An Efficient On-Chip Switched-Capacitor-Based Power Converter for a Microscale Energy Transducer

Abstract— An efficient on-chip inductorless switching power converter for solar energy harvesting is presented. The new energy-efficient switching power converter improves the charge transfer capability as well as charge sharing time from the harvester to the load. We also present an analytical model to estimate the optimal parameters for maximizing the system efficiency. The proposed interface circuits have been designed using 0.18-μm
CMOS technology node, and the circuit simulations demonstrate that the proposed strategy offers a system efficiency of 70% under three different light conditions. The operation mechanism of the proposed QP is as follows: during the positive half cycle, the capacitor C2 will be charged by the harvester, and the capacitor C1 will transfer its charges to C3. During the negative half cycle, the capacitor C1 will be charged by the harvester, and the capacitors C2 and C3 along with VIN will transfer their charge to the next stage capacitor or to the storage capacitor CSTO. Moreover, by placing PMOS and NMOS switches appropriately and by carefully controlling their gate voltage signals, the proposed QP achieves better pumping efficiency and lower reverse charge sharing. When the harvested energy is passed through an interface circuit, it loses its energy due to the on-resistance of the MOS transistor (conduction loss). < final year projects >