The invention relates to a circuit for the control of a piezoelectric drive (1). An output signal of a first measurement circuit (4) is applied to a first input of a phase detector (5), an output signal of a logic circuit (10) or an output signal of a second measurement circuit (13) is applied to a second input of the phase detector (5), a second output signal of the logic circuit (10) is applied as an input signal to a final stage (2) which serves to supply an alternating voltage to the piezoelectric drive (1), a loop filter (7) processes the output signal of the phase detector (5) and supplies a control signal to a voltage-controlled oscillator (6), whose output signal is supplied to the input of the logic circuit (10), and a delay element (8) has been provided to adjust the frequency of the optimum operating point and efficiency of the controlled piezoelectric drive (1).