On-chip Wide Range Bidirectional Current Sensor for Li-ion Battery Management System

Abstract

Abstract An on-chip wide range bidirectional current sensor for monitoring Li-ion battery model 18650 is proposed in this paper. In order to detect the bidirectional current, two feedback sensing loops are employed. The feedback sensing loops generate differential sensed current signals. The output summation driver is included to convert the differential current signals to a single-ended output voltage signal and improve the driving ability. The proposed design is implemented using a typical 0.25 μm 1P3M 60V BCD process. The core area is 0.2943 mm × 0.5640 mm. Based on the post layout simulation results, the sensing current is from –1.0 A to +1.0 A. The transimpedance is simulated to be 1.407 V/A. The inaccuracy error is from −0.2010% to 0.1030%. The measurement results reveal that the linear error is −0.390% to 0.215% given a sensing current from −0.8 A to +0.8 A.