基于AD7150微位移电容传感器的研究

利用了集成芯片AD7150完成了对微位移电容传感器的电容采样。对AD7150芯片设计了相应的外接电路,为了增强电路的抗干扰能力,加入相应滤波电路;通过单片机模拟I2C通信方式来进行AD7150的读写控制。测量结果给出了10 pF以下不同标称电容值的电容,误差在2.5%以内。初步实验结果表明,当接入双叉电容传感器探头时,电容值随测量距离的增大而增加;在不同位移量下,传感器的灵敏度不同,距离越近,灵敏度越高,最大灵敏度为686 fF/mm,给出了不同情况下的灵敏度分布,并总结了影响电容传感器工作的电路要点。

Research on Micro-Displacement Capacitance Sensor Based on AD7150

The capacitance sample of the micro displacement capacitive sensors was obtained by the integrated chip AD7150.The relevant external circuit which added the filter circuit to enhance the ability of the anti-interference was designed for AD7150 chip.The integrated chip AD7150 was controlled by micro control unit(MCU)to read and write through I2C communication.The measurement result shows that the deviation of capacitance measurements is less than 2.5% when using the different nominal capacitance values under 10 pF.The preliminary experimental result shows that the capacitance increases by increasing the distance between the electrode and the object when the dual interdigital sensor is connected to the circuit.The sensitivity is different in the different increment.With the smaller distance,the sensitivity is larger and the largest sensitivity is 686 fF/mm.The sensitivity distribution in the different increment at different starting points is given,and the factor affecting the capacitance of the sensor is summed up.