一种新型高精度电流检测电路的设计

Design of a new high-accuracy current sense circuit

针对待检测的负载电阻在实际电路中存在偏差问题,提出新型轨到轨电流检测电路。利用对称的轨到轨跨导运放电路,将输入电压转化成电流,通过两级运放组成的负反馈电路,将电流输出。该电流检测电路增加了输入电压范围,也没有了传统串联电阻检测结构的采样保持支路,并且对待检测电阻进行步进设计来减小误差,进一步提高检测电路的精度。该电路采用GLOBALFOUNDRIES 0.13μm RF SOI-CMOS工艺实现,工作电压为5 V,启动时间为27 ns,静态功耗为1.17 mW,电流检测电路检测精度高达99.43%。

This paper presents a novel rail-to-rail current-sensing circuit to solve the deviation of the load resistance.The input voltage is converted into current by a symmetrical rail-to-rail transconductance operational amplifier,while the output is generated by a negative feedback circuit composed of two stages operational amplifier.The current-sensing circuit increases the input voltage range without the employment of the sampler holding branch in the traditional series resistance sensing structure.The step-control design of the sensing-resistor is carried out to reduce the deviation and further improve the accuracy.The presented current-sensing circuit implemented in the GLOBALFOUNDRIES 0.13μm RF SOI-CMOS technology,exhibits the strat-up time of 27 ns,the static consumption of 1.17 mW,and the sensing accuracy of 99.43%under an operating voltage of 5 V.