage can reach 9V, 8 cents each, which is cost-effective.
2.
For the extended design, charging management alone is not enough. If you encounter some electronic products, such as multimeters, it requires a power supply of 9V, and our lithium battery is only 3.7V, so a boost IC is also needed, so I compatible it into this design, and then you can choose to paste it as needed. If it is only for powering some electronic products of about 3.7V, only the SMD power management IC part is needed. If it is for powering products such as multimeters, choose to paste the circuit with power management + boost circuit. The voltage value of the boost circuit can also be adjusted as needed.
The top circuit is the charging management circuit:
The bottom circuit is the boost circuit, which can be selected as needed:
3. Parameter Description
3.1 The charging current is determined by the battery. If the electronic product you want to modify is very small, you should choose a very small lithium battery, such as a 100mAh mini battery. Look at the battery protection board data sheet. If it supports 1C charging, configure the charging current to 100mA, and paste 10K on R5. Refer to the schematic diagram table:
3.2 The boost voltage is determined by the electronic product. If you are modifying a multimeter, look at what battery the multimeter is powered by. Generally, there are 9V batteries, or 4 1.5V dry batteries (a total of 6-6.5V), then adjust the resistance ratio of R1 and R2 as needed. Calculation formula: Vout=VFB*(R1+R2)/R2, where VFB=1.211V.
4. View Demonstration
5. Actual Demonstration
5.1 Change the mouse to TYPE-C charging:
5.2 Modify the multimeter to TYPE-C charging: