A MOSFET only, step-up DC DC micro power converter, for solar energy harvesting applications

In this paper, a step-up micro power converter for solar energy harvesting applications is presented. The circuit is based on a switched-capacitor voltage doubler architecture with MOSFET capacitors, which results in an area approximately eight times smaller than using MiM capacitors for the 0.13 žm CMOS technology. In order to compensate for the loss of efficiency, due to the larger parasitic capacitances, a charge reutilization scheme is employed. The circuit uses a phase controller, designed specifically to work with the series of two PV cells, in order to regulate the output voltage to 1.2 V. Electrical simulations of the circuit, together with an equivalent electrical model of a PV cell, show that the circuit can deliver a power of 536.1 žW to the load, while drawing a power of 799.8 žW from two PV cells stacked in series, corresponding to a maximum efficiency of 67%.