Adaptive step-down switched-capacitor power converter with z-domain observation-based line-load regulation

The paper presents an integrated switched-capacitor power converter, employing an efficient step-down conversion power stage and a cost-effective observation-based controller for both line and load regulations. The complete z-domain design makes system modeling and analysis consistent and efficient, avoiding the controversial domain transformations. The converter delivers up to 220 mW power with a maximum efficiency of 74.1%, surpassing a linear regulator’s theoretical limit. The output is adjustable from 1.25 to 2.0 V, with a 3.3-V input supply. The converter responds to a 100% load step change from 36 to 72 mA within only 165 ns. The measured DVS tracking time is no longer than 45 μs to a 0.55-V step change.