In some MOS ics, two MOS tubes are integrated in one IC, that is, dual MOS. For example, AO4800 is a dual NMOS, and AO4801A is a dual PMOS
It can be said that the IC on the protection board is to detect the voltage and current of the battery, such as overvoltage, overcurrent, low voltage, etc., and MOS is equivalent to a switch.
Protection IC Mosfet can achieve the following functions (four protections):
1. Overcharge protection. When the voltage of the battery cell exceeds the set value, the Mosfet tube is cut off by the protection IC. When the cell voltage returns to the allowed voltage, the Mosfet tube is restored.
2. Over-discharge protection: When the voltage of the battery cell decreases beyond the set value, the Mosfet tube is cut off by the protection IC. When the cell voltage returns to the allowed voltage, the Mosfet tube is restored.
3. Overcurrent protection. When the working current exceeds the set value, the Mosfet tube is cut off by the protection IC. When the operating current returns to the allowable voltage, the Mosfet tube is resumed.
4. Short circuit. In fact, this function is an extension of overcurrent protection. When the protection IC detects that the voltage between the positive and negative battery output is less than the specified value, it considers that the battery is in a short circuit state and immediately cuts off the circuit. Wait for the short circuit to be troubleshooting before resuming the circuit. When the battery is short-circuited, the output voltage of the positive and negative terminals is zero, and the actual voltage of the battery cell is normal.
The battery dual mos is powered by two field effect tubes, which mainly consumes less power and provides relatively large current.