Love tomb type No. 245-step-down 4A single lithium charger, CN3761

Input:
DC-044 socket, input voltage 4.5-30V

Output voltage: 4.2V

Output current: programmable within 4A

Equipped with 2 LEDs to indicate charging status

The latest measured results of V1: The output voltage jumped back and forth between 4.1-4.4 when measured by a multimeter under no load. It may be a problem with the source of the CN3761 chip. I am ordering from Lichuang.

Latest test (20210513): I tested it with a battery before installing the Lichuang chip. After loading, the multimeter showed that the output was normal and the voltage was stable.

I input 24V and output 4.2V2A. The inductance is actually 100uh.

The main heat source is PMOS, followed by diodes. You can directly touch the temperature on the back. It feels a little higher than expected. If my MOS selection is not suitable, please leave a message.

The multimeter detects that the voltage at both poles of the actual welded 60 milliohm current-sensing resistor is 118 millivolts, indicating that the output current has reached the preset value of 2A.

The target battery is 3000 mAh and the battery does not heat up.

My LED light was soldered incorrectly. I should have soldered red on the CHRG light to indicate charging.

The DONE light is recommended for welding blue and the green light indicates that charging is complete.

Comments on this test: It works