Patent ID: 7564163

Claim:
A structural vibration damping device comprising: a piezoelectric element adapted to be mounted on a structure; a shunt circuit inserted between two electrodes of said piezoelectric element; and an electric circuit for selectively opening and closing said shunt circuit, wherein: said electric circuit is operable, when a voltage between the electrodes of said piezoelectric element has a positive or negative extreme value due to a vibration of said structure, to close said shunt circuit so as to allow a current to flow between the electrodes of said piezoelectric element, and, when said current is reduced to zero, to open said shunt circuit so as to preclude the current flow until a voltage between the electrodes of said piezoelectric element subsequently has the extreme value; and each of said shunt circuit and said electric circuit is designed to be operated using only a power generated by said piezoelectric element, wherein said electric circuit includes an extreme-value detection circuit using a peak hold circuit, and a circuit having a function of selectively opening and closing said shunt circuit in response to an output of said extreme-value detection circuit.