论文标题
神经形态计算的BioSFQ电路家族：超导体技术的数字和模拟域桥接
BioSFQ circuit family for neuromorphic computing: Bridging digital and analog domains of superconductor technologies
论文作者
论文摘要
超导体单通量量子（SFQ）技术由于低能量耗散和高（可能高达100 GHz时的时钟速率）而对神经形态计算具有吸引力。我们最近提出了一个新的BioSFQ电路家族（V.K. Semenov等人，IEEE TAS，第32卷，第4、1400105、20222222222222页），其中将信息存储为超导环中的电流值，并以SFQ脉冲的传播速率转移，以传播的速度。在处理正数的最简单情况下，这种方法需要单线传输渠道。在更一般的双极数字中，它需要双轨转移通道。为了满足这种需求，我们开发了一个具有双轨输出的新比较器。该比较器是已设计，制造和测试的双极乘数的重要组成部分。我们讨论用于实现模拟双极分隔操作$ y/x $和平方根操作$ x^{1/2} $的BioSFQ电路。我们讨论了建议的BIOSFQ方法的战略优势，例如，BioSFQ细胞的固有异步性特征不需要明确的时钟信号。结果，BioSFQ电路没有赛车误差，并且耐受偶尔的传播SFQ脉冲碰撞。这种公差是由于在其灰色区域内运行的比较器生成的数据信号的随机性。这些电路是在MIT Lincoln实验室为超导电子电子产品开发的八个niobium层制造工艺中制造的。
Superconductor single flux quantum (SFQ) technology is attractive for neuromorphic computing due to low energy dissipation and high, potentially up to 100 GHz, clock rates. We have recently suggested a new family of bioSFQ circuits (V.K. Semenov et al., IEEE TAS, vol. 32, no. 4, 1400105, 2022) where information is stored as a value of current in a superconducting loop and transferred as a rate of SFQ pulses propagating between the loops. This approach, in the simplest case dealing with positive numbers, requires single-line transfer channels. In the more general case of bipolar numbers, it requires dual-rail transfer channels. To address this need, we have developed a new comparator with a dual-rail output. This comparator is an essential part of a bipolar multiplier that has been designed, fabricated, and tested. We discuss bioSFQ circuits for implementing an analog bipolar divide operation $Y/X$ and a square root operation $X^{1/2}$. We discuss strategic advantages of the suggested bioSFQ approach, e.g., an inherently asynchronous character of bioSFQ cells which do not require explicit clock signals. As a result, bioSFQ circuits are free of racing errors and tolerant to occasional collision of propagating SFQ pulses. This tolerance is due to stochastic nature of data signals generated by comparators operating within their gray zone. The circuits were fabricated in the eight-niobium-layer fabrication process SFQ5ee developed for superconductor electronics at MIT Lincoln Laboratory.
