电荷平衡和自动跟踪型加速度计电流数字转换  

Current to digital converter for charge-balancing and automatic tracking accelerometers

作　　者：谢元平[1] 丁浩珅 樊振方 于旭东 罗晖[1] XIE Yuanping;DING Haoshen;FAN Zhenfang;YU Xudong;LUO Hui(College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学前沿交叉学科学院,长沙410073

出　　处：《中国惯性技术学报》2022年第4期518-524,共7页Journal of Chinese Inertial Technology

基　　金：国家自然科学基金(62173335)。

摘　　要：针对惯性导航系统现有加速度计电流信号转换电路的不足,提出了一种基于电荷平衡和自动跟踪原理的加速度计电流数字转换方法(CDC),从工作原理上大幅提升转换电路性能。CDC对输入电流和反馈跟踪电流积分输出误差电压,依据该误差电压实时调整其数字输出d以及与d成比例的反馈跟踪电流,实时反馈控制使误差电压稳定在0附近,实现输入电流和反馈跟踪电流二者电荷平衡。设计了单路CDC电路用于原理验证和性能测试。实验表明,±40 mA电流范围内CDC电路标度因数不对称性优于5 ppm,非线性优于10 ppm,电流分辨率优于0.5 nA,动态范围大于164 dB;采用查找表技术补偿后-40℃~+60℃温度区间零偏变化小于30 nA、标度因数变化小于20 ppm,且各性能指标均有较大改善空间。电荷平衡和自动跟踪型加速度计电流数字转换技术具有动态范围大、精度高、分辨率高、易补偿等优点,具有非常好的应用前景。To overcome the shortcomings of existing current conversion circuits of accelerometer, a charge-balancing and automatic tracking current to digital conversion(CDC) method is proposed, which can promote the performance parameters greatly from principle. CDC integrals the input current and the feedback tracking current to produce a error voltage, and adjusts its digital output d and the feedback tracking current which is proportional to d in real time according to this error voltage. The real-time feedback control makes the error voltage stable around 0 to achieve charge balance between input current and feedback tracking current. A single channel CDC circuit is designed for principle verification and performance tests. The experiments show that the scale factor asymmetry and non-linearity of the CDC is better than 5 ppm and 10 ppm respectively in the current range of-40 mA~+40 mA, the current resolution is better than 0.5 nA, and the dynamic range is greater than 164 dB. After compensation with look-up table, the bias change is less than 30 nA and the scale factor change is less than 20 ppm in the temperature range of-40 ℃~+60 ℃, and all performance parameters may be improved in the follow-up work. The proposed CDC method has the advantages of wide dynamic range, high precision, high resolution and easy compensation, which has a very good application prospect.

关 键 词：加速度计 电流数字转换 电荷平衡 自动跟踪 标度因数 

分 类 号：U666.1[交通运输工程—船舶及航道工程]