COBI: A Degree-of-56 Column-Bipartite Densely Connected Digital Ising Chip with 8b Spin Coefficients

📋 论文概要

该论文提出了一种基于列二分图拓扑的数字Ising芯片COBI，在65nm工艺下实现了56度密集连接的自旋处理单元和8位自旋系数存储，用于高效求解组合优化问题。芯片集成了64个自旋处理单元，并通过嵌入式SRAM存储系数，成功应用于MIMO检测，求解时间小于72纳秒。

💡 主要创新点

• 采用列二分图（column-bipartite）拓扑结构，实现自旋间高达56度的密集连接，大幅提升Ising模型的映射能力。
• 使用8位可编程自旋系数并存储在嵌入式SRAM中，增强了芯片的灵活性和适用性，能解决多种组合优化问题。
• 在65nm工艺下实现了快速求解（<72ns）的实际问题应用，如MIMO检测，展示了实用化潜力。

🏷 关键词

📄 原文摘要

Abstract We present a 65nm digital Ising chip with an advanced column-bipartite topology, featuring densely connected spins with a degree of 56 and 8b coefficients for mapping and solving computationally intensive combinatorial optimization problems. A fabricated Ising test chip with 64 spin processing elements with spin coefficients stored in flexible embedded SRAM demonstrates solving practical problems, such as MIMO detection for a wireless network, with a fast solution time (<72ns). Combinatorial optimization problems (COPs) are prevalent in various industries, including logistics, networks, finance, drug discovery and wireless communications. Many of these problems are NP-hard and scale poorly on conventional CPUs and GPUs. Ising machines provide a promising alternative by mapping COP variables onto Ising spins, where spin interactions encode the energy function. The system then searches for low-energy states

👥 作者与机构

Yihao Wu1, Jooyoung Bae1, Seunghun Shin2, Bongjin Kim2

University of California, Santa Barbara, CA, 2Korea Advanced Institute of Science and Technology, Daejeon, Korea