Dual Mode Electronic Quality Factor Control of 2D Phased Array Ultrasound Transducers for Imaging and Neuromodulation

Abstract

Ultrasound (US) technology has emerged as a powerful modality in both medical imaging and therapy, offering non-invasive, real-time, and high-resolution capabilities. Conventional dual-mode systems employ separate US transducers for imaging and therapy, each mechanically configured during fabrication for a fixed quality factor (Q-factor) through the presence of a backing layer or air-based backing layer, respectively. This approach increases system cost, physical footprint, power consumption, and integration complexity while preventing seamless real-time switching between modes. A novel electronically configurable Q-factor control circuit architecture for a single set of 2D phased-array piezoelectric transducers is proposed in this work. The proposed method employs an active damping compensation technique to electronically reduce the Q-factor during imaging mode while preserving the high-Q state for the therapeutic mode, eliminating the need for mechanical reconfiguration. System and circuit-level simulations in TSMC 180 nm BCD technology using a PZT-5A air-backed transducer BVD model demonstrate a reduction in the Q-factor from 78.3 to 8.08 with fewer than 1% variation across PVT corners. These results place the Q-factor achieved in the imaging mode within the optimal range for high-resolution ultrasound imaging, while maintaining high-Q performance for the therapeutic mode.