Patent ID: 8330334

Claim:
An apparatus, comprising: a piezoelectric energy harvester; and a power conditioning circuit (PCC) including a switch and configured to drive the switch to output a first voltage in accordance with displacement of the piezoelectric energy harvester, which is determined based on a second voltage, wherein the piezoelectric energy harvester comprises: a shim; at least one piezoelectric layer configured to vibrate to generate the first voltage and formed over at least one of upper and lower surfaces of the shim; at least one magnetostrictive layer configured to vibrate to induce a change in magnetic field and formed over the at least one piezoelectric layer; and a coil configured to surround the piezoelectric layer and the magnetostrictive layer, wherein, when the magnetostrictive layer vibrates and induces the change in magnetic field, a current flows through the coil to generate the second voltage, the second voltage being an AC voltage, and wherein the first and second voltages are generated at substantially the same time due to the vibration.