Power harvesting with PZT ceramics and circuits design

Abstract

Power generated from a piezoelectric material usually comes with poor characteristics such as high voltage, low current and high impedance. In order to drive the embedded sensor circuit, piezoelectric power needs to be characterized and regulated. In this paper, we present an analysis on the power generation characteristics and the efficiency of power conversion of the stiff lead zirconate titanate (PZT) ceramics. Moreover, a power circuit design is put forward in the application where PZT elements are used for power generation in a TKR implant. A hybrid direct current (DC)-DC, comprising a switched capacitor (SC) DC-DC converter and a low dropout (LDO) linear voltage regulator, is presented. The variable ratio SC converter has been taped out with 0.35 μm CMOS technology. The test results show that the SC converter can transfer the input voltage that ranges from 5 to 14 V from the PZT ceramics into the voltage ranging from 2 to 2.5 V which will be dealt with by LDO circuit whose efficiency can reach 80%. © 2009 Springer Science+Business Media, LLC.