Class-C Pulsed Power Amplifier with Voltage Divider Integrated with High-Voltage Transistor and Switching Diodes for Handheld Ultrasound Instruments

Abstract

A novel Class-C pulsed power amplifier with a voltage divider integrated with a high-voltage transistor and switching diodes is proposed to reduce DC power consumption and increase the maximum output power for handheld ultrasound instruments. Ultrasonic transducers in ultrasound instruments are devices that convert electrical power into acoustic power or vice versa, which are triggered by power amplifiers. Efficient power conversion is also very important to avoid thermal issues in handheld ultrasound instruments owing to limited battery power and excessive heat generation caused by the enclosed structures of the handheld ultrasound instruments. Consequently, higher output power and lower DC power consumption are desirable for a power amplifier. Therefore, a circuit to control power amplifiers was developed. The measured output power (94.66 W) and DC power consumption (2.12 W) when using the proposed circuit are better than those when using the existing Class-C pulsed power amplifier (74.90 W and 2.77 W, respectively). In the pulse-echo measurement mode, the echo amplitude (12.34 mVp-p) and bandwidth (27.74%) of the proposed Class-C pulsed power amplifier were superior to those of the existing Class-C pulsed power amplifier (4.38 mVp-p and 23.25%, respectively). Therefore, the proposed structure can improve the performance of handheld ultrasound instruments.