A fully integrated multiphase CMOS charge-pump harvester with self-biased blocking network

This manuscript presents a CMOS-based charge-pump circuit incorporating two novel ideas: (i) a new low-threshold logic circuit for blocking the inverse biasing condition from the load through a controlled NMOS switch, and (ii) a simple ring oscillator-based multiphase arrangement for the discrete-time charge-pumping network. The theoretical base and conditions for using the simple multiphase arrangement establish the design constraints of the proposed circuits. The multiphase ring oscillator-based system design aims to harvest energy from low-voltage sources, demonstrating a startup threshold in the 100 mV range with a clear advantage compared with single-phase charge-pumps. The experimental results, obtained with a circuit prototype designed in a 180-nanometer CMOS process, demonstrate successful energy harvesting with a power consumption of 10 nW. The circuit achieves a (0.3-7) V output dynamic with an initial 100 mV at a 10 nA condition, exhibiting a 65 percent efficiency at room temperature with a 330 nF capacitive load in experimental measurements.