一种可防倒灌电流的高精度电流检测放大器OA

Current-sense amplifiers are widely used in motor control,battery management,and energy monitoring applications,where gain accuracy directly affects the precision of current measurement results.Conventional current-sense amplifiers suffer from significant gain error due to process variations in the input-stage resistors,making it difficult to meet high-precision measurement requirements.The traditional gate-source protection circuit for output transistors employs a Zener diode clamping structure,which is prone to generating reverse current when the output voltage becomes excessively high,potentially damaging the chip.To address the above issues,this paper proposed a high-precision current-sense amplifier with reverse current prevention.A post-package fuse trimming technique was adopted to calibrate the input-stage resistors,thereby eliminating gain error induced by process variations.Furthermore,a novel output transistor gate-source protection circuit was designed,which not only clamped the gate-source voltage of the output transistor but also suppressed the generation of reverse current.Simulation results show that,under the conditions of a supply voltage of 5 V,a common-mode input voltage of 12 V,a differential-mode input voltage of 100 mV,and a load resistance of 1 kΩ,the gain error of the system for current measurement does not exceed 0.12%.