High-power burst and chirp amplifier for MHz ultrasonics

Area of Science:

• Acoustics
• Electrical Engineering
• Materials Science

Background:

• Power ultrasound is crucial for applications like cleaning, welding, and surgery.
• High instantaneous power is needed for nonlinear effects such as cavitation.
• Existing commercial power amplifiers are often expensive and bulky.

Purpose of the Study:

• To design an inexpensive and compact power amplifier for high-power ultrasound.
• To enable wider adoption of power ultrasound technologies by reducing entry barriers.
• To provide precise control over output parameters like amplitude, frequency, and phase.

Main Methods:

• Developed a compact amplifier using parallel MOSFETs in a single-ended topology.
• Designed the amplifier to switch current through a transformer's primary side.
• Integrated logic-level control for output amplitude, frequency, and phase.
• Tested the amplifier with a 4 MHz focusing piezoelectric transducer in a high-intensity focused ultrasound setup.

Main Results:

• Achieved a peak power output of 4.4 kW (1.3 kV peak-to-peak voltage into 50 Ω).
• Demonstrated logic-level control over output parameters.
• Attained an efficiency of 74% at 100 W average power.
• Successfully operated the amplifier in a high-intensity focused ultrasound application.

Conclusions:

• The developed amplifier is a cost-effective and compact solution for high-power ultrasound.
• This design significantly lowers the barrier to entry for advanced ultrasonic applications.
• The amplifier's performance is suitable for demanding tasks like high-intensity focused ultrasound.