Design and realization of a DC/DC Buck-Boost for Wireless Sensor Networks using Renewable Energy S. Krit * , J. Laassiri ** and S.El Hajji *** * University Ibn Zohr, polydisciplinary Faculty of Ouarzazate BP 638, Morocco, krit_salah@yahoo.fr ** Department of informatics, Faculty of Sciences, University Ibn Tofail, BP 33, Morocco laassiri.jalal@gmail.com *** Department of Mathematic Informatics, University Mohamed V-Agdal, BP 1040, Morocco elhajji@fsr.ac.ma ABSTRACT In recent years, the number of wireless sensor networks (WSNs) deployments for real life applications has rapidly increased. Still, the energy problem remains one of the major barrier somehow preventing the complete exploitation of this technology. WSN uses a software technique to monitor device usage patterns, and combines it with hardware power information in runtime. Hardware systems have beenrecently proposed to increase the autonomy of embedded systems. WSNs are typically powered by batteries with a limited lifetime and, evenwhen additional energy can be harvested from the external environment (e.g., through solar cells or photovoltaic mechanisms), it remains alimited resource to be consumed judiciously. Efficient energy management is thus a key requirement for a credible design of a wireless sensor networks. One key design challenge is how to optimize the efficiency of WSNs. This paper proposes a new design architecture and implementations of power management dc- dcbuck-boost converter targeted for optimization of consumption of wireless sensor network applications. Key issues in WSNs are discussed. We operated real applications on the WSNs, The proposed system can operate at 2.4GHzand dissipates a power of 15 and 25 uW, respectively, from a 2.5 V supply. The noise performance at input, output and the frequency response is presented.. Keywords: WSNs, Software and Hardware system, dcdc buck-boost, Renewable Energy. 1 INTRODUCTION It is well known that the dc-dc converters with step-up/step- down characteristic are required in all applications where the input and the output voltage range overlap. For example, WSNs applications, portable devices, such as laptop computers and personal communication devices require ultra-low power circuitry to enable longer battery operation. The key to reducing power consumption while maintaining computational throughput and quality of services to use such systems at the lowest possible supply voltage. The use of step-up/step-down converters such as the buck-boost, allows one to set the output dc voltage to an arbitrary intermediate value. WSNs [1] are typically powered by batteries with a limited lifetime and, even when additional energy can be harvested from the external environment [2] (e.g., through solar cells or photovoltaic mechanisms), it remains a limited resource to be consumed judiciously. Efficient energy management is thus a key requirement for a credible design of a wireless sensor networks [3], [4]. One key design challenge is how to optimize the efficiency of WSNs [5]. This paper proposes a new design architecture and implementations of power management dc-dc buck-boost converter targeted for optimization of consumption of wireless sensor network applications. Key issues in WSNs are discussed. We operated real applications on the WSNs, The proposed system can operate at 2.4GHz and dissipates a power of 15 and 25 uW, respectively, from a 2.5 V supply. The noise performance at input, output and the frequency response is presented. 2 SOURCE OF ENERGY CONSUMPTION IN WIRELESS SENSOR NETWORKS In order to design a low power wireless sensor network, first step is to analyze the power dissipation characteristics of wireless senor node. Each node in the network is consists of four components: a sensor which connects the network to physical world, computation part which is consists of microcontroller or in some application microprocessor and is responsible for control of the sensors and communication, a transceiver for communicating between nodes and base station, and a power supply which is usually a battery. There are wide ranges of choices for each part of the node and choosing a right device will affect the energy