一种高精度限流电路的设计  

Design of a high-precision current limiting circuit

作　　者：陶敏 唐威 董振斌 李晶 TAO Min;TANG Wei;DONG Zhenbin;LI Jing(School of Electronic Engineering,Xi'an University of Posts and Telecommunications,Xi'an 710121,China;Shanghai Engineering Research Center of Electronic Circuit Intelligent Protection,Shanghai 201202,China;Wayon Electronics Co.,Ltd.,Shanghai 201202,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5期487-494,共8页Electronic Components And Materials

摘　　要：针对限流精度易受运算放大器失调电压、电流采样方式、工艺以及环境变化影响等问题,提出了一种带失调电压校正功能的高精度限流电路。设计失调电压校正电路,采用电流补偿方式对运算放大器进行校正,降低了运算放大器的失调电压;限流环路利用采样管对输出电流进行等比例采样,采样精度较高;为减小封装所带来的偏差,设计了数字修调电路,对其限流值偏差进行调节,提高限流精度。该电路采用0.18μm 1P3M BCD工艺实现。仿真结果表明,限流值在不同温度(-55~125℃)及不同电源电压(2.7~5.5 V)条件下,随温度变化率为0.56%,随电源电压变化率为1.65%,限流精度为2%,可修调范围为-58.5%~54.9%。To address the easily-affected accuracy of current limiting by operational amplifier offset voltage,current sampling method,process and environmental variations,a high-precision current limiting circuit was proposed with offset voltage correction function.The offset voltage correction circuit was designed and used in the current compensation method to correct the operational amplifier,which reduced its offset voltage.The sampling tube was used for proportional sampling of the output current in the current limiting loop,giving high sampling accuracy.To reduce deviations caused by packaging,a digital trimming circuit was designed to adjust the deviation of current limiting value,which can improve the current limit accuracy.The circuit was implemented using 0.18μm 1P3M BCD process.Simulation results show that current limiting value varies by 0.56%from-55℃to 125℃and by 1.65%from 2.7 V to 5.5 V.The accuracy of current limiting is 2%.The current limiting value is adjustable from-58.5%to 54.9%.

关 键 词：运算放大器 失调电压 电流采样 高精度 限流 

分 类 号：TN432[电子电信—微电子学与固体电子学]