Improved Current and Charge Amplifiers for Driving Piezoelectric Loads, and Issues in Signal Processing Design for Synthesis of Shunt Damping Circuits

Abstract

Piezoelectric transducers are known to exhibit less hysterisis when driven with current or charge rather than voltage. Despite this advantage, such methods have found little practical application due to the poor low-frequency response of present current and charge driver designs. This paper introduces the compliance feedback current driver containing a secondary voltage feedback loop to prevent DC charging of capacitive loads and to compensate for any voltage or current offsets within the circuit. Low-frequency bandwidths in the milli-Hertz range can be achieved. One application for such a device is the synthesis of piezoelectric shunt damping circuits. A number of block diagram transformations are presented to simplify the realization of analog or digital admittance transfer functions from aschematic circuit diagram.