具有高适应性的锂电池充电器IC的研究与设计

【作者】 张学海；

【导师】 李平；

【作者基本信息】 电子科技大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 锂电池由于具有体积小、质量轻、寿命长、能量密度高等优点,在便携式电子设备中得到了广泛应用。锂电池充电器作为电源管理系统的重要组成部分,其能否为锂电池安全高效地充电,对锂电池的性能及应用来说至关重要。为了对锂电池安全、可靠、快速、高效地充电,本文结合锂电池的基本特性以及常用的充电方法,设计了一款针对单节锂电池的充电器IC。本文采用了以恒流恒压充电法为基础的三阶段法:第一阶段使用小电流对电池进行预处理,对出现过放电的电池进行修复和保护;第二阶段采用较大的恒定电流对电池充电,实现快速充电的目的;第三阶段采用恒压充电,确保电池充满。此充电器IC的最大特点是其高适用性,可以使用各种不同的适配器和USB端口进行供电,尤其是当其结合电流限制适配器时,兼有线性式充电和脉冲式充电的优点,使充电效率大大提高。此外,本设计增加了芯片温度控制、电池温度检测与保护、电源状态检测和充电定时等功能等,实现了对充电过程的智能控制。本文采用0.5μm CMOS N阱工艺,降低了成本。通过HSPICE仿真可知,在各种工艺角,-40℃~125℃的温度范围和4.3V~6.5V的电源电压输入范围内,电池最终充电电压达到4.1V±0.56%。充电器IC结合限定电流为0.5A的电流限制适配器进行恒流充电时,其充电效率高达96%以上。此IC还具有外部电路简单的特点,只需与外部少数电容、电阻配合使用,就可以完成充电功能。文中首先对锂电池的组成及化学原理进行了简单介绍,然后介绍锂电池的特性及常用的充电方法,接着说明充电器IC的整体结构和原理,最后着重介绍内部具体电路的设计与实现,并给出了HSPICE仿真结果。更多还原

【Abstract】 Because of small size, light weight, long life and high energy densities, Li-ion and Li-polymer battery have become increasingly popular in portable electronic devices. Charger is an important component in the battery power management system. In order to charge battery safely, reliably, fast and efficiently, based on the Li-ion and Li-polymer battery’s character and general charging method, a charger IC for single Li-ion or Li-polymer battery is designed.The charging mode based on the CC/CV has been adopted, in which the process has been divided into three phases. At the first phase, the battery is pre-charged with a trickle current to repair and protect the over-discharged battery; at the secondary phase, the battery will be charged by a large constant current to allow the fast charging; at the last phase, the constant voltage charging is adopted to guarantee the battery fully charged. The particular characteristic of this IC is high applicability, because its power supply can use different adapters or USB ports, especially when using the current-limited adapter, it integrates the advantages of linear charging mode and pulse charging mode, which improves charging efficiency. Besides, the modules such as the chip temperature control, battery temperature detection and protection, power status detection and charge timing are also added to the system to allow the intelligent control of the charging process.The process of 0.5μm CMOS with N well has been applied, which reduces the cost. Through HSPICE simulation, battery’s final float voltage reaches 4.1V±0.56% at different process corners, the temperature between -40℃and 125℃, and input voltage between 4.3V and 6.5V. The charging efficiency is up to 96% in constant current charging phase when the IC is supplied by a current-limited adapter whose limited current is 0.5A. This IC simplifies the outside circuit so that it can accomplish all the charging functions only at the cooperation of few additional capacitances and resistances.In this paper, the composition and chemical principle of the Li-ion and Li-polymer battery are firstly presented, which are followed by their characteristic and common charging approaches introduction. And then, the whole structure and principle of this chager is illuminated. At last, the design and realization of actual circuits are emphasized, the HSPICE simulation results are provided as well.更多还原