Quasi Class-DE Driving of HIFU Transducer Arrays

Recently, a method was proposed to determine the parameters for each Class DE driver in high-intensity focused ultrasound arrays for efficient operation and to compensate for variations in the impedance of each array element. This work extends that method to consider the effect of switch resistance and to provide limited control on the power delivered to the transducers with a constant supply voltage while keeping a good efficiency. The method is experimentally validated using an integrated driver developed by the authors. This paper also shows that the frequency range for efficient electrical operation is close to the frequency where the transducer array presents a peak in the conversion efficiency.