# A low power fully-digital multi-level voltage monitor operating in a wide voltage range for energy harvesting iot

## Samenvatting

IoT devices operating on harvested energy from the environment need to deal with the variability of the available energy and consequently adapt the application workload. To support this adaptivity, this paper presents a fully-digital multi-level voltage monitor, operating from an unregulated supply voltage down to sub-threshold. The proposed fully-digital voltage monitor eliminates the overhead of analog components and additional power supplies. The proposed design is based on frequency variation with supply voltage of two specifically designed ring oscillators leveraging the dynamic leakage suppression logic. Simulation results of process variations including corners and random mismatch show a maximum standard deviation of 30mV over a supply voltage range from 0.3 V to 0. 9V after one-point calibration. The simulation results also indicate a maximum of 0.3%/°C relative voltage deviation over a temperature range from 0°C to 90°C. The total power consumption of the proposed voltage monitor is 7nW at 0. 5V, designed in a 28-nm FDSOI technology. The designed digital voltage monitor results in the smallest chip area of 293 $\mu m^{2}$, as compared to the state-of-the-art.

Originele taal-2 Engels 2021 22nd International Symposium on Quality Electronic Design (ISQED) Institute of Electrical and Electronics Engineers 13-18 6 9781728176413 https://doi.org/10.1109/ISQED51717.2021.9424325 Gepubliceerd - 10 mei 2021 22nd International Symposium on Quality Electronic Design, ISQED 2021 - Santa Clara, Verenigde Staten van AmerikaDuur: 7 apr 2021 → 9 apr 2021

### Congres

Congres 22nd International Symposium on Quality Electronic Design, ISQED 2021 Verenigde Staten van Amerika Santa Clara 7/04/21 → 9/04/21

### Bibliografische nota

Funding Information:
IV. Conclusion Energy harvesting sensor nodes require to adapt to the variation of supply voltage and manage the workload of the application accordingly. To achieve this, the sensor node generally needs analog circuits to enable voltage monitoring which generally suffer from the requirement of an additional clean power supply or having a relatively higher operating voltage. In this work, a fully-digital multi-level voltage monitoring system is presented for EHS operating over a wide voltage range from 0.3 V to 0.9 V without the requirement of any additional power supply. Also, the proposed digital approach results in low power consumption and the smallest chip area as compared to the state-of-the-art. Acknowledgment This work is partially funded by the Dutch NWO project ZERO. The authors would like to thank Paul Detterer of the ES group, TU/e, for his fruitful design feedback and discussions.