A wide load and voltage range switched-capacitor DC-DC converter with load-dependent configurability for DVS implementation in miniature sensors

Abstract

A new switched capacitor (SC) converter for powering miniature sensor systems with wide load current and output voltage ranges is proposed in this paper. By adopting a multiple-ratio SC stage and reconfigurable stage interconnect scheme, the proposed converter offers fine granularity of conversion ratios, which improves efficiency for light load operation. The multiple-leaf structure for switch size control further improves light load efficiency, while parallel stage configuration improves heavy load efficiency. Under light load (500 nA), the converter maintains an efficiency of greater than 62% with a peak efficiency of 78% over a wide voltage range (400 mV to 1.6 V). Furthermore, with an active state load of 200 μA, it maintains an efficiency of greater than 64% with a peak efficency of 72% over an output voltage range of 700 mV to 1.6 V. The effective step resolution of the proposed converter is 16 mVfrom a 4 V battery.