The need for large forces applied by piezoelectric actuators leads to increasing footprint, capacitance and voltage, in trade-off with low dissipation. Thus, new circuits shall be conceived. A novel architecture based on two-output, single-inductor, DC-AC converter is presented. It is fundamental to derive the circuit LTI model, so that a target waveform is obtained on the actuators, depending on the switches duty-cycle. State-space averaging and linearization are used to extract the model. The computed equations are exploited to predict the required duty-cycles to generate any desired target signal. The circuit model is validated by open-loop simulations, showing relative deviations <2.7%.