Volumetric efficiency is the main parameter that characterizes the increase in power of an engine at the same speed. A group of design parameters that affects the volumetric efficiency are opening-closing characteristics of the valves (opening and closing times, valve lift and shape of cam lobe). But the same values of these parameters in various speeds yield different volumetric values which make the problem much more difficult. The solution is to develop techniques that change these parameters with changing engine speed. The most ideal one is to achieve this variation continuously together with speed variation which is called continuously variable valve timing (CVVT). To achieve this goal piezo actuator driven hydraulic displacement magnifier has been used. To drive the piezo actuator an electronic control unit and high voltage power amplifier designed and then fully digital solution is developed and explained in this study.