An ultra-low-power supercapacitor voltage monitoring system for low-voltage energy harvesting

This paper proposes an ultra-low-power supercapacitor voltage monitoring system (VMS) for low-voltage energy harvesting. The proposed VMS consists of a voltage divider, control logic circuit, multiplexer (MUX), sample-and-hold circuit, nano-ampere current reference (IREF), and 4-bit successive approximation register analog to digital converter (SAR ADC). The proposed VMS monitors the supercapacitor voltage and converts it into digital codes. We employ power gating technique and a nano-ampere current reference circuit to achieve ultra-low power operation. Simulation results showed that our proposed VMS achieved the DNL/INL of 0.15/0.21LSB. Its ENOB was 3.83bit at 100 Hz and the average power dissipation was 58.0 nW.

[1]  Kristofer S. J. Pister,et al.  An ultralow-energy ADC for Smart Dust , 2003, IEEE J. Solid State Circuits.

[2]  D. Sylvester,et al.  IoT design space challenges: Circuits and systems , 2014, 2014 Symposium on VLSI Technology (VLSI-Technology): Digest of Technical Papers.

[3]  Nobutaka Kuroki,et al.  An 80-mV-to-1.8-V Conversion-Range Low-Energy Level Shifter for Extremely Low-Voltage VLSIs , 2017, IEEE Transactions on Circuits and Systems I: Regular Papers.

[4]  Nobutaka Kuroki,et al.  A nano-ampere current reference circuit and its temperature dependence control by using temperature characteristics of carrier mobilities , 2010, 2010 Proceedings of ESSCIRC.

[5]  박일규,et al.  Chip-type electric double layer capacitor and method for manufacturing the same , 2009 .

[6]  Julien Penders,et al.  Energy Harvesting for Autonomous Wireless Sensor Networks , 2010, IEEE Solid-State Circuits Magazine.

[7]  Nobutaka Kuroki,et al.  A 0.19-V minimum input low energy level shifter for extremely low-voltage VLSIs , 2015, 2015 IEEE International Symposium on Circuits and Systems (ISCAS).