Efficient 1-V Boost Converter Using Sub-50-mV NEMS Without Body Bias

Abstract

In this article, for the first time, we present the improvement in efficiency in a low-voltage dc-dc boost converter for the energy-harvesting applications using the experimentally demonstrated sub-50-mV nano electro-mechanical switch (NEMS). As per the measurement results, the sub-50-mV NEMS having a small air gap of only 100 nm exhibits very low hysteresis (<; 20 mV), low turn-on delay (15 ns), and low sub-threshold swing of 2 mV/decade. In addition to this, the fabricated NEMS is a propitious candidate toward ideal power switch with almost zero leakage current and a maximum ON-state conductance value of 0.1 A/(V·μm). This study explores a discontinuous-conduction mode (DCM) boost converter with specifications suitable for energy-harvesting applications using the NEMS-based design. The results are compared with the corresponding design using the MOSFET switches in 0.18- μm CMOS technology. This work illustrates that the NEMS-based DCM boost converter design has an improvement in the efficiency of around 30% at a switching frequency of 10 kHz over CMOS for the same ON-state resistance. This is because the proposed fabricated NEMS has extreme low pull-in voltage (50 mV) and low parasitic capacitances (~3.3 fF/μm).