How The Battery Protection Board Works

Lithium battery protection boards have different circuits and parameters depending on the IC used, voltage, etc. The commonly used protection ICs are 8261, DW01+, CS213, GEM5018, etc. Among them, Seiko's 8261 series has better accuracy, and of course, the price is more expensive. The latter ones are all from Taiwan. The domestic sub-market basically uses DW01+ and CS213. The following is an explanation of DW01+ with MOS tube 8205A (8pin):

The normal working process of the lithium battery protection board is as follows:

When the cell voltage is between 2.5V and 4.3V, the first and third pins of DW01 both output high level (equal to the supply voltage), and the second pin voltage is 0V. At this time, the voltage of the 1st and 3rd pins of DW01 will be applied to the 5th and 4th pins of 8205A respectively. The two electronic switches in 8205A are in a conducting state because their G poles are connected to the voltage from DW01, that is, Both electronic switches are on. At this time, the negative pole of the cell is directly connected to the P- terminal of the protection board, and the protection board has a voltage output.