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Moataz and Muhammad's Paper to be Presented in the 2018 IEEE ISSCC

Muhammad SwilamCongratulations to Moataz Abdelfattah from the Circuit Laboratory for Advanced Sensors and Systems and Muhammad Swilam from PMRL for the acceptance of their paper entitled "An On-Chip Resonant-Gate-Drive Switched-Capacitor Converter for Near-Threshold Computing Achieving 70.2% Efficiency at 0.92 A/mm2 Current Density and 0.4V Output," in the 2018 IEEE International Solid-State Circuits Conference (ISSCC), San Francisco, CA, Feb. 2018.

Near-threshold computing (NTC) is a promising approach to address the increasing demand for energy-efficiency in computing platforms. In NTC, the supply voltage is scaled down to realize quadratic energy savings while degrading the operating frequency only linearly, which can be compensated for by using many-core architectures. However, practical implementation of many-core NTC systems requires a large number of on-chip DC-DC converters to provide each core with independent voltages and fast dynamic voltage scaling at a reduced cost. Moreover, these converters must support heavy loads (few hundreds of milliamps) to supply the current required per core, or cluster of cores, while occupying minimal area (i.e. high current density) and achieving high power conversion efficiency at low output voltages.

To address this tradeoff, the dominant approach in the literature has been to preserve efficiency by increasing Cfly and mitigating the drop in current density by either using special capacitor technologies, such as deep-trench and high-density MIM capacitors, or through soft charging techniques. However, special capacitor technologies entail higher cost, and soft charging techniques are reported only at higher output voltages than required for NTC. In contrast, this paper increases Fsw to preserve current density while counteracting the increase in switching losses by utilizing an area-efficient resonant gate drive (RGD) circuit.