DC-DC 1-3 string lithium battery step-down charging conversion module

1. Introduction
There are commercially available 1~3-string lithium battery step-down charging modules. The step-down charging module is based on SY6912A. It has a wide voltage input (it is recommended to be used within 20V, and the input voltage is higher than the battery voltage), and the maximum sustainable output current is 2A. .
2. How to use
1. When charging 3 strings of lithium batteries, do not short-circuit pin 5 of the chip. When charging 2 strings, please short-circuit the pad marked with the number "2" on the top silk screen. When charging a single lithium battery, please short-circuit the pad. The pad with the number "1" marked on the top layer of silk screen is short-circuited.
2. When the power is connected and the battery is not connected, the LED flashes. When the battery is connected, the LED is always on. After charging, the LED goes out.
3. Precautions
1. When testing the charging of 2 strings of lithium battery packs at room temperature of 25 degrees, the temperature of the iron powder inductor is too high. , it is recommended to install a heat sink when used in a closed environment.
2. When using this module to charge the battery, please add an independent protection board to the battery.
3. The voltage provided by the input voltage source must be higher than the battery voltage, otherwise the output voltage will be unstable.
4. After using this module to charge the battery, it is strictly prohibited to short-circuit the VIN incoming line to GND or directly connect the VIN to the electrical equipment without removing the battery. Otherwise, the chip will be fried (the chip was accidentally shorted during the PS experiment).
5. If you need to use the NTC battery protection function, please refer to the design schematic diagram in the SY6912A data sheet and modify the R3 and R4 resistors.
P.S.
I originally bought an oscilloscope and wanted to test the output ripple, but I don’t know how to use it. If there is the same model of the DSO2512G oscilloscope at Station B (BV1354y1t7qt), please leave a message and let me know how to use it. I would be very grateful!