Development of CMOS Receiver Front-ends for Ultrasound Imaging Applications
Date Issued
2012
Date
2012
Author(s)
Wu, Min-Hua
Abstract
In diagnostic medicine, ultrasound imaging is one of the most widely used diagnostic tools due to its safety and relatively low cost. To facilitate system-on-chip implementation to minimize the cost, the development of CMOS ultrasound receiver front-end is essential. In this thesis, several architectures and circuit techniques are presented to increase the dynamic range and the linearity of the receiver. The first chapter introduces the fundamentals of an ultrasound imaging system, including a brief introduction to the whole system and the architecture of the receiver. Chapter 2 illustrates the challenges in ultrasound receiver design and the link budget calculation is demonstrated for system optimization. In Chapter 3, a highly integrated ultrasound receiver front-end is implemented by using a standard 0.18-um CMOS process. The high speed analog-to-digital converter is integrated in this design to provide digital data output. Moreover, in order to increase the dynamic range, the proposed front-end circuit provides three gain modes and a linear-in dB variable gain amplifier is employed to perform time gain compensation technique. In chapter 4, the signal integrity problem in system-on-chip and multichannel designs will be discussed. In this chapter, a feed-forward substrate noise cancellation scheme is proposed to suppress substrate crosstalk phenomenon. A quad-channel ultrasound receiver front-end is demonstrated in 65-nm CMOS process. In order to reduce the complexity and area of the circuit, a fully-differential programmable gain anti-aliasing filter is proposed by using a single OPAMP. The design and experimental results of a high-linear ultrasound receiver front-end are illustrated in Chapter 5. By using a CG-CS balun low-noise amplifier, the received single-ended signal can be converted to differential signal directly. To improve the linearity and output swing range, a capacitively-coupled programmable gain amplifier is proposed. The gain of the amplifier can be adjusted by controlling the switched-capacitors.
Subjects
ultrasound
receiver front-end
CMOS
ultrasound imaging
variable gain amplifier
time gain compensation
Type
thesis
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