Cxlb7281 is a high-precision linear charging circuit specially designed for two lithium batteries, which is very suitable for those low-cost and portable chargers. It can be widely used in PDA, mid, mobile devices and other fields.
Cxlb7281 determines its charging state by detecting the battery voltage: pre charging, constant current charging, constant voltage charging. When the battery voltage is less than the threshold voltage Vo (min), it is in the precharge state, and the current to the battery is small
For charging, the current of precharge can be adjusted through external resistance. After the pre charging makes the battery voltage reach VO (min), it enters the fast charging state of constant current charging, and the charging current can be adjusted through the peripheral resistance. After constant current charging makes the battery voltage rise to the full voltage Vo (reg) (8.4v in general), it enters into the constant voltage charging state. In this state, the charging current will gradually decrease until the stat port level changes from high, indicating the end of charging. After charging, the battery voltage will always be monitored. When the battery voltage is less than the threshold VO (RCH), the battery will be recharged and enter the next charging cycle. For the sake of safety, in the whole charging process, cxlb7281 can use the thermistor inside the battery and the appropriate peripheral resistance to monitor the temperature of the battery, so that the temperature of the battery can be controlled within the range set by the user.