High frequency GaN-based ultrasound pulse generator for high energy delivery

Pulse generator is the critical component in all ultrasound systems for driving a piezoelectric transducer to medical or nondestructive testing (NDT) applications with high-voltage, high frequency bipolar or unipolar pulse train. Other than conventional imaging short pulses, high power transmit ultrasonic system for medical applications requires MHz pulse bursts of up to tens of milliseconds. The capability of switching high voltage (±90V) at multi-MHz, delivering effective power efficiently, is crucial for practical systems. Gallium Nitride (GaN) high electron mobility transistors (HEMTs) have improved performances at high switching frequency with lower losses and higher power density than Silicon (Si) MOSFETs. This paper proposed a transformer push-pull pulse generator, different from more conventional implementation of pulsers for clinical use, with GaN power switches that are capable to produce a 50ms long burst pulse length with bipolar pulses of ±90V switching up to 10MHz.