Device for Operating a Piezo Actuator

A first energy control unit has a pilot controller with an applied setpoint energy and outputs a pilot control signal, and a regulator outputting a regulator signal as a function of the setpoint energy and an actual energy of the piezo actuator. The energy control unit creates a control signal representative for a current threshold of a charge current, depending on the pilot control and regulator signals. Furthermore, there is a second energy control unit for another setpoint energy and another control signal. A power output stage sets a charge current for the piezo actuator as a function of the predetermined control signal and performs this for the predetermined time. A scheduling unit predetermines, for setting the setpoint energy, the control signal and the time to the power output stage, and for setting the another setpoint energy, the another control signal and the time to the another power output stage.