A low‐power and area‐efficient ultrasound receiver using beamforming successive approximation register analog‐to‐digital converter with capacitive digital‐to‐analog converter combined delay cell structure for 3‐D imaging systems

Abstract

The authors present a low‐power area‐efficient subarray beamforming receiver (RX) structure for a miniaturized 3‐D ultrasound imaging system. Given that the delay‐and‐sum (DAS) and digitization functions consume most of the area and power in the receiver, the beamforming successive approximation register (SAR) analog‐to‐digital converter (ADC) shares its capacitive digital‐to‐analog converter (CDAC) with the delay cells. As a result, the delay cells implemented with capacitors are embedded in the CDAC with significant area reduction, further eliminating the need for power‐hungry ADC buffers. Furthermore, the dual reference 10‐bit SAR ADC reduces the area of CDAC by 32 times, achieving a switching energy reduction of 98.3%, compared to the conventional SAR ADC. As a result, the proposed beamforming SAR ADC, simulated using a 0.18 μm CMOS process, consumes 230 μW per channel, significantly reducing the per channel capacitance.

A 48-Channel High-Resolution Ultrasound Beamforming System for Ultrasound Endoscopy Applications

“…Figure 11 illustrates the use of a hybrid subarray beamforming architecture. This chitecture employs both an analog RX beamformer [23] and a digital RX beamformer. T analog beamformer focuses the signals between adjacent channels with small dela whereas the digital beamformer enhances the signal between relatively distant chann A memoryless structure can be realized using an RX-enabled signal generated by delay generator block.…”

A 48-Channel High-Resolution Ultrasound Beamforming System for Ultrasound Endoscopy Applications

“…Figure 10 illustrates the use of a hybrid subarray beamforming architecture. This architecture employs both an analog RX beamformer [22] and a digital RX beamformer. The analog beamformer is used to focus the signals between adjacent channels with small delays, while the digital beamformer is used to enhance the signal between relatively distant channels with large delays.…”