Design & Comparison of the Class D & Class E Power Amplifiers for Ultrasonic Frequencies

Ultrasound technology began to develop in the late 19 century. With the related study, there are many applications and integrations; for example, one of mechanical and electrical integration method in thesis mentioned that PA signals transform into acoustic energy and spread the energy, and then the acoustic energy converts into electrical energy as computing. In this case, we must know the correct ultrasounic piezoelectric transducer impedance values during working time first. In order to make the measurement of impedance values in limited environment more close to the measurement of impedance values in the no-flection interference, we have adopted a new method of calculation, discussing in whether limited environment will cause the impedance error.
Generally speaking, in the transmitting system, it cause much more energy in the power amplifier. The higher efficiency the power amplifier can reach, the less unnecessary consumption the system can reduce and the device can also be used longer. There are more Class D PAs applications deigned than Class E PAs for ultrasounic frequencies, so we want to design Class D & E power amplifiers and compare them in overall transfer efficiency. Compared with Class E sine wave signal, Class D output is square wave signal and the latter efficiency will not be 100 % correspond to the theory. This article will focus on designing Class D & E power amplifiers and compare with their advantages & disadvantages in the same load; moreover, Class E PAs have better power and efficiency than Class D PAs for ultrasoundic frequencies.