25.8 A Near- Threshold-Voltage Network-on-Chip with a Metastability Error Detection and Correction Technique for Supporting a Quad-Voltage/Frequency-Domain Ultra-Low-Power System-on-a-Chip

Abstract

Emerging embedded systems, such as autonomous robots/vehicles, demand a new system-on-a-chip (SoC) that is ultra-low power (mW or even sub-mW level) but highly robust. Such an SoC typically integrates heterogeneous building blocks for supporting a range of features, each ideally operating in an independent voltage and frequency (V/F) domain [1]. In such an architecture, a network-on-chip (NoC) has played a key role to enable high-speed and energy-efficient networking. However, it is increasingly challenging to meet a robustness target since each V/F domain uses a significantly different voltage, e.g., from nominal 1V to near-threshold voltage (NTV), and clock frequency, e.g., from hundreds of MHz to sub-MHz. Furthermore, any two clocks may have uncertain and time-varying phase and frequency relationships. These properties significantly worsen robustness, particularly metastability, in an NoC.