Energy and Power Consumption Analysis of a Wireless Sensor Node without a Voltage Regulator

Wireless sensor nodes are used in a wide range of areas such as environment monitoring, health monitoring, military and engineering applications to transfer sensor data from one location to another location. These sensor nodes usually have sensors, a microprocessor, transceiver, and a limited power supply. Most sensor nodes are configured to be in sleep mode and wakes up periodically and transfers the sensor data. In the sleep mode they consume less energy and most of the power is consumed in the wake-up time. The power consumption directly affects the life span of the sensor node. Sensor nodes typically use linear voltage regulators rather than switching ones to prevent switching noise, switching voltage ripples and to limit the footprint of the switching circuitry. Low dropout regulators are also used as they consume less energy than standard regulators and saves the battery energy. Even the low dropout regulators consume considerable amount of power at the high battery voltages and considerably high current flows through them. If there is way to save this energy, the lifespan of the sensor node can be extended. One way is avoiding the voltage regulator completely. Modern electronic components such as microcontrollers, sensors and transceivers can work in a wide range of voltages and they have internal voltage references. Therefore, the design of a sensor of a sensor node without voltage regulator is possible. In this paper we implemented a sensor node design without a voltage regulator, and we have evaluated and concluded that this design has up-to 40% energy saving compared with same sensor node design with a voltage regulator.