button battery 2025

　　How does the button battery 2025management system protect the button battery 2025in the event of button battery 2025over-discharge and short circuit?

　　Since the button battery 2025voltage cannot be reduced in the over-discharge protection state, the current consumption of the protection circuit is required to be extremely small. At this time, the control IC will enter a low power consumption state, and the power consumption of the entire protection circuit will be less than 0.1μA.

　　There is also a delay time between the control IC detecting that the button battery 2025voltage is lower than 2.3V and sending the shutdown V1 signal. The length of this delay time is determined by C3 and is usually set to about 100 milliseconds to avoid errors caused by interference. judge.

　　Over current protection

　　Due to the chemical characteristics of lithium-ion batteries, button battery 2025manufacturers stipulate that the maximum discharge current cannot exceed 2C (C=button battery 2025capacity/hour). When the button battery 2025is discharged with a current exceeding 2C, it will cause permanent damage to the button battery 2025or safety issues.

　　During the normal discharge process of the button battery 2025to the load, when the discharge current passes through two MOSFETs connected in series, a voltage will be generated at both ends due to the on-resistance of the MOSFETs. The voltage value U=I*RDS*2, RDS is a single MOSFET conduction resistance, the V- pin on the control IC detects the voltage value. If the load is abnormal for some reason, the loop current increases. When the loop current is large enough to make U>0.1V (this value is determined by the control IC (determined (different ICs have different values)), its DO pin will change from high voltage to zero voltage, causing V1 to turn from on to off, thereby cutting off the discharge circuit, making the current in the circuit zero, and causing overcurrent Protective effects.

　　There is also a delay time between the control IC detecting the occurrence of overcurrent and sending the shutdown V1 signal. The length of this delay time is determined by C3, usually about 13 milliseconds, to avoid misjudgment caused by interference.

　　From the above control process, it can be seen that the overcurrent detection value not only depends on the control value of the control IC, but also depends on the on-resistance of the MOSFET. When the on-resistance of the MOSFET is larger, for the same control IC, the over-current protection The smaller the value.

　　Short circuit protection

　　When the button battery 2025is discharging the load, if the loop current is so large that U>0.9V (this value is determined by the control IC, different ICs have different values), the control IC will judge that the load is short-circuited, and its DO pin will quickly The high voltage changes to zero voltage, causing V1 to turn from on to off, thus cutting off the discharge circuit and playing a role in short-circuit protection. The delay time of short circuit protection is very short, usually less than 7 microseconds. Its working principle is similar to overcurrent protection, but the judgment method is different and the protection delay time is also different.

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