Research And Optimization Of A Linear Li-Battery Charge Management Chip

With the development of mini bulk, Li batteries have gained much more attention than before. Because Li batteries have less weight, smaller size and higher available energy densities than its counterparts in the battery system (such as NiCd, NiMH), they are very suitable for portable electrical appliances. It promotes the development of battery technologies, charge control technologies. So it is well worth doing research on the design of the Li batteries power management chip.The Li battery IC use CC/CV charging mode which includes the 3 charging stages: the trickle charging, large constant current charging and constant voltage charging .The trickle charging uses small current at the initial of charging cycle to fix and protect the over-discharged battery; then, the battery will be charged by large constant current to allow the fast charging; finally, the constant voltage charging is adopted to guarantee that the battery is charged to its full capacity .The three phases approach allows shorter charging time and higher efficiency. The battery status detector, which is designed for constantly monitoring the voltage and current in battery to confirm the charging stage. The chip is a novel analog IC based on the CSMC 0.6um CMOS process technology.The range of power supply is wide, which is from 4.5V to 15V. Multiple functions can be implemented using the chip, such as sleep protection, temperature monitoring, trickle charge, high-accuracy constant current and voltage regulation, charge termination, automatic battery-recharge and charge-status indication.