Shota ISHIHARA Noriaki IDOBATA Masanori HARIYAMA Michitaka KAMEYAMA
Dynamically Programmable Gate Arrays (DPGAs) provide more area-efficient implementations than conventional Field Programmable Gate Arrays (FPGAs). One of typical DPGA architectures is multi-context architecture. An DPGA based on multi-context architecture is Multi-Context FPGA (MC-FPGA) which achieves fast switching between contexts. The problem of the conventional SRAM-based MC-FPGA is its large area and standby power dissipation because of the large number of configuration memory bits. Moreover, since SRAM is volatile, the SRAM-based multi-context FPGA is difficult to implement power-gating for standby power reduction. This paper presents an area-efficient and nonvolatile multi-context switch block architecture for MC-FPGAs based on a ferroelectric-capacitor functional pass-gate which merges a multiple-valued threshold function and a nonvolatile multiple-valued storage. The test chip for four contexts is fabricated in a 0.35 µm-CMOS/0.60 µm-ferroelectric-capacitor process. The transistor count of the proposed multi-context switch block is reduced to 63% in comparison with that of the SRAM-based one.
Naoya ONIZAWA Takahiro HANYU Vincent C. GAUDET
This paper presents a high-throughput bit-serial low-density parity-check (LDPC) decoder that uses an asynchronous interleaver. Since consecutive log-likelihood message values on the interleaver are similar, node computations are continuously performed by using the most recently arrived messages without significantly affecting bit-error rate (BER) performance. In the asynchronous interleaver, each message's arrival rate is based on the delay due to the wire length, so that the decoding throughput is not restricted by the worst-case latency, which results in a higher average rate of computation. Moreover, the use of a multiple-valued data representation makes it possible to multiplex control signals and data from mutual nodes, thus minimizing the number of handshaking steps in the asynchronous interleaver and eliminating the clock signal entirely. As a result, the decoding throughput becomes 1.3 times faster than that of a bit-serial synchronous decoder under a 90 nm CMOS technology, at a comparable BER.
Shangce GAO Qiping CAO Catherine VAIRAPPAN Jianchen ZHANG Zheng TANG
This paper describes an improved local search method for synthesizing arbitrary Multiple-Valued Logic (MVL) function. In our approach, the MVL function is mapped from its algebraic presentation (sum-of-products form) on a multiple-layered network based on the functional completeness property. The output of the network is evaluated based on two metrics of correctness and optimality. A local search embedded with chaotic dynamics is utilized to train the network in order to minimize the MVL functions. With the characteristics of pseudo-randomness, ergodicity and irregularity, both the search sequence and solution neighbourhood generated by chaotic variables enables the system to avoid local minimum settling and improves the solution quality. Simulation results based on 2-variable 4-valued MVL functions and some other large instances also show that the improved local search learning algorithm outperforms the traditional methods in terms of the correctness and the average number of product terms required to realize a given MVL function.
Nobuaki OKADA Michitaka KAMEYAMA
A fine-grain reconfigurable VLSI for various applications including arithmetic operations is developed. In the fine-grain architecture, it is important to define a cell function which leads to high utilization of a logic block and reduction of a switch block. From the point of view, a universal-literal-based multiple-valued cell suitable for bit-serial reconfigurable computation is proposed. A series-gating differential-pair circuit is effectively employed for implementing a full-adder circuit of Sum and a universal literal circuit. Therefore, a simple logic block can be constructed using the circuit technology. Moreover, interconnection complexity can be reduced by utilizing multiple-valued signaling, where superposition of serial data bits and a start signal which indicates heading of one-word is introduced. Differential-pair circuits are also effectively employed for current-output replication, which leads to high-speed signaling to adjacent cells The evaluation is done based on 90 nm CMOS design rule, and it is made clear that the area of the proposed cell can be reduced to 78% in comparison with that of the CMOS implementatiuon. Moreover, its area-time product becomes 92% while the delay time is increased by 18%.
In this paper, a multiple-valued current-mode (MVCM) circuit based on active-load dual-rail differential logic is proposed for a high-performance arithmetic VLSI system with crosstalk-noise immunity. The use of dual-rail complementary differential-pair circuits (DPCs), whose outputs are summed up by wiring makes it possible to reduce the common-mode noise, and yet enhance the switching speed. By using the diode-connected cross-coupled PMOS active loads, the rapid transition of switching in the DPC is relaxed appropriately, which can also eliminate spiked input noise. It is demonstrated that the noise reduction ratio and the switching delay of the proposed MVCM circuit in a 90 nm CMOS technology is superior to those of the corresponding ordinary implementation.
Kazuyasu MIZUSAWA Naoya ONIZAWA Takahiro HANYU
This paper presents a design of an asynchronous peer-to-peer half-duplex/full-duplex-selectable data-transfer system on-chip interconnected. The data-transfer method between channels is based on a 1-phase signaling scheme realized by using multiple-valued current-mode (MVCM) circuits and encoding, which performs high-speed communication. A data transmission is selectable by adding a mode-detection circuit that observes data-transmission modes; full-duplex, half-duplex and standby modes. Especially, since current sources are completely cut off during the standby mode, the power dissipation can be greatly reduced. Moreover, both half-duplex and full-duplex communication can be realized by sharing a common circuit except a signal-level conversion circuit. The proposed interface is implemented using 0.18-µm CMOS, and its performance improvement is discussed in comparison with those of the other ordinary asynchronous methods.
Qiping CAO Shangce GAO Jianchen ZHANG Zheng TANG Haruhiko KIMURA
In this paper, we propose a stochastic dynamic local search (SDLS) method for Multiple-Valued Logic (MVL) learning by introducing stochastic dynamics into the traditional local search method. The proposed learning network maintains some trends of quick descent to either global minimum or a local minimum, and at the same time has some chance of escaping from local minima by permitting temporary error increases during learning. Thus the network may eventually reach the global minimum state or its best approximation with very high probability. Simulation results show that the proposed algorithm has the superior abilities to find the global minimum for the MVL network learning within reasonable number of iterations.
Akira MOCHIZUKI Hirokatsu SHIRAHAMA Takahiro HANYU
This paper presents a high-speed 5454-bit multiplier using fully differential-pair circuits (DPCs) in 0.18 µm CMOS. The DPC is a key component in maintaining an input signal-voltage swing of 0.2 V while providing a large current-driving capability. The combination of the DPC and the multiple-valued current-mode linear summation makes the critical path shortened and transistor counts reduced. The multiplier has an estimated multiply time of 1.88 ns with 74.2 mW at 400 MHz from a 1.8 V supply occupying a 0.85 mm2 active area.
Naofumi HOMMA Takafumi AOKI Tatsuo HIGUCHI
This paper presents an algorithm-level interpretation of fast adder structures in binary/multiple-valued logic. The key idea is to employ a unified representation of addition algorithms called Counter Tree Diagrams (CTDs). The use of CTDs makes it possible to describe and analyze addition algorithms at various levels of abstraction. A high-level CTD represents a network of coarse-grained components associated with multiple-valued logic devices, while a low-level CTD represents a network of primitive components directly mapped onto binary logic devices. The level of abstraction in circuit representation can be changed by decomposition of CTDs. We can derive possible variations of adder structures by decomposing a high-level CTD into low-level CTDs. This paper demonstrates the interpretation of redundant arithmetic adders based on CTDs. We first introduce an extension of CTDs to represent possible redundant arithmetic adders with limited carry propagation. Using the extended version of CTDs, we can classify the conventional adder structures including those using emerging devices into three types in a systematic way.
Akira MOCHIZUKI Hirokatsu SHIRAHAMA Takahiro HANYU
A new static storage component, a quaternary flip-flop which consists of two-bit storage elements and three four-level voltage comparators, is proposed for a high-performance multiple-valued VLSI-processor datapath. A key circuit, a differential-pair circuit (DPC), is used to realize a high-speed multi-level voltage comparator. Since PMOS cross-coupled transistors are utilized as not only active loads of the DPC-based comparator but also parts of each storage element, the critical delay path of the proposed flip-flop can be shortened. Moreover, a dynamic logic style is also used to cut steady current paths through current sources in DPCs, which results in great reduction of its power dissipation. It is evaluated with HSPICE simulation in 0.18 µm CMOS that the power dissipations of the proposed quaternary flip-flop is reduced to 50 percent in comparison with that of a corresponding binary CMOS one.
Hajime SAWAMURA Takehisa TAKAHASHI
In our former paper, we formalized a Logic of Multiple-valued Argumentation (LMA) on an expressive knowledge representation language, Extended Annotated Logic Programming (EALP), in order to make it possible to construct arguments under uncertain information. In this paper, We confirm expressivity and applicability by applying LMA to arguments reflecting Easterners' preference over argumentation as well as Eastern thought and philosophy. In doing so, we exploit a wide variety of complete lattices as truth-values, showing the flexibility and adaptability of LMA to various multiple-valuedness required in argumentation under uncertain information. In particular, we consider a significant specialization of LMA to Tetralemma with an Eastern mind. Through various argument examples, it is shown that LMA allows for a kind of pluralistic argumentation, or a fusion of Eastern and Western argumentation.
Katsuhiko DEGAWA Takafumi AOKI Tatsuo HIGUCHI Hiroshi INOKAWA Yasuo TAKAHASHI
This paper presents a model-based study of SET (Single-Electron-Transistor) logic gate family for synthesizing binary, MV (Multiple-Valued) and mixed-mode logic circuits. The use of SETs combined with MOS transistors allows compact realization of basic logic functions that exhibit periodic transfer characteristics. The operation of basic SET logic gates is successfully confirmed through SPICE circuit simulation based on the physical device model of SETs. The proposed SET logic gates are useful for implementing binary logic circuits, MV logic circuits and binary-MV mixed-mode logic circuits in a highly flexible manner. As an example, this paper describes design of various parallel counters for carry-propagation-free arithmetic, where MV signals are effectively used to achieve higher functionality with lower hardware complexity.
Md.Munirul HAQUE Michitaka KAMEYAMA
A novel Multiple-Valued Field-Programmable VLSI (MV-FPVLSI) architecture using the Multiple-Valued Source-Coupled Logic (MVSCL) is proposed to implement special-purpose processors. An MV-FPVLSI consists of identical cells, which are connected to 8-neighborhood ones. To reduce the complexity of the interconnection block between two cells in an MV-FPVLSI, a bit-serial fine-grain pipeline architecture is introduced which allows single-wire data transmission and as a result, the data-transmission delay becomes very small in comparison with that of a conventional FPGA. To reduce the number of switches in the interconnection block further, a cell, using multiple-valued source-coupled logic circuits, is proposed, where the input currents can be linearly summed just by wiring without using any active devices. Not only the data, but also the control signal can be superposed by linear summation. As a result, no input switch is required which contributes to smaller data transmission delay. Moreover, an arbitrary 2-input logic function can be generated by linear summation of the input currents and threshold operations using these reconfigurable MVSCL circuits. As the MVSCL circuit has high driving capability in comparison with that of an equivalent CMOS circuit, high-speed logic operation is also possible while maintaining low power.
Hiroshi INOKAWA Yasuo TAKAHASHI Katsuhiko DEGAWA Takafumi AOKI Tatsuo HIGUCHI
This paper introduces a methodology for simulating single-electron-transistor (SET)-based multiple-valued logics (MVLs). First, a physics-based analytical model for SET is described, and then a procedure for extracting parameters from measured characteristics is explained. After that, simulated and experimental results for basic MVL circuits are compared. As an advanced example of SET-based logics, a latched parallel counter, which is one of the most important components in arithmetic circuits, is newly designed and analyzed by a simulation. It is found that a SET-based 7-3 counter can be constructed with less than 1/10 the number of devices needed for a conventional circuit and can operate at a moderate speed with 1/100 the conventional power consumption.
Ioannis M. THOIDIS Dimitrios SOUDRIS Adonios THANAILAKIS
Novel designs of multiple-valued logic (quaternary) half adder, full adder, and carry-lookahead adder are introduced. The proposed circuits are static and operate in voltage-mode. Moreover, there is no current flow in steady states, and thus, no static power dissipation. Although the comparison in transistor count shows that the proposed quaternary circuits are larger than two respective binary ones, benefits in parallel addition arise from the use of multiple-valued logic. Firstly, the ripple-carry additions are faster because the number of carries is half compared to binary ones and the propagation delay from the input carry through the output carry is relatively small. Secondly, the carry-lookahead scheme exhibits less complexity, which leads to overall reduction in transistor count for addition with large number of bits.
Katsutoshi SAEKI Heisuke NAKASHIMA Yoshifumi SEKINE
In this paper, we propose the CMOS implementation of a multiple-valued memory cell using -shaped negative-resistance devices. We first propose the construction of a multiple-stable circuit that consists of -shaped negative-resistance devices from four enhancement-mode MOSFETs without a floating voltage source, and connect this in parallel with a unit circuit. It is shown that the movement of -shaped negative-resistance characteristics in the direction of the voltage axis is due to voltage sources. Furthermore, we propose the construction of a multiple-valued memory cell using a multiple-stable circuit. It is shown that it is possible to write and hold data. If the power supply is switched on, it has a feature which enables operation without any electric charge leakage. It is possible, by connecting -shaped negative-resistance devices in parallel, to easily increase the number of multiple values.
Katsuhiko DEGAWA Takafumi AOKI Tatsuo HIGUCHI
This paper presents a Field-Programmable Digital Filter (FPDF) IC that employs carry-propagation-free redundant arithmetic algorithms for faster computation and multiple-valued current-mode circuit technology for high-density low-power implementation. The original contribution of this paper is to evaluate, through actual chip fabrication, the potential impact of multiple-valued current-mode circuit technology on the reduction of hardware complexity required for DSP-oriented programmable ICs. The prototype FPDF fabrication with 0.6 µm CMOS technology demonstrates that the chip area and power consumption can be reduced to 41% and 71%, respectively, compared with the standard binary logic implementation.
Qi-Ping CAO Zheng TANG Rong-Long WANG Xu-Gang WANG
This paper describes a new learning method for Multiple-Value Logic (MVL) networks using the local search method. It is a "non-back-propagation" learning method which constructs a layered MVL network based on canonical realization of MVL functions, defines an error measure between the actual output value and teacher's value and updates a randomly selected parameter of the MVL network if and only if the updating results in a decrease of the error measure. The learning capability of the MVL network is confirmed by simulations on a large number of 2-variable 4-valued problems and 2-variable 16-valued problems. The simulation results show that the method performs satisfactorily and exhibits good properties for those relatively small problems.
Noboru TAKAGI Kyoichi NAKASHIMA
The interconnection problem of binary circuits becomes seriously as the exponential growth of the circuits complexity has been driven by a combination of down scaling of the device size and up scaling of the chip size. Motivated by the problem, there is much research of circuits based on multiple-valued logic. On the other hand, caused by the signal propagation delay, there exist hazards in binary logic circuits. To analyze hazards in binary logic circuits, many multiple-valued logics have been proposed, and studied on their mathematical properties. The paper will discuss on a multiple-valued logic which is suitable for treating static hazards in multiple-valued logic circuits. Then, the paper will show that the prime implicants expressions of r-valued logic functions realize static hazards free r-valued logic circuits.
Hiromitsu KIMURA Takahiro HANYU Michitaka KAMEYAMA
This paper presents a multiple-valued logic-in-memory circuit with real-time programmability. The basic component, in which a dynamic storage function and a multiple-valued threshold function are merged, is implemented compactly by using charge storage and capacitive coupling with a DRAM-cell-based circuit structure under a 0.8-µm CMOS technology. The pass-transistor network using these basic components makes it possible to realize any multiple-valued-inputs binary-outputs logic circuits compactly. As a typical example, a fully parallel multiple-valued magnitude comparator is also implemented by using the proposed DRAM-cell-based pass-transistor network. Its execution time and power dissipation are reduced to about 11 percent and 29 percent, respectively, in comparison with those of a corresponding binary implementation. A prototype chip is also fabricated to confirm the basic operation of the proposed DRAM-cell-based logic-in-memory circuit.