一种差动式位移传感器芯片的信号调理电路设计

A Signal Conditioning Circuit Design of a Differential Dynamic Displacement Sensor Chip

设计了一种适用于线性可变差动式位移传感器(LVDT)的信号调理电路,该电路用于将LVDT的副边输出信号进行处理,并输出一个表征铁芯位移的直流电压;主要由解调电路、除法电路和运算放大器组成。LVDT副边输出为两个互补的正弦波信号,直接驱动信号调理电路;由于该信号调理电路采用了独特的比值架构,得到的是两个电压的差与和的比值,所以不要求LVDT初级激励使电压幅度保持稳定,同时,LVDT初级与次级线圈的相移以及干扰电压对该电路的功能不会产生影响,能有效地解决传统信号调理电路在测量精度和可靠性等方面的问题,具有更好的稳定性和性能优势,经过仿真验证及流片测试表明,该信号调理电路总误差≤1.49%/FS,线性度≤0.05%,满量程输出电压≥±10 V。各项功能指标均达到设计要求。

A signal conditioning circuit for a linear variable dynamic displacement sensor(LVDT)is designed,which is used to process the sub⁃border output signal of the LVDT and outputs a DC voltage of the iron core displacement.It is mainly composed of demodulation circuit,division circuit and amplifier.The LVDT secondary output is two complementary sine wave signals,which direct drives the signal conditioning circuit.The signal conditioning circuit uses a unique ratio architecture,which obtains the ratio of the difference and the sum of two voltage values,so it is not necessary for the LVDT primary excitation signal to make the voltage amplitude stable.At the same time,the phase shift of the LVDT primary and secondary coils and the interference voltage will not affect the function of the cir⁃cuit,effectively solving the problems of measurement precision and stability,and possessing better stability and performance advantages.The results of simulation verification and streaming tests show that the total error of the signal conditioning circuit is no bigger than 1.49%of FS,the linearity is no bigger than 0.05%,and the full range output voltage is no less than 10 V.All functional indicators meet the design requirements.