Nickel Hydride No. 5 batteries

　　Nickel Hydride No. 5 batteries all need a protection circuit to effectively monitor the charging and discharging status of the battery, and to shut down the charging and discharging circuit under certain conditions to prevent damage to the battery. When the protection board is normal, Vdd is High level, Vss and VM are low level, DO and CO are high level. When any parameter of Vdd, Vss and VM changes, the level of DO or CO terminal will change. The principle of lithium battery protection board is as follows:

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

　　4. Over-discharge release voltage: In the over-discharge state, Vdd gradually rises to the voltage between VDD-VSS when the DO terminal changes from low level to high level.

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

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

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

　　8. Charger detection voltage: In the over-discharge state, VM gradually drops from 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 to the VDD terminal (IDD) is the current consumption during normal operation.

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

　　Balancing principle of lithium battery protection board:

　　Lithium battery protection board balancing principle Commonly used balancing charging technologies include constant shunt resistance balancing charging, on-off shunt resistor balancing charging, average battery voltage balancing charging, switched capacitor balancing charging, buck converter balancing charging, inductor balancing charging, etc. When charging a group of Nickel Hydride No. 5 batteries in series, each battery should be charged evenly, otherwise the performance and life of the entire battery group will be affected during use.

　　However, the existing single-cell lithium battery protection chips do not contain the balanced charge control function. The balanced charge control function of the multi-cell lithium battery protection chip requires an external CPU; it is realized through serial communication with the protection chip (such as I2C bus), which increases the This increases the complexity and design difficulty of the protection circuit, reduces the efficiency and reliability of the system, and increases power consumption.

　　According to the needs of the application, the balancing principle of lithium battery protection board can realize protection and equal charging of power lithium battery packs of any structure and voltage level after changing the protection chip model and series number, and the power level of switching devices and energy consumption components in the circuit. .

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