Control And Detection Circuit Design And Experiments Of Vacuum Microelectronic Accelerometer

Micro acceleration sensor with high precision has attracted lots of researchers in these years and one key technology in such sensors is the control and signal detection circuit.Foreign and domestic research on the signal process circuit for the acceleration sensor was summarized and analyzed. Meanwhile, to solve the current problems as low sensitivity, high noise and low stability of the vacuum microelectronic acceleration sensor designed by microsystem center, Chongqing University. The PID based close loop control model was set up based on the analysis of the vacuum microelectronic acceleration sensor structure and working principle; The modulation and coherent demodulation based signal detection and process method was proposed based on the weak signal detection theory and the noise analysis of this sensor; The control and detection circuit was designed and realized based on the ASIC interface of the vacuum microelectronic acceleration sensor. The experiment results, which included threshold voltage as 0.7 V, emission current curve as 100 uA, sensitivity as 1.06206 V/g, linearity as 0.9%, frequency bandwidth as 120 Hz and improved stability, showed that the sensor was ready for use.The major work accomplished are as follows:(1) Key technical issues like sensitivity, noise and stability of the vacuum microelectronic acceleration sensor was analyzed. Based on this, the schematic of control and detection system for the vacuum microelectronic acceleration sensor was designed.;(2) Mechanical characteristics of the sensing unit of vacuum microelectronic acceleration sensor was analyzed and its theoretical model was also set up. According to the structure and working principle of the vacuum microelectronic acceleration sensor, the schematic of the control circuit for the sensor was given along with its PID based close loop control model;(3) The signal characteristics and the noise sources of the vacuum microelectronic acceleration sensor were analyzed. The modulation and coherent demodulation based signal detection and process method was proposed and the detection circuit was chosen according to the weak signal detection principle;(4) The control and detection circuit for the vacuum microelectronic acceleration sensor was designed and realized based on the existing ASIC interface;(5) A platform was built up and was used to accomplish the evaluation of the following parameters/characteristics of the vacuum microelectronic accelerometer: Threshold voltage, emission current curve, sensitivity, linearity, frequency response, zero-bias stability and temperature response.