Collaborative Research: High-Performance Time-Interleaved Analog-to-Digital Converter Design with Digitally Assisted Calibration for Low-Power Broadband Applications

无线通信行业在过去十年中经历了非凡的增长，导致了时尚的低功耗手持设备，具有文本消息、语音通信、社交网络、在线购物、互联网浏览、互动电视和移动视频博客等多用途功能。目前约有30亿人使用这些智能手持设备，预计未来几年需求将大幅增长。尽管这些设备提供的功能是惊人的，远远超过了几年前大多数人的预期，但下一代设备的预期功能将远远超过今天的可用功能。这些设备中的一个关键组件是模数转换器(ADC)，它将射频模拟信号转换为数字信号，可以由充当智能设备大脑的强大处理器处理。该研究项目致力于设计具有卓越性能且可在极低功率水平下运行的下一代自测试ADC。这将延长手持设备电池充电的间隔时间。这项工作的意义在于为未来智能手持设备的发展提供了必要的关键部件。这项研究的预期结果是先进的ADC设计，具有更高的性能和可靠性，同时降低功耗和延长电池寿命。手持个人通信平台的趋势是将整个频谱数字化，从而允许在软件中实现所有无线电功能。用于手持个人通信平台的下一代接收器将需要具有高分辨率和低功耗的超宽带模数转换器(ADC)。这项工作的重点是开发具有无与伦比的功率效率和性能的射频接收机的模数转换器。本研究的目的是为无线通信系统提供一种高分辨率、低功耗的宽带模数转换器的实用实现方法。为了实现这一目标，提出了五个目标：1)通过电路结构和校准技术的共同开发，开发一种低功耗、高分辨率的宽带时间交错混合逐次逼近寄存器/流水线结构；2)开发一种固有的无不可恢复误差的子模数转换器结构，适用于线性、非线性和定时误差的高速背景校准；3)开发一种具有精细相位数字控制的相位时钟发生器结构，以实现精确的时序偏差校准；4)开发一种实现最优联合gain/offset/discontinuity/nonlinearity/phase-skew校准的后台全速校准算法；5)采用最先进的工艺设计、制作和测试了一个混合时间交错背景校准宽带ADC原型，以实验验证该方法的性能潜力。就更广泛的影响而言，这项研究将对电子设备的效率、可靠性和生产成本产生重大影响，并将有助于确保消费电子行业的可持续增长。在这一项目下，将招募和指导来自代表性不足群体的研究生和本科生。

The wireless communications industry has experienced exceptional growth in the past decade resulting in sleek low-power handheld devices with multi-purpose functionality such as text-messaging, voice communications, social networking, on-line shopping, internet browsing, interactive TV, and mobile video blogging. Around 3 billion people currently use these smart handheld devices and demand is expected to grow substantially in years to come. Though the functionality these devices provide is phenomenal and far exceeds what most envisioned even a few years ago, the anticipated capabilities of next-generation devices will far eclipse what is available today. A critical component in these devices is an analog-to-digital converter (ADC) that converts radio frequency analog signals into digital signals that can be processed by powerful processors which serve as the brain of smart devices. This research project focuses on the design of next-generation, self-testing ADCs that have superior performance and can operate at extremely low power levels. This will extend the time between recharging of batteries in handheld devices. The significance of this work is in providing a key component necessary for the future development of smart handheld devices. The expected outcome of this research is advanced ADC designs with enhanced performance and reliability while reducing power dissipation and increasing battery life.The trend in handheld personal communication platforms is to digitize the entire spectrum thereby allowing implementation of all radio functions in software. Next-generation receivers for handheld personal communication platforms will require very broadband analog-to-digital converters (ADCs) with both high resolution and low power consumption. This work focuses on the development of ADCs for radio frequency receivers with unmatched power efficiency and performance. The goal of this research is to introduce a practical method for realizing broadband ADCs for wireless communication systems with superior resolution and low power characteristics. To achieve this goal, five objectives have been established: 1) Develop a low-power high-resolution broadband time-interleaved hybrid successive approximation register (SAR)/pipelined architecture through the co-development of circuit structures and calibration techniques; 2) Develop a sub-ADC structure with inherent absence of non-recoverable errors suitable for at-speed background calibration of linear, nonlinear, and timing errors; 3) Develop a phase clock generator architecture with fine-phase digital control enabling accurate timing skew calibration; 4) Develop a background at-speed calibration algorithm that achieves optimal joint gain/offset/discontinuity/nonlinearity/phase-skew calibration; and 5) Design, fabricate, and test a prototype hybrid time-interleaved background-calibrated broadband ADC in a state-of-the-art process to experimentally verify performance potential of this approach. In terms of broader impacts, this research will have significant impact on efficiency, reliability, and production costs of electronic devices and will contribute to ensuring the sustainable growth of the consumer electronics industry. Graduate and undergraduate students from underrepresented groups will be recruited and mentored under this project.