A Low-Intensity Pulsed Ultrasound Interface ASIC for Wearable Medical Therapeutic Device Applications

Abstract

Low-intensity pulsed ultrasound (LIPUS) is a non-invasive medical therapy that has attracted recent research interest due to its therapeutic effects. However, most LIPUS driver systems currently available are large and expensive. We have proposed a LIPUS interface application-specific integrated circuit (ASIC) for use in wearable medical devices to address some of the challenges related to the size and cost of the current technologies. The proposed ASIC is a highly integrated system, incorporating a DCDC module based on a charge pump architecture, a high voltage level shifter, a half-bridge driver, a voltage-controlled oscillator, and a corresponding digital circuit module. Consequently, the functional realization of this ASIC as a LIPUS driver system requires only a few passive components. Experimental tests indicated that the chip is capable of an output of 184.2 mW or 107.2 mW with a power supply of 5 V or 3.7 V, respectively, and its power conversion efficiency is approximately 30%. This power output capacity allows the LIPUS driver system to deliver a spatial average temporal average (SATA) of 29.5 mW/cm2 or 51.6 mW/cm2 with a power supply of 3.7 V or 5 V, respectively. The total die area, including pads, is 4 mm2. The ASIC does not require inductors, improving its magnetic resonance imaging (MRI) compatibility. In summary, the proposed LIPUS interface chip presents a promising solution for the development of MRI-compatible and cost-effective wearable medical therapy devices.