In measurement, the entire BBP design with the proposed gate-level structures exhibits high robustness in power supply and frequency variations. It can function normally at a minimum of 0.33 V power supply, which is over 100 mV below typical threshold voltage. In the test of the ACRL circuits, the ACRL cells show 30 - 70% delay reduction when compared to the standard static CMOS cells. And the ACRL custom PIE decoder works at the minimum of 0.26 V power supply, which is 40 mV lower than the minimum operating voltage archived by the PIE decoder in the BBP implemented with standard cells. / In this thesis, methodologies and examples are proposed for subthreshold digital circuit design. There is also a full study on subthreshold characteristics of devices and circuits in very-low-voltage operation. The EPC C1G2 baseband processor (BBP) for passive UHF (ultra high frequency) RFID (radio frequency identification) tag is selected as a subthreshold design example, as it is a digital design typified with instable very low supply voltage and requires ultra low power in operation. To tailor the BBP for lower operating voltage in subthreshold region, optimized structures and topologies are proposed in different hierarchical levels. In the system view, the BBP is partitioned according to the clock domain and the constraints of timing. Go down to the RTL and gate level, pipelining, parallelism, clock gating and one-hot state transition are implemented in the logic design according to the actual requirement. In this way energy awareness and power saving are achieved with enhanced robustness to operate in subthreshold region. The BBP with the proposed logic structures has been fabricated in several deep submicron CMOS technologies. Transistor level design is the bottom level for IC designers, the proposed active control ratioed logic (ACRL) is a logic style with fast pull-up network and less capacitance, particularly suitable for the implementation of high fan-in AOI-familiar (and-or-inverter) structure. Some general ACRL cells designs, 32-bit equality comparator and, a custom PIE decoder with ACRL cells, which is the important block of BBP with critical timing, have been fabricated in 130 nm CMOS technology. / Subthreshold designs are required in many actual applications. Especially, the subthreshold digital systems and circuits have become more and more popular in portable devices and passive systems. In conception subthreshold digital circuits are very-low-voltage circuits, they have great reduction of power consumption but suffer from long logic delay as the driving current for logic transition and propagation is greatly reduced. / Shi, Weiwei. / Adviser: C.S. Choy. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 146-152). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344755 |
| Date | January 2011 |
| Contributors | Shi, Weiwei., Chinese University of Hong Kong Graduate School. Division of Electronic Engineering. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xi, 159 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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