| Li-ion and Li-polymer battery are being widely used. The charger with safe, reliable, fast and high efficient is important for performance and application of battery. In this thesis, the chemic structure, performance and charging method of Li-ion and Li-polymer battery are studied. And based on the effect of charging process and method to battery's performance, some key points in charging are raised and then a battery charger protect IC for single Li-ion or Li-polymer battery is designed.Following principle of the Li-ion battery fast charging and the study of existing charging approaches, we add the trickle mode pre-charge and constant temperature charging mode based on the CC/CV mode, i.e. pre-charge the battery using trickle current at the initial of charging cycle to fix and protect the over-discharged battery; after which, the battery will be charged by large constant current to allow the fast charging; finally, the constant voltage charging is adopted to guarantee the battery was charged to its full capacity. Under the condition that the temperature has raised to a certain threshold at the constant current charging stage, the system will switch to constant temperature charging mode to protect the circuit. Besides, the battery under and over temperature protection module, battery status detection module, and power status detection module are also added in the system to allow the intelligent control of the charging process.In this thesis, the composition and chemical principle of the Li-ion battery are presented firstly, which is followed by its characteristic and common charging approaches introduction. Finally, the whole system is discussed where actual circuit design and realization are emphasized. The HSPICE simulation and the testing results are also provided. Finally this Li+ battery IC is successfully from design to marketing. |
