During these last years, the demand of miniaturized voltage transformers increased with the fast multiplication of portable equipment's. The miniaturization of the electromagnetic transformer is more difficult. An interesting solution consists of the use of the piezoelectric transformer of small dimensions which coupling among the primary and the secondary is assured by a mechanical vibration. However, piezoelectric transformers suffer from hysteresis, losses, viscous friction; the cumulative effect of these factors leads the piezoelectric transformer performance decrease. In this work we propose methods to improve the piezoelectric transformer mode thickness performance, the principle exposed, said SST (Synchronized Switch on transformer), is derived from the technique of semi passive structural damping SSDI (Synchronized Switch Damping we Inductor), these methods are non-linear based on the increase of the secondary voltage of the transformer thus increasing efficiency.