Design of a quartz crystal microbalance driving circuit based on detection of RNA virus

The main objective of this paper is to develop a driving circuit for a QCM sensor based on the detection of RNA virus. The circuit uses negative capacitance compensation technology, automatic gain control circuit and differential operation circuit, and this structure will improve the starting conditions of the resonant circuit and achieve continuous stability of the circuit oscillation. Thus the QCM front-end oscillation driving circuit can oscillate stably in a liquid phase environment. By connecting the Bessel band-pass filter, The circuit is stable under three harmonics at 15MHz, Removing some clutter in the oscillation process, and the obtained frequency is limited to a certain range, ensuring that the single-chip machine can read out the most accurate crystal frequency. Through the rail-to-rail operational amplifier chip, the frequency signal is fixed within a certain interval to ensure that the microcontroller can read the valid output frequency signal. Further, a frequency counter is used to count and display the read frequencies. Finally, the stability of the circuit is verified experimentally, and the experimental results and the theoretical calculation results of the formula are analyzed for error. When the experiment requires high parameters, the temperature fuzzy self-correcting PID control algorithm is used to control the operating environment temperature of the instrument within a basically constant range to reduce the error.