**2.1 Circuit simulations**

Above described circuit was initially simulated using LTSpice IV [6]. In presented case micropump was modeled using previously measured capacitance C0 of 12 nF [7]. Synthesized rectangular signal frequency, which represents micropump excitation, was set at 100 Hz with 50% symmetry. High-frequency switching of transistors Q3 and Q4 was swept from 10 kHz to 33 kHz, whilst recording resulting micropump excitation voltage. Resulting recorded micropump voltage at 100 Hz is depicted in **Figure 3**.

**Figure 2.**

*Excitation part of the mutually exclusive SMPS driver design.*

Initial simulations have shown, that the output voltage, depicted in **Figure 3**, features a pronounced, unwanted asymmetry of positive and negative half-cycle amplitudes in order of 50 V. This consequentially causes a DC offset voltage, which deteriorates the piezo actuator deflection over time or even prevents proper micropump performance.

**Figure 3.** *Micropump excitation voltage simulation.*
