新型运载火箭中电容式液位传感器接口专用集成电路

摘要

In order to improve the capacitance detection performance of capacitive liquid level sensor in new aerospace carrier rocket,an interface(Application Specitic Integrated Circuit)ASIC of capacitive liquid level sensor in aerospace carrier rocket was designed.First,the system of the whole circuit was designed,w hich converted the output capacitance of capacitive liquid level sensor to voltage that had linear relationship with the output capacitance of the sensor.And then,the linearity,noise character-istics and temperature environment adaptability of interface ASIC were analyzed and studied.At last, the interface ASIC was fabricated in a standard 0.5 μm CMOS process and the performances of the chip were tested.The test results show that the linearity of capacitance detection of the ASIC is 0.005%,output noise is 3.7 aF/(when the capacitance which will be detected is 40 pF),the stability of capacitance detection is 7.4× 10-5pF(w hen the reference capacitance is 40 pF,the capacitance which will be detected is 40 pF,1 σ,1 h),the output zero position temperature coefficient is 4.5 μV/℃.The test results prove that the capacitance detection performance of the ASIC reaches the standard of capacitive liquid level sensormeasurement chip with the highest performance abroad, which can be widely used in many kinds of capacitive detection sensors.%为了提高新型航天运载火箭中电容式液位传感器系统的电容检测性能,设计了一款适用于航天运载火箭中电容式液位传感器的接口专用集成电路(Application Specitic Integrated Circuit,ASIC)芯片.首先,完成了整体电路的系统级设计,实现了对电容式液位传感器输出电容的线性检测,将传感器输出电容量转化为与之呈线性关系的电压量输出.然后,对接口ASIC芯片的线性度、噪声特性和温度环境适应性进行了理论分析与研究.最后,采用0.5 μm CM OS工艺完成接口ASIC的流片,并进行了芯片的性能测试.实际测试结果显示,芯片电容检测非线性为0.005%,输出噪声密度3.7 aF/ Hz(待测电容40 pF),电容测量稳定性7.4×10-5pF(参考电容40 pF,待测电容40 pF,1 σ,1 h),输出零位温度系数4.5 μV/℃.测试结果证明,该接口ASIC的电容检测性能已经达到国外最高性能的电容式液位传感器液位测量芯片的水准,可以广泛应用到多种电容式检测传感器中.