| Abstract [eng] |
This thesis investigates the design, analysis, and evaluation of high-voltage pulse generator topologies intended for ultrasonic transducer excitation systems. The work focuses on the influence of transistor technology and output stage topology on the electrical performance of ultrasonic pulsers, particularly in applications requiring fast rise times, high pulse fidelity, and efficient energy transfer. The relationship between the pulser output stage and the capacitive behavior of the transducer is analyzed in order to identify the most important pulse quality parameters affecting ultrasonic system performance. Special attention is given to pulse rise time, fall time, pulse width accuracy, propagation delay, voltage stability, frequency response, and output efficiency. Several pulse generator topologies are investigated and compared, including unipolar and bipolar architectures with different output stage driving approaches. The study evaluates the suitability of modern transistor technologies for high-voltage ultrasonic applications. The influence of transistor parasitic parameters such as gate charge, output capacitance, on-resistance, and switching speed on the generated pulse quality is discussed. Experimental measurements were performed using custom-built pulser prototypes under different load conditions and operating frequencies. Dedicated signal processing and automated measurement methods were developed to extract pulse parameters from oscilloscope waveform data. The obtained results include pulse width error analysis, cumulative timing error evaluation, propagation delay measurements, frequency response characterization, and high-voltage level stability analysis. The results demonstrate that transistor selection and output topology significantly influence the achievable pulse quality and switching performance of ultrasonic excitation systems. The developed methodologies and obtained results provide practical guidelines for the design of high-speed ultrasonic pulse generators and contribute to the optimization of modern ultrasonic measurement and imaging systems. |
