Design Of Low Power Single Lithium-Ion Battery Charge-Discharge Protective Chip

With the development of portable electronic products, as its power supply, the secondary battery has attracted increasingly attention. Due to high energy density, long cycle life, memoryless effects and low self discharge rate, the lithium ion battery becomes a most popular member of the battery family. However, lithium ion batteries can be easily damaged by overcharge, excessive discharge or over current. Thus attention must be paid to the battery protection circuit. For the applications and the function, the protection circuit must be featured by low power and low operating voltage. For this reason, the paper presents a protection chip XD1128 combined with the fruitful results of research. The paper is designed on the basis of the project"Theoretical research and design of key technique for deep-submicron mixed signal ASIC".The principle of lithium ion battery and the protection circuit is introduced in this paper as well as its status and development trend. And then from its application style and the basic function, the battery protection circuit is proposed. Also the chip is supplied by the battery, in order to reduce the power dissipation of protection circuit, this paper focuses on the design and analysis of the circuit working in weak inversion region. Based on the research, one lithium ion battery protection chip is presented. The system is consisted of overcharge detecting circuit, excessive discharge detecting circuit, over current detecting circuit, load short detecting circuit, 0V battery charge inhibition, voltage reference, delay controlled circuit and standby circuit, that would be described in chapters.XD1128 is based on the 0.35μm 30V BCD process and simulated by HSPICE. The simulation results show that the design is of high performance and satisfies the design requirement.