Design of a Flexible Reactivation Cell for Safe Power-Mode Transition in Power-Gated Circuits |
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Authors: | Calimera A Benini L Macii A Macii E Poncino M |
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Affiliation: | Dipt. di Autom. e Inf., Politec. di Torino, Turin, Italy; |
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Abstract: | Power-gating is one of the most promising and widely adopted solutions for controlling sub-threshold leakage power in nanometer circuits. Although single-cycle power-mode transition reduces wake-up latency, it develops large discharge current spikes, thereby causing IR-drop and inductive ground bounce for the neighboring circuit blocks, which can suffer from power plane integrity degradation. We propose a new reactivation solution that helps in controlling power supply fluctuations and achieving minimum reactivation times. Our structure limits the turn-on current below a given threshold through a sequential activation of the sleep transistors (STs), which are connected in parallel and sized using a novel optimal sizing algorithm. We also introduce a distributed physical implementation, which allows minimum layout disruption after ST insertion and minimizes routing congestion. |
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