Abstract: An adaptive closed-loop driving method for piezoelectric sensors is designed,and its circuit implementation is introduced from the aspects of anti-saturation charge amplifier,band-pass filter,shaping circuit and power amplifier.It is theoretically demonstrated that the system meets the self-oscillation condition.The feasibility of this method is verified by experiments.The method only needs a unipolar power supply to process AC signals,and provides positive and negative square wave bipolar driving,which increases the driving energy by 4 times compared with unipolar driving,and greatly simplifies the circuit.Compared with open-loop driving,this method can adapt to the natural frequency of the sensor,improve the driving efficiency and reliability,and be universal.

Key words: Piezoelectric sensor, Closed-loop driving, Self-adaption, Self-oscillation, Power amplification