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Design of High-Voltage Linear Amplifier for Driving Integrated 2-D Ultrasound Transducer Array

Title
Design of High-Voltage Linear Amplifier for Driving Integrated 2-D Ultrasound Transducer Array
Other Titles
2-D 초음파 트랜스듀서 배열을 구동하기 위한 고전압 선형 증폭기 설계
Author
구송현
Alternative Author(s)
Gu, Song Hyun
Advisor(s)
권오경
Issue Date
2014-02
Publisher
한양대학교
Degree
Master
Abstract
The ultrasound imaging system is widely used for anatomy visualization because it allows for noninvasive and real-time imaging without any side effects. It visualizes the inside of human body and distinguishes internal tissues using ultrasound transducer and front-end circuit. The ultrasound transducer transmits an acoustic wave into the human body and receives the waves reflected back from the internal tissues. Recently, thousands of ultrasound transducers are highly required for the high resolution three-dimensional (3-D) ultrasound imaging system. However, the high equivalent impedance of the ultrasound transducer having small area causes impedance matching problems. In order to solve this problem, an integration of the front-end circuit is necessary underneath the ultrasound transducer. The high-voltage (HV) transmitter used to send an ultrasound signal into the human body is classified into HV pulser and HV linear amplifier. To integrate an HV transmitter underneath an ultrasound transducer, the HV pulser is widely used because it has a simple circuit structure and low power consumption. However, harmonic components of transmitted ultrasound generated by the HV pulser degrade the spatial resolution of ultrasound image. The HV linear amplifier which generates the arbitrary waveforms is adopted to reduce the harmonic components of transmitted ultrasound. The HV linear amplifier should be implemented in a small area with low power consumption to be integrated into the limited area of the ultrasound transducer. This thesis proposes an HV linear amplifier that drives the integrated 2-D ultrasound transducer array. It is composed of a transconductance amplifier, a transimpedance amplifier, and a feedback network. Current feedback (CFB) topology that has fixed bandwidth independent of voltage gain is adopted to reduce the power consumption. In order to save the chip area, the HV linear amplifier is designed by reducing the number of laterally double-diffused MOSFETs (LDMOSFETs). The voltage gain and the 3 dB bandwidth of the HV linear amplifier are 42.9 dB and 6.2 MHz, respectively. The HV linear amplifier consumes static power of 5.6 mW in total and occupies a chip area of 0.017 mm2.|초음파 영상 시스템은 부작용 없이 환자에게 비침습성 영상과 실시간 영상을 제공하기 때문에 해부적 시각화에 널리 사용된다. 초음파 영상 시스템은 초음파 트랜스듀서와 프런트-엔드 회로를 사용하여 내부 조직을 구분하고 사람의 신체 내부를 영상화한다. 초음파 트랜스듀서는 사람의 신체에 음파를 전송하고 내부 조직에서 반사되는 음파를 수신한다. 최근 들어서, 고해상도 3-D 초음파 영상 시스템을 위하여 많은 수의 초음파 트랜스듀서가 매우 요구된다. 그러나 작은 면적을 차지하는 초음파 트랜스듀서의 높은 등가 임피던스는 임피던스 매칭 문제를 발생시킨다. 이러한 임피던스 매칭 문제를 해결하기 위하여 초음파 트랜스듀서 아래에 프런트-엔드 회로의 집적은 필수적이다. 사람의 신체에 초음파를 전송하는데 사용되는 고전압 전송기는 고전압 펄서와 고전압 선형 증폭기로 분류된다. 초음파 트랜스듀서 아래에 고전압 전송기를 집적하기 위해서 간단한 회로와 적은 소비전력을 가지는 고전압 펄서가 널리 사용된다. 그러나 고전압 펄서에서 전송되는 초음파의 고조파 성분들은 초음파 영상의 공간 해상도를 떨어뜨린다. 임의 파형을 생성하는 고전압 선형 증폭기는 전송되는 초음파의 고조파 성분들을 줄이기 위해서 채택된다. 고전압 선형 증폭기는 초음파 트랜스듀서의 제한된 면적에 집적되기 위해서 적은 전력 소비으로 작은 면적에 구현되어야 한다. 본 논문에서는 집적된 2-D 초음파 트랜스듀서 배열을 구동하기 위해서 트랜스컨덕턴스 증폭기와 트랜스임피던스 증폭기, 부궤환 네트워크로 구성된 고전압 선형 증폭기를 제안하였다. 고전압 선형 증폭기의 전력 소비를 줄이기 위하여 전압 이득과 무관한 고정된 대역폭을 가지는 전류 부궤환 구조가 채택되었다. 칩의 면적을 줄이기 위하여 LDMOSFET의 개수를 줄여서 설계되었다. 고전압 선형 증폭기는 42.9 dB의 전압 이득과 42.9 dB의 3 dB 대역폭을 가진다. 고전압 선형 증폭기는 5.6 mW의 전체 정적 전력을 소비하고 0.017 mm2의 면적을 차지한다.; The ultrasound imaging system is widely used for anatomy visualization because it allows for noninvasive and real-time imaging without any side effects. It visualizes the inside of human body and distinguishes internal tissues using ultrasound transducer and front-end circuit. The ultrasound transducer transmits an acoustic wave into the human body and receives the waves reflected back from the internal tissues. Recently, thousands of ultrasound transducers are highly required for the high resolution three-dimensional (3-D) ultrasound imaging system. However, the high equivalent impedance of the ultrasound transducer having small area causes impedance matching problems. In order to solve this problem, an integration of the front-end circuit is necessary underneath the ultrasound transducer. The high-voltage (HV) transmitter used to send an ultrasound signal into the human body is classified into HV pulser and HV linear amplifier. To integrate an HV transmitter underneath an ultrasound transducer, the HV pulser is widely used because it has a simple circuit structure and low power consumption. However, harmonic components of transmitted ultrasound generated by the HV pulser degrade the spatial resolution of ultrasound image. The HV linear amplifier which generates the arbitrary waveforms is adopted to reduce the harmonic components of transmitted ultrasound. The HV linear amplifier should be implemented in a small area with low power consumption to be integrated into the limited area of the ultrasound transducer. This thesis proposes an HV linear amplifier that drives the integrated 2-D ultrasound transducer array. It is composed of a transconductance amplifier, a transimpedance amplifier, and a feedback network. Current feedback (CFB) topology that has fixed bandwidth independent of voltage gain is adopted to reduce the power consumption. In order to save the chip area, the HV linear amplifier is designed by reducing the number of laterally double-diffused MOSFETs (LDMOSFETs). The voltage gain and the 3 dB bandwidth of the HV linear amplifier are 42.9 dB and 6.2 MHz, respectively. The HV linear amplifier consumes static power of 5.6 mW in total and occupies a chip area of 0.017 mm2.
URI
https://repository.hanyang.ac.kr/handle/20.500.11754/130864http://hanyang.dcollection.net/common/orgView/200000423264
Appears in Collections:
GRADUATE SCHOOL[S](대학원) > INFORMATION DISPLAY ENGINEERING(정보디스플레이공학과) > Theses (Master)
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