A 0.35-V inductorless DC-DC converter using non-SOI CMOS technology

We developed a 0.35-V inductorless DC-DC converter using non-SOI CMOS technology. To activate a ring oscillator circuit at an input voltage of 0.35 V, we deployed depletion-mode NMOS transistors in a ring oscillator. Generated 0.35-V clock signals were boosted to nominal 0.7-V clock signals by voltage doubler circuits using depletion-mode NMOS transistors. Finally, these clock signals were used in a boosted-gate charge pump circuit. Through SPICE simulations, we verified that our DC-DC converter generated an output voltage of 3.8 V at an input voltage of 0.35 V. The load current was 1.6 uA, and the total power consumption was 56 uW.