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运行的电子产品。为了达到极高的能效，这种电路在低电压下工作，按照传统的定义，它们是“关闭”的，并使用微小的泄漏电流，类似于滴水的水龙头，以进行有用的工作。这种方法有望在电源方面带来革命性的设计，但一个关键的障碍是低压电路对晶体管制造工艺、电压和温度的变化高度敏感，这限制了产品产量。调整芯片操作以适应这种变化的自适应系统可能解决这一问题，并提供足够的产量来部署大容量的超低功率电路。该项目的目标是为超低功耗芯片创造一种新的范例，其中变异的“免疫系统”在内部调整电路级旋钮，以满足不同变体的系统级要求。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，并使一系列目前在商业上不可行的应用成为可能。虽然该项目的应用范围是具有广泛社会吸引力的可穿戴计算，但该项目也计划让女性和少数族裔学生大量参与教育推广活动。尽管目前制造超低功耗IC的努力强制应用了传统的固定电压、固定频率方法，但该项目认识到，芯片应该保证某些系统级指标，然后释放对传统固定参数的限制，这些参数可以充当旋钮，以补偿工艺技术或环境的变化。这些旋钮被用于反馈控制的“免疫系统”，以补偿变化。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有限的空间中管理芯片操作的软件。在芯片级，该方法将动态电压调节和自适应电压调节方法的变体与基于模式的电源管理控制和块特定调节相结合，以保持适当的功能并满足系统指标。此外，建议的方案使用集成元件和系统设计的联合设计，以确保即使在低电压下工艺、电压和温度变化的指数影响下的稳健操作。

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.