A Survey on Analog-to-Digital Converter Integrated Circuits for Miniaturized High Resolution Ultrasonic Imaging System.

As traditional ultrasonic imaging systems (UIS) are expensive, bulky, and power-consuming, miniaturized and portable UIS have been developed and widely utilized in the biomedical field. The performance of integrated circuits (ICs) in portable UIS obviously affects the effectiveness and quality of ultrasonic imaging. In the ICs for UIS, the analog-to-digital converter (ADC) is used to complete the conversion of the analog echo signal received by the analog front end into digital for further processing by a digital signal processing (DSP) or microcontroller unit (MCU). The accuracy and speed of the ADC determine the precision and efficiency of UIS. Therefore, it is necessary to systematically review and summarize the characteristics of different types of ADCs for UIS, which can provide valuable guidance to design and fabricate high-performance ADC for miniaturized high resolution UIS. In this paper, the architecture and performance of ADC for UIS, including successive approximation register (SAR) ADC, sigma-delta (Σ-∆) ADC, pipelined ADC, and hybrid ADC, have been systematically introduced. In addition, comparisons and discussions of different types of ADCs are presented. Finally, this paper is summarized, and presents the challenges and prospects of ADC ICs for miniaturized high resolution UIS.

Echo Signal Receiving and Data Conversion Integrated Circuits for Portable High-Frequency Ultrasonic Imaging System.

Ultrasonic imaging has become a very promising technology, and it has been widely applied in biomedicine, geology, and other fields due to its advantages of safety, nondamaging, and real time. Especially, the portable high-frequency (>20 MHz) ultrasonic imaging system (UIS) has been generally used in biomedical detection and diagnosis. In the complex actual environment, the effect of integrated circuits (ICs) on the performance of portable high-frequency UIS is obvious. In the echo signal transmission link, the analog front end (AFE) and the analog-to-digital converter (ADC) are the two most critical modules, where AFE is used to receive and preprocess the analog ultrasonic echo signals and ADC to convert the analog signals from the AFE output to digital. The structure and performance of the ICs integrated into terminal equipment and in-probe for the portable high-frequency UIS are introduced and discussed. Some typical commercial ICs are also summarized. Based on the requirements and challenges of portable high-frequency UIS, the future development directions of ICs mainly include high integration, ultralow power consumption, high speed, and high precision, which can provide valuable reference and advice for the design of AFE and ADC for portable high-frequency UIS.