SHF: Small: Variation "Immune System" for Ultra Low Power Systems-on-Chip

各种各样的新兴应用需要在超低功率水平下工作的电子设备。为了实现极高的能效，这种电路在低电压下工作，在这种情况下，它们按照传统定义是“关”的，并使用微小的漏电流（类似于滴水的电流）来做有用的工作。这种方法有望彻底改变电源侧的设计，但一个关键的障碍是低电压电路对晶体管制造工艺、电压和温度变化的高度敏感性，这限制了产品的良率。调整芯片操作以考虑这种变化的自适应系统可以潜在地解决这个问题，并提供足够的产量以大量部署超低功率电路。该项目的目标是为超低功耗芯片创建一个新的范例，其中变体“免疫系统”在内部调整电路级旋钮，以满足各种变体的系统级要求。该项目的技术成果可以提高制造产量，降低商业产品的成本，并实现一系列目前在商业上不可行的应用。虽然应用范围是具有广泛社会吸引力的可穿戴计算，但该项目还计划让女性和少数民族学生大量参与教育推广活动。虽然目前构建超低功耗IC的努力强制采用传统的固定电压，固定频率方法，该项目认识到芯片应该保证某些系统级度量并且然后释放对传统上固定的参数的约束，其可替代地充当旋钮以补偿工艺技术或环境中的变化。这些旋钮用于反馈控制的“免疫系统”，以补偿变化。在这项工作中的具体研究创造了用于管理变化的低开销硬件旋钮，并共同设计了用于在资源受限的空间中管理芯片操作的软件。在芯片级，该方法将动态电压缩放和自适应电压缩放方法的变体与基于模式的功率管理控制和块特定调谐相结合，以保持适当的功能并满足系统指标。此外，所提出的方案使用集成组件和系统设计的协同设计，以确保稳健的操作，尽管在低电压下的工艺，电压和温度变化的指数影响。

A wide variety of emerging applications require electronics that operate at ultra-low power levels. To achieve extreme energy efficiency, such circuits operate at low voltages where they are "off" by conventional definitions and use tiny leakage currents, analogous to dripping faucets, to do useful work. This approach promises to revolutionize design on the power side, but a critical obstacle is the heightened sensitivity of low voltage circuits to variations in the transistor fabrication process, voltage and temperature, which limit product yield. An adaptive system that adjusts chip operation to account for such variations could potentially solve this problem and provide adequate yield to deploy ultra-low power circuits in high volumes. This project's objective is to create a new paradigm for ultra-low power chips in which a variation "immune system" internally adjusts circuit level knobs to meet system level requirements across variations. The technical results from this project could improve manufacturing yield, lower costs for commercial products, and enable a swath of applications that are currently not commercially viable. While the scope of applications is in wearable computing having a broad societal appeal, the project also plans to heavily involve of female and minority students in educational outreach activities.While current efforts to build ultra-low power ICs forcibly apply the conventional fixed voltage, fixed frequency approach, this project recognizes that chips should guarantee certain system level metrics and then release constraints on parameters that are conventionally fixed, which can instead act as knobs to compensate for variations in the process technology or environment. These knobs are used in the feedback controlled "immune system" to compensate for variations. Specific research in this effort creates low overhead hardware knobs for managing variations, and co-designs software for managing chip operation in a resource constrained space. At the chip level, this approach combines variants of dynamic voltage scaling and adaptive voltage scaling methods with mode based power management control and block specific tuning to maintain proper function and meet system metrics. Additionally, the proposed scheme uses co-design of integrated components and system design to ensure robust operation despite the exponential impact of process, voltage and temperature variations at low voltage.