Lithium battery protection chip and principle analysis

Lithium battery protection chip: At present, iron-lithium batteries are used more and more widely. From mobile phones, MP3, MP4, GPS, toys and other portable devices to gas meters that need to continue to save data, their market capacity has reached hundreds of millions per month. In order to guard against abnormal conditions such as overcharge, overdischarge, and overcurrent affecting the battery life of lithium batteries, iron-lithium battery protection devices are usually used to guard against damage to the battery due to abnormal conditions. The working principle of lithium battery protection chip includes overcharge protection, overdischarge protection, overcurrent protection, short circuit protection, etc. Lithium battery protection chip principle 1. Analysis of the critical components in the working principle of the protection chip: IC: It is the core of the protection chip. It first samples the battery voltage and then issues various instructions through judgment. MOS tube: It is important for switching purposes. 2. The protection chip works normally: the MOS tube on the protection chip may be in the off state at the beginning. After the battery is connected to the protection chip, the MOS tube must be triggered first, and the P+ and P- terminals have output voltage. The common method of triggering is to short-circuit B- and P- with wires. 3. Protection chip over-discharge protection: After connecting a suitable load to P+ and P-, the lithium battery pack starts to discharge, and the current flows from the positive electrode of the battery through the load, D2 and MOS1 to the negative electrode of the battery; when the battery is discharged to 2.5v When the IC samples and issues instructions, MOS1 is cut off, the loop is disconnected, and the battery is protected. 5. Overcurrent protection: After connecting a suitable load to P+ and P-, the battery starts to discharge and its current direction is like I2. The current flows from the positive pole of the battery through the load, D2 and MOS1 to the negative pole of the battery. When the load decreases suddenly , IC samples the voltage that appears by suddenly increasing the current through the VM pin. At this time, the IC samples and issues instructions to turn off MOS1, the loop is disconnected, and the battery is protected. 6. Short circuit protection: After connecting an empty load to P+ and P-, the battery starts to discharge the current direction as I2. The current flows from the positive pole of the battery through the load, D2, MOS1 to the negative pole of the battery, and the IC is sampled through the VM pin to a sudden increase The voltage generated by the current is then sampled by the IC and issued a command to turn off MOS1, the circuit is disconnected, and the lithium battery is protected. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to sort and test the capacity of lithium batteries?