Body-Area Powering With Human Body-Coupled Power Transmission and Energy Harvesting ICs

Abstract

This paper presents the body-coupled power transmission and ambient energy harvesting ICs. The ICs utilize human body-coupling to deliver power to the entire body, and at the same time, harvest energy from ambient EM waves coupling through the body. The IC improves the recovered power level by adapting to the varying skin-electrode interface parasitic impedance at both the TX and RX. To maximize the power output from the TX, the dynamic impedance matching is performed amidst environment-induced variations. At the RX, the Detuned Impedance Booster (DIB) and the Bulk Adaptation Rectifier (BAR) are proposed to improve the power recovery and extend the power coverage further. In order to ensure the maximum power extraction despite the loading variations, the Dual-Mode Buck-Boost Converter (DM-BBC) is proposed. The ICs fabricated in 40 nm 1P8M CMOS recovers up to 100 μW from the body-coupled power transmission and 2.5 μW from the ambient body-coupled energy harvesting. The ICs achieve the full-body area power delivery, with the power harvested from the ambiance via the body-coupling mechanism independent of placements on the body. Both approaches show power sustainability for wearable electronics all around the human body. Index Terms-Body area network, body-coupled power transmission, body-coupled energy harvesting, energy harvesting, power transfer, impedance matching, rectifier, maximum power point tracking. I. INTRODUCTION OWERING wearable electronics such as earbuds, smart bandaids, and electrocardiography (ECG) sensors are challenging [1]-[3]. The limited battery lifetime incurs charging overhead, causes service disruptions, and inconveniences the users [4][5], which is aggravated further as the number of wearables increases. To address the issue and allow for sustainable operations, power transmission, and energy harvesting approaches have been proposed. Near-field power transmission approaches using the inductive link impose stringent requirements on the alignment Manuscript received DD-MMM-YYYY.

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