ULTRA LOW POWER HYBRID MICRO ENERGY HARVESTER USING RF, THERMAL AND VIBRATION FOR BIOMEDICAL DEVICES

Jahariah Sampe,Md Shabiul Islam,Burhanuddin Yeop Majlis,Farah Fatin Zulkifli,Nor Afidatul Asni Semsudin

doi:10.22159/ijpps.2016v8s2.15213

Jahariah Sampe, Md Shabiul Islam + Show 3 more

Open Access

https://doi.org/10.22159/ijpps.2016v8s2.15213

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Abstract

<p class="lead">The objective of this research is to design ultra-low power Hybrid Micro Energy Harvester (HMEH) circuit using hybrid inputs of radio frequency (RF), thermal and vibration for biomedical devices. In the HMEH architecture, three input sources (RF, thermal and vibration) are combined in parallel to solve the limitation issue of a single source energy harvester and to improve the system performance. Energy will be scavenged from the human body for thermal and vibration sources by converting directly temperature difference and human movement to electrical energy. The inputs are set to 0.02V and 0.5V for thermal and vibration respectively with the frequency of 1 kHz. Meanwhile, RF source is absorbed from radio wave propagation in our surrounding. For this work, the frequency is set to 915MHz and the output voltages for input ranges of-20dBm to 5dBm are recorded. The performance analysis of the HMEH is divided into two; thermal and vibration harvester circuit and RF harvester circuit. These proposed HMEH circuits are modeled, designed and simulated using PSPICE software. Vibration produces AC input and will be converted to DC using a rectifier. A comparator is used to compare the two sources (thermal and vibration) and boost converter is proposed to step-up these small input sources. Meanwhile, due to RF large frequency, the voltage multiplier is practical for both rectify and step up the input instead of the boost converter. LC resonant network is used to amplify low ambient input of RF passively before it goes to 4–stages voltage multiplier. The proposed HMEH able to achieve the output ranges of 2.0 to 4.0V with 1MΩ load. The results obtained in this research work shows that the proposed design able to produce sufficient voltage for biomedical application requirement which lies between 2.0–4.0 V from the ambient input of 0.02 to 0.5V for thermal and vibration while-9dBm for RF signal.</p>

Highlights

Nowadays, energy harvester plays an essential role to provide Ultra Low Power (ULP) input source for the wireless device instead of a battery
The input selection is determined by a comparator using Op amp and conducted in positive saturation level to produce desired output
The inputs are integrated with boost converter circuit using V1 as an input

Summary

Introduction

Energy harvester plays an essential role to provide Ultra Low Power (ULP) input source for the wireless device instead of a battery. Researchers proved that the inner ear can be scavenged to generate energy and possible to run the implantable devices. By combining energy harvester sources, the low power technique is utilized to recharge the battery continuously for achieving autonomous operation [1]. Many energy harvesting sources like vibration, RF, thermal, solar and wind are obtainable depends on their efficiency, the size of harvester and availability. Energy harvesting of thermal and vibration from the human body are global accessibility and it is demanding widespread attention for implantable devices and powering wearable. The power generated from ambient energy can reach microwatt (μW) range and possible to run low power devices. In addition for human vibration, energy can be scavenged from the natural motion of the human chest during breathing [2]

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