Investigating a CNT-based Dickson charge pump with linearly distributed capacitance working in FSL

Abstract

The increasing demand for energy-efficient on-chip high-voltage generation in Internet of Things (IoT) and Internet of Medical Things (IoMT) applications has driven the need for low-power and fast-response charge pump (CP) designs. The interest about these blocks arises in the last decades resulting in the proposal of more accurate models, new topologies, unconventional uses and tropicalized implementations. In this last framework, for the first time, a 4-stage Dickson charge pump with a linearly distributed capacitance strategy is designed and simulated in 32-nm Stanford University’s carbon nanotube field-effect transistor (CNTFET) technology. Simulations were performed for different values of slope parameters a (0, −0.2, −0.5, −0.8) of the proposed linearly distributed capacitance model by varying the input voltages (V_in = 300, 400, and 500 mV). For performing the simulations, total capacitance distribution of (C_T), load capacitance (C_L) and load resistance (R_L) were chosen to be 10 pF, 100 pF, 10 MΩ, respectively, with C_L/C_T = 10. The simulation results show that the best performance is achieved for slope parameter a = -0.5 with PCE of 78.86 %, VCE of 98.49 %, an output resistance of 0.18 MΩ and power consumption of 79 nW for an input voltage of 400 mV. Further, the impact of process variations of CNTFET on proposed CP for slope parameter a = -0.5 is also investigated in this work. The appraisal performance parameters of the proposed strategy are well-suited for IoT and IoMT applications.