The entire charging process of the mobile phone is controlled by the charging management IC. The complete charging process can be divided into 6 stages: trickle charging mode, pre-charging mode, constant current charging mode, constant voltage charging mode, charging completion mode, and secondary charging mode .
complete charging process
1. Trickle charge mode
Trickle charging generally charges the battery with a very small current (tens to 100 milliamperes). It usually occurs when the battery is so low that it cannot be turned on. The active material is activated first to form a stable SEI film, because a If a large current is used at the beginning, the service life of the battery will be greatly affected.
2. Precharge mode (0.1C)
The pre-charge mode charges the battery with a small current (about a few hundred milliamperes), the purpose of which is to prepare for the next stage of constant current charging. In the pre-charge mode, the battery voltage is slowly increased by charging with a small current to prevent the battery voltage from rising too quickly after constant current charging. Insufficient to maintain power on, the voltage drops and the system shuts down.
3. Constant current charging mode (0.2C-1C)
Constant current charging, charging the battery with a constant current (larger current). At this stage, the energy of the battery increases rapidly and the battery voltage gradually increases.
4. Constant voltage charging mode
When the battery voltage rises to the switching point (the battery voltage is close to 4.2V), it will enter the constant voltage charging stage. At this time, the output voltage of the charging management IC is constant at 4.2V, the charging current gradually decreases, and the battery power gradually becomes saturated.
5. Charging completion mode (charging current or timer or a combination of both)
When the current decreases to a certain level (generally 0.01C-0.1C of the battery capacity), the charging management IC will shut off the charging current and notify the mobile phone system to indicate that the charging is complete.
6. Second charge mode
After the charging is completed, due to the power consumption of the mobile phone system and the battery itself, the battery power decreases and the voltage drops . When the voltage drops to a certain threshold value, the mobile phone system will be triggered to charge again. Generally, there are only two processes of constant current and constant voltage for secondary charging.
