Modelling of Implantable Photovoltaic Cells Based on Human Skin Types

Abstract

Implantable electronic devices are emerging as important healthcare technologies due to their sustainable operation and low risk of infection. To overcome the drawbacks of the built-in battery in implantable devices, energy harvesting from the human body or another external source is required.. Energy harvesting using appropriately sized and properly designed photovoltaic cells enable implantable medical devices to be autonomous and self-powered. Among the challenges in using PV cells is the small fraction of incident light that penetrates the skin. Thus, it is necessary to involve such physical properties in the energy harvesting system design. Consequently, we propose a novel photodiode model that considers skin loss in different ethnic groups. Our physical simulations have been implemented using COMSOL and MATLAB. Circuit and system modelling has been performed using Cadence 180nm technology. Our results show that the transmittance of near infrared light is almost the same in three skin types: Caucasian, Asian and African. Maximum power delivery of 12 µW (African skin) and 14 µW (Caucasian and Asian skin) were achieved at 0.45 V. With the help of a power management unit, an output voltage of 1.8-2 V was achieved using the PV cells.

Wirelessly Powered and Modular Flexible Implantable Device

“…The WPT is enabled through inductive loop. There are two typologies of magnetic WPT: inductive and capacitive coupling [15]. In inductively coupled wireless power transmission systems the inductance of one of the antennas, typically the transmitter, is designed or measured empirically and then, the other antenna, normally the receiver, is designed in order to match the same resonant frequency and consequently, inductance.…”

Biointegrated and Wirelessly Powered Implantable Brain Devices: A Review

“…Photovoltaic energy harvesting from light [139]- [142] is another enthralling tool to wirelessly power the implantable devices. In [139], to replace the batteries for uninterrupted functioning of implants, an implantable device made of tiny, thin solar cells (gallium arsenide, 5 mg) along with a wireless logical control module based on RF signal to activate µ-LEDs, was introduced and depicted in Fig.…”

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“…Since the skin layers are complex, it is a challenge to achieve accurate simulation using a monolayer model [7]. Beer-Lambert Law is normally applied to analyze the optical performance rapidly in the photovoltaic effect in 1D simulation.…”