Lithium battery protection board circuit Detailed explanation of the principle of lithium battery protection board

　　The reason why lithium battery (rechargeable type) needs protection is determined by its own characteristics. Since the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short circuited, and ultra-high temperature charging and discharging, the lithium battery components of the lithium battery will always appear with a delicate protection board and a current fuse.

　　Lithium battery (rechargeable type) needs protection because of its own characteristics. Since the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short circuited, and ultra-high temperature charging and discharging, the lithium battery components of the lithium battery will always appear with a delicate protection board and a current fuse.

　　Lithium battery protection function

　　The protection function of lithium battery is usually completed by the protection circuit board and current devices such as PTC. The protection board is composed of electronic circuits, which can accurately monitor the voltage of the cell and the charging and discharging circuit at all times under the environment of -40℃ to +85℃. Current, timely control the on and off of the current loop; PTC prevents severe damage to the battery in high temperature environments.

　　Ordinary lithium battery protection boards usually include control ICs, MOS switches, resistors, capacitors and auxiliary devices FUSE, PTC, NTC, ID, memory, etc. Among them, the control IC controls the MOS switch to turn on under all normal conditions to make the cell and the external circuit conduct, and when the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the cell’s Safety.

　　When the protection board is normal, Vdd is high, Vss and VM are low, DO and CO are high. When any parameter of Vdd, Vss, VM is changed, the level of DO or CO will be Changes.

　　Principle of Lithium Battery Protection Board

　　The reason why lithium battery (rechargeable type) needs protection is determined by its own characteristics. Since the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short circuited, and ultra-high temperature charging and discharging, the lithium battery components of the lithium battery will always appear with a delicate protection board and a current fuse.

　　The protection function of lithium battery is usually completed by the protection circuit board and current devices such as PTC. The protection board is composed of electronic circuits, which can accurately monitor the voltage of the cell and the charging and discharging circuit at all times under the environment of -40℃ to +85℃. Current, timely control the on and off of the current loop; PTC prevents severe damage to the battery in high temperature environments.

　　Ordinary lithium battery protection boards usually include control ICs, MOS switches, resistors, capacitors and auxiliary devices FUSE, PTC, NTC, ID, memory, etc. Among them, the control IC controls the MOS switch to turn on under all normal conditions to make the cell and the external circuit conduct, and when the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the cell’s Safety.

　　When the protection board is normal, Vdd is high, Vss and VM are low, DO and CO are high. When any parameter of Vdd, Vss, VM is changed, the level of DO or CO will be Changes.

　　1. Overcharge detection voltage: Under normal conditions, Vdd gradually increases to the voltage between VDD and VSS when the CO terminal changes from high level to low level.

　　2. Overcharge release voltage: In the charging state, Vdd gradually decreases to the voltage between VDD and VSS when the CO terminal changes from low level to high level.

　　3. Overdischarge detection voltage: Under normal conditions, Vdd gradually decreases to the voltage between VDD and VSS when the DO terminal changes from high level to low level.

　　4. Overdischarge release voltage: In the overdischarge state, Vdd gradually rises to the voltage between VDD and VSS when the DO terminal changes from low level to high level.

　　5. Overcurrent 1 detection voltage: In the normal state, VM gradually rises to the voltage between VM and VSS when DO changes from high level to low level.

　　6. Overcurrent 2 detection voltage: In the normal state, VM rises from OV to the voltage between VM and VSS when the DO terminal changes from high to low at a speed of 1ms or more and 4ms or less.

　　7. Load short-circuit detection voltage: In the normal state, VM starts from OV and rises to the voltage between VM and VSS when the DO terminal changes from high to low at a speed of 1μS or more and 50μS or less.

　　8. Charger detection voltage: In the over-discharge state, VM gradually decreases with OV to the voltage between VM and VSS when DO changes from low level to high level.

　　9. Current consumption during normal operation: Under normal conditions, the current flowing through the VDD pin (IDD) is the current consumption during normal operation.

　　10. Over-discharge current consumption: In the discharging state, the current (IDD) flowing through the VDD terminal is the over-discharge current consumption.