Bio-medical Electronics

◈ CMOS X-ray detector 

    ◇ Introduction


- As analog image capturing devices using a film have been replaced by digital devices such as charge-coupled devices(CCDs)
and complementary metal-oxide semiconductor(CMOS) image sensors, imagers was miniaturized and capable of performing
the real-time image processing. Nowadays, digital imagers are widely used in many applications such as mobile devices,
industrial robots, and medical electronics. Especially, CMOS image sensors are increasingly adopted because they have
advantages of low-power consumption, high-resolution pixel and circuit integration capabilities.

- Image sensor group in IELAB has been researching low power, wide dynamic range, low noise, high speed, and high
bit-depth technologies in CMOS image sensors for from consumer to medical applications.

    ◇ Research area
      · Wafer-scale CMOS X-ray detector
          - High-resolution column-parallel ADC
          - 3-side buttable readout architecture
          - Reference, bias, and signal transmission techniques for large-sized IC


CMOS image sensor

Wafer-scale CMOS X-ray detector

    ◇ Research results
      · CMOS X-ray detector
          - Process: 0.35-μm 1P4M CMOS process
          - Sensitivity: 0.11 V/mR
          - MTF: 32.8% at 4.86 lp/mm
          - ADC resolution: 14.3 bits
          - Max. frame rate: 60 frames/s

Captured images (line pair, characters, package)

Chip Microphotograph

◈ Bio-Signal Monitoring System 

    ◇ Introduction
         - In recent years, with the rapid growth of portable electronics market, the demand for a human-computer interface (HCI)
          has continued to increase We have been developed readout front-end for the HCI. Our goal is to create bio-sensors with
          high performance and low power consumption.

    ◇ Research area
      · Bio-sensors 

    ◇ Research results

      · EMG readout front-end
          - Process: 0.18 μm CMOS
          - Area: 1.2 × 1.1 
          - CMRR: 105 dB
          - Power dissipation: 19 

Chip Microphotograph

Extracted EMG signal from readout front-end

◈ 3-D Ultrasound Imaging System

    ◇ Introduction


- 3-D ultrasound imaging systems are increasingly used for medical diagnosis such as fetal examination, assessment of cardiac
function, and tumor localization, etc. For implementation of high-resolution 3-D ultrasound imaging systems, 2-D active
capacitive micro-machined ultrasound transducer (CMUT) array have been interest over the year. We have researched the
2-D active CMUT array based 3-D ultrasound imaging systems with high-resolution and high frame rate.

    ◇ Research area

      · 2-D active capacitive micro-machined ultrasound transducer (CMUT) array
      · High-performance data acquisition(DAQ) system for ultrasound imaging system

    ◇ Research results

      · Three-side buttable 16×16 active CMUT array
          - Fully-integrated 16×16 transceivers with transmitting beamforming
          - Programmable beamforming methods
          - 159 % frame rate enhancement

Measured output waveforms of fabricated active CMUT array

Measured input referred pressure noise

Acquired 3-D ultrasound image by using
spring phantom with 0.6 mm diameter

    ◇ Chip
          - Process : 120V 0.35-μm BCD process
          - Area : 7 mm × 4.4 mm
          - Input referred pressure noise : 0.6 mPa/√Hz
          - Output voltage of HV pulse : 120V
          - Minimum delay control step : 5ns