Ultra-Low-Power ECG Monitoring Sensor Based on a Continuous-Time Delta-Sigma Modulator With an On-Chip PMIC

Abstract

This paper presents an 860.8-nW ultra-low-power continuous-time delta-sigma modulator (CTDSM) with a power management integrated circuit (PMIC) for Internet of Things (IoT) applications. The proposed CTDSM employs a switched-resistor and a dynamic amplifier to address the problem of resistor and capacitor sizing in CTDSMs with a low-frequency signal bandwidth. The use of a dynamic amplifier capable of operating in both active and sleep modes minimizes the power consumption of the first integrator. The proposed low-power CTDSM operates using a supply voltage from the PMIC, achieves a total current consumption of only 1.1 μA, and can be applied as a flexible sensor system in IoT applications. These results are verified through real-time acquisition of electrocardiogram waveform monitoring. © 2025 IEEE.