Capacitive adiabatic logic based on gap-closing MEMS devices

Abstract

This paper presents the energy analysis of capacitive adiabatic logic (CAL) based on gap-closing MEMS devices. CAL uses variable capacitance components instead of transistor elements to have a new balance between on-and off-state losses. Ultra-low power consumption in CAL requires an energy efficient way for charging and discharging of the variable capacitance. First, we investigate "pure" electrical model of the two-terminal variable-gap capacitor and demonstrate that any hysteresis in CV-characteristic leads to losses of the stored energy. Next, we propose the design of a four-terminal gap-closing MEMS capacitive element to implement variable capacitance element for CAL and build its Verilog-A compact model. Further, we analyze the energy transfer and losses within this device during adiabatic charging and discharging. The received results demonstrate that the variable gap devices with hysteresis have a non-adiabatic losses during operation with four-phase power clock. Finally, the cascadability of the signal throw buffer chain is presented.

Contactless four-terminal MEMS variable capacitor for capacitive adiabatic logic

“…Consequently, this solution suffers from a high non-adiabatic loss, which is independent of the operating frequency (i.e. that cannot be suppressed by increasing the ramping time) [11]. By contrast, the comb-drive MEMS variable capacitor avoids electrical and mechanical contacts [12].…”