Browsing by Author "Shi, Yiyu"

Now showing 1 - 5 of 5

A Novel Fully Synthesizable All-Digital RF Transmitter for IoT Applications
(2018-01-01)
Li, Yilei
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Dhwaj, Kirti
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Wong, Chien-Heng
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Du, Yuan
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Du, Li
In this paper, a fully synthesizable all-digital transmitter (ADTX) is first proposed. This transmitter (TX) uses Cartesian architecture and supports wide-band quadratic-amplitude modulation with wide carrier frequency range. Furthermore, the design methodology for ADTX and corresponding bandpass filter is discussed. This TX is synthesized with digital register transfer level-graphic database system flow, and can be easily implemented in any standard CMOS technology. An exemplary TX is synthesized by TSMC 28-nm standard cell library with extremely small area (0.0009 mm(2)) and supports carrier frequency as high as 6 GHz with excellent error vector magnitude (<-30 dB). To the best of the authors' knowledge, this is the first work on a fully synthesizable design of RF transistors, allowing easy technology migration and portability.
Analytical Clustering Score with Application to Postplacement Register Clustering
(2016-07)
Xu, Chang
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Luo, Guojie
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Li, Peixin
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Shi, Yiyu
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Jiang, Iris Hui-Ru
Circuit clustering is usually done through discrete optimizations to enable circuit size reduction or design-specific cluster formation. In this article, we are interested in the register-clustering technique for clock-power reduction by leveraging new opportunities introduced by multibit flip-flop (MBFF). Currently, INTEGRA is the only existing postplacement MBFF clustering optimizer with a subquadratic time complexity. However, it severely degrades the wirelength, especially for realistic designs, which may nullify the benefits of MBFF clustering. In contrast, we formulate an analytical clustering score with a nonlinear programming framework, in which the wirelength objective can be seamlessly integrated and the solver has empirical subquadratic time complexity. With the MBFF library, the application of our analytical clustering method achieves comparable clock power to the state-of-the-art techniques, but further reduces the wirelength by about 25%. Even without the MBFF library, we can still achieve 30% clock wirelength reduction. In addition, the proposed method can potentially be integrated into an in-placement MBFF clustering solver and be applied to other problems that require formulating clustering scores in their objective functions.
Fast and Accurate Emissivity and Absolute Temperature Maps Measurement for Integrated Circuits
(2014)
Yu, Hsueh-Ling
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Li, Yih-Lang
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Liao, Tzu-Yi
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Wang, Tianchen
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Shi, Yiyu
The comparison of temperatures (temperature correlation) obtained by measuring instruments and by thermal simulation is commonly necessary. Currently the way in which thermal maps are obtained by infrared thermographer yields inaccurate results since the emissivity values of all elements in an IC are ignored and measurement method assumes a constant emissivity. Without the correct settings of emissivity in infrared thermographer, the temperature variation could reach up to as high as 300 %. Coating black paint on the IC surface is a widely used method to assume the IC with constant emissivity and simplify the measurement procedures. Coating a uniform black thin film on an IC is a highly skillful technique and the coated black paint is un-removable. In certain cases, it is not convenient or possible to do so - for example, as monitoring a working chip. This article proposes the first practical and feasible method for emissivity map measurement. Two reference plates are utilized to obtain an emissivity map, from which real emissivity value of each pixel of the infrared thermographer is obtained. Firstly the radiances of IC and two reference plates are measured by the infrared thermographer. After that, the emissivity map of the IC can be calculated by the radiances. According to the experimental results herein, the uncertainty in the emissivity measured using this method is very low, of the order of 0.01, consistent with the minimum resolution of all currently available infrared thermographic instruments. With the emissivity map, the high accuracy temperature map is then obtained. The comparison of the temperature maps simulated by the extend version of Noxim (Access Noxim) as well as measured by the thermographer with constant emissivity and with the accurate emissivity map are presented in this article. This work contributes to the field of thermal analysis and simulation. Accurate circuit characteristics can be obtained through accurate thermal map; on the other hand, the closeness between the thermal simulation result and the real thermal map can also be realized.
Fast and Accurate Emissivity and Absolute Temperature Maps Measurement for Integrated Circuits
(2018-05-01)
Yu, Hsueh-Ling
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Li, Yih-Lang
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Liao, Tzu-Yi
;
Wang, Tianchen
;
Tsai, Shu-Fei
The comparison of temperatures between measurement and simulation (i.e., temperature correlation) is commonly needed in many thermal studies. However, existing methods to measure temperature maps are either inaccurate or inconvenient due to various assumptions or measurement conditions needed. It still remains a missing piece in the literature how to accurately and flexibly measure temperature maps. Toward this, we propose a practical and feasible method for emissivity map measurement. Two reference plates are utilized to obtain an emissivity map, from which real emissivity value of each pixel of the infrared thermographer is obtained. According to the experimental results herein, the deviation of the emissivity measured using this method is on the order of 0.01, consistent with the minimum resolution of all currently available infrared thermographic instruments. With the emissivity map, highly accurate temperature map is then obtained. The method can be flexibly applied to various test samples whether the emissivity of the test sample changes with the wavelength or not. Experimental results on real ICs indicate that compared with commonly used infrared thermographer with uniform emissivity setting or black coating approaches, our method can obtain significantly better temperature correlation.
Memcomputing: the Cape of Good Hope
(2014-01-01)
Shi, Yiyu
;
Chen, Hung-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics