Ultra-deep submicron technology and system-on-chip have resulted in a considerable portion of power dissipated on buses, in which the major sources of the power dissipation are: 1) the self transition activities on the signal lines and 2) the coupled transition activities of the lines. However, there has been no easy way of optimizing 1 and 2 simultaneously at an early stage of the synthesis process. In this paper, we propose a new (on-chip) bus synthesis algorithm to minimize the total sum of 1 and 2 in the microarchitecture synthesis. Specifically, unlike the previous approaches in which 1 and 2 are minimized sequentially without any interaction between them, or only one of them is minimized, we, given a scheduled dataflow graph to be synthesized, minimize 1 and 2 simultaneously by formulating and solving the two important issues in an integrated fashion: binding data transfers to buses and determining a (physical) order of signal lines in each bus, both of which are the most critical factors that affect the results of 1 and 2. Experimental results on a number of benchmark problems show that the proposed integrated low-power bus synthesis algorithm reduces power consumption by 24.8%, 40.3%, and 18.1% on average over those in (Chang and Pedram 1995, for minimizing 1 only), (Shin and Sakurai 2001, for 2 only) and (Shin and Sakurai 2001 and Chang and Pegram 1995, for 1 and then 2), respectively.

Low threshold voltage (V/sub t/) can be applied to domino logic to improve the performance in dual threshold voltage technology. Then, the keeper transistor should be up-sized to compensate for reduced noise margin due to the significant subthreshold current of low V/sub t/ transistor. However, a large keeper transistor degrades performance. To resolve the tradeoff between performance and noise margin, the authors propose a new domino logic which incorporates a dual keeper structure and delay logic gates. Detailed timing analysis of the proposed domino logic yields optimal timing conditions wherein a contention-free skew-tolerant window is maximized. A broad range of the skew-tolerant window connotes robustness against noise and design parameter variations, while reduced contention between keeper and evaluation NMOS transistors ensures high-speed switching. The authors show that the dual keeper structure increases noise tolerance and delay logic gates fortify signal skew tolerance. Simulation results verify that the proposed domino logic is robust to noise and signal skew while presenting high performance and power efficiency.

Electrostatic discharge (ESD) accounts for over 30% of chip failure which occurred during chip manufacturing. Inadvertent touching by human body or contact with assembler tray can lead to such ESD failures. The most dominant ESD model is the charged-device model (CDM) wherein energy-destructive failure is incorporated resulting from rapid inflow, or outflow, of high current. Conventional modeling and simulations of the CDM are engineered to describe the behavior of ESD protection circuits, hence have a limitation to account for chip-level charge transfer. This paper presents a new methodology to simulate CDM behavior at chip level. A hierarchical approach associated with a CDM macromodel is developed to model a full-chip structure comprised of several functional subsystems and multiple power supplies. Full-chip CDM simulation provides the analysis of chip-level discharge paths and failure mechanisms, especially focusing on the gate oxide reliability. The proposed method can easily be applied to the CDM failure analysis of any product ICs in the early design stage. As an example, simulation results of a mixed-signal application-specific integrated circuit processed in a 0.25-/spl mu/m CMOS technology show high correlation with the measurement data.

Minimum delay associated with the hold time requirement is of concern to circuit designers, since race-through hazards are inherent in any multiple clock organization or clock distribution tree irrespective of clock frequency. The monotonic property of domino logic aggravates the min-delay path failure through coupling-induced speedup. To tackle the min-delay problem for domino logic, we propose a min-delay optimization algorithm considering coupling effects. Experimental results indicate that our algorithm yields a significant increase of min-delay without incurring max-delay violation.

Coupling effect due to line-to-line capacitance is of serious concern in timing analysis of circuits in ultra deep submicrometer CMOS technology. Often coupling delay is heavily dependent on temporal correlation of signal switching in relevant wires. Temporal decorrelation by shifting timing window can alleviate performance degradation induced by tight coupling. This paper presents an algorithm for minimizing circuit delay through timing window modulation in dual V/sub t/ technology. Experimental results on the ISCAS85 benchmark circuits indicate that the critical delay will be reduced significantly when low V/sub t/ is applied properly.

Realization of high-performance domino logic depends strongly on energy-efficient and noise-tolerant interconnect design in ultradeep submicrometer processes. We characterize the cycle-averaged power model for interconnects accounting for switching statistics and dynamic behaviors. For the sake of signal integrity, cross-coupling effects are also characterized, which reflect logical correlation between adjacent wires. Based on the new models for interconnect power and capacitive crosstalk, we optimize the coupling power consumed by interconnects with crosstalk constraints. Experimental results show that optimized designs save the power consumption about 14% on average.

In this paper, we describe skewed static logic (S/sup 2/L) with topology-dependent dual Vt which exhibits an energy-efficient operation. S/sup 2/L consumes less dynamic and static power compared to monotonic static (MS) CMOS. Speed degradation of S/sup 2/L, if any, can be offset by an accelerator circuit. We have designed NAND-NOR gate chains using 0.18-/spl mu/m CMOS technology and verified that S/sup 2/L reduces energy-delay product over MS CMOS by 27%-50%. We have also designed 32-b carry-lookahead adders and verified that S/sup 2/L with dual Vt reduces delay by 43% and energy-delay product by 31% for 1-V power supply over conventional CMOS circuit. Synthesis algorithm for S/sup 2/L is developed and the experimental results show S/sup 2/L consumes 23% less power than MS CMOS with minor increase in delay.

High-speed domino logic is now prevailing in performance critical block of a chip. Low Voltage Swing Clock (LVSC) domino logic family is developed for substantial dynamic power saving. To boost up the transition speed in proposed circuitry, a well-established dual threshold voltage technique is exploited. Dual supply voltage technique in the LVSC domino logic is geared to reduce power consumption in clock tree and logic gates effectively. Delay Constrained Power Optimization (DCPO) algorithm allocates low supply voltage to logic gates such that dynamic power consumed by logic gates is minimized. Delay time variations due to gate-to-source voltage change and and input signal arrival time difference are considered for accurate timing analysis in DCPO.

A novel tool for full-chip verification is reported for CDM-ESD protection. Until recently, ESD protection has been simulated in device level, leading to the well known limitations on capturing global features such as the power protection circuits and package parasitics. In practice, fatal failures occur due to unexpected discharged paths in multi-power supply chips, which can only be verified by chip-level simulation. Associated with the new concept of macromodelling, hierarchical approach provides effective analysis methodology for mixed-signal chips. The hierarchical approach provides the analysis of chip-level discharging paths and reliability of gate oxide. Simulation results on a CMOS ASIC chip processed in a 0.25-μ technology are in accordance with the measurement data. Scanning electron microscope locates a gate oxide fault as our analysis predicted.

We introduce a new dual threshold voltage technique for domino logic. Since domino logic is much more sensitive to noise, noise margins have to be taken into account when applying dual threshold voltages to domino logic. To guarantee the signal integrity in domino logic, we carefully consider the effect of transistor sizing and threshold voltage selection. For optimal design, tradeoffs need to be mad? among noise margin, power, and performance. Based on the characteristics of each logic gate, we propose noise and power constrained domino logic synthesis for high performance. ISCAS85 benchmark re sults show that performance can be improved up to 18.62%, with 2% active power increase, while maintaining noise margin.

Ultra deep submicron (UDSM) technology and system-on-chip (SoC) have resulted in a considerable portion of power dissipated on buses, in which the major sources of the power dissipation are (1) the transition activities on the signal lines and (2) the coupling capacitances of the lines. However, there has been no easy way of optimizing (1) and (2) simultaneously at an early stage of the synthesis process. In this paper, we propose a new (on-chip) bus synthesis algorithm to minimize the total sum of (1) and (2) in the microarchitecture synthesis. Specifically, unlike the previous approaches in which (1) and (2) are minimized sequentially without any interaction between them, or only one of them is minimized, we, given a scheduled dataflow graph to be synthesized, minimize (1) and (2) simultaneously by formulating and solving the two important issues in an integrated fashion: binding data transfers to buses and determining a (physical) order of signal lines in each bus, both of which are the most critical factors that affect the results of (1) and (2). Experimental results on a number of benchmark problems show that the proposed integrated low-power bus synthesis algorithm reduces power consumption by 24.8%, 40.3% and 18.1% on average over those in [12] (for minimizing (1) only), [1] (for (2) only) and [12, 1] (for (1) and then (2)), respectively.

In this paper, we present a new approach to the problem of inverter elimination in domino logic synthesis. A small piece of static CMOS logic is introduced to the circuit to avoid significant area penalty resulting from duplication. To maximize the domino logic part and to minimize the static CMOS logic part, a generalized automatic test pattern generation (ATPG)-based logic transformation is proposed to eliminate or relocate a target inverter. Based on the new concept of dominating set of mandatory assignment (DSMA) and the corresponding implication graph, we propose algorithms to identify a minimum candidate set for a target inverter. Experimental results show that logic transformation based on the implication graph can reduce transistor counts by 25% on average, while the delay increases less than 3%.

In this article we present a new approach to the problem of local logic transformation for reducing power dissipation in logic circuits. The proposed approach overcomes one of the critical limitations common to the previous approaches of local logic transformations for low power, namely, a sequential greedy transformation that identifies signals with high switching activities and then resynthesizes the signals one by one. Instead, we identify a set of signal lines as a group for logic transformation, and determine an order of transformation of the signals with the maximum reduction of power dissipation in the circuit. As a practically feasible solution to this problem, we develop a power model called a finite state input transition (FIT) model, which allows the efficient measurement of the change of power dissipation of the circuit for every possible sequence of logic transformations among the signal lines. Experimental results show that the proposed approach performs an extensive local logic transformation, reducing power consumption by 33% on average without any increase of circuit delay.

Dynamic logic is susceptible to noise, especially in the ultra-deep submicrometer dual threshold voltage technology. When the dual threshold voltage is applied to the domino logic, noise immunity must be carefully considered since the significant subthreshold current of the low threshold voltage transistor makes the dynamic node much more susceptible to noise. In the first part of this paper, we introduce a new keeper transistor sizing method to determine the optimal keeper transistor size in terms of speed, power, and noise immunity. With the use of data obtained by presimulation, it is unnecessary to simulate all the design corners corresponding to the feasible NMOS evaluation transistor size ranges to find the optimal keeper transistor size. HSPICE simulation results show that the proposed keeper transistor sizing method can be broadly applied to all the domino logic gates. In the second part of this paper, we propose a new dual threshold voltage domino logic synthesis with the keeper transistor sizing to minimize the power consumption while meeting delay and noise constraints. With the optimal keeper transistor size determined by the proposed keeper transistor sizing method, the dual threshold voltage assignment to domino logic can be simplified to the discrete threshold voltage selection. Experimental results for ISCAS85 benchmark circuits show significant savings on leakage power and active power.

Coupling effect due to line-to-line capacitance is of serious concern in timing analysis of circuits in ultra deep submicron CMOS technology. Often coupling delay is strongly dependent on temporal correlation of signal switching in relevant wires. Temporal decorrelation by shifting timing window can alleviate performance degradation induced by tight coupling. This paper presents an algorithm for minimizing circuit delay through timing window modulation in dual $V_t$ technology. Experimental results on the ISCAS85 benchmark circuits indicate that the critical delay will be reduced significantly when low $V_t$ is applied properly.

Dynamic logic is much susceptible to noise specially in ul tra deep submicron technology The keeper transistor has to be carefully sized to maintain noise margin without much speed penalty In this paper we analyze the keeper tran sistor sizing with respect to the size of NMOS transistors in the evaluation tree Based on the analytical results we propose a keeper transistor sizing method HSPICE simula tion results show that the proposed keeper transistor sizing method can be broadly applied to all domino logic gates

Based on the new concept of crosstalk immunity set (CIS), procedures to minimize capacitive crosscoupling effects are developed for domino logic circuit. The nets in a CIS are by definition free from capacitive crosscoupling effects in any combination of input vectors. New algorithms for CIS identification and CIS-driven phase assignment are proposed to maximize the chance of crosstalk minimization in routing step. Our routing algorithm augmented with CIS information searches for optimal solution to minimize maximum crosstalk the circuit would experience. Experimental results show that the reduction of maximum crosstalk is as much as 30% with CIS-augmented routing.

Based on the new concept of crosstalk immunity set (CIS), procedures to minimize capacitive cross-coupling effects are developed for domino logic circuit. The nets in a crosstalk immunity set are free from crosstalk effects for any combination of input vectors. New algorithms for CIS identification and minimization are proposed to maximize the chance of crosstalk minimization in routing step. Our routing algorithm augmented with CIS information searches for optimal solution to minimize maximum crosstalk the circuit would experience. Experimental results show that the reduction of maximum crosstalk is up to 30% with CIS-augmented routing.

Coupling effects between on-chip interconnects must be addressed in ultra deep submicron VLSI and system-on-a-chip (SoC) designs. A new low-power bus encoding scheme is proposed to minimize coupled switchings which dominate the on-chip bus power consumption. The coupling-driven bus invert method use slim encoder and decoder architecture to minimize the hardware overhead. Experimental results indicate that our encoding methods save effective switchings as much as 30% in an 8-bit bus with one-cycle redundancy.

Realization of high-performance domino logic depends strongly on energy-efficient and noise-tolerant interconnect design in ultra deep sub-micron processes. We characterize the cycle-averaged power model for interconnects accounting for switching statistics and dynamic behaviors. For the sake of signal integrity, cross-coupling effects are also characterized which reflect logical correlation between adjacent wires. Based on the new models for interconnect power and capacitive crosstalk, we optimize the coupling power consumed by interconnects with crosstalk constraints. Experimental results show that optimized designs save the power consumption significantly.

In this paper we present a new approach to the problem of local logic transformation for reduction of power dissipation in logic circuits. Based on the finite-state input transition (FIT) power dissipation model, we introduce a cost function which accounts for the effects of input capacitance, input slew rate, internal parasitic capacitance of logic gates, interconnect capacitance, as well as switching power. Our approach provides an efficient way of estimating estimating the global effect of local logic transformations in logic circuits. In our approach, the FIT model for the transitive fanout cells of a locally transformed subcircuit can be reused to measure the global power dissipation by varying the input probabilities of the transitive fanout cells. Local logic transformation is carried our based on compatible sets of permissible functions (CSPF). Experimental results show that local logic transformation based on CSPF using our cost function can reduce power consumption by about 36% on average without increase in the worst-case circuit delay.

In this paper, we present a new approach to the problem of inverter elimination in domino logic synthesis. A small piece of static CMOS logic is introduced to the circuit to avoid significant area penalty resulting from duplication. To maximize the domino logic part and to minimize the static CMOS logic part, a generalized ATPG based logic transformation is proposed to eliminate or relocate a target inverter. Based on the new concept of dominating set of mandatory assignment (DSMA) and the corresponding implication graph, we propose algorithms to identify a minimum candidate set for a target inverter. Experimental results show that logic transformation based on an implication graph can reduce transistor counts by 25% and power delay product by 25% on average.

To provide efficient search and retrieval of video data from large archives, we need to model video data appropriately. We propose a video data model and describe the design and implementation of the annotation-based video retrieval system VIRON (Video Information Retrieval On Notation) based on the proposed model. This model provides the mechanism of sharing and reusing annotations among users by introducing descriptor schema. In order to process a query efficiently, an annotated video unit is mapped into a unified video annotation stream. VIRON is composed of three tools: CVU manager, which is used to manage and visualize conceptual video units; annotator to annotate video data by offering an interactive video player; and a video query tool to pose and process video queries.