1. Lithium battery manufacturers tell you that the current of the lithium -ion battery protection board is determined by protecting the IC detection voltage and the internal resistance of the MOS tube. If the protection IC cannot be changed, the MOS tube can be changed, such as DW01 and 8205MOS. ~ 5A, double the two MOS tubes and links will double. There are 3 ~ 4 MOS pipes in large -capacity mobile power supply.

2. Protective current of the protective board = overcurrent detection voltage/MOS tube internal resistance (because the two MOS tubes are connected in series, the internal resistance of the MOS tube should be taken 2)

3. The selection of lithium -ion batteries should be determined according to the capacity of the battery. Generally, there are no special requirements for batteries below 2000mAh. Select the general protective board. The protection current is 2 ~ 5A. The discharge current of the general battery is 1C, 2000mAh The above battery protection current is as above 3A as possible. Regarding the power lithium battery, many of them are not added with protective boards, but when there are PTCs in series, when the temperature is too high, the power is automatically cut off.

The power battery manufacturer believes that the lithium -ion battery protection board is different according to the use of IC, voltage and other circuits and parameters. The following is explained by DW01 with MOS tube 8205A:

1. The normal working process of the lithium -ion battery protection board is: when the battery voltage is between 2.5V and 4.3V, the 1 pin and third pin of DW01 output high levels (equal to power supply voltage), the second foot voltage It is 0V. At this time, the voltage of the 1 foot and the third foot of the DW01 will be added to the 5th and 4th pin of 8205A, respectively. The two electronic switches in 8205A are in the direction state of the DW01. The electronic switch is open. At this time, the negative electrode of the battery is equivalent to direct connecting the P-end of the protective board. The protective board has voltage output.

2. Principles of protecting the protection board over discharge protection: When the battery is discharged through an external load, the voltage of the cells will slowly decrease. At the same time, the internal DW01 will monitor the battery voltage in real time through the R1 resistor. At 2.3V, the DW01 will believe that the battery voltage is already in the state of the discharge voltage, and the output voltage of 1 foot is immediately disconnected to turn the voltage of the 1 foot to 0V.