arXiv subjects

Ignatius Bezzam

Publications and source records attributed to Ignatius Bezzam.

5 recordsLinked to original sources

arXiv2026

Time--to--Digital Converter (TDC)--Based Resonant Compute--in--Memory for INT8 CNNs with Layer--Optimized SRAM Mapping

In recent years, Compute-in-memory (CiM) architectures have emerged as a promising solution for deep neural network (NN) accelerators. Multiply-accumulate~(MAC) is considered a {\textit de facto} unit operation in NNs. By leveraging the inherent parallel processing capabilities of CiM, NNs that require numerous MAC operations can be executed more efficiently. This is further facilitated by storing the weights in SRAM, reducing the need for extensive data movement and enhancing overall computational speed and efficiency. Traditional CiM architectures execute MAC operations in the analog domain, employing an Analog-to-Digital converter (ADC) to convert the analog MAC values into digital outputs. However, these ADCs introduce significant increase in area and power consumption, as well as introduce non-linearities. This work proposes a resonant time-domain compute-in-memory (TDC-CiM) architecture that eliminates the need for an ADC by using a time-to-digital converter (TDC) to digitize analog MAC results with lower power and area cost. A dedicated 8T SRAM cell enables reliable bitwise MAC operations, while the readout uses a 4-bit TDC with pulse-shrinking delay elements, achieving 1 GS/s sampling with a power consumption of only 1.25 mW. In addition, a weight stationary data mapping strategy combined with an automated SRAM macro selection algorithm enables scalable and energy-efficient deployment across CNN workloads. Evaluation across six CNN models shows that the algorithm reduces inference energy consumption by up to 8x when scaling SRAM size from 32~KB to 256~KB, while maintaining minimal accuracy loss after quantization. The feasibility of the proposed architecture is validated on an 8~KB SRAM memory array using TSMC 28~nm technology. The proposed TDC-CiM architecture demonstrates a throughput of 320~GOPS with an energy efficiency of 38.46~TOPS/W.

eess.SP↗

arXiv2025

TSPC-PFD: TSPC-Based Low-Power High-Resolution CMOS Phase Frequency Detector

Phase Frequency Detectors (PFDs) are essential components in Phase-Locked Loop (PLL) and Delay-Locked Loop (DLL) systems, responsible for comparing phase and frequency differences and generating up/down signals to regulate charge pumps and/or, consequently, Voltage-Controlled Oscillators (VCOs). Conventional PFD designs often suffer from significant dead zones and blind zones, which degrade phase detection accuracy and increase jitter in high-speed applications. This paper addresses PFD design challenges and presents a novel low-power True Single-Phase Clock (TSPC)-based PFD. The proposed design eliminates the blind zone entirely while achieving a minimal dead zone of 40 ps. The proposed PFD, implemented using TSMC 28 nm technology, demonstrates a low-power consumption of 4.41 uW at 3 GHz input frequency with a layout area of $10.42\mu m^2$.

cs.ET↗

arXiv2024

Architectural Exploration of Application-Specific Resonant SRAM Compute-in-Memory (rCiM)

While general-purpose computing follows Von Neumann's architecture, the data movement between memory and processor elements dictates the processor's performance. The evolving compute-in-memory (CiM) paradigm tackles this issue by facilitating simultaneous processing and storage within static random-access memory (SRAM) elements. Numerous design decisions taken at different levels of hierarchy affect the figure of merits (FoMs) of SRAM, such as power, performance, area, and yield. The absence of a rapid assessment mechanism for the impact of changes at different hierarchy levels on global FoMs poses a challenge to accurately evaluating innovative SRAM designs. This paper presents an automation tool designed to optimize the energy and latency of SRAM designs incorporating diverse implementation strategies for executing logic operations within the SRAM. The tool structure allows easy comparison across different array topologies and various design strategies to result in energy-efficient implementations. Our study involves a comprehensive comparison of over 6900+ distinct design implementation strategies for EPFL combinational benchmark circuits on the energy-recycling resonant compute-in-memory (rCiM) architecture designed using TSMC 28 nm technology. When provided with a combinational circuit, the tool aims to generate an energy-efficient implementation strategy tailored to the specified input memory and latency constraints. The tool reduces 80.9% of energy consumption on average across all benchmarks while using the six-topology implementation compared to baseline implementation of single-macro topology by considering the parallel processing capability of rCiM cache size ranging from 4KB to 192KB.

cs.AR↗

arXiv2022

Power and Skew Reduction Using Resonant Energy Recycling in 14-nm FinFET Clocks

As the demand for high-performance microprocessors increases, the circuit complexity and the rate of data transfer increases resulting in higher power consumption. We propose a clocking architecture that uses a series LC resonance and inductor matching technique to address this bottleneck. By employing pulsed resonance, the switching power dissipated is recycled back. The inductor matching technique aids in reducing the skew, increasing the robustness of the clock network. This new resonant architecture saves over 43% power and 91% skew clocking a range of 1--5 GHz, compared to a conventional primary-secondary flip-flop-based CMOS architecture.

eess.SY↗

arXiv2020

Resonant Energy Recycling SRAM Architecture

Although we may be at the end of Moore's law, lowering chip power consumption is still the primary driving force for the designers. To enable low-power operation, we propose a resonant energy recovery static random access memory (SRAM). We propose the first series resonance scheme to reduce the dynamic power consumption of the SRAM operation. Besides, we identified the requirement of supply boosting of the write buffers for proper resonant operation. We evaluated the resonant 144KB SRAM cache through SPICE and test chip using a commercial 28nm CMOS technology. The experimental results show that the resonant SRAM can save up to 30% dynamic power at 1GHz operating frequency compared to the state-of-the-art design.

cs.ET↗