What is the relationship between the mobile phone battery protection board and the USB interface?

For now, almost all mobile phones use lithium batteries, and from the perspective of charging methods, the charging method of lithium batteries is voltage-limiting and constant-current, which is controlled by an IC chip. Specifically, it is first detected to be charged. The voltage of the battery determines the magnitude of the current that passes through the charge. In addition to the charging head of the mobile phone itself, we all like to use the computer or mobile power to charge the mobile phone. Some of us have leakage when charging with the USB interface, and the charging is faster. These phenomena are all Why? What is the relationship between the mobile phone battery protection board and the USB interface? Today, Guoren Chuangfa will analyze these issues with everyone.

First of all, if the voltage is lower than 3V when the mobile phone is charging, the mobile phone will be pre-charged first. The charging current is 1/10 of the set current. When the voltage rises to 3V, the mobile phone will enter the standard During the charging process, and constant current charging with the set current, when the battery voltage rises to 4.20V, the mobile phone will change to constant voltage charging and keep the charging voltage at 4.20V. At this time, the charging current will gradually decrease, and when the current drops to 1/10 of the set charging current, the charging will be completely finished.

Secondly, many friends have also mentioned this problem, reflecting that many mobile phones use computer USB charging to have leakage problems. In fact, this is not the case. The lithium batteries of mobile digital products have protective plates, which are limited. The function of the lowest voltage and limiting the charging current, and whether the current mobile phone uses a charger or a computer USB, to put it bluntly, which USB cable must be used, what kind of charge is used, only the difference between the charging current, the other end of the line, As long as it is not a copycat power supply with contact problems, it will be fine. The difference between a regular power supply and a computer USB is only in the charging speed. Before this, experts have tested that using the USB of the laptop to charge the mobile phone. Compared with the original charger to charge the mobile phone, the charging voltage is slightly higher, about 5V and 4.2V before and after, while the charging current is slightly lower. It is about 190mA and 220mA, but when changing to the USB of the desktop, the charging voltage is still 5V, and the charging current is increased to 230mA, so we can draw the conclusion that using the computer USB to charge the mobile phone and the original charger to charge the mobile phone, The only difference is the difference in current and charging speed, and it has nothing to do with safety.

Finally, even if you touch the phone during the charging process, your hand will feel numb, and it is just induction electricity. This is the same as air. Humidity has a certain relationship with the clothes you wear. It is similar to static electricity. If you really feel uncomfortable, the solution is also very simple. Put the host on the ground to solve it.