A Fully Energy-Autonomous Temperature-to-Time Converter Powered by a Triboelectric Energy Harvester for Biomedical Applications

Abstract

This article presents a fully energy-autonomous temperature-to-time converter (TTC), entirely powered up by a triboelectric nanogenerator (TENG) for biomedical applications. Existing sensing systems either consume too much power to be sustained by energy harvesting or have poor accuracy. Also, the harvesting of low-frequency energy input has been challenging due to high reverse leakage of a rectifier. The proposed dynamic leakage suppression full-bridge rectifier (DLS-FBR) reduces the reverse leakage current by more than 1000×, enabling harvesting from sparse and sporadic energy sources; this enables the TTC to function with a TENG as the sole power source operating at <1-Hz human motion. Upon harvesting 0.6 V in the storage capacitor, the power management unit (PMU) activates the low-power TTC, which performs one-shot conversion of temperature to pulsewidth. Designed for biomedical applications, the TTC enables a temperature measurement range from 15 • C to 45 • C. The energy-autonomous TTC is fabricated in 0.18-µm 1P6M CMOS technology, consuming 0.14 pJ/conversion with 0.014-ms conversion time. Index Terms-Biomedical applications, dynamic leakage suppression full-bridge rectifier (DLS-FBR), energy harvesting, energy autonomous, Internet of Things (IoT), low leakage, low power, temperature-to-time converter (TTC). I. INTRODUCTIONT EMPERATURE information acquisition is essential in assessing and monitoring the operation conditions of sensor nodes/devices widely employed in assisted diagnostics, remote healthcare, and Internet-of-Things (IoT) nodes in general. With the devices worn or implanted in patients,

Human body IoT systems based on the triboelectrification effect: energy harvesting, sensing, interfacing and communication

“…Tan et al reported a fully energy-autonomous temperature-to-time converter (TTC) based on the TENG for biomedical applications. 93 The proposed TTC was attached to the arm to be driven by the low frequency (<1 Hz) of human arm motion. After the storage capacitor collected a voltage of 0.6 V, the low-power TTC, which performed one-shot conversion of temperature to pulse width, was activated by the power management unit.…”