Investigation of Timing Parameters in Single-Flux-Quantum Circuits Using Low Critical-Current Junctions and Low Bias Voltages
Investigation of Timing Parameters in Single-Flux-Quantum Circuits Using Low Critical-Current Junctions and Low Bias Voltages
复制标题
使用低临界电流结和低偏置电压的单通量量子电路中的时序参数研究
DOI：
10.1109/tasc.2021.3067827
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发表时间：
2021
影响因子：
1.8
通讯作者：
and A. Fujimaki
中科院分区：
文献类型：
--
作者：
M. Kuniyoshi;K. Murase;I. Nagaoka;K. Sano;M. Tanaka;T. Yamashita;and A. Fujimaki
本文研究了低功耗单通量量子(SFQ)电路的功耗、工作频率和误码率之间的权衡。SFQ电路的功耗可以通过降低约瑟夫森结(JJ)的临界电流(值)或偏置电压()来降低。在考虑4.2℃热噪声的情况下，数值分析了降压时时序参数波动的漂移和扩散。降压后的时序行为相对简单，基于信噪比，而较低值时的时序行为则比较复杂，这是因为JJ在降压驱动下的动态行为。模拟结果表明，工作频率因定时窗口变窄而降低，但当定时窗口减小或降至常规值的6.25%时，能量效率最高，降低定时窗口后的能量降低比常规定时窗减小后的能量减少好26%。此外，如果较小的错误率(例如)是可接受的，则与SFQ电路必须表现出无错误操作的情况相比，在显著更高的时钟频率下将有望进一步提高能效。
In this study, the trade-off among power consumptions, operating frequencies, and error rates in low-power single-flux-quantum (SFQ) circuit is investigated. The power consumption of SFQ circuits can be reduced by the lowering critical currents (values) of the Josephson junctions (JJs), or the bias voltage (). The shifts and spreads of timing parameter fluctuations whenandwere lowered were numerically analyzed, with consideration of thermal noise at 4.2 K. The timing behaviors afterwas lowered were relatively simple, being based on the signal-to-noise ratio, whereas those for loweredvalues were complicated because of the dynamic behaviors of JJs driven at reduced voltage. The simulation results imply that the operating frequencies decreased because the timing windows narrowed, but the highest energy efficiency was obtained when we loweredorto 6.25% of their conventional values, and the energy reduction after lowering ofwas 26% better than that after lowering of. Moreover, if a small error rate (for example) is acceptable, further improvement in energy efficiency would be expected at significantly higher clock frequencies than would be the case if the SFQ circuit must exhibit error-free operation.