Integrated Switched-Capacitor Voltage Regulator
Arizona State University
Oracle Principal Investigator
Hesam Fathi Moghadam, Senior Manager
Efficient, stable, and fast power delivery against fluctuating workloads have become a critical concern for applications from battery-powered devices to high-performance servers. With high density on-chip or package-integrated capacitors, integrated switched-capacitor (SC) voltage converters provide high efficiency down-conversion from a battery or off-chip voltage regulation modules. A number of SC voltage converters and regulators have been proposed recently that show higher efficiency at increasingly wider range of output voltages [1-9]. At each output voltage point, however, the load current could still fluctuate causing large voltage droops, and the conversion efficiency could degrade at different load currents with sub-optimal converter designs.
Literature on the voltage regulation of switched-capacitor converters has primarily focused on output voltage comparison against reference voltage [1-9]. To provide optimal voltage converter performance and efficiency across the two dimensions of voltage and current, we postulate that current sensing along with voltage comparison would be a necessity. On-chip current sensing has been employed in a number of previous buck converter designs for the purpose of current-mode feedback control [10-11]. However, load current sensing has not been largely adopted for SC converters, since they are mainly based on voltage-mode charge and discharge operations.
This project aims to expand on the initial works done by Arizona State University on current-sensing-based workload optimization techniques as well as understand the tradeoffs between using on-chip capacitors and package-integrated capacitors to implement the SC voltage converters.
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