Switched-capacitor filter based Type-III compensation for switched-mode Buck converters

In this paper, we present a novel switched-capacitor filter based Type-III compensation architecture for closed-loop regulation of fixed-frequency switched-mode Buck converters. Compared to the conventional all-analog filter, the proposed compensator can be fully-integrated onto the die resulting in reduced footprint and cost. In addition, the filter time constants scale linearly with the Buck converter´s switching time-period, resulting in increased programmability and ease-of-use. A prototype of a voltage-mode PWM controller with programmable Buck Converter switching frequencies of 0.5 and 1 MHz, has been implemented and validated in a 0.36-μm BCD process, consumes 1.1 mA of static current from a 3.3 V supply, and occupies ~ 0.65 mm² of active area on-chip.