一种高精度过流保护电路的设计  

Design of an over-current protection circuit with high precision

作　　者：张金洋 汪西虎 董振斌 王江涛 徐佳豪 ZHANG Jinyang;WANG Xihu;DONG Zhenbin;WANG Jiangtao;XU Jiahao(School of Electronic Engineering,Xi􀆳an University of Posts and Telecommunications,Xi􀆳an710121,China;Shanghai Engineering Research Center of Electronic Circuit Intelligent Protection,Shanghai201202,China;Wayon Electronics Co.,Ltd.,Shanghai201202,China)

机构地区：[1]西安邮电大学电子工程学院,陕西西安710121 [2]上海电子线路智能保护工程技术研究中心,上海201202 [3]上海维安电子有限公司,上海201202

出　　处：《电子元件与材料》2022年第4期429-435,共7页Electronic Components And Materials

摘　　要：提出了一种应用于锂电池保护芯片的高精度过流保护电路。电路采用键合丝实现电流采样,避免了额外导通电阻及功耗的引入;过流阈值设定通过参考电压电路实现,具有较强的灵活性;预放大电路采用完全对称的负反馈结构有效抑制自身失配带来的影响,同时能够将微小误差电压可靠检测并放大,以此减小比较器失配电压的干扰;比较器电路对参考电压及采样电压进行比较,从而实现过流状态判断及响应。电路设计基于0.18μm BCD(Bipolar-CMOS-DMOS)工艺实现。仿真结果表明,整体电路过流阈值精度为5.5%;负载电流在0.5~3 A范围内变化时,采样精度为99.97%。An over-current protection circuit with high precision was proposed for Li-ion battery protection chip.To avoid additional on-resistance and power consumption,bonding wires were used to realize current-sensing.The over-current threshold setting was realized by the reference voltage circuit,which had strong flexibility.The pre-amplification circuit effectively suppressed the impact of self-mismatch by a completely symmetrical negative feedback structure,which also could detect and amplify the small error voltage reliably to reduce the interference of the comparator mismatch voltage.The reference voltage and the sensing voltage were compared with the comparator circuit to realize the judgment and response of the over-current state.The circuit design was based on 0.18μm BCD(Bipolar-CMOS-DMOS)process.Simulation results show that the overall circuit over-current threshold precision is 5.5%and the sensing precision is 99.97%at the load current from 0.5 A to 3 A.

关 键 词：锂电池过流保护 电流采样 负反馈 高精度 灵活性 

分 类 号：TN433[电子电信—微电子学与固体电子学]