A 10-MHz Green-Mode Automatic Reconfigurable Switching Converter for DVS-Enabled VLSI Systems

Abstract

A power-efficient, high-frequency, automatic reconfigurable switching converter is presented in this paper for DVS-enabled VLSI systems. Tailored to the system-level power management, the proposed cross-layered green-mode (GM) operation scheme adaptively configures the converter into three operation structures to achieve a seamless step-up/down voltage conversion with minimized power loss. In addition, an adaptive power transistor sizing (APTS) scheme is incorporated to further improve efficiency on the transistor level. To enable high-frequency operation in all power regulation conditions, an i L-assisted single-bound hysteresis controller (SBHC) is also proposed in this work. Meanwhile, in order to suppress output spectrum variations induced by the hysteresis controller, an adaptive frequency compensator (AFC) is employed. The proposed converter was fabricated with IBM 130-nm CMOS process, with a total chip area of 1 mm2. Its output voltage can be seamlessly regulated from 0.9 to 2.2 V, with a maximum load power of 400 mW. The input voltage is designed at 1.5 V, but is variable at any level between 0.9 and 1.8 V. The switching frequency of the converter is regulated at 10 MHz in all three operation modes, with ±3% deviation. Experimental results show a 26.7- μs/V down-tracking and 93.3-μs/V up-tracking speed for dynamic voltage scaling (DVS) reference tracking. Line regulation is maintained below 0.8% throughout the full input voltage range, with a lowest value of 0.17%. The power efficiency stays above 80% over the entire 400-mW power range, with a peak value of 92.1% at 1.2-V output and 250-mW load power.