A Wide-Bandwidth Ultrasound Receiver and On-Chip Ultrasound Transmitter for Ultrasound Capsule Endoscopy

Kyeongwon Jeong, Gichan Yun, Jaesuk Choi, Injun Choi, Jeehoon Son, Jae Youn Hwang, Sohmyung Ha, Minkyu Je

Research output: Contribution to journalArticlepeer-review

Abstract

This article presents an ultrasound (US) transceiver IC including a highly power-efficient US receiver (RX) and a high-voltage (HV) US transmitter (TX) for US capsule endoscopy (USCE) systems for the first time. The proposed USCE system employs the developed IC, a single-element piezoelectric transducer (PZT), and a mechanically rotating reflector to obtain 360° transmural scans while traveling through the gastrointestinal (GI) tract. Since the USCE system operates with a tiny battery, power efficiency is greatly important. To reduce power consumption by decreasing the required operating speed of the analog-to-digital converter (ADC), we propose a new RX structure employing synchronized analog envelope detection. It is unlike conventional US RX ICs that necessitate power-hungry high-speed ADCs to acquire the US signal residing at a high center frequency with wide bandwidth. Instead, the proposed work employs an analog envelope detector based on a quadrature demodulation method. As a result, it uses only a single circuit path rather than two (I and Q) paths by using a demodulation carrier whose phase is synchronized with the incoming US signal. A ping-pong noise-shaping (NS) SAR ADC is adopted to improve resolution while maintaining low power consumption. Besides, the TX IC, including an on-chip charge pump, is designed to generate HV pulses to drive the PZT. The prototype IC is fabricated in a 0.18 μm bipolar-CMOS-DMOS (BCD) process. The RX consumes 2.3 mW, and the ADC achieves a 53.71 dB SNDR and a 66.45 dB SFDR. The TX generates 25 V pulses with 25 ns pulsewidth. US B-mode images of a water tank and a custom phantom are successfully obtained by using the prototype capsule endoscopy system employing the fabricated IC chip.

Original languageEnglish (US)
Pages (from-to)2778-2789
Number of pages12
JournalIEEE Journal of Solid-State Circuits
Volume58
Issue number10
DOIs
StatePublished - Oct 1 2023

Keywords

  • Analog front-end
  • US receiver (RX)
  • US transmitter (TX)
  • piezoelectric transducer (PZT)
  • synchronized analog envelop detector
  • ultrasound (US) capsule endoscopy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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