Wideband Switching Power Amplifier for Imaging SONAR

Abstract

A piezo transducer translates the applied voltage to a sound wave, demanding a power amplifier as a preprocessor to ensure an interpretable echo. The distinctive characteristic of the problem arises from the fact that such transducers are predominantly capacitive. This paper presents a class-D sonar amplifier designed and built to drive a particular acoustic transducer with a 50 Ω impedance at a resonant frequency of 400 kHz. Because of its high efficiency and compact nature, the class-D has been chosen as the power amplifier topology over its linear counterparts. When triggered with self-oscillating driver IR2086STRPBF, the bridge inverter generates a high-frequency square wave. The proposed parallel IMN enables high voltage gain and restricts the total harmonic distortion (THD). Thus, peak power of 500 W from a low-voltage source of 60–96 Vdc is ensured by employing a boost-type IMN. The simulation and experimental results show that the designed amplifier has reduced power losses when operated in the inductive.