Design and analysis of charge-recovery driving circuits for portable peristaltic micropumps with piezoelectric actuators

Micropumps fabricated by micro-electro-mechanical systems (MEMS) technology are being continuously improved for biomedical applications. Among all kinds of pumps, piezoelectric peristaltic micropumps are most likely to be applied in implementations for the development of high precision drug delivery systems. The micropump can be used in portable devices, where power saving is a critical issue for almost all kinds of portable device. In this work, we consider the design of a power-saving technique for the lead–zirconate–titanate (PZT) micropump system, which allows mobile injection to reduce the power consumption under driving conditions. The modified driving circuits of piezoelectric micropumps are developed with charge recovery using energy storage capacitance. Capacitive charge recovery can be used to recover part of the charge stored within the PZT actuator. The modified driving circuit uses the two-phase charging method whose time duration between two charges is discussed. We discovered that the pump obtains an extra 34%, 13% and 4.2% flow rate at 80 Vpp, 120 Vpp, and 160 Vpp, respectively. The experiential function is investigated to present the effect of time duration and the relationship between the flow rates and the displacement of PZT.