Akihiko Chiba

Variable supply-voltage scheme for low-power high-speed CMOS digital design

This paper describes a variable supply-voltage (VS) scheme. From an external supply, the VS scheme automatically generates minimum internal supply voltages by feedback control of a buck converter, a speed detector, and a timing controller so that they meet the demand on its operation frequency. A 32-b RISC core processor is developed in a 0.4-/spl mu/m CMOS technology which optimally controls the internal supple voltages with the VS scheme and the threshold voltages through substrate bias control. Performance in MIPS/W is improved by a factor of more than two compared with its conventional CMOS design.

Plasma Free Amino Acid Profiling of Five Types of Cancer Patients and Its Application for Early Detection

Background Recently, rapid advances have been made in metabolomics-based, easy-to-use early cancer detection methods using blood samples. Among metabolites, profiling of plasma free amino acids (PFAAs) is a promising approach because PFAAs link all organ systems and have important roles in metabolism. Furthermore, PFAA profiles are known to be influenced by specific diseases, including cancers. Therefore, the purpose of the present study was to determine the characteristics of the PFAA profiles in cancer patients and the possibility of using this information for early detection. Methods and Findings Plasma samples were collected from approximately 200 patients from multiple institutes, each diagnosed with one of the following five types of cancer: lung, gastric, colorectal, breast, or prostate cancer. Patients were compared to gender- and age- matched controls also used in this study. The PFAA levels were measured using high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)–mass spectrometry (MS). Univariate analysis revealed significant differences in the PFAA profiles between the controls and the patients with any of the five types of cancer listed above, even those with asymptomatic early-stage disease. Furthermore, multivariate analysis clearly discriminated the cancer patients from the controls in terms of the area under the receiver-operator characteristics curve (AUC of ROC >0.75 for each cancer), regardless of cancer stage. Because this study was designed as case-control study, further investigations, including model construction and validation using cohorts with larger sample sizes, are necessary to determine the usefulness of PFAA profiling. Conclusions These findings suggest that PFAA profiling has great potential for improving cancer screening and diagnosis and understanding disease pathogenesis. PFAA profiles can also be used to determine various disease diagnoses from a single blood sample, which involves a relatively simple plasma assay and imposes a lower physical burden on subjects when compared to existing screening methods.

A 200 MHz 13 mm/sup 2/ 2-D DCT macrocell using sense-amplifying pipeline flip-flop scheme

The two-dimensional discrete cosine transform (2D DCT) has been widely recognized as a key processing unit for image data compression/decompression. In this paper, the implementation of a 200 MHz 13.3 mm/sup 2/ 8/spl times/8 2-D DCT macrocell capable of HDTV rates, based on a direct realization of the DCT, and using distributed arithmetic is presented. The macrocell, fabricated using 0.8 /spl mu/m base-rule CMOS technology and 0.5 /spl mu/m MOSFETs, performs the DCT processing with 1 sample-(pixel)-per-clock throughput. The fast speed and small area are achieved by a novel sense-amplifying pipeline flip-flop (SA-F/F) circuit technique in combination with nMOS differential logic. The SA-F/F, a class of delay flip-flops, can be used as a differential synchronous sense-amplifier, and can amplify dual-rail inputs with swings lower than 100 mV. A 1.6 ns 20 bit carry skip adder used in the DCT macrocell, which was designed by the same scheme, is also described. The adder is 50% faster and 30% smaller than a conventional CMOS carry look ahead adder, which reduces the macrocell size by 15% compared to a conventional CMOS implementation. >

A 60 mW MPEG4 video codec using clustered voltage scaling with variable supply-voltage scheme

This MPEG4 video codec implements essential functions in the MPEG4 committee draft. It consumes 60 mW at 30 MHz, 30% of the power dissipation of a conventional CMOS design. Measured power dissipation is summarized. 70% power reduction is achieved by low-power techniques at circuit and architectural levels. A 16b RISC processor provides software programmability. Binary shape decoding uses 20% of the computation power of the RISC processor at 30MHz clock, with negligible increase in chip power dissipation. Three-step hierarchical motion estimation reduces power dissipation.

A top-down low power design technique using clustered voltage scaling with variable supply-voltage scheme

A novel design technique which combines a variable supply-voltage scheme and a clustered voltage scaling is presented (VS-CVS scheme). A theory to choose the optimum supply voltages in the VS-CVS scheme is discussed which enables us to perform chip design in a top-down fashion. Level-shifting flip-flops are developed which reduce power, delay and area penalties significantly. Application of this technique to an MPEG4 video codec saves 55% of the power dissipation without degrading circuit performance compared to a conventional CMOS design.

A 300 MIPS/W RISC core processor with variable supply-voltage scheme in variable threshold-voltage CMOS

A 300 MIPS/W RISC core processor with variable supply-voltage (VS) scheme in variable threshold-voltage CMOS (VTCMOS) is presented. Performance in MIPS/W can be improved by a factor of more than two with no modification in the RISC core except for substrate contacts for the VTCMOS. From a 3.3 V external power supply the VS scheme automatically generates minimum internal supply voltages which meet the demand on its operation frequency.

200 MHz video compression macrocells using low-swing differential logic

Improving the performance of fully dedicated macrocells is key to realizing HDTV-resolution video de/compression LSIs operating at more than 100 MHz, having reasonable power consumption and chip size small enough for consumer applications. Existing circuit techniques are either not sufficiently fast or are area consuming. However, these problems are overcome by using low-swing differential logic to realise such macrocells.<<ETX>>

0.5- mu m 3.3-V BiCMOS standard cells with 32-kilobyte cache and ten-port register file

BiCMOS standard cell macros, including a 0.5-W 3-ns register file, a 0.6-W 5-ns 32-kbyte cache, a 0.2-W 3-ns table look-aside buffer (TLB), and a 0.1-W 3-ns adder, are designed with a 0.5- mu m BiCMOS technology. A supply voltage of 3.3 V is used to achieve low power consumption. Several BiCMOS/CMOS circuits, such as a self-aligned threshold inverter (SATI) sense amplifier and an ECL HIT logic are used to realize high-speed operation at the low supply voltage. The performance of the BiCMOS macros is verified using a fabricated test chip. >

Special memory and embedded memory macros in MPEG environment

Special memory and embedded memories used in a newly designed MPEG2 decoder LSI are described. Orthogonal memory is employed in a IDCT (Inverse Discrete Cosine Transform) block for small area and power. FIFOs and other dual-port memories are designed by using a single-port RAM operated twice in one clock cycle to reduce cost. As for testability, direct test mode is implemented for small area. An instruction RAM is placed outside the pad area in parallel to a normal instruction ROM and activated by Al-masterslice for extensive debugging and an early sampling. Other memory related techniques and the key features of the decoder are also described.

Abstract 4633: A novel screening marker for breast cancer composed of plasma free amino acid concentrations “AminoIndex”

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Introduction Amino acids balance is changed in patients of various diseases due to metabolic transition while it is maintained in healthy human. For example, it is known to change in liver dysfunction, renal failure, and cancers. Therefore, it is expected that the detection of metabolic transition using amino acid profiles is a promising screening marker of various cancers. We previously showed significant changes of plasma amino acid profiles and discriminating functions using plasma amino acid concentrations “AminoIndex” in various cancer patients including breast cancer. In this study, further possibilities of “AminoIndex” for breast cancer were investigated by case-control study from multiple medical facilities. Subjects and Methods Plasma samples were collected from Japanese breast cancer patients those were hospitalized in three hospitals and finally diagnosed before any medical treatment (N=295). Those of controls were also collected from subjects who were undergone comprehensive medical examination at two hospitals (N=2,147). Plasma amino acid concentrations were measured by LC-MS. Among them, 90 patients (30 from each hospital) in chronological order and 450 age-matched control subjects were chosen as training data set. And the rest (205 patients and 1,697 controls, respectively) were used as test data set to valid the inferred “AminoIndex”. Using training data set, plasma amino acid concentration were compared and then “AminoIndex”, multivariate logistic regression function composed of plasma amino acid concentrations, was inferred to discriminate breast cancer from control subjects. Results Plasma concentrations of several amino acids were significantly changed in breast cancer patients compared to control subjects. Predicted “AminoIndex” for breast cancer was resulted the multivariate logistic function composed with six amino acids. To evaluate the performance of the index predicted, the ROC curve for each predictive score was calculated, and this gave an AUC of ROC of 0.764 using the study data. Then, validation of predicted “AminoIndex” was performed using test data set, resulting almost same diagnostic performance. Furthermore, predicted “AminoIndex” showed notably features; the index could discriminate breast cancer patients almost equally in any stages, and the index showed not only higher discrimination performance than those of existing tumor markers but also distributed independently of the levels of various tumor markers. Therefore, predicted “AminoIndex” would be suitable for screening and early detection of breast cancer patients. Conclusion and Perspectives In this study, we demonstrated that change of plasma amino acid profile would be an indicator of breast cancer and a helpful tool for early detection of breast cancer patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4633.