Design of Planar Capacitance Detection Circuit Based on Communication Incentives

In order to meet the application requirements of active isolation systems for float pose detection in a certain space, capacitance displacement sensors based on parallel plate capacitance detection have emerged. Among them, the measurement circuit is a key part to ensure the performance of the capacitance displacement sensor. This article innovatively proposes a six degree of freedom pose estimation scheme based on planar capacitance detection. With the help of 12 electrodes distributed in 5 planes of the float, the six degree of freedom pose estimation of the float is achieved. Based on this, an AC excitation detection method is adopted to design a corresponding weak capacitance detection circuit, which is verified through simulation and actual measurement. The results indicate that the noise of the capacitor-voltage conversion module in both circuits is within $20\mu V/\sqrt {Hz} {\text{@}}0.1{\text{Hz}}$ nearby, capacitance changes at the fF level can be measured.