Exploiting nonlinear oscillator dynamics for on-chip thermal sensing

Real-time monitoring of temperature in FPGAs is crucial to ensure system reliability, as local temperature variations can affect their performance. For these purposes, virtual temperature sensors such as Ring Oscillator (RO)-based sensors are widely used. However, efficiently implementing them with a minimal number of Look-Up Tables (LUTs) remains a significant challenge. In this paper, we propose a novel temperature sensor architecture based on nonlinear oscillators, implemented on a 28 nm Artix-7 FPGA. The proposed approach minimizes the usage of FPGA resources while maintaining accurate thermal sensing. As a result, several nonlinear oscillators are analyzed, achieving better sensitivity (0.020%/°C) over a 25 % wider temperature range compared to other RO-based temperature sensors reported in the literature for the 28 nm technology node. These results highlight the potential of these oscillators as efficient, low-resource alternatives for real-time thermal monitoring in FPGA.