Boosting Wide-Range Conversion Efficiency With Dynamic Voltage-Domain Stacking

This article presents dynamic voltage-domain stacking, which incorporates the attractive efficiency benefits of voltage-domain stacking into a wide-input-range conversion system. This is achieved by combining two novel switched-capacitor converter topologies with an integrated finite-state machine into a highly reconfigurable system. First, a zooming gearbox converter efficiently enables a wide input range while only implementing three conversion ratios. Second, a reconfigurable ladder converter continuously compensates for imbalance between the dynamically stacked voltage domains. A prototype has been fabricated in a 40-nm baseline CMOS technology to provide a stable supply voltage to four loads across an input voltage range from 4 V down to 0.55 V. Measurements show a best-in-class average efficiency of 80.1% and a peak efficiency of 92.1%.