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A high efficiency adaptive frequency hopping (AFH) controlled step-down switch capacitor (SC) DC-DC converter with deep-green mode (DGM) operation is proposed for system-on-chip (SoC) applications. To obtain the high power conversion efficiency and the small output voltage ripple over a wide load current range, the proposed driving capability control can modulate the load current driving with the closed-loop operation. The AFH control can dynamically adjust the switching frequency according to the distinct output load conditions, so as to ensure adequate load current supply function as well as output voltage regulation. In addition, the DGM operation can mask the switching clock to reduce power loss at ultra light loads for improving power efficiency. This work is implemented by 40 nm CMOS technology. Simulated results demonstrate that the propped SC converter delivers wide load range from 1mA to 300mA. The power conversion efficiency is achieved over 72 % and the output voltage ripple is guaranteed smaller than 30 mV.
Date of Conference: 20-23 May 2012