Proactive Supply Noise Mitigation with Low-Latency Minor Voltage Regulator and Lightweight Current Prediction

Abstract

Power supply noise induces extra timing delay or even malfunctions in modern power-demanding VLSI chips. Traditional reactive noise mitigation is often too late to suppress emergent supply noise due to the long latency of voltage boosting. This paper proposes a proactive method for mitigating emergent supply noises and avoiding unexpected failures in power-hungry VLSI designs with two contributions. First, a major-minor voltage regulator (MMVR) structure, which enables quick and widerange voltage scaling with small ripples, is proposed. Second, a lightweight current predictor consisting of a six-layer decision tree regressor achieves over 0.98 correlation for 50-cycle-ahead prediction in 25 RISC-V benchmark programs. Experimental results with a multi-core RISC-V design show that the proposed method mitigates the supply noise within 30 mV while the noise exceeds 70 mV with the conventional reactive mitigation. Also, the average supply voltage is compensated during the powerdemanding operation.